task_name
string | initial_board
string | solution
string | puzzle_id
string | title
string | rules
string | initial_observation
string | rows
int64 | cols
int64 | visual_elements
string | description
string | task_type
string | data_source
string | difficulty
string | hint
string |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
normal_sudoku_4570
|
.95..1.7617.965.2...647.195..41.76525...4.718.1.58..4.3..7...6...1.5.437...2...8.
|
495821376173965824286473195834197652569342718712586943358714269921658437647239581
|
Basic 9x9 Sudoku 4570
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 9 5 . . 1 . 7 6
1 7 . 9 6 5 . 2 .
. . 6 4 7 . 1 9 5
. . 4 1 . 7 6 5 2
5 . . . 4 . 7 1 8
. 1 . 5 8 . . 4 .
3 . . 7 . . . 6 .
. . 1 . 5 . 4 3 7
. . . 2 . . . 8 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
495821376173965824286473195834197652569342718712586943358714269921658437647239581 #1 Easy (364)
Naked Single: r4c8=5
Naked Single: r6c8=4
Naked Single: r2c8=2
Naked Single: r1c8=7
Full House: r7c8=6
Hidden Single: r2c4=9
Hidden Single: r3c5=7
Hidden Single: r1c3=5
Hidden Single: r2c1=1
Hidden Single: r4c4=1
Hidden Single: r5c9=8
Hidden Single: r6c4=5
Hidden Single: r1c1=4
Hidden Single: r2c9=4
Hidden Single: r7c7=2
Hidden Single: r1c5=2
Hidden Single: r6c9=3
Full House: r6c7=9
Naked Single: r9c7=5
Hidden Single: r7c2=5
Hidden Single: r7c6=4
Hidden Single: r9c2=4
Hidden Single: r7c3=8
Naked Single: r2c3=3
Full House: r2c7=8
Full House: r1c7=3
Full House: r1c4=8
Full House: r3c6=3
Naked Single: r8c4=6
Full House: r5c4=3
Naked Single: r8c2=2
Naked Single: r9c6=9
Naked Single: r4c5=9
Naked Single: r3c2=8
Full House: r3c1=2
Naked Single: r5c2=6
Full House: r4c2=3
Full House: r4c1=8
Naked Single: r8c1=9
Full House: r8c6=8
Naked Single: r7c5=1
Full House: r7c9=9
Full House: r9c9=1
Full House: r9c5=3
Naked Single: r9c3=7
Full House: r9c1=6
Full House: r6c1=7
Naked Single: r5c6=2
Full House: r5c3=9
Full House: r6c3=2
Full House: r6c6=6
|
normal_sudoku_3001
|
..4.68..7.....38.....1...9...78.9.4..4.7125.99...467.8..16...8.3....1..6.6...52..
|
234968157196573824578124693617859342843712569952346718421637985385291476769485231
|
Basic 9x9 Sudoku 3001
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 4 . 6 8 . . 7
. . . . . 3 8 . .
. . . 1 . . . 9 .
. . 7 8 . 9 . 4 .
. 4 . 7 1 2 5 . 9
9 . . . 4 6 7 . 8
. . 1 6 . . . 8 .
3 . . . . 1 . . 6
. 6 . . . 5 2 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
234968157196573824578124693617859342843712569952346718421637985385291476769485231 #1 Extreme (26692) bf
Brute Force: r5c4=7
Brute Force: r5c5=1
Naked Single: r6c6=6
Naked Single: r4c6=9
Naked Single: r1c6=8
Hidden Single: r8c6=1
Hidden Single: r5c9=9
Skyscraper: 4 in r2c9,r8c7 (connected by r28c4) => r3c7,r79c9<>4
Naked Triple: 1,3,6 in r134c7 => r6c7<>1, r67c7<>3
Naked Single: r6c7=7
2-String Kite: 1 in r1c7,r6c2 (connected by r4c7,r6c8) => r1c2<>1
2-String Kite: 6 in r2c8,r4c1 (connected by r4c7,r5c8) => r2c1<>6
Discontinuous Nice Loop: 3 r3c3 -3- r3c7 -6- r4c7 =6= r5c8 =3= r5c3 -3- r3c3 => r3c3<>3
Locked Candidates Type 1 (Pointing): 3 in b1 => r46c2<>3
Discontinuous Nice Loop: 8 r9c1 -8- r5c1 =8= r5c3 =3= r6c3 -3- r6c4 =3= r9c4 =4= r9c1 => r9c1<>8
Discontinuous Nice Loop: 9 r9c4 -9- r9c3 -8- r8c2 =8= r3c2 =3= r1c2 =9= r1c4 -9- r9c4 => r9c4<>9
Hidden Pair: 8,9 in r9c35 => r9c5<>3, r9c5<>7
Discontinuous Nice Loop: 1 r2c9 -1- r9c9 -3- r9c4 -4- r2c4 =4= r2c9 => r2c9<>1
Forcing Chain Contradiction in r1 => r2c3<>5
r2c3=5 r1c1<>5
r2c3=5 r1c2<>5
r2c3=5 r2c3<>6 r2c8=6 r5c8<>6 r5c8=3 r5c3<>3 r6c3=3 r6c4<>3 r6c4=5 r1c4<>5
r2c3=5 r2c3<>6 r2c8=6 r5c8<>6 r5c8=3 r4c79<>3 r4c5=3 r7c5<>3 r7c9=3 r7c9<>5 r8c8=5 r1c8<>5
Forcing Chain Contradiction in c9 => r2c9<>2
r2c9=2 r2c9<>5
r2c9=2 r2c9<>4 r3c9=4 r3c9<>5
r2c9=2 r2c9<>4 r2c4=4 r9c4<>4 r9c4=3 r7c5<>3 r7c9=3 r7c9<>5
Forcing Chain Contradiction in c3 => r9c9=1
r9c9<>1 r9c9=3 r9c4<>3 r6c4=3 r6c3<>3 r5c3=3 r5c8<>3 r5c8=6 r2c8<>6 r2c3=6 r2c3<>2
r9c9<>1 r4c9=1 r4c9<>2 r3c9=2 r3c3<>2
r9c9<>1 r4c9=1 r4c9<>2 r6c8=2 r6c3<>2
r9c9<>1 r9c9=3 r9c4<>3 r7c5=3 r7c5<>2 r7c12=2 r8c3<>2
Swordfish: 3 r569 c348 => r1c8<>3
Discontinuous Nice Loop: 2 r4c1 -2- r4c9 -3- r5c8 -6- r4c7 =6= r4c1 => r4c1<>2
Forcing Chain Contradiction in r7 => r4c9=2
r4c9<>2 r4c9=3 r4c5<>3 r7c5=3 r9c4<>3 r9c4=4 r9c1<>4 r7c1=4 r7c1<>2
r4c9<>2 r4c2=2 r7c2<>2
r4c9<>2 r4c9=3 r4c5<>3 r7c5=3 r7c5<>2
Discontinuous Nice Loop: 5 r1c2 -5- r4c2 -1- r4c7 =1= r1c7 =3= r1c2 => r1c2<>5
Discontinuous Nice Loop: 5 r1c4 -5- r6c4 -3- r4c5 =3= r4c7 -3- r1c7 =3= r1c2 =9= r1c4 => r1c4<>5
Turbot Fish: 5 r1c1 =5= r1c8 -5- r8c8 =5= r7c9 => r7c1<>5
AIC: 1 1- r1c7 -3- r3c9 =3= r7c9 =5= r7c2 -5- r4c2 -1- r4c7 =1= r6c8 -1 => r12c8,r4c7<>1
Hidden Single: r6c8=1
Hidden Single: r1c7=1
Hidden Single: r1c2=3
Hidden Single: r1c4=9
Hidden Rectangle: 1/5 in r2c12,r4c12 => r2c1<>5
XY-Chain: 5 5- r1c1 -2- r1c8 -5- r8c8 -7- r9c8 -3- r5c8 -6- r4c7 -3- r4c5 -5 => r4c1<>5
Locked Candidates Type 2 (Claiming): 5 in c1 => r23c2,r3c3<>5
Finned Swordfish: 5 c348 r268 fr1c8 => r2c9<>5
Naked Single: r2c9=4
Hidden Single: r3c6=4
Full House: r7c6=7
W-Wing: 5/3 in r3c9,r4c5 connected by 3 in r7c59 => r3c5<>5
Locked Candidates Type 1 (Pointing): 5 in b2 => r2c8<>5
W-Wing: 2/4 in r7c1,r8c4 connected by 4 in r9c14 => r7c5,r8c23<>2
Sue de Coq: r8c23 - {5789} (r8c8 - {57}, r9c3 - {89}) => r7c2<>9
Naked Pair: 2,5 in r67c2 => r23c2<>2, r48c2<>5
Naked Single: r4c2=1
Naked Single: r4c1=6
Naked Single: r4c7=3
Full House: r4c5=5
Full House: r5c8=6
Full House: r6c4=3
Naked Single: r5c1=8
Full House: r5c3=3
Naked Single: r3c7=6
Naked Single: r2c8=2
Naked Single: r9c4=4
Naked Single: r1c8=5
Full House: r1c1=2
Full House: r3c9=3
Full House: r7c9=5
Naked Single: r2c4=5
Full House: r8c4=2
Naked Single: r2c5=7
Full House: r3c5=2
Naked Single: r9c1=7
Naked Single: r8c8=7
Full House: r9c8=3
Naked Single: r3c3=8
Naked Single: r7c1=4
Naked Single: r7c2=2
Naked Single: r2c1=1
Full House: r3c1=5
Full House: r3c2=7
Naked Single: r2c2=9
Full House: r2c3=6
Naked Single: r9c3=9
Full House: r9c5=8
Naked Single: r7c7=9
Full House: r7c5=3
Full House: r8c5=9
Full House: r8c7=4
Naked Single: r6c2=5
Full House: r8c2=8
Full House: r8c3=5
Full House: r6c3=2
|
normal_sudoku_3981
|
......4.22.18.4.79..492.8.....6..14.14539.627....4.9.84.9.1.78..2.4...9181.7.92.4
|
698537412231864579754921836982675143145398627376142958469213785527486391813759264
|
Basic 9x9 Sudoku 3981
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . . . 4 . 2
2 . 1 8 . 4 . 7 9
. . 4 9 2 . 8 . .
. . . 6 . . 1 4 .
1 4 5 3 9 . 6 2 7
. . . . 4 . 9 . 8
4 . 9 . 1 . 7 8 .
. 2 . 4 . . . 9 1
8 1 . 7 . 9 2 . 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
698537412231864579754921836982675143145398627376142958469213785527486391813759264 #1 Extreme (22252) bf
Hidden Single: r2c6=4
Hidden Single: r3c3=4
Hidden Single: r3c7=8
Hidden Single: r9c6=9
Hidden Single: r9c2=1
Hidden Single: r8c4=4
Hidden Single: r4c8=4
Hidden Single: r9c7=2
Hidden Single: r2c1=2
Hidden Single: r1c9=2
Locked Candidates Type 1 (Pointing): 1 in b3 => r6c8<>1
Hidden Pair: 8,9 in r14c2 => r14c2<>3, r14c2<>5, r1c2<>6, r14c2<>7
Brute Force: r5c1=1
Hidden Single: r4c7=1
Brute Force: r5c3=5
Naked Single: r5c7=6
Naked Single: r5c9=7
Full House: r5c6=8
Hidden Single: r8c5=8
2-String Kite: 5 in r2c7,r9c5 (connected by r8c7,r9c8) => r2c5<>5
Turbot Fish: 5 r2c7 =5= r8c7 -5- r8c1 =5= r7c2 => r2c2<>5
Hidden Single: r2c7=5
Full House: r8c7=3
Skyscraper: 3 in r2c5,r7c6 (connected by r27c2) => r13c6,r9c5<>3
Hidden Single: r7c6=3
Hidden Single: r9c3=3
Hidden Single: r7c4=2
2-String Kite: 5 in r3c2,r8c6 (connected by r7c2,r8c1) => r3c6<>5
Locked Candidates Type 1 (Pointing): 5 in b2 => r1c1<>5
2-String Kite: 5 in r4c9,r9c5 (connected by r7c9,r9c8) => r4c5<>5
Naked Single: r4c5=7
Swordfish: 5 c458 r169 => r16c6<>5
W-Wing: 3/6 in r2c2,r3c9 connected by 6 in r7c29 => r3c12<>3
Locked Candidates Type 2 (Claiming): 3 in r3 => r1c8<>3
Multi Colors 1: 6 (r2c2) / (r2c5), (r3c9,r7c2,r8c6,r9c8) / (r7c9,r9c5) => r1c5,r3c12,r6c2<>6
Locked Pair: 5,7 in r3c12 => r1c13,r3c6<>7
Hidden Single: r1c6=7
2-String Kite: 6 in r3c6,r9c8 (connected by r8c6,r9c5) => r3c8<>6
XY-Chain: 3 3- r1c5 -5- r1c4 -1- r6c4 -5- r4c6 -2- r4c3 -8- r1c3 -6- r2c2 -3 => r1c1,r2c5<>3
Naked Single: r2c5=6
Full House: r2c2=3
Naked Single: r3c6=1
Naked Single: r9c5=5
Full House: r1c5=3
Full House: r1c4=5
Full House: r8c6=6
Full House: r9c8=6
Full House: r6c4=1
Full House: r7c9=5
Full House: r7c2=6
Naked Single: r6c2=7
Naked Single: r3c8=3
Naked Single: r6c6=2
Full House: r4c6=5
Naked Single: r8c3=7
Full House: r8c1=5
Naked Single: r1c8=1
Full House: r3c9=6
Full House: r4c9=3
Full House: r6c8=5
Naked Single: r3c2=5
Full House: r3c1=7
Naked Single: r6c3=6
Full House: r6c1=3
Naked Single: r4c1=9
Full House: r1c1=6
Naked Single: r1c3=8
Full House: r1c2=9
Full House: r4c2=8
Full House: r4c3=2
|
normal_sudoku_982
|
.42.1...61.87..3.2...........46.3..1619...783...1.7964296..54.7435.716..781..6...
|
342519876158764392967328145874693251619452783523187964296835417435971628781246539
|
Basic 9x9 Sudoku 982
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 4 2 . 1 . . . 6
1 . 8 7 . . 3 . 2
. . . . . . . . .
. . 4 6 . 3 . . 1
6 1 9 . . . 7 8 3
. . . 1 . 7 9 6 4
2 9 6 . . 5 4 . 7
4 3 5 . 7 1 6 . .
7 8 1 . . 6 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
342519876158764392967328145874693251619452783523187964296835417435971628781246539 #1 Easy (366)
Naked Single: r7c1=2
Hidden Single: r6c9=4
Hidden Single: r6c6=7
Hidden Single: r5c2=1
Hidden Single: r7c3=6
Hidden Single: r8c7=6
Hidden Single: r8c6=1
Naked Single: r8c3=5
Naked Single: r5c3=9
Naked Single: r8c1=4
Naked Single: r2c3=8
Naked Single: r9c1=7
Full House: r9c3=1
Naked Single: r6c3=3
Full House: r3c3=7
Hidden Single: r7c8=1
Hidden Single: r8c9=8
Hidden Single: r4c5=9
Hidden Single: r1c8=7
Hidden Single: r4c2=7
Hidden Single: r3c7=1
Hidden Single: r9c8=3
Hidden Single: r4c1=8
Naked Single: r6c1=5
Full House: r6c2=2
Full House: r6c5=8
Naked Single: r7c5=3
Full House: r7c4=8
Hidden Single: r1c7=8
Naked Single: r1c6=9
Naked Single: r1c1=3
Full House: r1c4=5
Full House: r3c1=9
Naked Single: r2c6=4
Naked Single: r3c9=5
Full House: r9c9=9
Naked Single: r2c5=6
Naked Single: r5c6=2
Full House: r3c6=8
Naked Single: r2c8=9
Full House: r3c8=4
Full House: r2c2=5
Full House: r3c2=6
Naked Single: r8c8=2
Full House: r4c8=5
Full House: r8c4=9
Full House: r9c7=5
Full House: r4c7=2
Naked Single: r3c5=2
Full House: r3c4=3
Naked Single: r5c4=4
Full House: r5c5=5
Full House: r9c5=4
Full House: r9c4=2
|
normal_sudoku_2830
|
.89.3.7..537....896.47983..9..1.3..7..1.7.9..76..59..1.723.4.9....9.72...9..2..73
|
289536714537241689614798352925183467841672935763459821172364598358917246496825173
|
Basic 9x9 Sudoku 2830
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 8 9 . 3 . 7 . .
5 3 7 . . . . 8 9
6 . 4 7 9 8 3 . .
9 . . 1 . 3 . . 7
. . 1 . 7 . 9 . .
7 6 . . 5 9 . . 1
. 7 2 3 . 4 . 9 .
. . . 9 . 7 2 . .
. 9 . . 2 . . 7 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
289536714537241689614798352925183467841672935763459821172364598358917246496825173 #1 Extreme (3846)
Naked Single: r2c3=7
Hidden Single: r5c7=9
Hidden Single: r9c8=7
Hidden Single: r8c4=9
Hidden Single: r3c4=7
Hidden Single: r7c2=7
Hidden Single: r6c1=7
Hidden Single: r7c4=3
Hidden Single: r3c6=8
Locked Candidates Type 1 (Pointing): 5 in b2 => r1c89<>5
Locked Candidates Type 1 (Pointing): 5 in b8 => r9c37<>5
Locked Candidates Type 1 (Pointing): 5 in b7 => r8c89<>5
Locked Candidates Type 2 (Claiming): 2 in r2 => r1c46<>2
2-String Kite: 2 in r1c1,r4c8 (connected by r4c2,r5c1) => r1c8<>2
Discontinuous Nice Loop: 4 r5c8 -4- r6c7 -8- r6c3 -3- r6c8 =3= r5c8 => r5c8<>4
Discontinuous Nice Loop: 6 r5c8 -6- r5c6 -2- r6c4 =2= r6c8 =3= r5c8 => r5c8<>6
Discontinuous Nice Loop: 4 r8c1 -4- r9c1 =4= r9c7 -4- r6c7 -8- r6c3 -3- r8c3 =3= r8c1 => r8c1<>4
Grouped Discontinuous Nice Loop: 4 r5c9 -4- r5c12 =4= r4c2 =2= r4c8 -2- r6c8 =2= r6c4 =4= r6c78 -4- r5c9 => r5c9<>4
Forcing Chain Contradiction in b6 => r1c1=2
r1c1<>2 r1c1=1 r3c2<>1 r3c8=1 r3c8<>5 r45c8=5 r4c7<>5
r1c1<>2 r5c1=2 r4c2<>2 r4c8=2 r4c8<>5
r1c1<>2 r5c1=2 r5c1<>3 r5c8=3 r5c8<>5
r1c1<>2 r1c9=2 r3c9<>2 r3c9=5 r5c9<>5
Full House: r3c2=1
Discontinuous Nice Loop: 8 r7c7 -8- r6c7 -4- r9c7 =4= r9c1 -4- r8c2 -5- r8c3 =5= r4c3 -5- r4c7 =5= r7c7 => r7c7<>8
Forcing Chain Contradiction in r5c9 => r7c7=5
r7c7<>5 r7c9=5 r3c9<>5 r3c9=2 r5c9<>2
r7c7<>5 r7c9=5 r5c9<>5
r7c7<>5 r4c7=5 r4c3<>5 r4c3=8 r9c3<>8 r9c3=6 r9c46<>6 r78c5=6 r4c5<>6 r4c78=6 r5c9<>6
r7c7<>5 r4c7=5 r4c3<>5 r8c3=5 r8c2<>5 r8c2=4 r9c1<>4 r9c7=4 r9c7<>8 r46c7=8 r5c9<>8
Naked Triple: 4,6,8 in r178c9 => r5c9<>6, r5c9<>8
Locked Candidates Type 1 (Pointing): 6 in b6 => r4c5<>6
Locked Candidates Type 1 (Pointing): 8 in b6 => r9c7<>8
2-String Kite: 1 in r1c6,r9c7 (connected by r1c8,r2c7) => r9c6<>1
Locked Candidates Type 1 (Pointing): 1 in b8 => r2c5<>1
Naked Triple: 5,6,8 in r9c346 => r9c1<>8, r9c7<>6
Skyscraper: 8 in r5c1,r9c3 (connected by r59c4) => r46c3,r78c1<>8
Naked Single: r4c3=5
Naked Single: r6c3=3
Naked Single: r7c1=1
Naked Single: r8c1=3
Naked Single: r9c1=4
Full House: r5c1=8
Naked Single: r8c2=5
Naked Single: r9c7=1
Hidden Single: r5c8=3
Hidden Single: r8c5=1
Hidden Single: r2c6=1
Hidden Single: r1c8=1
Hidden Single: r5c9=5
Naked Single: r3c9=2
Full House: r3c8=5
Hidden Single: r2c4=2
Hidden Single: r5c6=2
Naked Single: r5c2=4
Full House: r4c2=2
Full House: r5c4=6
Hidden Single: r6c8=2
Skyscraper: 4 in r1c9,r6c7 (connected by r16c4) => r2c7<>4
Naked Single: r2c7=6
Full House: r1c9=4
Full House: r2c5=4
Naked Single: r1c4=5
Full House: r1c6=6
Full House: r9c6=5
Naked Single: r4c5=8
Full House: r6c4=4
Full House: r9c4=8
Full House: r7c5=6
Full House: r6c7=8
Full House: r4c7=4
Full House: r9c3=6
Full House: r7c9=8
Full House: r4c8=6
Full House: r8c3=8
Full House: r8c9=6
Full House: r8c8=4
|
normal_sudoku_5781
|
5.2..9.8.7...8.4....12.5.393..7..5.11.4953.78.75.2.394..8.9...591.5..8..25....96.
|
542379186793186452861245739389764521124953678675821394438697215916532847257418963
|
Basic 9x9 Sudoku 5781
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
5 . 2 . . 9 . 8 .
7 . . . 8 . 4 . .
. . 1 2 . 5 . 3 9
3 . . 7 . . 5 . 1
1 . 4 9 5 3 . 7 8
. 7 5 . 2 . 3 9 4
. . 8 . 9 . . . 5
9 1 . 5 . . 8 . .
2 5 . . . . 9 6 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
542379186793186452861245739389764521124953678675821394438697215916532847257418963 #1 Easy (376)
Naked Single: r3c8=3
Naked Single: r6c8=9
Hidden Single: r6c2=7
Hidden Single: r6c7=3
Hidden Single: r5c4=9
Hidden Single: r8c1=9
Hidden Single: r5c1=1
Hidden Single: r9c7=9
Hidden Single: r8c4=5
Hidden Single: r1c1=5
Hidden Single: r9c2=5
Hidden Single: r8c7=8
Hidden Single: r4c7=5
Naked Single: r4c8=2
Full House: r5c7=6
Full House: r5c2=2
Naked Single: r8c8=4
Naked Single: r3c7=7
Naked Single: r7c8=1
Full House: r2c8=5
Naked Single: r1c7=1
Full House: r7c7=2
Naked Single: r1c9=6
Full House: r2c9=2
Hidden Single: r1c5=7
Hidden Single: r7c6=7
Hidden Single: r9c5=1
Hidden Single: r8c6=2
Hidden Single: r8c5=3
Naked Single: r8c9=7
Full House: r8c3=6
Full House: r9c9=3
Naked Single: r4c3=9
Naked Single: r7c1=4
Naked Single: r9c3=7
Full House: r2c3=3
Full House: r7c2=3
Full House: r7c4=6
Naked Single: r1c2=4
Full House: r1c4=3
Naked Single: r2c4=1
Naked Single: r2c6=6
Full House: r2c2=9
Full House: r3c5=4
Full House: r4c5=6
Naked Single: r6c4=8
Full House: r9c4=4
Full House: r9c6=8
Naked Single: r4c2=8
Full House: r4c6=4
Full House: r6c1=6
Full House: r6c6=1
Full House: r3c2=6
Full House: r3c1=8
|
normal_sudoku_1661
|
2...8..56..56..2..6..2.5.3..9.754..2..21963...6732859.7..5....3....1.7....1....25
|
234987156975631248618245937193754862852196374467328591789562413526413789341879625
|
Basic 9x9 Sudoku 1661
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
2 . . . 8 . . 5 6
. . 5 6 . . 2 . .
6 . . 2 . 5 . 3 .
. 9 . 7 5 4 . . 2
. . 2 1 9 6 3 . .
. 6 7 3 2 8 5 9 .
7 . . 5 . . . . 3
. . . . 1 . 7 . .
. . 1 . . . . 2 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
234987156975631248618245937193754862852196374467328591789562413526413789341879625 #1 Extreme (12506) bf
Hidden Single: r3c6=5
Hidden Single: r6c7=5
Brute Force: r5c6=6
Naked Single: r6c5=2
Naked Single: r6c6=8
Naked Single: r4c4=7
Full House: r5c5=9
Hidden Single: r6c2=6
Hidden Single: r3c4=2
Hidden Single: r4c9=2
Locked Candidates Type 1 (Pointing): 1 in b4 => r2c1<>1
Almost Locked Set XZ-Rule: A=r8c124689 {2345689}, B=r9c1247 {34689}, X=6, Z=3 => r8c3<>3
Hidden Triple: 2,3,5 in r8c126 => r8c12<>4, r8c12<>8, r8c16<>9
Almost Locked Set Chain: 1- r1c347 {1349} -3- r4c3 {38} -8- r4c78 {168} -1- r6c9 {14} -4- r2358c9 {14789} -1 => r2c8,r3c7<>1
Discontinuous Nice Loop: 4 r7c8 -4- r7c5 -6- r9c5 =6= r9c7 -6- r4c7 =6= r4c8 =1= r7c8 => r7c8<>4
Finned Franken Swordfish: 9 r37b2 c367 fr1c4 fr3c9 => r1c7<>9
Discontinuous Nice Loop: 9 r2c6 -9- r1c4 -4- r1c7 -1- r1c6 =1= r2c6 => r2c6<>9
Locked Candidates Type 1 (Pointing): 9 in b2 => r1c3<>9
Grouped Continuous Nice Loop: 4/8 3= r4c1 =1= r6c1 -1- r6c9 =1= r23c9 -1- r1c7 -4- r1c3 -3- r4c3 =3= r4c1 =1 => r1c24<>4, r4c1<>8
Naked Single: r1c4=9
Locked Candidates Type 1 (Pointing): 4 in b2 => r79c5<>4
Naked Single: r7c5=6
Hidden Single: r8c3=6
Hidden Single: r9c7=6
Hidden Single: r4c8=6
Hidden Single: r8c9=9
Hidden Single: r7c8=1
Hidden Single: r2c1=9
Hidden Single: r3c7=9
Hidden Single: r7c3=9
Naked Single: r7c6=2
Naked Single: r8c6=3
Naked Single: r8c1=5
Naked Single: r9c5=7
Naked Single: r8c2=2
Naked Single: r3c5=4
Full House: r2c5=3
Naked Single: r9c6=9
Naked Single: r3c3=8
Naked Single: r4c3=3
Full House: r1c3=4
Naked Single: r4c1=1
Full House: r4c7=8
Naked Single: r1c7=1
Full House: r7c7=4
Full House: r7c2=8
Full House: r8c8=8
Full House: r8c4=4
Full House: r9c4=8
Naked Single: r6c1=4
Full House: r6c9=1
Naked Single: r1c6=7
Full House: r1c2=3
Full House: r2c6=1
Naked Single: r3c9=7
Full House: r3c2=1
Full House: r2c2=7
Naked Single: r5c1=8
Full House: r5c2=5
Full House: r9c1=3
Full House: r9c2=4
Naked Single: r2c8=4
Full House: r2c9=8
Full House: r5c9=4
Full House: r5c8=7
|
normal_sudoku_1221
|
4...968.3.......1..6.1.8..49...7...5.48..2..7..56.9.4..9......22....345...4.2.7..
|
412596873853247916769138524926874135148352697375619248597481362281763459634925781
|
Basic 9x9 Sudoku 1221
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
4 . . . 9 6 8 . 3
. . . . . . . 1 .
. 6 . 1 . 8 . . 4
9 . . . 7 . . . 5
. 4 8 . . 2 . . 7
. . 5 6 . 9 . 4 .
. 9 . . . . . . 2
2 . . . . 3 4 5 .
. . 4 . 2 . 7 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
412596873853247916769138524926874135148352697375619248597481362281763459634925781 #1 Extreme (20866) bf
Grouped Discontinuous Nice Loop: 7 r2c3 -7- r2c46 =7= r1c4 -7- r1c8 -2- r3c78 =2= r3c3 =9= r2c3 => r2c3<>7
Brute Force: r5c6=2
2-String Kite: 9 in r6c6,r8c9 (connected by r8c4,r9c6) => r6c9<>9
Almost Locked Set XZ-Rule: A=r4c6 {14}, B=r235c5 {1345}, X=1, Z=4 => r2c6<>4
Almost Locked Set XZ-Rule: A=r6c59 {138}, B=r235c5 {1345}, X=3, Z=1 => r6c6<>1
Naked Single: r6c6=9
Grouped Discontinuous Nice Loop: 1 r7c5 -1- r7c7 =1= r456c7 -1- r6c9 -8- r6c5 =8= r4c4 =4= r4c6 =1= r56c5 -1- r7c5 => r7c5<>1
Almost Locked Set XY-Wing: A=r6c1579 {12378}, B=r13c8,r2c9,r3c7 {25679}, C=r3c15 {357}, X,Y=5,7, Z=2 => r2c7<>2
Almost Locked Set XY-Wing: A=r1c8 {27}, B=r2c679 {5679}, C=r3c1578 {23579}, X,Y=2,9, Z=7 => r1c4<>7
Locked Candidates Type 1 (Pointing): 7 in b2 => r2c12<>7
Forcing Chain Contradiction in c4 => r7c4<>5
r7c4=5 r79c6<>5 r2c6=5 r2c6<>7 r2c4=7 r2c4<>4
r7c4=5 r9c6<>5 r9c6=1 r4c6<>1 r4c6=4 r4c4<>4
r7c4=5 r7c4<>4
Forcing Net Contradiction in r8c9 => r1c8=7
r1c8<>7 (r3c8=7 r3c1<>7) r1c8=2 r1c4<>2 r1c4=5 (r1c2<>5) r3c5<>5 r3c5=3 r3c1<>3 r3c1=5 r2c2<>5 r9c2=5 (r9c6<>5 r9c6=1 r9c9<>1) (r9c6<>5 r9c6=1 r8c5<>1) r1c2<>5 r1c4=5 (r1c2<>5) r5c4<>5 r5c5=5 r5c5<>1 r6c5=1 r6c9<>1 r8c9=1 (r8c9<>9 r8c4=9 r9c4<>9) r6c9<>1 r6c9=8 r4c8<>8 r4c4=8 r9c4<>8 r9c4=5 r1c4<>5 r1c4=2 r1c8<>2 r1c8=7
Locked Candidates Type 1 (Pointing): 2 in b3 => r3c3<>2
Forcing Net Contradiction in c2 => r2c5=4
r2c5<>4 (r2c4=4 r4c4<>4 r4c6=4 r4c6<>1) (r2c4=4 r2c4<>2 r1c4=2 r1c3<>2 r1c3=1 r4c3<>1) r7c5=4 (r7c5<>8) r7c5<>6 r8c5=6 r8c5<>8 r6c5=8 r6c9<>8 r6c9=1 r4c7<>1 r4c2=1
r2c5<>4 (r2c4=4 r2c4<>2 r1c4=2 r1c3<>2 r1c3=1 r8c3<>1) r7c5=4 (r7c5<>8) r7c5<>6 r8c5=6 (r8c5<>1) r8c5<>8 r6c5=8 r6c9<>8 r6c9=1 r8c9<>1 r8c2=1
Forcing Chain Contradiction in c4 => r3c8=2
r3c8<>2 r3c7=2 r3c7<>5 r2c7=5 r2c6<>5 r2c6=7 r2c4<>7
r3c8<>2 r4c8=2 r4c8<>8 r4c4=8 r4c4<>4 r7c4=4 r7c4<>7
r3c8<>2 r3c7=2 r6c7<>2 r6c2=2 r6c2<>7 r8c2=7 r8c4<>7
Forcing Chain Contradiction in r9c4 => r5c8<>3
r5c8=3 r5c4<>3 r5c4=5 r9c4<>5
r5c8=3 r456c7<>3 r7c7=3 r7c7<>1 r456c7=1 r6c9<>1 r6c9=8 r6c5<>8 r4c4=8 r9c4<>8
r5c8=3 r5c8<>9 r9c8=9 r9c4<>9
Forcing Chain Contradiction in r9 => r4c8<>6
r4c8=6 r4c3<>6 r5c1=6 r9c1<>6
r4c8=6 r9c8<>6
r4c8=6 r5c8<>6 r5c8=9 r5c7<>9 r23c7=9 r2c9<>9 r2c9=6 r9c9<>6
Sue de Coq: r45c7 - {12369} (r23c7 - {569}, r4c8,r6c79 - {1238}) => r7c7<>6
Forcing Chain Contradiction in r6 => r4c3<>3
r4c3=3 r6c1<>3
r4c3=3 r6c2<>3
r4c3=3 r4c8<>3 r4c8=8 r4c4<>8 r6c5=8 r6c5<>3
r4c3=3 r4c3<>6 r4c7=6 r4c7<>2 r6c7=2 r6c7<>3
Forcing Chain Verity => r6c2<>1
r2c3=3 r2c3<>9 r3c3=9 r3c3<>7 r3c1=7 r6c1<>7 r6c2=7 r6c2<>1
r3c3=3 r3c3<>7 r3c1=7 r6c1<>7 r6c2=7 r6c2<>1
r7c3=3 r7c7<>3 r7c7=1 r456c7<>1 r6c9=1 r6c2<>1
Forcing Chain Verity => r6c7<>1
r2c3=3 r2c3<>9 r3c3=9 r3c3<>7 r3c1=7 r6c1<>7 r6c2=7 r6c2<>2 r6c7=2 r6c7<>1
r3c3=3 r3c3<>7 r3c1=7 r6c1<>7 r6c2=7 r6c2<>2 r6c7=2 r6c7<>1
r7c3=3 r7c7<>3 r7c7=1 r6c7<>1
Forcing Chain Contradiction in r7 => r7c1<>3
r7c1=3 r7c1<>8
r7c1=3 r7c1<>5 r7c56=5 r9c6<>5 r9c6=1 r4c6<>1 r4c6=4 r4c4<>4 r7c4=4 r7c4<>8
r7c1=3 r7c7<>3 r7c7=1 r45c7<>1 r6c9=1 r6c9<>8 r6c5=8 r7c5<>8
r7c1=3 r7c7<>3 r456c7=3 r4c8<>3 r4c8=8 r7c8<>8
Forcing Chain Contradiction in r7 => r7c4<>7
r7c4=7 r7c4<>4 r7c6=4 r4c6<>4 r4c6=1 r9c6<>1 r9c6=5 r7c56<>5 r7c1=5 r7c1<>8
r7c4=7 r7c4<>8
r7c4=7 r7c4<>4 r4c4=4 r4c4<>8 r6c5=8 r7c5<>8
r7c4=7 r7c4<>4 r4c4=4 r4c4<>8 r4c8=8 r7c8<>8
Discontinuous Nice Loop: 2/3 r6c2 =7= r6c1 -7- r3c1 =7= r3c3 =9= r3c7 =5= r2c7 -5- r2c6 -7- r2c4 =7= r8c4 -7- r8c2 =7= r6c2 => r6c2<>2, r6c2<>3
Naked Single: r6c2=7
Hidden Single: r6c7=2
Turbot Fish: 3 r2c4 =3= r3c5 -3- r6c5 =3= r6c1 => r2c1<>3
XY-Wing: 1/8/3 in r4c8,r6c19 => r4c2<>3
Locked Candidates Type 1 (Pointing): 3 in b4 => r39c1<>3
Grouped Discontinuous Nice Loop: 5 r2c1 -5- r79c1 =5= r9c2 =3= r2c2 =8= r2c1 => r2c1<>5
Naked Single: r2c1=8
Finned X-Wing: 8 r47 c48 fr7c5 => r89c4<>8
Hidden Pair: 4,8 in r47c4 => r4c4<>3
Locked Candidates Type 2 (Claiming): 3 in r4 => r5c7<>3
Sue de Coq: r56c5 - {1358} (r3c5 - {35}, r4c46 - {148}) => r7c5<>5
Discontinuous Nice Loop: 8 r8c5 -8- r8c2 =8= r9c2 =3= r9c8 -3- r4c8 -8- r4c4 =8= r7c4 -8- r8c5 => r8c5<>8
Locked Candidates Type 1 (Pointing): 8 in b8 => r7c8<>8
Hidden Rectangle: 3/6 in r4c78,r7c78 => r4c7<>6
Hidden Single: r4c3=6
Hidden Single: r4c2=2
Locked Candidates Type 1 (Pointing): 1 in b4 => r79c1<>1
Naked Pair: 1,3 in r47c7 => r5c7<>1
W-Wing: 3/5 in r2c2,r3c5 connected by 5 in r1c24 => r2c4,r3c3<>3
Hidden Single: r5c4=3
Naked Single: r5c1=1
Full House: r6c1=3
Naked Single: r5c5=5
Naked Single: r3c5=3
W-Wing: 8/1 in r6c9,r8c2 connected by 1 in r68c5 => r8c9<>8
Hidden Single: r8c2=8
Avoidable Rectangle Type 1: 2/9 in r5c67,r6c67 => r5c7<>9
Naked Single: r5c7=6
Full House: r5c8=9
Hidden Single: r2c9=6
Hidden Single: r8c5=6
Naked Single: r7c5=8
Full House: r6c5=1
Full House: r6c9=8
Naked Single: r7c4=4
Naked Single: r4c6=4
Full House: r4c4=8
Naked Single: r4c8=3
Full House: r4c7=1
Naked Single: r7c8=6
Full House: r9c8=8
Naked Single: r7c7=3
Hidden Single: r9c2=3
Naked Single: r2c2=5
Full House: r1c2=1
Naked Single: r2c6=7
Naked Single: r2c7=9
Full House: r3c7=5
Naked Single: r3c1=7
Full House: r3c3=9
Naked Single: r1c3=2
Full House: r1c4=5
Full House: r2c4=2
Full House: r2c3=3
Naked Single: r7c1=5
Full House: r9c1=6
Naked Single: r9c4=9
Full House: r8c4=7
Naked Single: r7c6=1
Full House: r7c3=7
Full House: r8c3=1
Full House: r9c6=5
Full House: r9c9=1
Full House: r8c9=9
|
normal_sudoku_4345
|
.3.4.....26..3.14.874..2.35.1..4.5.9...5...1.54.8..32....35....456.8...33....485.
|
931475682265938147874162935618243579723596418549817326182359764456781293397624851
|
Basic 9x9 Sudoku 4345
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 3 . 4 . . . . .
2 6 . . 3 . 1 4 .
8 7 4 . . 2 . 3 5
. 1 . . 4 . 5 . 9
. . . 5 . . . 1 .
5 4 . 8 . . 3 2 .
. . . 3 5 . . . .
4 5 6 . 8 . . . 3
3 . . . . 4 8 5 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
931475682265938147874162935618243579723596418549817326182359764456781293397624851 #1 Extreme (14190) bf
Hidden Single: r3c3=4
Hidden Single: r8c2=5
Hidden Single: r4c5=4
2-String Kite: 2 in r4c3,r9c5 (connected by r4c4,r5c5) => r9c3<>2
Almost Locked Set XY-Wing: A=r5c124579 {2456789}, B=r1269c3 {15789}, C=r3c1457 {15689}, X,Y=5,8, Z=7,9 => r5c3<>7, r5c3<>9
Forcing Chain Contradiction in r7c7 => r7c6<>1
r7c6=1 r8c46<>1 r8c9=1 r8c9<>3 r3c9=3 r3c9<>5 r3c4=5 r3c4<>1 r89c4=1 r7c6<>1
Almost Locked Set XY-Wing: A=r9c2 {29}, B=r69c3 {179}, C=r7c12368 {126789}, X,Y=1,2, Z=9 => r7c3<>9
Forcing Chain Contradiction in r7c7 => r9c5<>1
r9c5=1 r8c46<>1 r8c9=1 r8c9<>3 r3c9=3 r3c9<>5 r3c4=5 r3c4<>1 r89c4=1 r9c5<>1
Brute Force: r5c4=5
Hidden Single: r3c9=5
Hidden Single: r3c8=3
Hidden Single: r8c9=3
Hidden Single: r3c1=8
Locked Candidates Type 1 (Pointing): 1 in b1 => r1c56<>1
Locked Candidates Type 2 (Claiming): 1 in r8 => r9c4<>1
Naked Triple: 6,7,9 in r45c1,r6c3 => r4c3<>7, r56c2<>6, r56c2<>9
Naked Single: r6c2=4
Hidden Single: r2c2=6
Locked Candidates Type 2 (Claiming): 9 in c2 => r7c1,r9c3<>9
Naked Pair: 1,7 in r7c1,r9c3 => r7c3<>1, r7c3<>7
Hidden Pair: 5,8 in r12c6 => r1c6<>6, r12c6<>7, r12c6<>9
XY-Chain: 6 6- r4c1 -7- r6c3 -9- r2c3 -5- r2c6 -8- r2c9 -7- r6c9 -6 => r4c8<>6
XY-Chain: 7 7- r2c9 -8- r2c6 -5- r2c3 -9- r6c3 -7 => r6c9<>7
Naked Single: r6c9=6
Locked Candidates Type 1 (Pointing): 6 in b9 => r7c6<>6
Locked Candidates Type 2 (Claiming): 6 in c6 => r4c4,r5c5<>6
Naked Triple: 1,7,9 in r678c6 => r45c6<>7, r5c6<>9
W-Wing: 9/7 in r6c3,r7c6 connected by 7 in r7c1,r9c3 => r6c6<>9
Locked Candidates Type 1 (Pointing): 9 in b5 => r139c5<>9
Locked Candidates Type 1 (Pointing): 9 in b2 => r89c4<>9
Hidden Single: r9c2=9
Locked Candidates Type 1 (Pointing): 2 in b7 => r7c79<>2
Uniqueness Test 1: 2/8 in r5c23,r7c23 => r5c3<>2, r5c3<>8
Naked Single: r5c3=3
Naked Single: r5c6=6
Naked Single: r4c6=3
Hidden Single: r4c1=6
Skyscraper: 7 in r2c9,r4c8 (connected by r24c4) => r1c8,r5c9<>7
Turbot Fish: 7 r4c8 =7= r5c7 -7- r5c1 =7= r7c1 => r7c8<>7
XY-Wing: 4/8/7 in r25c9,r5c7 => r1c7<>7
Locked Candidates Type 1 (Pointing): 7 in b3 => r79c9<>7
Sashimi X-Wing: 7 c36 r69 fr7c6 fr8c6 => r9c45<>7
Hidden Single: r9c3=7
Naked Single: r6c3=9
Naked Single: r7c1=1
Naked Single: r2c3=5
Naked Single: r5c1=7
Full House: r1c1=9
Full House: r1c3=1
Naked Single: r7c9=4
Naked Single: r2c6=8
Naked Single: r5c7=4
Naked Single: r5c9=8
Full House: r4c8=7
Naked Single: r1c6=5
Naked Single: r2c9=7
Full House: r2c4=9
Naked Single: r5c2=2
Full House: r4c3=8
Full House: r4c4=2
Full House: r5c5=9
Full House: r7c2=8
Full House: r7c3=2
Naked Single: r8c8=9
Naked Single: r1c9=2
Full House: r9c9=1
Naked Single: r9c4=6
Full House: r9c5=2
Naked Single: r7c8=6
Full House: r1c8=8
Naked Single: r1c7=6
Full House: r1c5=7
Full House: r3c7=9
Naked Single: r3c4=1
Full House: r3c5=6
Full House: r6c5=1
Full House: r8c4=7
Full House: r6c6=7
Naked Single: r7c7=7
Full House: r7c6=9
Full House: r8c6=1
Full House: r8c7=2
|
normal_sudoku_5619
|
.6.28.4.5..8..632......78...5.87421..246.97588..52.9.46....25....54681.2.....56..
|
761283495598146327243957861359874216124639758876521934687312549935468172412795683
|
Basic 9x9 Sudoku 5619
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 6 . 2 8 . 4 . 5
. . 8 . . 6 3 2 .
. . . . . 7 8 . .
. 5 . 8 7 4 2 1 .
. 2 4 6 . 9 7 5 8
8 . . 5 2 . 9 . 4
6 . . . . 2 5 . .
. . 5 4 6 8 1 . 2
. . . . . 5 6 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
761283495598146327243957861359874216124639758876521934687312549935468172412795683 #1 Extreme (11136) bf
Hidden Single: r4c7=2
Brute Force: r5c7=7
Naked Single: r6c7=9
Hidden Single: r4c5=7
Hidden Single: r5c8=5
Hidden Single: r7c7=5
Hidden Single: r4c6=4
Hidden Single: r5c4=6
Hidden Single: r2c6=6
Hidden Single: r9c6=5
Hidden Single: r8c6=8
Naked Single: r8c7=1
Naked Single: r1c7=4
Full House: r3c7=8
Naked Triple: 1,3,9 in r1c6,r23c4 => r23c5<>1, r23c5<>9, r3c5<>3
Locked Candidates Type 1 (Pointing): 9 in b2 => r79c4<>9
Naked Triple: 3,7,9 in r79c9,r8c8 => r79c8<>3, r79c8<>7, r79c8<>9
Hidden Pair: 4,8 in r7c28 => r7c2<>1, r7c2<>3, r7c2<>7, r7c2<>9
Hidden Triple: 2,4,5 in r239c1 => r239c1<>1, r29c1<>7, r239c1<>9, r39c1<>3
Naked Pair: 4,5 in r2c15 => r2c2<>4
X-Wing: 7 c18 r18 => r1c3,r8c2<>7
Remote Pair: 1/3 r1c6 -3- r6c6 -1- r5c5 -3- r5c1 => r1c1<>1, r1c1<>3
Hidden Single: r5c1=1
Full House: r5c5=3
Full House: r6c6=1
Full House: r1c6=3
Hidden Single: r1c3=1
Hidden Single: r9c2=1
Naked Single: r9c5=9
Naked Single: r7c5=1
Hidden Single: r9c8=8
Naked Single: r7c8=4
Naked Single: r7c2=8
Hidden Single: r9c1=4
Naked Single: r2c1=5
Naked Single: r2c5=4
Full House: r3c5=5
Naked Single: r3c1=2
Hidden Single: r3c2=4
Hidden Single: r9c3=2
Hidden Single: r3c3=3
Locked Candidates Type 1 (Pointing): 3 in b7 => r8c8<>3
Hidden Single: r6c8=3
Full House: r4c9=6
Naked Single: r6c2=7
Full House: r6c3=6
Naked Single: r4c3=9
Full House: r4c1=3
Full House: r7c3=7
Naked Single: r2c2=9
Full House: r1c1=7
Full House: r8c1=9
Full House: r8c2=3
Full House: r1c8=9
Full House: r8c8=7
Full House: r3c8=6
Naked Single: r7c4=3
Full House: r7c9=9
Full House: r9c9=3
Full House: r9c4=7
Naked Single: r2c4=1
Full House: r2c9=7
Full House: r3c9=1
Full House: r3c4=9
|
normal_sudoku_3020
|
.......5...2..3...6.8......5.374916...963..75467...9.37.651..39.9.3.75.6..5..671.
|
371498652952163847648275391523749168819632475467851923786514239194327586235986714
|
Basic 9x9 Sudoku 3020
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . . . . 5 .
. . 2 . . 3 . . .
6 . 8 . . . . . .
5 . 3 7 4 9 1 6 .
. . 9 6 3 . . 7 5
4 6 7 . . . 9 . 3
7 . 6 5 1 . . 3 9
. 9 . 3 . 7 5 . 6
. . 5 . . 6 7 1 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
371498652952163847648275391523749168819632475467851923786514239194327586235986714 #1 Extreme (14264) bf
Hidden Single: r6c3=7
Hidden Single: r7c9=9
Hidden Single: r5c5=3
Hidden Single: r8c7=5
Hidden Single: r5c9=5
Hidden Single: r7c3=6
Hidden Single: r5c4=6
Brute Force: r4c5=4
Finned X-Wing: 4 r68 c18 fr8c3 => r9c1<>4
Forcing Net Verity => r5c7=4
r5c7=2 (r5c1<>2) (r7c7<>2) r4c9<>2 (r4c9=8 r9c9<>8) r4c2=2 r7c2<>2 r7c6=2 r7c6<>4 r9c4=4 r9c9<>4 r9c9=2 (r8c8<>2) (r9c1<>2) r4c9<>2 (r4c9=8 r9c9<>8) r4c2=2 r6c1<>2 r8c1=2 r8c5<>2 r8c5=8 r8c8<>8 r8c8=4 r6c8<>4 r6c1=4 (r5c1<>4) (r5c2<>4) r5c3<>4 r5c7=4
r5c7=4 r5c7=4
r5c7=8 (r5c1<>8) (r7c7<>8) r4c9<>8 (r4c9=2 r9c9<>2) r4c2=8 r7c2<>8 r7c6=8 r7c6<>4 r9c4=4 r9c9<>4 r9c9=8 (r8c8<>8) (r9c1<>8) r4c9<>8 (r4c9=2 r9c9<>2) r4c2=8 r6c1<>8 r8c1=8 r8c5<>8 r8c5=2 r8c8<>2 r8c8=4 (r7c7<>4 r7c2=4 r5c2<>4) r6c8<>4 r6c1=4 (r5c1<>4) r5c3<>4 r5c7=4
Hidden Single: r6c1=4
Locked Candidates Type 1 (Pointing): 1 in b4 => r5c6<>1
2-String Kite: 4 in r1c3,r7c6 (connected by r7c2,r8c3) => r1c6<>4
Turbot Fish: 4 r1c3 =4= r8c3 -4- r8c8 =4= r9c9 => r1c9<>4
W-Wing: 9/1 in r2c1,r5c3 connected by 1 in r8c13 => r1c3,r5c1<>9
Hidden Single: r5c3=9
Hidden Rectangle: 6/8 in r1c57,r2c57 => r1c5<>8
Discontinuous Nice Loop: 4 r3c8 -4- r8c8 =4= r8c3 =1= r8c1 -1- r2c1 -9- r2c8 =9= r3c8 => r3c8<>4
Skyscraper: 4 in r1c3,r2c8 (connected by r8c38) => r2c2<>4
Almost Locked Set XZ-Rule: A=r457c2 {1248}, B=r157c6 {1248}, X=4, Z=1 => r1c2<>1
Forcing Chain Contradiction in r7 => r3c8=9
r3c8<>9 r3c8=2 r6c8<>2 r6c8=8 r4c9<>8 r4c2=8 r7c2<>8
r3c8<>9 r3c8=2 r6c8<>2 r6c8=8 r6c456<>8 r5c6=8 r7c6<>8
r3c8<>9 r3c8=2 r13c7<>2 r7c7=2 r7c7<>8
W-Wing: 8/2 in r4c9,r7c7 connected by 2 in r68c8 => r9c9<>8
Discontinuous Nice Loop: 2 r1c5 -2- r8c5 -8- r8c8 =8= r7c7 -8- r2c7 -6- r2c5 =6= r1c5 => r1c5<>2
Discontinuous Nice Loop: 2 r5c2 -2- r4c2 =2= r4c9 -2- r9c9 -4- r8c8 =4= r8c3 =1= r8c1 -1- r5c1 =1= r5c2 => r5c2<>2
Discontinuous Nice Loop: 2 r7c6 -2- r5c6 =2= r5c1 -2- r4c2 =2= r4c9 -2- r9c9 -4- r9c4 =4= r7c6 => r7c6<>2
Skyscraper: 2 in r4c9,r7c7 (connected by r47c2) => r9c9<>2
Naked Single: r9c9=4
Hidden Single: r2c8=4
Hidden Single: r8c3=4
Full House: r1c3=1
Naked Single: r2c1=9
Naked Single: r1c1=3
Hidden Single: r7c6=4
Hidden Single: r8c1=1
Hidden Single: r5c2=1
Hidden Single: r3c7=3
Hidden Single: r9c2=3
Naked Pair: 2,8 in r15c6 => r36c6<>2, r6c6<>8
Remote Pair: 2/8 r1c6 -8- r5c6 -2- r5c1 -8- r9c1 -2- r7c2 -8- r7c7 -2- r8c8 -8- r8c5 => r1c7,r3c5<>2, r1c7,r2c5<>8
Naked Single: r1c7=6
Naked Single: r2c7=8
Full House: r7c7=2
Full House: r7c2=8
Full House: r8c8=8
Full House: r9c1=2
Full House: r6c8=2
Full House: r8c5=2
Full House: r5c1=8
Full House: r4c2=2
Full House: r4c9=8
Full House: r5c6=2
Naked Single: r2c4=1
Naked Single: r1c6=8
Naked Single: r2c9=7
Naked Single: r3c6=5
Full House: r6c6=1
Naked Single: r6c4=8
Full House: r6c5=5
Naked Single: r1c9=2
Full House: r3c9=1
Naked Single: r2c2=5
Full House: r2c5=6
Naked Single: r3c5=7
Naked Single: r9c4=9
Full House: r9c5=8
Full House: r1c5=9
Naked Single: r3c2=4
Full House: r1c2=7
Full House: r1c4=4
Full House: r3c4=2
|
normal_sudoku_2537
|
...7.6....861.2..7...3.9..6.6.43........6.43.413..867..94.73...65289...3.37..5..9
|
329786154586142397741359826265437981978561432413928675194273568652894713837615249
|
Basic 9x9 Sudoku 2537
|
puzzles2_17_clue
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . 7 . 6 . . .
. 8 6 1 . 2 . . 7
. . . 3 . 9 . . 6
. 6 . 4 3 . . . .
. . . . 6 . 4 3 .
4 1 3 . . 8 6 7 .
. 9 4 . 7 3 . . .
6 5 2 8 9 . . . 3
. 3 7 . . 5 . . 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
329786154586142397741359826265437981978561432413928675194273568652894713837615249 #1 Easy (366)
Naked Single: r8c2=5
Naked Single: r8c4=8
Naked Single: r9c2=3
Naked Single: r7c2=9
Hidden Single: r1c6=6
Hidden Single: r6c7=6
Hidden Single: r4c2=6
Hidden Single: r7c5=7
Hidden Single: r7c6=3
Hidden Single: r3c6=9
Naked Single: r6c6=8
Hidden Single: r6c3=3
Hidden Single: r5c8=3
Hidden Single: r2c9=7
Hidden Single: r8c7=7
Hidden Single: r9c5=1
Naked Single: r8c6=4
Full House: r8c8=1
Naked Single: r9c1=8
Full House: r7c1=1
Naked Single: r9c7=2
Naked Single: r9c4=6
Full House: r7c4=2
Full House: r9c8=4
Hidden Single: r6c4=9
Full House: r5c4=5
Naked Single: r6c5=2
Full House: r6c9=5
Naked Single: r7c9=8
Naked Single: r7c7=5
Full House: r7c8=6
Hidden Single: r1c9=4
Naked Single: r1c2=2
Naked Single: r5c2=7
Full House: r3c2=4
Naked Single: r5c6=1
Full House: r4c6=7
Naked Single: r5c9=2
Full House: r4c9=1
Naked Single: r5c1=9
Full House: r5c3=8
Naked Single: r4c3=5
Full House: r4c1=2
Naked Single: r3c3=1
Full House: r1c3=9
Naked Single: r3c7=8
Naked Single: r1c8=5
Naked Single: r3c5=5
Naked Single: r4c7=9
Full House: r4c8=8
Naked Single: r1c1=3
Naked Single: r1c5=8
Full House: r2c5=4
Full House: r1c7=1
Full House: r2c7=3
Naked Single: r2c8=9
Full House: r3c8=2
Full House: r3c1=7
Full House: r2c1=5
|
normal_sudoku_6687
|
.1.2...4.983574621.5..3.79854..2.....29..6..43617..8...9...5..643....28..753..419
|
617298543983574621254631798548123967729856134361749852192485376436917285875362419
|
Basic 9x9 Sudoku 6687
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 1 . 2 . . . 4 .
9 8 3 5 7 4 6 2 1
. 5 . . 3 . 7 9 8
5 4 . . 2 . . . .
. 2 9 . . 6 . . 4
3 6 1 7 . . 8 . .
. 9 . . . 5 . . 6
4 3 . . . . 2 8 .
. 7 5 3 . . 4 1 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
617298543983574621254631798548123967729856134361749852192485376436917285875362419 #1 Easy (208)
Naked Single: r2c2=8
Full House: r2c7=6
Naked Single: r8c2=3
Naked Single: r9c9=9
Naked Single: r4c2=4
Naked Single: r5c2=2
Full House: r3c2=5
Naked Single: r9c8=1
Naked Single: r6c3=1
Naked Single: r3c8=9
Naked Single: r3c9=8
Naked Single: r9c7=4
Naked Single: r6c1=3
Naked Single: r8c3=6
Naked Single: r3c6=1
Naked Single: r7c7=3
Naked Single: r6c6=9
Naked Single: r6c8=5
Naked Single: r1c3=7
Naked Single: r3c4=6
Naked Single: r1c7=5
Full House: r1c9=3
Naked Single: r7c8=7
Full House: r8c9=5
Naked Single: r1c6=8
Full House: r1c5=9
Full House: r1c1=6
Naked Single: r8c6=7
Naked Single: r5c7=1
Full House: r4c7=9
Naked Single: r6c5=4
Full House: r6c9=2
Full House: r4c9=7
Naked Single: r4c3=8
Full House: r5c1=7
Naked Single: r3c1=2
Full House: r3c3=4
Full House: r7c3=2
Naked Single: r5c8=3
Full House: r4c8=6
Naked Single: r4c6=3
Full House: r9c6=2
Full House: r4c4=1
Naked Single: r8c5=1
Full House: r8c4=9
Naked Single: r5c4=8
Full House: r5c5=5
Full House: r7c4=4
Naked Single: r9c1=8
Full House: r7c1=1
Full House: r7c5=8
Full House: r9c5=6
|
normal_sudoku_4760
|
2.....1....82415.....56.283..93..7.....692.51.62.75.98.7...68...237...1.4...2....
|
256839147738241569194567283519384726847692351362175498975416832623758914481923675
|
Basic 9x9 Sudoku 4760
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
2 . . . . . 1 . .
. . 8 2 4 1 5 . .
. . . 5 6 . 2 8 3
. . 9 3 . . 7 . .
. . . 6 9 2 . 5 1
. 6 2 . 7 5 . 9 8
. 7 . . . 6 8 . .
. 2 3 7 . . . 1 .
4 . . . 2 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
256839147738241569194567283519384726847692351362175498975416832623758914481923675 #1 Extreme (11290) bf
Locked Candidates Type 1 (Pointing): 3 in b2 => r1c2<>3
Brute Force: r5c6=2
Hidden Single: r3c7=2
Hidden Single: r2c4=2
Hidden Single: r6c5=7
Naked Single: r3c5=6
Hidden Single: r5c4=6
Locked Pair: 3,4 in r56c7 => r4c89,r5c8,r6c9,r8c7<>4, r5c8,r9c7<>3
Naked Single: r5c8=5
Locked Candidates Type 1 (Pointing): 4 in b3 => r1c23<>4
Locked Candidates Type 1 (Pointing): 9 in b3 => r789c9<>9
Locked Candidates Type 2 (Claiming): 8 in r5 => r4c12,r6c1<>8
Locked Candidates Type 2 (Claiming): 6 in c7 => r89c9,r9c8<>6
Skyscraper: 2 in r6c3,r8c2 (connected by r68c9) => r4c2,r7c3<>2
Hidden Single: r8c2=2
Hidden Single: r6c3=2
Naked Single: r6c9=8
2-String Kite: 1 in r6c1,r7c5 (connected by r4c5,r6c4) => r7c1<>1
W-Wing: 9/5 in r1c2,r7c1 connected by 5 in r4c12 => r23c1,r9c2<>9
W-Wing: 5/1 in r4c1,r7c3 connected by 1 in r47c5 => r78c1<>5
Naked Single: r7c1=9
Hidden Single: r4c1=5
Naked Pair: 1,4 in r67c4 => r9c4<>1
Locked Candidates Type 1 (Pointing): 1 in b8 => r7c3<>1
Naked Single: r7c3=5
Hidden Single: r1c2=5
Hidden Single: r8c5=5
Naked Single: r8c9=4
Naked Single: r7c9=2
Naked Single: r4c9=6
Naked Single: r7c8=3
Naked Single: r4c8=2
Naked Single: r7c5=1
Full House: r7c4=4
Naked Single: r9c8=7
Naked Single: r4c5=8
Full House: r1c5=3
Naked Single: r6c4=1
Full House: r4c6=4
Full House: r4c2=1
Naked Single: r2c8=6
Full House: r1c8=4
Naked Single: r9c9=5
Naked Single: r6c1=3
Full House: r6c7=4
Full House: r5c7=3
Naked Single: r9c2=8
Naked Single: r2c1=7
Naked Single: r5c2=4
Naked Single: r8c1=6
Full House: r9c3=1
Naked Single: r9c4=9
Full House: r1c4=8
Naked Single: r1c3=6
Naked Single: r2c9=9
Full House: r1c9=7
Full House: r2c2=3
Full House: r3c2=9
Full House: r1c6=9
Full House: r3c6=7
Naked Single: r3c1=1
Full House: r5c1=8
Full House: r5c3=7
Full House: r3c3=4
Naked Single: r8c7=9
Full House: r8c6=8
Full House: r9c6=3
Full House: r9c7=6
|
normal_sudoku_2436
|
1.9.....35..3...9.3.46....2813...27592.73.14664.1..938.3....5.4.9..8.....5..7..69
|
169827453582314697374695812813946275925738146647152938731269584496583721258471369
|
Basic 9x9 Sudoku 2436
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
1 . 9 . . . . . 3
5 . . 3 . . . 9 .
3 . 4 6 . . . . 2
8 1 3 . . . 2 7 5
9 2 . 7 3 . 1 4 6
6 4 . 1 . . 9 3 8
. 3 . . . . 5 . 4
. 9 . . 8 . . . .
. 5 . . 7 . . 6 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
169827453582314697374695812813946275925738146647152938731269584496583721258471369 #1 Medium (504)
Hidden Single: r1c3=9
Hidden Single: r7c2=3
Locked Candidates Type 1 (Pointing): 5 in b1 => r2c569<>5
Hidden Single: r4c9=5
Naked Single: r6c8=3
Naked Single: r5c7=1
Full House: r6c7=9
Hidden Single: r2c1=5
Hidden Single: r4c2=1
Hidden Single: r9c9=9
Hidden Single: r5c5=3
Hidden Single: r6c2=4
Naked Single: r4c1=8
Naked Single: r5c2=2
Naked Single: r5c3=5
Full House: r5c6=8
Full House: r6c3=7
Hidden Single: r1c4=8
Naked Single: r1c8=5
Hidden Single: r2c3=2
Hidden Single: r7c1=7
Hidden Single: r8c4=5
Locked Candidates Type 2 (Claiming): 2 in c4 => r7c56,r89c6<>2
Naked Pair: 7,8 in r3c27 => r3c6<>7, r3c8<>8
Naked Single: r3c8=1
Naked Single: r2c9=7
Full House: r8c9=1
Naked Single: r8c8=2
Full House: r7c8=8
Naked Single: r3c7=8
Naked Single: r8c3=6
Naked Single: r8c1=4
Full House: r9c1=2
Naked Single: r9c7=3
Full House: r8c7=7
Full House: r8c6=3
Naked Single: r3c2=7
Naked Single: r7c3=1
Full House: r9c3=8
Naked Single: r9c4=4
Full House: r9c6=1
Naked Single: r1c2=6
Full House: r2c2=8
Naked Single: r4c4=9
Full House: r7c4=2
Naked Single: r2c6=4
Naked Single: r1c7=4
Full House: r2c7=6
Full House: r2c5=1
Naked Single: r1c5=2
Full House: r1c6=7
Naked Single: r4c6=6
Full House: r4c5=4
Naked Single: r6c5=5
Full House: r6c6=2
Naked Single: r7c6=9
Full House: r3c6=5
Full House: r3c5=9
Full House: r7c5=6
|
normal_sudoku_2215
|
871562943..91...5.5....9.81968....1.1536874292479.1.6..9...5.7....71............2
|
871562943639148257524379681968234715153687429247951368396825174482713596715496832
|
Basic 9x9 Sudoku 2215
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
8 7 1 5 6 2 9 4 3
. . 9 1 . . . 5 .
5 . . . . 9 . 8 1
9 6 8 . . . . 1 .
1 5 3 6 8 7 4 2 9
2 4 7 9 . 1 . 6 .
. 9 . . . 5 . 7 .
. . . 7 1 . . . .
. . . . . . . . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
871562943639148257524379681968234715153687429247951368396825174482713596715496832 #1 Unfair (986)
Naked Single: r5c3=3
Naked Single: r1c8=4
Naked Single: r5c7=4
Full House: r5c9=9
Naked Single: r6c3=7
Full House: r4c2=6
Naked Single: r3c8=8
Naked Single: r2c8=5
Hidden Single: r2c3=9
Hidden Single: r6c6=1
Naked Single: r1c6=2
Naked Single: r1c3=1
Full House: r1c2=7
Hidden Single: r2c4=1
Hidden Single: r9c5=9
Naked Single: r9c8=3
Full House: r8c8=9
Hidden Single: r9c2=1
Hidden Single: r7c7=1
Hidden Single: r9c1=7
Hidden Single: r2c6=8
Hidden Single: r8c2=8
Hidden Single: r8c3=2
Hidden Single: r9c3=5
Locked Candidates Type 1 (Pointing): 3 in b7 => r2c1<>3
Locked Candidates Type 2 (Claiming): 4 in r9 => r7c45,r8c6<>4
W-Wing: 3/4 in r3c4,r4c6 connected by 4 in r9c46 => r4c4<>3
XY-Chain: 8 8- r6c9 -5- r6c5 -3- r4c6 -4- r9c6 -6- r9c7 -8 => r6c7,r7c9<>8
Hidden Single: r6c9=8
Hidden Single: r9c7=8
Naked Single: r9c4=4
Full House: r9c6=6
Naked Single: r3c4=3
Naked Single: r4c4=2
Full House: r7c4=8
Naked Single: r8c6=3
Full House: r4c6=4
Full House: r7c5=2
Naked Single: r3c2=2
Full House: r2c2=3
Hidden Single: r7c1=3
Hidden Single: r2c7=2
Remote Pair: 6/4 r2c1 -4- r8c1 -6- r7c3 -4- r7c9 => r2c9<>6
Naked Single: r2c9=7
Full House: r3c7=6
Naked Single: r2c5=4
Full House: r2c1=6
Full House: r3c3=4
Full House: r3c5=7
Full House: r8c1=4
Full House: r7c3=6
Full House: r7c9=4
Naked Single: r4c9=5
Full House: r8c9=6
Full House: r8c7=5
Naked Single: r4c5=3
Full House: r4c7=7
Full House: r6c7=3
Full House: r6c5=5
|
normal_sudoku_3241
|
.7...98....8....9.95...8..6.894.1653.3..9..846..38591.89..1.36....8.31.9.1396..48
|
276549831348176592951238476789421653135697284624385917892714365467853129513962748
|
Basic 9x9 Sudoku 3241
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 7 . . . 9 8 . .
. . 8 . . . . 9 .
9 5 . . . 8 . . 6
. 8 9 4 . 1 6 5 3
. 3 . . 9 . . 8 4
6 . . 3 8 5 9 1 .
8 9 . . 1 . 3 6 .
. . . 8 . 3 1 . 9
. 1 3 9 6 . . 4 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
276549831348176592951238476789421653135697284624385917892714365467853129513962748 #1 Extreme (7362)
Hidden Single: r2c3=8
Hidden Single: r8c7=1
Hidden Single: r7c7=3
Hidden Single: r1c6=9
Hidden Single: r4c7=6
Hidden Single: r9c9=8
Hidden Single: r4c3=9
Hidden Single: r6c7=9
Hidden Single: r6c5=8
Hidden Single: r5c8=8
Hidden Single: r7c2=9
Hidden Single: r8c4=8
Finned Franken Swordfish: 2 r49b6 c167 fr4c5 fr6c9 => r6c6<>2
Grouped AIC: 7 7- r4c1 -2- r4c5 =2= r5c46 -2- r5c7 -7 => r5c13<>7
Sashimi Swordfish: 7 r459 c167 fr4c5 fr5c4 => r6c6<>7
Naked Single: r6c6=5
Naked Triple: 2,4,7 in r4c1,r6c23 => r5c123<>2
Naked Single: r5c2=3
Finned Franken Swordfish: 2 c28b6 r268 fr1c8 fr3c8 fr5c7 => r2c7<>2
Forcing Chain Contradiction in r9c1 => r8c5<>2
r8c5=2 r4c5<>2 r4c1=2 r9c1<>2
r8c5=2 r8c5<>5 r8c13=5 r9c1<>5
r8c5=2 r9c6<>2 r9c6=7 r9c1<>7
Forcing Chain Contradiction in r9c1 => r2c7<>7
r2c7=7 r3c8<>7 r8c8=7 r8c8<>2 r8c123=2 r9c1<>2
r2c7=7 r2c7<>5 r9c7=5 r9c1<>5
r2c7=7 r5c7<>7 r6c9=7 r6c3<>7 r4c1=7 r9c1<>7
Discontinuous Nice Loop: 2/7 r7c6 =4= r2c6 -4- r2c7 -5- r9c7 =5= r7c9 -5- r7c4 =5= r8c5 =4= r7c6 => r7c6<>2, r7c6<>7
Naked Single: r7c6=4
Finned Swordfish: 7 r267 c349 fr2c5 fr2c6 => r3c4<>7
Grouped Discontinuous Nice Loop: 7 r2c9 -7- r6c9 =7= r6c3 -7- r4c1 =7= r4c5 -7- r3c5 =7= r2c456 -7- r2c9 => r2c9<>7
Locked Candidates Type 1 (Pointing): 7 in b3 => r3c5<>7
W-Wing: 2/7 in r5c7,r8c8 connected by 7 in r3c78 => r9c7<>2
Skyscraper: 2 in r4c5,r9c6 (connected by r49c1) => r5c6<>2
Turbot Fish: 2 r3c7 =2= r5c7 -2- r5c4 =2= r4c5 => r3c5<>2
Discontinuous Nice Loop: 4 r2c1 -4- r2c7 =4= r3c7 -4- r3c5 -3- r2c5 =3= r2c1 => r2c1<>4
Almost Locked Set XZ-Rule: A=r49c1 {257}, B=r8c8,r9c7 {257}, X=5, Z=2 => r8c1<>2
Almost Locked Set Chain: 2- r2c245679 {1234567} -3- r3c3457 {12347} -7- r9c7 {57} -5- r49c1 {257} -2 => r2c1<>2
Sashimi Swordfish: 2 c156 r149 fr2c5 fr2c6 => r1c4<>2
Almost Locked Set Chain: 7- r4c1 {27} -2- r4c5 {27} -7- r5c46 {267} -2- r5c7 {27} -7- r9c7 {57} -5- r49c1 {257} -7 => r8c1<>7
Forcing Chain Contradiction in r9c1 => r1c8=3
r1c8<>3 r1c8=2 r8c8<>2 r8c23=2 r9c1<>2
r1c8<>3 r1c8=2 r8c8<>2 r8c8=7 r9c7<>7 r9c7=5 r9c1<>5
r1c8<>3 r1c8=2 r8c8<>2 r8c8=7 r7c9<>7 r6c9=7 r6c3<>7 r4c1=7 r9c1<>7
Hidden Single: r2c1=3
Hidden Single: r3c5=3
AIC: 4 4- r3c3 =4= r3c7 -4- r2c7 -5- r9c7 =5= r9c1 -5- r8c1 -4 => r1c1,r8c3<>4
Hidden Single: r8c1=4
Discontinuous Nice Loop: 1 r1c3 -1- r1c1 =1= r5c1 =5= r9c1 -5- r9c7 -7- r8c8 -2- r8c2 -6- r8c3 =6= r1c3 => r1c3<>1
Discontinuous Nice Loop: 4 r1c3 -4- r3c3 =4= r3c7 =7= r3c8 =2= r8c8 -2- r8c2 -6- r8c3 =6= r1c3 => r1c3<>4
Hidden Single: r1c5=4
Finned Swordfish: 2 c156 r249 fr1c1 => r2c2<>2
Turbot Fish: 2 r6c2 =2= r8c2 -2- r8c8 =2= r7c9 => r6c9<>2
Naked Single: r6c9=7
Full House: r5c7=2
Hidden Single: r4c1=7
Full House: r4c5=2
W-Wing: 6/2 in r1c3,r8c2 connected by 2 in r6c23 => r2c2,r8c3<>6
Naked Single: r2c2=4
Naked Single: r2c7=5
Naked Single: r6c2=2
Full House: r6c3=4
Full House: r8c2=6
Naked Single: r2c5=7
Full House: r8c5=5
Naked Single: r9c7=7
Full House: r3c7=4
Naked Single: r8c8=2
Full House: r3c8=7
Full House: r7c9=5
Full House: r8c3=7
Naked Single: r9c6=2
Full House: r7c4=7
Full House: r7c3=2
Full House: r9c1=5
Naked Single: r2c6=6
Full House: r5c6=7
Full House: r5c4=6
Naked Single: r1c3=6
Naked Single: r3c3=1
Full House: r1c1=2
Full House: r5c1=1
Full House: r3c4=2
Full House: r5c3=5
Naked Single: r1c9=1
Full House: r1c4=5
Full House: r2c4=1
Full House: r2c9=2
|
normal_sudoku_2697
|
59...37.2...4.75.9..7..5...7.1.3..2.34......7..87.4..3.83.7.2..17.5..3..62534..78
|
594863712236417589817295634761938425342156897958724163483679251179582346625341978
|
Basic 9x9 Sudoku 2697
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
5 9 . . . 3 7 . 2
. . . 4 . 7 5 . 9
. . 7 . . 5 . . .
7 . 1 . 3 . . 2 .
3 4 . . . . . . 7
. . 8 7 . 4 . . 3
. 8 3 . 7 . 2 . .
1 7 . 5 . . 3 . .
6 2 5 3 4 . . 7 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
594863712236417589817295634761938425342156897958724163483679251179582346625341978 #1 Extreme (2716)
Hidden Single: r5c1=3
Hidden Single: r3c3=7
Hidden Single: r9c4=3
Hidden Single: r7c7=2
Hidden Single: r7c5=7
Hidden Single: r9c8=7
Hidden Single: r5c9=7
Hidden Single: r9c3=5
Naked Single: r7c2=8
Hidden Single: r1c1=5
Locked Pair: 5,6 in r46c2 => r23c2,r5c3<>6
Naked Triple: 1,6,9 in r7c46,r9c6 => r8c56<>6, r8c56<>9
Locked Candidates Type 1 (Pointing): 6 in b8 => r7c89<>6
Skyscraper: 2 in r2c3,r3c4 (connected by r5c34) => r2c5,r3c1<>2
Naked Triple: 1,6,8 in r1c45,r2c5 => r3c45<>1, r3c45<>6, r3c45<>8
Locked Candidates Type 2 (Claiming): 6 in r3 => r12c8<>6
2-String Kite: 4 in r1c8,r7c1 (connected by r1c3,r3c1) => r7c8<>4
2-String Kite: 9 in r6c1,r8c8 (connected by r7c1,r8c3) => r6c8<>9
Empty Rectangle: 9 in b6 (r9c67) => r5c6<>9
W-Wing: 8/2 in r2c1,r8c5 connected by 2 in r6c15 => r2c5<>8
Locked Candidates Type 1 (Pointing): 8 in b2 => r1c8<>8
W-Wing: 9/2 in r3c5,r5c3 connected by 2 in r6c15 => r5c5<>9
Uniqueness Test 4: 1/3 in r2c28,r3c28 => r23c8<>1
Discontinuous Nice Loop: 1/2/6/8 r5c5 =5= r5c8 -5- r7c8 =5= r7c9 =4= r7c1 =9= r6c1 =2= r6c5 =5= r5c5 => r5c5<>1, r5c5<>2, r5c5<>6, r5c5<>8
Naked Single: r5c5=5
Discontinuous Nice Loop: 6/8/9 r4c7 =4= r4c9 =5= r7c9 =1= r3c9 -1- r1c8 -4- r3c7 =4= r4c7 => r4c7<>6, r4c7<>8, r4c7<>9
Naked Single: r4c7=4
Locked Candidates Type 1 (Pointing): 8 in b6 => r5c46<>8
Locked Candidates Type 2 (Claiming): 9 in r4 => r5c4,r6c5<>9
Hidden Single: r3c5=9
Naked Single: r3c4=2
Naked Pair: 5,6 in r4c29 => r4c46<>6
Hidden Rectangle: 1/6 in r5c46,r7c46 => r7c6<>1
AIC: 8 8- r3c1 -4- r7c1 -9- r7c4 =9= r4c4 =8= r4c6 -8- r8c6 -2- r8c5 =2= r6c5 -2- r6c1 =2= r2c1 =8= r2c8 -8 => r2c1,r3c78<>8
Naked Single: r2c1=2
Naked Single: r2c3=6
Naked Single: r6c1=9
Naked Single: r1c3=4
Naked Single: r2c5=1
Naked Single: r5c3=2
Full House: r8c3=9
Full House: r7c1=4
Full House: r3c1=8
Naked Single: r1c8=1
Naked Single: r2c2=3
Full House: r2c8=8
Full House: r3c2=1
Naked Single: r3c7=6
Naked Single: r3c9=4
Full House: r3c8=3
Naked Single: r6c7=1
Naked Single: r8c9=6
Naked Single: r9c7=9
Full House: r5c7=8
Full House: r9c6=1
Naked Single: r4c9=5
Full House: r7c9=1
Naked Single: r8c8=4
Full House: r7c8=5
Naked Single: r5c6=6
Naked Single: r4c2=6
Full House: r6c2=5
Naked Single: r6c8=6
Full House: r5c8=9
Full House: r5c4=1
Full House: r6c5=2
Naked Single: r7c6=9
Full House: r7c4=6
Naked Single: r8c5=8
Full House: r1c5=6
Full House: r1c4=8
Full House: r8c6=2
Full House: r4c6=8
Full House: r4c4=9
|
normal_sudoku_1187
|
....62...826.5.9..3458972612.46...39.93.4...5..8..94...3..247....2...3...879.....
|
179462583826153974345897261214675839793248615568319427631524798952781346487936152
|
Basic 9x9 Sudoku 1187
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . 6 2 . . .
8 2 6 . 5 . 9 . .
3 4 5 8 9 7 2 6 1
2 . 4 6 . . . 3 9
. 9 3 . 4 . . . 5
. . 8 . . 9 4 . .
. 3 . . 2 4 7 . .
. . 2 . . . 3 . .
. 8 7 9 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
179462583826153974345897261214675839793248615568319427631524798952781346487936152 #1 Unfair (1224)
Naked Single: r3c6=7
Naked Single: r2c7=9
Naked Single: r3c2=4
Naked Single: r3c7=2
Full House: r3c5=9
Hidden Single: r2c3=6
Hidden Single: r7c2=3
Hidden Single: r8c3=2
Hidden Single: r4c9=9
Hidden Single: r4c3=4
Hidden Single: r5c5=4
Hidden Single: r6c3=8
Locked Candidates Type 1 (Pointing): 1 in b1 => r1c4<>1
Locked Candidates Type 1 (Pointing): 7 in b1 => r1c89<>7
Locked Candidates Type 1 (Pointing): 8 in b8 => r8c89<>8
Skyscraper: 6 in r5c7,r7c9 (connected by r57c1) => r6c9,r9c7<>6
Hidden Single: r5c7=6
AIC: 1 1- r2c4 =1= r2c6 =3= r9c6 -3- r9c5 -1- r9c7 =1= r4c7 =8= r5c8 -8- r5c6 -1 => r2c6,r56c4<>1
Naked Single: r2c6=3
Naked Single: r1c4=4
Full House: r2c4=1
Naked Single: r7c4=5
Naked Single: r8c4=7
Naked Single: r5c4=2
Full House: r6c4=3
Hidden Single: r1c9=3
Hidden Single: r9c5=3
Hidden Single: r4c6=5
Hidden Single: r7c9=8
Hidden Single: r7c1=6
Hidden Single: r6c2=6
Hidden Single: r6c1=5
Hidden Single: r8c2=5
Turbot Fish: 1 r5c1 =1= r4c2 -1- r4c7 =1= r9c7 => r9c1<>1
Naked Single: r9c1=4
W-Wing: 8/1 in r4c7,r5c6 connected by 1 in r6c58 => r4c5,r5c8<>8
Hidden Single: r4c7=8
Naked Single: r1c7=5
Full House: r9c7=1
Naked Single: r1c8=8
Naked Single: r7c8=9
Full House: r7c3=1
Full House: r1c3=9
Full House: r8c1=9
Naked Single: r9c6=6
Naked Single: r8c8=4
Naked Single: r9c9=2
Full House: r9c8=5
Full House: r8c9=6
Naked Single: r2c8=7
Full House: r2c9=4
Full House: r6c9=7
Naked Single: r5c8=1
Full House: r6c8=2
Full House: r6c5=1
Naked Single: r5c1=7
Full House: r5c6=8
Full House: r4c5=7
Full House: r8c5=8
Full House: r1c1=1
Full House: r4c2=1
Full House: r8c6=1
Full House: r1c2=7
|
normal_sudoku_4871
|
..1.3.48..4....71.8..1....3.3..1...4......15.61...9...189345267.769825.125.671...
|
921736485345298716867154923532817694798463152614529378189345267476982531253671849
|
Basic 9x9 Sudoku 4871
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 1 . 3 . 4 8 .
. 4 . . . . 7 1 .
8 . . 1 . . . . 3
. 3 . . 1 . . . 4
. . . . . . 1 5 .
6 1 . . . 9 . . .
1 8 9 3 4 5 2 6 7
. 7 6 9 8 2 5 . 1
2 5 . 6 7 1 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
921736485345298716867154923532817694798463152614529378189345267476982531253671849 #1 Easy (324)
Naked Single: r7c5=4
Hidden Single: r6c2=1
Hidden Single: r7c2=8
Naked Single: r9c2=5
Hidden Single: r7c1=1
Naked Single: r7c4=3
Full House: r7c8=6
Naked Single: r8c6=2
Naked Single: r8c4=9
Naked Single: r9c5=7
Full House: r9c6=1
Hidden Single: r8c3=6
Hidden Single: r8c7=5
Hidden Single: r3c4=1
Hidden Single: r5c6=3
Hidden Single: r3c6=4
Hidden Single: r3c3=7
Hidden Single: r3c5=5
Naked Single: r6c5=2
Naked Single: r5c5=6
Full House: r2c5=9
Naked Single: r6c9=8
Naked Single: r6c7=3
Naked Single: r9c9=9
Naked Single: r6c8=7
Naked Single: r5c9=2
Naked Single: r9c7=8
Naked Single: r4c8=9
Full House: r4c7=6
Full House: r3c7=9
Naked Single: r5c2=9
Naked Single: r3c8=2
Full House: r3c2=6
Full House: r1c2=2
Naked Single: r1c4=7
Naked Single: r1c6=6
Naked Single: r1c9=5
Full House: r1c1=9
Full House: r2c9=6
Naked Single: r2c6=8
Full House: r2c4=2
Full House: r4c6=7
Naked Single: r4c1=5
Naked Single: r2c1=3
Full House: r2c3=5
Naked Single: r4c4=8
Full House: r4c3=2
Naked Single: r6c3=4
Full House: r6c4=5
Full House: r5c4=4
Naked Single: r8c1=4
Full House: r5c1=7
Full House: r5c3=8
Full House: r9c3=3
Full House: r8c8=3
Full House: r9c8=4
|
normal_sudoku_1164
|
......24.32.1648.9.48..2..6.89.....25.279.3...34..6.9.896......2715.....453689127
|
615978243327164859948352716189435672562791384734826591896217435271543968453689127
|
Basic 9x9 Sudoku 1164
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . . . 2 4 .
3 2 . 1 6 4 8 . 9
. 4 8 . . 2 . . 6
. 8 9 . . . . . 2
5 . 2 7 9 . 3 . .
. 3 4 . . 6 . 9 .
8 9 6 . . . . . .
2 7 1 5 . . . . .
4 5 3 6 8 9 1 2 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
615978243327164859948352716189435672562791384734826591896217435271543968453689127 #1 Easy (322)
Naked Single: r7c3=6
Naked Single: r9c9=7
Full House: r9c8=2
Hidden Single: r6c3=4
Hidden Single: r6c2=3
Hidden Single: r5c5=9
Hidden Single: r2c2=2
Naked Single: r7c2=9
Full House: r8c1=2
Hidden Single: r1c7=2
Hidden Single: r2c5=6
Hidden Single: r2c9=9
Hidden Single: r2c6=4
Naked Single: r8c6=3
Naked Single: r8c5=4
Naked Single: r7c4=2
Naked Single: r8c9=8
Naked Single: r6c4=8
Naked Single: r8c8=6
Full House: r8c7=9
Naked Single: r5c6=1
Naked Single: r4c6=5
Naked Single: r5c2=6
Full House: r1c2=1
Naked Single: r5c8=8
Full House: r5c9=4
Naked Single: r7c6=7
Full House: r1c6=8
Full House: r7c5=1
Naked Single: r4c5=3
Naked Single: r6c5=2
Full House: r4c4=4
Hidden Single: r4c7=6
Hidden Single: r1c1=6
Hidden Single: r6c9=1
Naked Single: r4c8=7
Full House: r4c1=1
Full House: r6c1=7
Full House: r6c7=5
Full House: r3c1=9
Naked Single: r2c8=5
Full House: r2c3=7
Full House: r1c3=5
Naked Single: r3c7=7
Full House: r7c7=4
Naked Single: r3c4=3
Full House: r1c4=9
Naked Single: r1c9=3
Full House: r1c5=7
Full House: r3c5=5
Full House: r3c8=1
Full House: r7c8=3
Full House: r7c9=5
|
normal_sudoku_4940
|
3..78.6.25672.384.2.86...73...17..387..9.8.6.8....67...7....48..82.6.3.74.38.7.26
|
394785612567213849218649573645172938731958264829436751976321485182564397453897126
|
Basic 9x9 Sudoku 4940
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
3 . . 7 8 . 6 . 2
5 6 7 2 . 3 8 4 .
2 . 8 6 . . . 7 3
. . . 1 7 . . 3 8
7 . . 9 . 8 . 6 .
8 . . . . 6 7 . .
. 7 . . . . 4 8 .
. 8 2 . 6 . 3 . 7
4 . 3 8 . 7 . 2 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
394785612567213849218649573645172938731958264829436751976321485182564397453897126 #1 Extreme (3072)
Hidden Single: r3c3=8
Hidden Single: r6c1=8
Hidden Single: r3c4=6
Hidden Single: r4c5=7
Hidden Single: r8c9=7
Hidden Single: r1c4=7
Hidden Single: r9c4=8
Hidden Single: r5c6=8
Hidden Single: r1c9=2
Hidden Single: r9c9=6
Hidden Single: r5c8=6
Hidden Single: r1c1=3
Hidden Single: r2c3=7
Hidden Single: r7c2=7
Hidden Single: r3c9=3
Locked Candidates Type 2 (Claiming): 1 in c1 => r7c3,r9c2<>1
Skyscraper: 1 in r2c9,r9c7 (connected by r29c5) => r3c7,r7c9<>1
Hidden Rectangle: 6/9 in r4c13,r7c13 => r7c3<>9
Finned X-Wing: 5 r18 c68 fr8c4 => r7c6<>5
Discontinuous Nice Loop: 9 r1c6 -9- r2c5 -1- r2c9 =1= r1c8 =5= r1c6 => r1c6<>9
Discontinuous Nice Loop: 5 r9c7 -5- r9c2 -9- r8c1 -1- r8c8 =1= r9c7 => r9c7<>5
Grouped Discontinuous Nice Loop: 5 r6c2 -5- r6c4 =5= r78c4 -5- r9c5 =5= r9c2 -5- r6c2 => r6c2<>5
Almost Locked Set XY-Wing: A=r7c1349 {13569}, B=r29c5 {159}, C=r8c1,r9c2 {159}, X,Y=1,5, Z=9 => r7c5<>9
Forcing Chain Contradiction in r9c5 => r1c6=5
r1c6<>5 r1c8=5 r3c7<>5 r3c7=9 r9c7<>9 r9c7=1 r9c5<>1
r1c6<>5 r1c8=5 r8c8<>5 r8c46=5 r9c5<>5
r1c6<>5 r1c8=5 r1c8<>1 r2c9=1 r2c9<>9 r2c5=9 r9c5<>9
Hidden Single: r3c7=5
Locked Candidates Type 1 (Pointing): 4 in b2 => r3c2<>4
Locked Candidates Type 2 (Claiming): 5 in r4 => r5c23,r6c3<>5
Naked Triple: 1,4,9 in r156c3 => r4c3<>4, r4c3<>9
Turbot Fish: 9 r2c9 =9= r1c8 -9- r1c3 =9= r6c3 => r6c9<>9
Empty Rectangle: 9 in b7 (r49c7) => r4c1<>9
Naked Single: r4c1=6
Naked Single: r4c3=5
Naked Single: r7c3=6
Hidden Single: r9c2=5
Naked Pair: 1,9 in r29c5 => r37c5<>1, r3c5<>9
Naked Single: r3c5=4
Remote Pair: 9/1 r2c9 -1- r2c5 -9- r9c5 -1- r9c7 => r7c9<>9
Naked Single: r7c9=5
Naked Single: r7c4=3
Naked Single: r7c5=2
Hidden Single: r2c9=9
Full House: r1c8=1
Full House: r2c5=1
Full House: r3c6=9
Full House: r3c2=1
Naked Single: r8c8=9
Full House: r6c8=5
Full House: r9c7=1
Full House: r9c5=9
Naked Single: r7c6=1
Full House: r7c1=9
Full House: r8c1=1
Naked Single: r6c4=4
Full House: r8c4=5
Full House: r8c6=4
Full House: r4c6=2
Naked Single: r6c5=3
Full House: r5c5=5
Naked Single: r5c7=2
Full House: r4c7=9
Full House: r4c2=4
Naked Single: r6c9=1
Full House: r5c9=4
Naked Single: r1c2=9
Full House: r1c3=4
Naked Single: r5c2=3
Full House: r5c3=1
Full House: r6c3=9
Full House: r6c2=2
|
normal_sudoku_2937
|
.2..8....8.1....476....42..98..4.7....39....617...5.2..1.3....4.69...5..7....6..2
|
427689153891532647635714298986243715253971486174865329512397864369428571748156932
|
Basic 9x9 Sudoku 2937
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 2 . . 8 . . . .
8 . 1 . . . . 4 7
6 . . . . 4 2 . .
9 8 . . 4 . 7 . .
. . 3 9 . . . . 6
1 7 . . . 5 . 2 .
. 1 . 3 . . . . 4
. 6 9 . . . 5 . .
7 . . . . 6 . . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
427689153891532647635714298986243715253971486174865329512397864369428571748156932 #1 Extreme (10532)
Hidden Single: r4c1=9
Hidden Single: r8c2=6
Discontinuous Nice Loop: 8 r8c4 -8- r6c4 -6- r6c3 -4- r1c3 =4= r1c1 -4- r8c1 =4= r8c4 => r8c4<>8
Grouped Discontinuous Nice Loop: 7 r3c5 -7- r3c3 =7= r1c3 =4= r1c1 -4- r8c1 =4= r8c4 =7= r13c4 -7- r3c5 => r3c5<>7
Forcing Chain Contradiction in c3 => r6c7<>8
r6c7=8 r2c7<>8 r2c1=8 r3c3<>8
r6c7=8 r6c7<>4 r6c3=4 r6c3<>6 r4c3=6 r4c3<>2 r7c3=2 r7c3<>8
r6c7=8 r6c4<>8 r9c4=8 r9c3<>8
Forcing Chain Contradiction in c9 => r8c1<>8
r8c1=8 r2c1<>8 r2c7=8 r3c9<>8
r8c1=8 r8c1<>3 r9c2=3 r9c2<>4 r5c2=4 r5c7<>4 r6c7=4 r6c7<>9 r6c9=9 r6c9<>8
r8c1=8 r8c9<>8
Forcing Net Contradiction in r3 => r6c4=8
r6c4<>8 (r6c4=6 r6c3<>6 r6c3=4 r1c3<>4) (r6c4=6 r6c3<>6 r6c3=4 r9c3<>4) r9c4=8 r9c3<>8 r9c3=5 r1c3<>5 r1c3=7 r3c3<>7 r3c4=7 r3c4<>1
r6c4<>8 (r9c4=8 r9c4<>1) (r6c9=8 r8c9<>8) r6c4=6 (r6c3<>6 r6c3=4 r5c2<>4 r5c2=5 r5c8<>5 r5c8=1 r9c8<>1) (r6c3<>6 r6c3=4 r1c3<>4 r1c1=4 r8c1<>4) r4c4<>6 r4c3=6 r4c3<>2 r7c3=2 r8c1<>2 r8c1=3 r8c9<>3 r8c9=1 r9c7<>1 r9c5=1 r3c5<>1
r6c4<>8 (r6c9=8 r5c8<>8) r6c4=6 r6c3<>6 r6c3=4 r5c2<>4 r5c2=5 r5c8<>5 r5c8=1 r3c8<>1
r6c4<>8 (r6c9=8 r8c9<>8) r6c4=6 (r6c3<>6 r6c3=4 r1c3<>4 r1c1=4 r8c1<>4) r4c4<>6 r4c3=6 r4c3<>2 r7c3=2 r8c1<>2 r8c1=3 r8c9<>3 r8c9=1 r3c9<>1
Finned Swordfish: 8 r259 c178 fr9c3 => r7c1<>8
Hidden Single: r2c1=8
Discontinuous Nice Loop: 9 r3c9 -9- r6c9 =9= r6c7 =4= r5c7 =8= r5c8 -8- r3c8 =8= r3c9 => r3c9<>9
Almost Locked Set XZ-Rule: A=r4c689 {1235}, B=r5c56 {127}, X=2, Z=1 => r4c4<>1
Almost Locked Set Chain: 2- r157c1 {2345} -3- r23c2 {359} -5- r13c3 {457} -4- r7c13,r9c3 {2458} -2 => r8c1<>2
Locked Candidates Type 1 (Pointing): 2 in b7 => r7c56<>2
Forcing Chain Verity => r2c5<>2
r8c4=2 r4c4<>2 r4c4=6 r6c5<>6 r2c5=6 r2c5<>2
r8c5=2 r2c5<>2
r8c6=2 r8c6<>8 r8c89=8 r79c7<>8 r5c7=8 r5c7<>4 r6c7=4 r6c3<>4 r6c3=6 r6c5<>6 r2c5=6 r2c5<>2
Forcing Chain Contradiction in r9c2 => r3c5<>5
r3c5=5 r123c4<>5 r9c4=5 r9c4<>4 r8c4=4 r8c1<>4 r8c1=3 r9c2<>3
r3c5=5 r2c45<>5 r2c2=5 r5c2<>5 r5c2=4 r9c2<>4
r3c5=5 r7c5<>5 r7c13=5 r9c2<>5
Forcing Chain Contradiction in r3c5 => r3c9<>1
r3c9=1 r3c5<>1
r3c9=1 r3c9<>8 r3c8=8 r5c8<>8 r5c7=8 r5c7<>4 r6c7=4 r6c3<>4 r6c3=6 r6c5<>6 r6c5=3 r3c5<>3
r3c9=1 r3c9<>8 r8c9=8 r8c6<>8 r7c6=8 r7c6<>9 r79c5=9 r3c5<>9
Forcing Chain Contradiction in c6 => r8c4<>2
r8c4=2 r8c4<>4 r8c1=4 r8c1<>3 r1c1=3 r1c6<>3
r8c4=2 r2c4<>2 r2c6=2 r2c6<>3
r8c4=2 r4c4<>2 r4c4=6 r6c5<>6 r6c5=3 r4c6<>3
Forcing Chain Contradiction in r2 => r1c1<>5
r1c1=5 r2c2<>5
r1c1=5 r7c1<>5 r7c1=2 r7c3<>2 r4c3=2 r4c4<>2 r2c4=2 r2c4<>5
r1c1=5 r1c1<>4 r1c3=4 r6c3<>4 r6c3=6 r6c5<>6 r2c5=6 r2c5<>5
Naked Pair: 3,4 in r18c1 => r5c1<>4
Forcing Chain Contradiction in r2 => r3c2<>5
r3c2=5 r2c2<>5
r3c2=5 r5c2<>5 r5c2=4 r6c3<>4 r6c3=6 r6c5<>6 r4c4=6 r4c4<>2 r2c4=2 r2c4<>5
r3c2=5 r5c2<>5 r5c2=4 r6c3<>4 r6c3=6 r6c5<>6 r2c5=6 r2c5<>5
Forcing Chain Contradiction in r3c5 => r8c5<>1
r8c5=1 r3c5<>1
r8c5=1 r8c5<>2 r5c5=2 r4c4<>2 r4c4=6 r6c5<>6 r6c5=3 r3c5<>3
r8c5=1 r8c5<>2 r8c6=2 r8c6<>8 r7c6=8 r7c6<>9 r79c5=9 r3c5<>9
Forcing Chain Contradiction in r3c5 => r8c6<>1
r8c6=1 r89c4<>1 r13c4=1 r3c5<>1
r8c6=1 r8c6<>8 r8c89=8 r79c7<>8 r5c7=8 r5c7<>4 r5c2=4 r6c3<>4 r6c3=6 r6c5<>6 r6c5=3 r3c5<>3
r8c6=1 r8c6<>8 r7c6=8 r7c6<>9 r79c5=9 r3c5<>9
Forcing Chain Contradiction in r2 => r9c2<>5
r9c2=5 r2c2<>5
r9c2=5 r7c1<>5 r7c1=2 r7c3<>2 r4c3=2 r4c4<>2 r2c4=2 r2c4<>5
r9c2=5 r9c4<>5 r123c4=5 r2c5<>5
Naked Pair: 3,4 in r8c1,r9c2 => r9c3<>4
Discontinuous Nice Loop: 3 r1c6 -3- r1c1 -4- r1c3 =4= r6c3 =6= r6c5 =3= r4c6 -3- r1c6 => r1c6<>3
Continuous Nice Loop: 9 3= r2c6 =2= r2c4 -2- r4c4 -6- r6c5 -3- r4c6 =3= r2c6 =2 => r2c6<>9
Grouped Discontinuous Nice Loop: 3 r2c7 -3- r2c6 =3= r4c6 -3- r6c5 -6- r6c3 -4- r1c3 =4= r1c1 =3= r1c789 -3- r2c7 => r2c7<>3
Grouped Discontinuous Nice Loop: 7 r1c6 -7- r13c4 =7= r8c4 -7- r8c8 =7= r7c8 =6= r7c7 -6- r2c7 -9- r1c789 =9= r1c6 => r1c6<>7
Locked Candidates Type 1 (Pointing): 7 in b2 => r8c4<>7
Hidden Rectangle: 5/7 in r1c34,r3c34 => r1c4<>5
Grouped Discontinuous Nice Loop: 5 r3c9 -5- r3c4 =5= r2c45 -5- r2c2 =5= r5c2 =4= r5c7 =8= r5c8 -8- r3c8 =8= r3c9 => r3c9<>5
Forcing Chain Verity => r1c1=4
r1c7=3 r1c1<>3 r1c1=4
r6c7=3 r6c7<>4 r6c3=4 r1c3<>4 r1c1=4
r9c7=3 r9c2<>3 r9c2=4 r8c1<>4 r1c1=4
Naked Single: r8c1=3
Naked Single: r9c2=4
Naked Single: r5c2=5
Naked Single: r5c1=2
Full House: r7c1=5
Naked Single: r4c3=6
Full House: r6c3=4
Naked Single: r9c3=8
Full House: r7c3=2
Naked Single: r4c4=2
Hidden Single: r8c4=4
Hidden Single: r5c7=4
Hidden Single: r8c5=2
Hidden Single: r6c5=6
Hidden Single: r2c6=2
Hidden Single: r5c8=8
Hidden Single: r7c7=8
Naked Single: r8c9=1
Naked Single: r8c8=7
Full House: r8c6=8
Hidden Single: r4c6=3
Naked Single: r4c9=5
Full House: r4c8=1
Hidden Single: r3c9=8
Hidden Single: r7c8=6
Hidden Single: r1c7=1
Naked Single: r1c6=9
Naked Single: r1c9=3
Full House: r6c9=9
Full House: r6c7=3
Naked Single: r7c6=7
Full House: r5c6=1
Full House: r7c5=9
Full House: r5c5=7
Naked Single: r1c8=5
Naked Single: r9c7=9
Full House: r2c7=6
Full House: r3c8=9
Full House: r9c8=3
Naked Single: r1c3=7
Full House: r1c4=6
Full House: r3c3=5
Naked Single: r2c4=5
Naked Single: r3c2=3
Full House: r2c2=9
Full House: r2c5=3
Naked Single: r9c4=1
Full House: r3c4=7
Full House: r3c5=1
Full House: r9c5=5
|
normal_sudoku_5252
|
.....31..3..1..62..5..6...3..5....48.9.8.....2...45..15....2.76....7.51.647..1..2
|
976523184384197625152468793765219348491836257238745961519382476823674519647951832
|
Basic 9x9 Sudoku 5252
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . . 3 1 . .
3 . . 1 . . 6 2 .
. 5 . . 6 . . . 3
. . 5 . . . . 4 8
. 9 . 8 . . . . .
2 . . . 4 5 . . 1
5 . . . . 2 . 7 6
. . . . 7 . 5 1 .
6 4 7 . . 1 . . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
976523184384197625152468793765219348491836257238745961519382476823674519647951832 #1 Extreme (9292)
Hidden Single: r4c3=5
Hidden Single: r8c8=1
Grouped Discontinuous Nice Loop: 8 r1c5 -8- r2c56 =8= r2c23 -8- r13c1 =8= r8c1 -8- r8c6 =8= r79c5 -8- r1c5 => r1c5<>8
Grouped Discontinuous Nice Loop: 8 r7c2 -8- r8c123 =8= r8c6 -8- r79c5 =8= r2c5 =5= r2c9 -5- r5c9 -7- r5c6 -6- r4c46 =6= r4c2 =1= r7c2 => r7c2<>8
Almost Locked Set XZ-Rule: A=r134678c4 {2345679}, B=r139c8 {3589}, X=5, Z=3 => r9c4<>3
Almost Locked Set XY-Wing: A=r8c1469 {34689}, B=r124679c2 {1234678}, C=r1279c5 {23589}, X,Y=2,3, Z=4,8 => r8c2<>4, r8c2<>8
Forcing Chain Contradiction in r9 => r7c2<>4
r7c2=4 r9c2<>4
r7c2=4 r7c2<>1 r4c2=1 r4c2<>6 r4c46=6 r5c6<>6 r5c6=7 r5c9<>7 r5c9=5 r5c8<>5 r1c8=5 r1c4<>5 r9c4=5 r9c4<>4
r7c2=4 r7c2<>1 r7c3=1 r7c3<>9 r8c13=9 r8c9<>9 r8c9=4 r9c7<>4
Forcing Chain Contradiction in r9 => r7c3<>4
r7c3=4 r9c2<>4
r7c3=4 r7c3<>9 r8c13=9 r8c9<>9 r8c9=4 r79c7<>4 r3c7=4 r3c7<>7 r456c7=7 r5c9<>7 r5c9=5 r5c8<>5 r1c8=5 r1c4<>5 r9c4=5 r9c4<>4
r7c3=4 r7c3<>9 r8c13=9 r8c9<>9 r8c9=4 r9c7<>4
Grouped Discontinuous Nice Loop: 9 r7c4 -9- r7c3 =9= r8c13 -9- r8c9 -4- r7c7 =4= r7c4 => r7c4<>9
Forcing Chain Contradiction in r7c7 => r7c3<>8
r7c3=8 r7c3<>9 r8c13=9 r8c9<>9 r8c9=4 r79c7<>4 r3c7=4 r3c7<>7 r456c7=7 r5c9<>7 r5c9=5 r2c9<>5 r2c5=5 r2c5<>8 r79c5=8 r8c6<>8 r8c13=8 r7c3<>8
Forcing Chain Contradiction in r2c3 => r2c5<>8
r2c5=8 r79c5<>8 r8c6=8 r8c13<>8 r9c2=8 r9c2<>4 r12c2=4 r2c3<>4
r2c5=8 r2c3<>8
r2c5=8 r79c5<>8 r8c6=8 r8c13<>8 r9c2=8 r9c2<>4 r8c13=4 r8c9<>4 r8c9=9 r8c1<>9 r13c1=9 r2c3<>9
Locked Candidates Type 1 (Pointing): 8 in b2 => r8c6<>8
Locked Candidates Type 2 (Claiming): 8 in r8 => r9c2<>8
Grouped Discontinuous Nice Loop: 4 r9c4 -4- r9c2 -3- r8c23 =3= r8c4 -3- r7c4 -4- r9c4 => r9c4<>4
Almost Locked Set XY-Wing: A=r3c4678 {24789}, B=r8c1469 {34689}, C=r1279c5 {23589}, X,Y=2,3, Z=8 => r3c1<>8
Almost Locked Set XY-Wing: A=r1c45,r2c5,r3c4 {24579}, B=r45c6,r6c4 {3679}, C=r7c4 {34}, X,Y=3,4, Z=7 => r4c4<>7
Forcing Chain Contradiction in c6 => r7c2=1
r7c2<>1 r7c3=1 r7c3<>9 r8c13=9 r8c9<>9 r12c9=9 r3c8<>9 r3c8=8 r3c6<>8 r2c6=8 r2c6<>4
r7c2<>1 r7c3=1 r7c3<>9 r8c13=9 r8c9<>9 r8c9=4 r79c7<>4 r3c7=4 r3c6<>4
r7c2<>1 r7c2=3 r7c4<>3 r7c4=4 r8c6<>4
Almost Locked Set XY-Wing: A=r4c12467 {123679}, B=r12c5 {259}, C=r3c14678 {124789}, X,Y=1,2, Z=9 => r4c5<>9
Almost Locked Set XY-Wing: A=r4c12467 {123679}, B=r1279c5 {23589}, C=r3c14678 {124789}, X,Y=1,2, Z=3 => r4c5<>3
Almost Locked Set Chain: 4- r8c469 {3469} -3- r1279c5 {23589} -2- r1c123,r2c23,r3c1 {1246789} -1- r4c12,r5c1,r6c23 {134678} -4 => r8c1<>4
Finned Franken Swordfish: 3 r48b9 c247 fr8c3 fr9c8 => r9c2<>3
Naked Single: r9c2=4
Grouped AIC: 7 7- r2c2 -8- r2c6 =8= r3c6 -8- r3c8 -9- r12c9 =9= r8c9 =4= r7c7 -4- r7c4 -3- r46c4 =3= r5c5 =1= r4c5 -1- r4c1 -7 => r13c1,r46c2<>7
Naked Triple: 3,6,8 in r46c2,r6c3 => r5c3<>3, r5c3<>6
Finned X-Wing: 7 r36 c47 fr3c6 => r1c4<>7
Discontinuous Nice Loop: 2 r1c3 -2- r3c3 =2= r3c4 =7= r6c4 -7- r5c6 -6- r5c8 =6= r6c8 -6- r6c3 =6= r1c3 => r1c3<>2
Discontinuous Nice Loop: 9 r1c8 -9- r3c8 -8- r3c6 =8= r2c6 -8- r2c2 -7- r1c2 =7= r1c9 -7- r5c9 -5- r5c8 =5= r1c8 => r1c8<>9
Discontinuous Nice Loop: 9 r1c9 -9- r3c8 -8- r3c6 =8= r2c6 -8- r2c2 -7- r1c2 =7= r1c9 => r1c9<>9
Empty Rectangle: 9 in b7 (r28c9) => r2c3<>9
Discontinuous Nice Loop: 9 r3c1 -9- r3c8 -8- r3c6 =8= r2c6 -8- r2c3 -4- r5c3 -1- r3c3 =1= r3c1 => r3c1<>9
Naked Triple: 1,4,7 in r345c1 => r1c1<>4
Finned Swordfish: 9 c159 r128 fr7c5 fr9c5 => r8c46<>9
Naked Triple: 3,4,6 in r78c4,r8c6 => r79c5<>3
Hidden Single: r5c5=3
Hidden Single: r4c5=1
Naked Single: r4c1=7
Hidden Single: r5c7=2
Hidden Single: r1c5=2
Hidden Single: r4c4=2
Hidden Single: r8c2=2
Hidden Single: r3c3=2
Hidden Single: r3c1=1
Naked Single: r5c1=4
Naked Single: r5c3=1
Locked Candidates Type 1 (Pointing): 9 in b1 => r1c4<>9
Locked Candidates Type 1 (Pointing): 3 in b7 => r6c3<>3
Locked Candidates Type 2 (Claiming): 3 in r9 => r7c7<>3
X-Wing: 7 c47 r36 => r3c6<>7
Finned X-Wing: 4 r37 c47 fr3c6 => r1c4<>4
Naked Single: r1c4=5
Naked Single: r1c8=8
Naked Single: r2c5=9
Naked Single: r9c4=9
Naked Single: r1c1=9
Full House: r8c1=8
Naked Single: r3c8=9
Naked Single: r7c5=8
Full House: r9c5=5
Naked Single: r9c8=3
Full House: r9c7=8
Naked Single: r6c8=6
Full House: r5c8=5
Naked Single: r6c3=8
Naked Single: r6c4=7
Naked Single: r5c9=7
Full House: r5c6=6
Full House: r4c6=9
Naked Single: r2c3=4
Naked Single: r6c2=3
Full House: r4c2=6
Full House: r4c7=3
Full House: r6c7=9
Naked Single: r3c4=4
Naked Single: r1c9=4
Naked Single: r8c6=4
Naked Single: r1c3=6
Full House: r1c2=7
Full House: r2c2=8
Naked Single: r2c9=5
Full House: r3c7=7
Full House: r7c7=4
Full House: r3c6=8
Full House: r8c9=9
Full House: r2c6=7
Naked Single: r7c4=3
Full House: r7c3=9
Full House: r8c3=3
Full House: r8c4=6
|
normal_sudoku_6160
|
..1.9...39.3.8...586.2...9...2...31.1...2..5..8.9....2219..45.6..8.529.175...923.
|
421596783973481625865273194592648317146327859387915462219834576638752941754169238
|
Basic 9x9 Sudoku 6160
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 1 . 9 . . . 3
9 . 3 . 8 . . . 5
8 6 . 2 . . . 9 .
. . 2 . . . 3 1 .
1 . . . 2 . . 5 .
. 8 . 9 . . . . 2
2 1 9 . . 4 5 . 6
. . 8 . 5 2 9 . 1
7 5 . . . 9 2 3 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
421596783973481625865273194592648317146327859387915462219834576638752941754169238 #1 Extreme (4078)
Naked Single: r7c3=9
Hidden Single: r7c7=5
Hidden Single: r7c1=2
Hidden Single: r8c7=9
Hidden Single: r3c4=2
Hidden Single: r6c4=9
Locked Candidates Type 1 (Pointing): 3 in b7 => r8c4<>3
Locked Candidates Type 1 (Pointing): 8 in b8 => r45c4<>8
Locked Candidates Type 1 (Pointing): 7 in b9 => r126c8<>7
W-Wing: 6/4 in r6c8,r9c3 connected by 4 in r8c8,r9c9 => r6c3<>6
2-String Kite: 6 in r5c3,r8c4 (connected by r8c1,r9c3) => r5c4<>6
Sashimi X-Wing: 6 c35 r59 fr4c5 fr6c5 => r5c6<>6
W-Wing: 4/6 in r6c8,r9c3 connected by 6 in r5c37 => r6c3<>4
AIC: 4 4- r6c8 -6- r5c7 =6= r5c3 -6- r9c3 -4- r9c9 =4= r8c8 -4 => r12c8<>4
AIC: 1/3 3- r3c6 =3= r3c5 -3- r7c5 -7- r8c4 -6- r9c5 -1- r6c5 =1= r6c6 -1 => r3c6<>1, r6c6<>3
Discontinuous Nice Loop: 7 r2c4 -7- r8c4 -6- r9c5 -1- r9c4 =1= r2c4 => r2c4<>7
Discontinuous Nice Loop: 8 r3c7 -8- r1c8 =8= r7c8 -8- r7c4 =8= r9c4 =1= r9c5 -1- r3c5 =1= r3c7 => r3c7<>8
Continuous Nice Loop: 4/7/8 8= r5c7 =6= r5c3 -6- r9c3 -4- r9c9 -8- r7c8 =8= r1c8 -8- r1c7 =8= r5c7 =6 => r5c7<>4, r5c7<>7, r1c1,r3c9<>8
Hidden Single: r3c1=8
Sue de Coq: r12c7 - {14678} (r5c7 - {68}, r3c79 - {147}) => r6c7<>6
Continuous Nice Loop: 3/4/7 5= r3c6 =3= r3c5 -3- r7c5 -7- r7c8 =7= r8c8 =4= r6c8 -4- r6c7 -7- r6c3 -5- r3c3 =5= r3c6 =3 => r6c5<>3, r45c9,r6c15<>4, r36c6,r6c5,r7c4<>7
Hidden Single: r6c1=3
Hidden Single: r8c2=3
Naked Pair: 1,6 in r69c5 => r3c5<>1, r4c5<>6
Hidden Single: r3c7=1
X-Wing: 5 r36 c36 => r14c6<>5
Empty Rectangle: 7 in b3 (r6c37) => r3c3<>7
Locked Candidates Type 1 (Pointing): 7 in b1 => r45c2<>7
Locked Pair: 4,9 in r45c2 => r12c2,r4c1,r5c3<>4
X-Wing: 4 c39 r39 => r3c5<>4
Hidden Single: r4c5=4
Naked Single: r4c2=9
Naked Single: r5c2=4
Hidden Single: r5c9=9
W-Wing: 6/7 in r1c6,r8c4 connected by 7 in r37c5 => r12c4<>6
Locked Candidates Type 1 (Pointing): 6 in b2 => r46c6<>6
Naked Pair: 7,8 in r4c69 => r4c4<>7
X-Wing: 6 r48 c14 => r9c4<>6
Skyscraper: 7 in r3c5,r4c6 (connected by r34c9) => r12c6<>7
Naked Single: r1c6=6
Naked Single: r2c6=1
Naked Single: r2c4=4
Naked Single: r6c6=5
Naked Single: r3c6=3
Naked Single: r4c4=6
Naked Single: r6c3=7
Naked Single: r3c5=7
Full House: r1c4=5
Naked Single: r4c1=5
Full House: r5c3=6
Naked Single: r6c5=1
Naked Single: r8c4=7
Naked Single: r6c7=4
Full House: r6c8=6
Naked Single: r3c9=4
Full House: r3c3=5
Full House: r9c3=4
Full House: r8c1=6
Full House: r1c1=4
Full House: r8c8=4
Naked Single: r7c5=3
Full House: r9c5=6
Naked Single: r5c7=8
Full House: r4c9=7
Full House: r9c9=8
Full House: r4c6=8
Full House: r5c6=7
Full House: r5c4=3
Full House: r7c8=7
Full House: r7c4=8
Full House: r9c4=1
Naked Single: r2c8=2
Full House: r1c8=8
Naked Single: r1c7=7
Full House: r1c2=2
Full House: r2c2=7
Full House: r2c7=6
|
normal_sudoku_2449
|
.2...378556.872.198..5.126.43...5...758..96..61.7......4.2.6...386...1..2.5.1..46
|
921643785564872319873591264432165978758429631619738452147286593386954127295317846
|
Basic 9x9 Sudoku 2449
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 2 . . . 3 7 8 5
5 6 . 8 7 2 . 1 9
8 . . 5 . 1 2 6 .
4 3 . . . 5 . . .
7 5 8 . . 9 6 . .
6 1 . 7 . . . . .
. 4 . 2 . 6 . . .
3 8 6 . . . 1 . .
2 . 5 . 1 . . 4 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
921643785564872319873591264432165978758429631619738452147286593386954127295317846 #1 Extreme (3008)
Hidden Single: r3c1=8
Hidden Single: r3c6=1
Hidden Single: r2c8=1
Naked Single: r2c1=5
Naked Single: r2c2=6
Naked Single: r5c1=7
Hidden Single: r5c2=5
Hidden Single: r8c3=6
Hidden Single: r9c9=6
Hidden Single: r1c2=2
Hidden Single: r3c8=6
Locked Candidates Type 1 (Pointing): 9 in b4 => r137c3<>9
2-String Kite: 9 in r3c5,r7c1 (connected by r1c1,r3c2) => r7c5<>9
Discontinuous Nice Loop: 2 r4c9 -2- r4c3 -9- r4c7 -8- r9c7 =8= r9c6 =7= r8c6 -7- r8c9 -2- r4c9 => r4c9<>2
Discontinuous Nice Loop: 9 r7c7 -9- r7c1 =9= r9c2 =7= r9c6 =8= r9c7 -8- r4c7 -9- r7c7 => r7c7<>9
Discontinuous Nice Loop: 4 r8c5 -4- r8c6 -7- r9c6 =7= r9c2 =9= r3c2 -9- r3c5 -4- r8c5 => r8c5<>4
Grouped AIC: 7/9 7- r4c8 =7= r4c9 =1= r5c9 =4= r5c45 -4- r6c6 -8- r9c6 -7- r9c2 -9- r7c1 =9= r7c8 -9 => r7c8<>7, r4c8<>9
Hidden Rectangle: 2/7 in r4c89,r8c89 => r4c8<>2
Naked Single: r4c8=7
AIC: 3 3- r3c9 =3= r3c3 =7= r7c3 -7- r7c9 =7= r8c9 =2= r8c8 -2- r5c8 -3 => r56c9<>3
Discontinuous Nice Loop: 8 r7c9 -8- r7c5 =8= r9c6 =7= r9c2 -7- r7c3 =7= r7c9 => r7c9<>8
Locked Candidates Type 1 (Pointing): 8 in b9 => r46c7<>8
Naked Single: r4c7=9
Naked Single: r4c3=2
Full House: r6c3=9
Skyscraper: 9 in r3c5,r9c4 (connected by r39c2) => r1c4,r8c5<>9
Naked Single: r8c5=5
Sue de Coq: r5c45 - {1234} (r5c8 - {23}, r4c45,r6c6 - {1468}) => r6c5<>4, r6c5<>8, r5c9<>2
XY-Chain: 6 6- r1c4 -4- r8c4 -9- r9c4 -3- r7c5 -8- r4c5 -6 => r1c5,r4c4<>6
Naked Single: r4c4=1
Naked Single: r4c9=8
Full House: r4c5=6
Hidden Single: r1c4=6
Hidden Single: r5c9=1
Hidden Single: r7c5=8
Naked Single: r9c6=7
Naked Single: r8c6=4
Full House: r6c6=8
Naked Single: r9c2=9
Full House: r3c2=7
Naked Single: r8c4=9
Full House: r9c4=3
Full House: r5c4=4
Full House: r9c7=8
Naked Single: r7c1=1
Full House: r1c1=9
Full House: r7c3=7
Naked Single: r8c8=2
Full House: r8c9=7
Naked Single: r1c5=4
Full House: r1c3=1
Full House: r3c5=9
Naked Single: r7c9=3
Naked Single: r5c8=3
Full House: r5c5=2
Full House: r6c5=3
Naked Single: r3c9=4
Full House: r2c7=3
Full House: r3c3=3
Full House: r6c9=2
Full House: r2c3=4
Naked Single: r7c7=5
Full House: r6c7=4
Full House: r6c8=5
Full House: r7c8=9
|
normal_sudoku_620
|
.2.61..3...3.....1....37..4849276513256341897137..5......7.3....9...8.7.3.51.....
|
524619738763824951918537624849276513256341897137985246482793165691458372375162489
|
Basic 9x9 Sudoku 620
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 2 . 6 1 . . 3 .
. . 3 . . . . . 1
. . . . 3 7 . . 4
8 4 9 2 7 6 5 1 3
2 5 6 3 4 1 8 9 7
1 3 7 . . 5 . . .
. . . 7 . 3 . . .
. 9 . . . 8 . 7 .
3 . 5 1 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
524619738763824951918537624849276513256341897137985246482793165691458372375162489 #1 Easy (294)
Naked Single: r5c8=9
Naked Single: r5c6=1
Naked Single: r5c9=7
Full House: r5c2=5
Naked Single: r4c9=3
Naked Single: r4c2=4
Naked Single: r4c3=9
Full House: r4c5=7
Naked Single: r6c1=1
Full House: r6c2=3
Hidden Single: r7c6=3
Hidden Single: r7c4=7
Hidden Single: r1c5=1
Hidden Single: r2c3=3
Hidden Single: r8c7=3
Hidden Single: r9c2=7
Hidden Single: r8c3=1
Naked Single: r3c3=8
Naked Single: r1c3=4
Full House: r7c3=2
Naked Single: r2c2=6
Naked Single: r1c6=9
Naked Single: r3c2=1
Full House: r7c2=8
Naked Single: r1c7=7
Naked Single: r3c4=5
Naked Single: r1c1=5
Full House: r1c9=8
Naked Single: r3c1=9
Full House: r2c1=7
Naked Single: r8c4=4
Naked Single: r2c4=8
Full House: r6c4=9
Full House: r6c5=8
Naked Single: r8c1=6
Full House: r7c1=4
Naked Single: r9c6=2
Full House: r2c6=4
Full House: r2c5=2
Naked Single: r8c5=5
Full House: r8c9=2
Naked Single: r2c7=9
Full House: r2c8=5
Naked Single: r6c9=6
Naked Single: r7c8=6
Naked Single: r9c9=9
Full House: r7c9=5
Naked Single: r3c8=2
Full House: r3c7=6
Naked Single: r7c5=9
Full House: r7c7=1
Full House: r9c5=6
Naked Single: r9c7=4
Full House: r6c7=2
Full House: r6c8=4
Full House: r9c8=8
|
normal_sudoku_3670
|
..7..5....9........6..21..9.35.6.94778....56.6...5..388.65..794.73..96.595...6.83
|
317495826294678351568321479135862947789134562642957138826513794473289615951746283
|
Basic 9x9 Sudoku 3670
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 7 . . 5 . . .
. 9 . . . . . . .
. 6 . . 2 1 . . 9
. 3 5 . 6 . 9 4 7
7 8 . . . . 5 6 .
6 . . . 5 . . 3 8
8 . 6 5 . . 7 9 4
. 7 3 . . 9 6 . 5
9 5 . . . 6 . 8 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
317495826294678351568321479135862947789134562642957138826513794473289615951746283 #1 Extreme (16606) bf
Hidden Single: r9c2=5
Hidden Single: r5c7=5
Hidden Single: r7c3=6
Hidden Single: r6c1=6
Hidden Single: r7c8=9
Hidden Single: r5c1=7
Hidden Single: r9c1=9
Naked Triple: 1,2,4 in r148c8 => r2c8<>1, r2c8<>2, r23c8<>4
Brute Force: r4c8=4
Finned Franken Swordfish: 1 c28b6 r167 fr5c9 fr8c8 => r7c9<>1
W-Wing: 2/1 in r1c8,r6c7 connected by 1 in r8c8,r9c7 => r12c7<>2
Sashimi Swordfish: 2 c278 r167 fr8c8 fr9c7 => r7c9<>2
Naked Single: r7c9=4
Naked Pair: 1,2 in r69c7 => r12c7<>1
Grouped Discontinuous Nice Loop: 1 r8c4 -1- r8c8 =1= r1c8 -1- r12c9 =1= r5c9 -1- r5c5 =1= r456c4 -1- r8c4 => r8c4<>1
Forcing Chain Contradiction in r9c3 => r6c2<>1
r6c2=1 r6c7<>1 r9c7=1 r9c3<>1
r6c2=1 r7c2<>1 r7c2=2 r9c3<>2
r6c2=1 r6c2<>4 r56c3=4 r9c3<>4
Skyscraper: 1 in r7c2,r8c8 (connected by r1c28) => r8c1<>1
Discontinuous Nice Loop: 2 r5c6 -2- r5c9 -1- r6c7 =1= r9c7 -1- r9c3 =1= r7c2 =2= r7c6 -2- r5c6 => r5c6<>2
Discontinuous Nice Loop: 2 r9c4 -2- r9c7 -1- r9c3 =1= r7c2 =2= r7c6 -2- r9c4 => r9c4<>2
Turbot Fish: 2 r5c9 =2= r6c7 -2- r9c7 =2= r9c3 => r5c3<>2
Grouped Discontinuous Nice Loop: 2 r1c1 -2- r1c8 =2= r8c8 -2- r9c7 =2= r6c7 -2- r6c23 =2= r4c1 -2- r1c1 => r1c1<>2
Grouped Discontinuous Nice Loop: 1 r6c4 -1- r6c7 -2- r6c23 =2= r4c1 =1= r4c4 -1- r6c4 => r6c4<>1
Grouped Discontinuous Nice Loop: 2 r6c6 -2- r7c6 =2= r7c2 =1= r1c2 -1- r12c1 =1= r4c1 =2= r4c46 -2- r6c6 => r6c6<>2
Almost Locked Set XZ-Rule: A=r1c28 {124}, B=r4c1,r6c2 {124}, X=4, Z=1 => r1c1<>1
XY-Chain: 3 3- r1c1 -4- r8c1 -2- r7c2 -1- r7c5 -3 => r1c5<>3
Almost Locked Set XY-Wing: A=r1c28 {124}, B=r5c9 {12}, C=r6c27 {124}, X,Y=1,4, Z=2 => r1c9<>2
Forcing Chain Contradiction in r1c2 => r1c1=3
r1c1<>3 r1c1=4 r8c1<>4 r8c1=2 r7c2<>2 r7c2=1 r1c2<>1
r1c1<>3 r1c1=4 r8c1<>4 r8c1=2 r8c8<>2 r1c8=2 r1c2<>2
r1c1<>3 r1c1=4 r1c2<>4
Forcing Chain Contradiction in r1c2 => r2c8=5
r2c8<>5 r2c1=5 r3c1<>5 r3c1=4 r8c1<>4 r8c1=2 r7c2<>2 r7c2=1 r1c2<>1
r2c8<>5 r2c1=5 r3c1<>5 r3c1=4 r8c1<>4 r8c1=2 r8c8<>2 r1c8=2 r1c2<>2
r2c8<>5 r2c1=5 r3c1<>5 r3c1=4 r1c2<>4
Naked Single: r3c8=7
Hidden Single: r3c1=5
Forcing Chain Contradiction in r9c3 => r6c2=4
r6c2<>4 r6c2=2 r7c2<>2 r7c2=1 r9c3<>1
r6c2<>4 r6c2=2 r6c7<>2 r9c7=2 r9c3<>2
r6c2<>4 r56c3=4 r9c3<>4
Naked Single: r6c6=7
Naked Pair: 1,2 in r1c28 => r1c9<>1
Naked Single: r1c9=6
Hidden Single: r2c4=6
Hidden Single: r2c5=7
Hidden Single: r9c4=7
Locked Candidates Type 1 (Pointing): 1 in b8 => r5c5<>1
Swordfish: 1 r178 c258 => r9c5<>1
Naked Single: r9c5=4
Hidden Single: r8c1=4
Naked Pair: 1,2 in r1c2,r2c1 => r2c3<>1, r2c3<>2
X-Wing: 1 r69 c37 => r5c3<>1
Naked Single: r5c3=9
Naked Single: r5c5=3
Naked Single: r5c6=4
Naked Single: r7c5=1
Naked Single: r7c2=2
Full House: r1c2=1
Full House: r7c6=3
Full House: r9c3=1
Full House: r9c7=2
Full House: r8c8=1
Full House: r1c8=2
Naked Single: r8c5=8
Full House: r1c5=9
Full House: r8c4=2
Naked Single: r2c1=2
Full House: r4c1=1
Full House: r6c3=2
Naked Single: r2c6=8
Full House: r4c6=2
Full House: r4c4=8
Naked Single: r6c7=1
Full House: r6c4=9
Full House: r5c4=1
Full House: r5c9=2
Full House: r2c9=1
Naked Single: r1c4=4
Full House: r1c7=8
Full House: r3c4=3
Naked Single: r2c3=4
Full House: r2c7=3
Full House: r3c7=4
Full House: r3c3=8
|
normal_sudoku_2313
|
2.6.358.7..367..5.5.7..14368713.....6..1.7.48..9..617....56.78.9..7.....76..1...5
|
296435817143678952587921436871342569635197248429856173312569784954783621768214395
|
Basic 9x9 Sudoku 2313
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
2 . 6 . 3 5 8 . 7
. . 3 6 7 . . 5 .
5 . 7 . . 1 4 3 6
8 7 1 3 . . . . .
6 . . 1 . 7 . 4 8
. . 9 . . 6 1 7 .
. . . 5 6 . 7 8 .
9 . . 7 . . . . .
7 6 . . 1 . . . 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
296435817143678952587921436871342569635197248429856173312569784954783621768214395 #1 Extreme (3066)
Naked Single: r3c1=5
Hidden Single: r3c8=3
Hidden Single: r4c2=7
Hidden Single: r1c3=6
Hidden Single: r5c1=6
Hidden Single: r5c4=1
Hidden Single: r1c6=5
Hidden Single: r1c9=7
Hidden Single: r3c3=7
Hidden Single: r7c7=7
Hidden Single: r2c5=7
Hidden Single: r7c5=6
Locked Candidates Type 1 (Pointing): 8 in b1 => r8c2<>8
Locked Candidates Type 1 (Pointing): 2 in b3 => r2c6<>2
Locked Candidates Type 1 (Pointing): 4 in b4 => r6c45<>4
Locked Candidates Type 2 (Claiming): 4 in c3 => r7c12,r8c2<>4
X-Chain: 3 r7c1 =3= r6c1 -3- r6c9 =3= r5c7 -3- r9c7 =3= r9c6 => r7c6<>3
Discontinuous Nice Loop: 2/6/9 r4c7 =5= r4c5 =4= r8c5 -4- r8c9 =4= r7c9 -4- r7c3 -2- r5c3 -5- r5c7 =5= r4c7 => r4c7<>2, r4c7<>6, r4c7<>9
Naked Single: r4c7=5
Hidden Single: r4c8=6
Hidden Single: r8c7=6
Locked Candidates Type 2 (Claiming): 2 in c8 => r78c9,r9c7<>2
AIC: 9 9- r9c7 -3- r5c7 =3= r5c2 -3- r6c1 -4- r2c1 -1- r2c9 =1= r1c8 =9= r9c8 -9 => r7c9,r9c46<>9
Hidden Single: r7c6=9
Locked Candidates Type 1 (Pointing): 9 in b5 => r3c5<>9
Locked Candidates Type 2 (Claiming): 2 in r7 => r8c23,r9c3<>2
W-Wing: 8/4 in r2c6,r9c3 connected by 4 in r19c4 => r9c6<>8
XY-Wing: 4/8/2 in r24c6,r3c5 => r456c5<>2
XY-Wing: 2/4/8 in r24c6,r6c4 => r3c4<>8
XY-Chain: 2 2- r3c5 -8- r2c6 -4- r1c4 -9- r1c8 -1- r8c8 -2 => r8c5<>2
Hidden Single: r3c5=2
Naked Single: r3c4=9
Full House: r3c2=8
Naked Single: r1c4=4
Full House: r2c6=8
Sue de Coq: r9c46 - {2348} (r9c78 - {239}, r8c5 - {48}) => r8c6<>4
W-Wing: 3/2 in r6c9,r8c6 connected by 2 in r4c69 => r8c9<>3
X-Wing: 3 c19 r67 => r67c2<>3
XY-Chain: 2 2- r4c6 -4- r4c5 -9- r5c5 -5- r5c3 -2- r7c3 -4- r9c3 -8- r9c4 -2 => r6c4,r89c6<>2
Naked Single: r6c4=8
Full House: r9c4=2
Naked Single: r8c6=3
Naked Single: r6c5=5
Naked Single: r9c8=9
Naked Single: r9c6=4
Full House: r4c6=2
Full House: r8c5=8
Naked Single: r5c5=9
Full House: r4c5=4
Full House: r4c9=9
Naked Single: r1c8=1
Full House: r1c2=9
Full House: r8c8=2
Naked Single: r9c7=3
Full House: r9c3=8
Naked Single: r2c9=2
Full House: r2c7=9
Full House: r5c7=2
Full House: r6c9=3
Naked Single: r5c3=5
Full House: r5c2=3
Naked Single: r6c1=4
Full House: r6c2=2
Naked Single: r8c3=4
Full House: r7c3=2
Naked Single: r2c1=1
Full House: r2c2=4
Full House: r7c1=3
Naked Single: r7c2=1
Full House: r7c9=4
Full House: r8c9=1
Full House: r8c2=5
|
normal_sudoku_2663
|
8..5.6.1..65...4..1..9...5.3..8..59..5.6931.7.1..52...5....9..1..1..5.3..831....5
|
897546312265731489134928756326817594458693127719452863572389641641275938983164275
|
Basic 9x9 Sudoku 2663
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
8 . . 5 . 6 . 1 .
. 6 5 . . . 4 . .
1 . . 9 . . . 5 .
3 . . 8 . . 5 9 .
. 5 . 6 9 3 1 . 7
. 1 . . 5 2 . . .
5 . . . . 9 . . 1
. . 1 . . 5 . 3 .
. 8 3 1 . . . . 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
897546312265731489134928756326817594458693127719452863572389641641275938983164275 #1 Extreme (40052) bf
Hidden Single: r2c3=5
Hidden Single: r5c5=9
Hidden Single: r8c6=5
Locked Candidates Type 1 (Pointing): 8 in b8 => r23c5<>8
Skyscraper: 9 in r2c9,r9c7 (connected by r29c1) => r1c7,r8c9<>9
Brute Force: r5c6=3
Locked Candidates Type 1 (Pointing): 1 in b5 => r4c279<>1
Hidden Pair: 1,5 in r5c27 => r5c27<>2, r5c2<>4, r5c7<>6, r5c7<>8
Brute Force: r5c7=1
Naked Single: r5c2=5
Hidden Single: r6c2=1
Hidden Single: r7c9=1
Hidden Single: r4c7=5
Forcing Net Contradiction in r9 => r5c3<>4
r5c3=4 (r5c1<>4) r5c4<>4 r5c4=6 r5c1<>6 r5c1=2 r9c1<>2
r5c3=4 (r5c4<>4 r5c4=6 r5c1<>6 r5c1=2 r2c1<>2) r5c3<>8 r5c8=8 (r2c8<>8) (r6c7<>8) (r6c8<>8) r6c9<>8 r6c3=8 r6c3<>9 r6c1=9 r2c1<>9 r2c1=7 r2c8<>7 r2c8=2 r2c4<>2 r78c4=2 r9c5<>2
r5c3=4 r5c3<>8 r5c8=8 (r6c7<>8) (r6c8<>8) r6c9<>8 r6c3=8 r6c3<>9 r6c1=9 r9c1<>9 r9c7=9 r9c7<>2
r5c3=4 (r5c4<>4 r5c4=6 r5c1<>6 r5c1=2 r2c1<>2) r5c3<>8 r5c8=8 (r2c8<>8) (r6c7<>8) (r6c8<>8) r6c9<>8 r6c3=8 r6c3<>9 r6c1=9 r2c1<>9 r2c1=7 r2c8<>7 r2c8=2 r9c8<>2
Forcing Net Contradiction in r9 => r5c3<>6
r5c3=6 (r5c1<>6) r5c4<>6 r5c4=4 r5c1<>4 r5c1=2 r9c1<>2
r5c3=6 (r5c4<>6 r5c4=4 r5c1<>4 r5c1=2 r2c1<>2) r5c3<>8 r5c8=8 (r2c8<>8) (r6c7<>8) (r6c8<>8) r6c9<>8 r6c3=8 r6c3<>9 r6c1=9 r2c1<>9 r2c1=7 r2c8<>7 r2c8=2 r2c4<>2 r78c4=2 r9c5<>2
r5c3=6 r5c3<>8 r5c8=8 (r6c7<>8) (r6c8<>8) r6c9<>8 r6c3=8 r6c3<>9 r6c1=9 r9c1<>9 r9c7=9 r9c7<>2
r5c3=6 (r5c4<>6 r5c4=4 r5c1<>4 r5c1=2 r2c1<>2) r5c3<>8 r5c8=8 (r2c8<>8) (r6c7<>8) (r6c8<>8) r6c9<>8 r6c3=8 r6c3<>9 r6c1=9 r2c1<>9 r2c1=7 r2c8<>7 r2c8=2 r9c8<>2
Forcing Net Contradiction in r8 => r7c4<>6
r7c4=6 (r7c3<>6) (r7c5<>6) (r8c5<>6) r9c5<>6 r4c5=6 r4c3<>6 r6c3=6 (r5c1<>6 r5c1=2 r2c1<>2) r6c3<>9 r6c1=9 r2c1<>9 r2c1=7 r8c1<>7
r7c4=6 (r7c3<>6) (r7c5<>6) (r8c5<>6) r9c5<>6 r4c5=6 r4c3<>6 r6c3=6 r6c3<>9 r6c1=9 (r8c1<>9) r9c1<>9 r9c7=9 r8c7<>9 r8c2=9 r8c2<>7
r7c4=6 (r6c4<>6) r5c4<>6 r5c4=4 r6c4<>4 r6c4=7 r8c4<>7
r7c4=6 r7c4<>3 r7c5=3 r7c5<>8 r8c5=8 r8c5<>7
r7c4=6 (r7c3<>6) (r7c5<>6) (r8c5<>6) r9c5<>6 r4c5=6 r4c3<>6 r6c3=6 (r5c1<>6 r5c1=2 r2c1<>2) r6c3<>9 r6c1=9 r2c1<>9 r2c1=7 r2c8<>7 r13c7=7 r8c7<>7
Forcing Net Contradiction in r9 => r9c7<>7
r9c7=7 r9c7<>9 r9c1=9 r9c1<>2
r9c7=7 (r9c8<>7 r2c8=7 r2c1<>7) r9c7<>9 r9c1=9 r2c1<>9 r2c1=2 r2c4<>2 r78c4=2 r9c5<>2
r9c7=7 r9c7<>2
r9c7=7 r9c7<>9 r9c1=9 (r2c1<>9 r2c1=2 r5c1<>2) r6c1<>9 r6c3=9 r6c3<>8 r5c3=8 r5c3<>2 r5c8=2 r9c8<>2
Brute Force: r5c4=6
Empty Rectangle: 4 in b9 (r5c18) => r8c1<>4
Discontinuous Nice Loop: 4 r4c3 -4- r5c1 -2- r5c8 =2= r4c9 =6= r4c3 => r4c3<>4
Forcing Chain Contradiction in r9 => r6c1<>4
r6c1=4 r9c1<>4
r6c1=4 r6c4<>4 r78c4=4 r9c5<>4
r6c1=4 r6c4<>4 r78c4=4 r9c6<>4
r6c1=4 r5c1<>4 r5c8=4 r9c8<>4
Forcing Chain Contradiction in r9 => r6c8<>4
r6c8=4 r5c8<>4 r5c1=4 r9c1<>4
r6c8=4 r6c4<>4 r78c4=4 r9c5<>4
r6c8=4 r6c4<>4 r78c4=4 r9c6<>4
r6c8=4 r9c8<>4
Forcing Net Contradiction in c8 => r4c2<>4
r4c2=4 (r4c6<>4) r5c1<>4 r9c1=4 r9c6<>4 (r9c6=7 r8c4<>7 r2c4=7 r2c8<>7) r3c6=4 r3c6<>8 r2c6=8 r2c8<>8 r2c8=2
r4c2=4 (r4c6<>4 r6c4=4 r8c4<>4) r5c1<>4 (r5c1=2 r9c1<>2) r9c1=4 (r9c1<>9 r9c7=9 r9c7<>2) r9c6<>4 r9c6=7 r8c4<>7 r8c4=2 r9c5<>2 r9c8=2
Forcing Net Contradiction in c8 => r5c1=4
r5c1<>4 (r5c1=2 r2c1<>2) r6c3=4 r6c3<>9 r6c1=9 r2c1<>9 r2c1=7 r2c8<>7
r5c1<>4 (r5c1=2 r4c2<>2 r4c2=7 r4c3<>7 r4c3=6 r7c3<>6) (r5c1=2 r4c2<>2 r4c2=7 r7c2<>7) r9c1=4 (r7c3<>4) r7c2<>4 r7c2=2 r7c3<>2 r7c3=7 r7c8<>7
r5c1<>4 r9c1=4 r9c6<>4 r9c6=7 r9c8<>7
Locked Candidates Type 1 (Pointing): 4 in b6 => r8c9<>4
Grouped Discontinuous Nice Loop: 2 r9c8 -2- r5c8 =2= r4c9 =4= r6c9 -4- r6c4 =4= r78c4 -4- r9c56 =4= r9c8 => r9c8<>2
Forcing Chain Contradiction in c8 => r6c1<>6
r6c1=6 r6c8<>6
r6c1=6 r89c1<>6 r7c3=6 r7c8<>6
r6c1=6 r4c3<>6 r4c9=6 r4c9<>4 r6c9=4 r6c4<>4 r78c4=4 r9c56<>4 r9c8=4 r9c8<>6
Locked Candidates Type 1 (Pointing): 6 in b4 => r7c3<>6
Discontinuous Nice Loop: 2 r8c2 -2- r4c2 -7- r6c1 -9- r6c3 =9= r1c3 -9- r1c2 =9= r8c2 => r8c2<>2
Grouped Discontinuous Nice Loop: 4 r7c4 -4- r6c4 -7- r6c1 -9- r89c1 =9= r8c2 =4= r7c23 -4- r7c4 => r7c4<>4
Almost Locked Set XY-Wing: A=r7c23 {247}, B=r9c68 {467}, C=r2567c8 {24678}, X,Y=4,6, Z=7 => r9c1<>7
Forcing Chain Contradiction in r8 => r2c1<>7
r2c1=7 r8c1<>7
r2c1=7 r6c1<>7 r6c1=9 r89c1<>9 r8c2=9 r8c2<>7
r2c1=7 r6c1<>7 r6c1=9 r89c1<>9 r8c2=9 r8c2<>4 r8c45=4 r9c6<>4 r9c6=7 r8c4<>7
r2c1=7 r6c1<>7 r6c1=9 r89c1<>9 r8c2=9 r8c2<>4 r8c45=4 r9c6<>4 r9c6=7 r8c5<>7
r2c1=7 r2c8<>7 r13c7=7 r8c7<>7
XY-Wing: 7/9/2 in r26c1,r4c2 => r13c2<>2
2-String Kite: 2 in r5c8,r7c2 (connected by r4c2,r5c3) => r7c8<>2
Empty Rectangle: 2 in b1 (r25c8) => r5c3<>2
Naked Single: r5c3=8
Full House: r5c8=2
Forcing Chain Contradiction in c4 => r4c2=2
r4c2<>2 r4c3=2 r13c3<>2 r2c1=2 r2c4<>2
r4c2<>2 r7c2=2 r7c4<>2
r4c2<>2 r4c2=7 r4c56<>7 r6c4=7 r6c4<>4 r8c4=4 r8c4<>2
W-Wing: 7/4 in r7c2,r9c6 connected by 4 in r79c8 => r7c45<>7
Sashimi Swordfish: 7 c148 r268 fr7c8 fr9c8 => r8c7<>7
Sue de Coq: r7c78 - {24678} (r7c2 - {47}, r8c79,r9c7 - {2689}) => r9c8<>6, r7c35<>4, r7c3<>7
Naked Single: r7c3=2
Naked Single: r7c4=3
Hidden Single: r2c1=2
Naked Single: r2c4=7
Naked Single: r2c8=8
Naked Single: r6c4=4
Full House: r8c4=2
Naked Single: r2c6=1
Naked Single: r6c8=6
Naked Single: r2c5=3
Full House: r2c9=9
Naked Single: r4c6=7
Full House: r4c5=1
Naked Single: r4c9=4
Full House: r4c3=6
Naked Single: r9c6=4
Full House: r3c6=8
Naked Single: r9c8=7
Full House: r7c8=4
Naked Single: r9c5=6
Naked Single: r7c2=7
Naked Single: r7c5=8
Full House: r7c7=6
Full House: r8c5=7
Naked Single: r9c1=9
Full House: r9c7=2
Naked Single: r8c9=8
Full House: r8c7=9
Naked Single: r6c1=7
Full House: r8c1=6
Full House: r8c2=4
Full House: r6c3=9
Naked Single: r6c9=3
Full House: r6c7=8
Naked Single: r3c2=3
Full House: r1c2=9
Naked Single: r1c9=2
Full House: r3c9=6
Naked Single: r3c7=7
Full House: r1c7=3
Naked Single: r1c5=4
Full House: r1c3=7
Full House: r3c3=4
Full House: r3c5=2
|
normal_sudoku_3137
|
.....8.....7.269...3.41758...61...29....6217.1..7..65...1.7.2..4....1..5.5...3...
|
214958367587326941639417582376145829945862173128739654891574236463281795752693418
|
Basic 9x9 Sudoku 3137
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . . 8 . . .
. . 7 . 2 6 9 . .
. 3 . 4 1 7 5 8 .
. . 6 1 . . . 2 9
. . . . 6 2 1 7 .
1 . . 7 . . 6 5 .
. . 1 . 7 . 2 . .
4 . . . . 1 . . 5
. 5 . . . 3 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
214958367587326941639417582376145829945862173128739654891574236463281795752693418 #1 Extreme (31756) bf
Hidden Single: r3c6=7
Hidden Single: r8c6=1
Locked Candidates Type 1 (Pointing): 2 in b8 => r5c4<>2
Grouped Discontinuous Nice Loop: 9 r5c4 -9- r1c4 =9= r13c5 -9- r8c5 -8- r789c4 =8= r5c4 => r5c4<>9
Almost Locked Set XY-Wing: A=r3c357 {1259}, B=r2567c9 {13468}, C=r7c12,r89c3 {23689}, X,Y=2,6, Z=1 => r3c9<>1
Forcing Net Contradiction in r7c8 => r1c9<>1
r1c9=1 (r1c9<>6) (r1c9<>2 r3c9=2 r3c9<>6) r1c9<>7 r9c9=7 r9c9<>6 r7c9=6 (r7c2<>6) r3c9<>6 r3c1=6 r1c2<>6 r8c2=6 r8c2<>7 r8c7=7 r1c7<>7 r1c9=7 r1c9<>1
Forcing Net Contradiction in r7c8 => r1c9<>3
r1c9=3 (r1c9<>6) (r1c9<>2 r3c9=2 r3c9<>6) r1c9<>7 r9c9=7 r9c9<>6 r7c9=6 (r7c2<>6) r3c9<>6 r3c1=6 r1c2<>6 r8c2=6 r8c2<>7 r8c7=7 r1c7<>7 r1c9=7 r1c9<>3
Forcing Net Contradiction in r7c8 => r1c9<>4
r1c9=4 (r1c9<>6) (r1c9<>2 r3c9=2 r3c9<>6) r1c9<>7 r9c9=7 r9c9<>6 r7c9=6 (r7c2<>6) r3c9<>6 r3c1=6 r1c2<>6 r8c2=6 r8c2<>7 r8c7=7 r1c7<>7 r1c9=7 r1c9<>4
Forcing Net Contradiction in r7c8 => r5c1<>8
r5c1=8 (r5c4<>8) r2c1<>8 r2c1=5 (r4c1<>5) r2c4<>5 r2c4=3 r5c4<>3 r5c4=5 (r4c5<>5) r4c6<>5 r4c7=5 r3c7<>5 r3c7=1 (r2c8<>1) r2c9<>1 r2c2=1 r2c2<>8 r2c1=8 r5c1<>8
Brute Force: r5c6=2
Locked Candidates Type 1 (Pointing): 9 in b5 => r6c23<>9
Forcing Net Contradiction in c7 => r1c2<>9
r1c2=9 (r1c2<>4) r1c2<>1 r2c2=1 r2c2<>4 r1c3=4 r1c7<>4
r1c2=9 (r3c1<>9) r3c3<>9 r3c5=9 (r6c5<>9 r6c6=9 r6c6<>4) (r9c5<>9) r8c5<>9 r8c5=8 r9c5<>8 r9c5=4 r7c6<>4 r4c6=4 r4c7<>4
r1c2=9 (r5c2<>9) (r3c1<>9) r3c3<>9 r3c5=9 r8c5<>9 r8c5=8 (r7c4<>8) (r8c4<>8) r9c4<>8 r5c4=8 r5c2<>8 r5c2=4 r5c7<>4
r1c2=9 (r3c1<>9) r3c3<>9 r3c5=9 (r9c5<>9) r8c5<>9 r8c5=8 r9c5<>8 r9c5=4 r9c7<>4
Brute Force: r5c7=1
Naked Single: r3c7=5
Hidden Single: r3c5=1
Hidden Single: r6c8=5
Locked Candidates Type 1 (Pointing): 9 in b2 => r1c13<>9
Skyscraper: 5 in r4c5,r5c3 (connected by r1c35) => r4c1,r5c4<>5
Discontinuous Nice Loop: 6 r1c2 -6- r3c1 =6= r3c9 =2= r1c9 =7= r9c9 =1= r9c8 -1- r1c8 =1= r1c2 => r1c2<>6
Locked Candidates Type 1 (Pointing): 6 in b1 => r79c1<>6
Discontinuous Nice Loop: 8 r4c5 -8- r5c4 -3- r2c4 -5- r1c5 =5= r4c5 => r4c5<>8
Almost Locked Set XZ-Rule: A=r9c13457 {246789}, B=r25679c9 {134678}, X=7, Z=6 => r9c8<>6
Almost Locked Set XZ-Rule: A=r2789c8 {13469}, B=r2567c9 {13468}, X=6, Z=1 => r1c8<>1
Hidden Single: r1c2=1
Almost Locked Set XZ-Rule: A=r25679c9 {134678}, B=r7c12,r89c3,r9c1 {236789}, X=7, Z=6 => r7c8<>6
Almost Locked Set XY-Wing: A=r3c3 {29}, B=r245c2 {4789}, C=r123457c1 {2356789}, X,Y=2,7, Z=9 => r5c3<>9
Forcing Chain Contradiction in c7 => r1c4<>5
r1c4=5 r2c4<>5 r2c1=5 r2c1<>8 r2c2=8 r2c2<>4 r1c3=4 r1c7<>4
r1c4=5 r1c5<>5 r4c5=5 r4c6<>5 r4c6=4 r4c7<>4
r1c4=5 r7c4<>5 r7c6=5 r7c6<>4 r9c5=4 r9c7<>4
Forcing Chain Contradiction in r7 => r1c8<>4
r1c8=4 r1c3<>4 r2c2=4 r2c2<>8 r2c1=8 r2c1<>5 r2c4=5 r7c4<>5 r7c6=5 r7c6<>4
r1c8=4 r7c8<>4
r1c8=4 r1c3<>4 r2c2=4 r2c2<>8 r2c1=8 r2c1<>5 r2c4=5 r7c4<>5 r7c6=5 r4c6<>5 r4c6=4 r4c7<>4 r56c9=4 r7c9<>4
Forcing Chain Contradiction in r8 => r1c3<>2
r1c3=2 r13c1<>2 r9c1=2 r9c1<>7 r8c2=7 r8c2<>6
r1c3=2 r13c1<>2 r9c1=2 r9c4<>2 r8c4=2 r8c4<>6
r1c3=2 r1c3<>4 r2c2=4 r2c2<>8 r2c1=8 r2c1<>5 r2c4=5 r2c4<>3 r1c45=3 r1c8<>3 r1c8=6 r8c8<>6
Naked Triple: 4,5,8 in r1c3,r2c12 => r1c1<>5
Discontinuous Nice Loop: 8 r5c2 -8- r2c2 =8= r2c1 =5= r5c1 =9= r5c2 => r5c2<>8
Forcing Chain Contradiction in r7 => r2c9<>4
r2c9=4 r56c9<>4 r4c7=4 r4c7<>8 r4c12=8 r56c3<>8 r89c3=8 r7c1<>8
r2c9=4 r2c2<>4 r2c2=8 r7c2<>8
r2c9=4 r2c2<>4 r2c2=8 r2c1<>8 r2c1=5 r2c4<>5 r7c4=5 r7c4<>8
r2c9=4 r56c9<>4 r4c7=4 r4c7<>8 r89c7=8 r7c9<>8
Discontinuous Nice Loop: 4 r9c8 -4- r9c5 =4= r7c6 =5= r7c4 -5- r2c4 -3- r2c9 -1- r2c8 =1= r9c8 => r9c8<>4
Forcing Chain Contradiction in r7 => r4c1<>8
r4c1=8 r7c1<>8
r4c1=8 r2c1<>8 r2c2=8 r7c2<>8
r4c1=8 r2c1<>8 r2c1=5 r2c4<>5 r7c4=5 r7c4<>8
r4c1=8 r4c7<>8 r89c7=8 r7c9<>8
Discontinuous Nice Loop: 4 r4c7 -4- r1c7 =4= r1c3 -4- r2c2 -8- r4c2 =8= r4c7 => r4c7<>4
Locked Candidates Type 1 (Pointing): 4 in b6 => r79c9<>4
Finned Swordfish: 4 r247 c268 fr4c5 => r6c6<>4
Naked Single: r6c6=9
Almost Locked Set Chain: 4- r2c12 {458} -5- r134579c1 {2356789} -8- r39c3 {289} -2- r4c12,r5c123,r6c3 {2345789} -4 => r6c2<>4
Forcing Chain Contradiction in r8 => r2c9=1
r2c9<>1 r2c9=3 r56c9<>3 r4c7=3 r4c7<>8 r4c2=8 r4c2<>7 r8c2=7 r8c2<>6
r2c9<>1 r9c9=1 r9c9<>6 r9c4=6 r8c4<>6
r2c9<>1 r2c9=3 r1c8<>3 r1c8=6 r8c8<>6
Hidden Single: r9c8=1
AIC: 8 8- r5c4 -3- r2c4 =3= r2c8 =4= r7c8 =9= r8c8 -9- r8c5 -8 => r6c5,r789c4<>8
Hidden Single: r5c4=8
Locked Candidates Type 1 (Pointing): 3 in b5 => r1c5<>3
Finned Swordfish: 8 r247 c127 fr7c9 => r89c7<>8
Hidden Single: r4c7=8
Locked Candidates Type 1 (Pointing): 3 in b6 => r7c9<>3
Naked Pair: 3,4 in r6c59 => r6c3<>3, r6c3<>4
Naked Triple: 2,8,9 in r369c3 => r8c3<>2, r8c3<>8, r8c3<>9
Naked Single: r8c3=3
Naked Single: r8c7=7
Naked Single: r9c7=4
Full House: r1c7=3
Naked Single: r1c4=9
Naked Single: r1c8=6
Naked Single: r2c8=4
Naked Single: r1c5=5
Full House: r2c4=3
Naked Single: r1c1=2
Naked Single: r3c9=2
Full House: r1c9=7
Full House: r1c3=4
Naked Single: r8c8=9
Full House: r7c8=3
Naked Single: r2c2=8
Full House: r2c1=5
Naked Single: r3c3=9
Full House: r3c1=6
Naked Single: r5c3=5
Naked Single: r8c5=8
Naked Single: r6c2=2
Naked Single: r9c5=9
Naked Single: r6c3=8
Full House: r9c3=2
Naked Single: r8c2=6
Full House: r8c4=2
Naked Single: r9c4=6
Full House: r7c4=5
Full House: r7c6=4
Full House: r4c6=5
Naked Single: r7c2=9
Naked Single: r9c9=8
Full House: r7c9=6
Full House: r7c1=8
Full House: r9c1=7
Naked Single: r5c2=4
Full House: r4c2=7
Naked Single: r4c1=3
Full House: r4c5=4
Full House: r5c1=9
Full House: r5c9=3
Full House: r6c5=3
Full House: r6c9=4
|
normal_sudoku_2649
|
.1..7...4..5.197..7..8.....6..7...2..7.25613.5.......7.9.5.....1...679..........3
|
819672354235419786746835219681793425974256138523148697397524861158367942462981573
|
Basic 9x9 Sudoku 2649
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 1 . . 7 . . . 4
. . 5 . 1 9 7 . .
7 . . 8 . . . . .
6 . . 7 . . . 2 .
. 7 . 2 5 6 1 3 .
5 . . . . . . . 7
. 9 . 5 . . . . .
1 . . . 6 7 9 . .
. . . . . . . . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
819672354235419786746835219681793425974256138523148697397524861158367942462981573 #1 Extreme (31116) bf
Forcing Net Contradiction in r3 => r3c8<>3
r3c8=3 (r3c8<>9) r3c8<>1 r3c9=1 (r3c9<>9) r3c9<>9 r3c3=9 (r1c3<>9 r1c8=9 r1c8<>5) r1c1<>9 r5c1=9 r5c9<>9 r4c9=9 r4c9<>5 r4c7=5 r1c7<>5 r1c6=5 r3c6<>5
r3c8=3 (r3c8<>9) r3c8<>1 r3c9=1 (r3c9<>9) r3c9<>9 r3c3=9 r1c1<>9 r5c1=9 r5c9<>9 r4c9=9 r4c9<>5 r4c7=5 r3c7<>5
r3c8=3 r3c8<>5
r3c8=3 r3c8<>1 r3c9=1 r3c9<>5
Forcing Net Contradiction in r3 => r3c8<>6
r3c8=6 (r3c8<>9) r3c8<>1 r3c9=1 (r3c9<>9) r3c9<>9 r3c3=9 (r1c3<>9 r1c8=9 r1c8<>5) r1c1<>9 r5c1=9 r5c9<>9 r4c9=9 r4c9<>5 r4c7=5 r1c7<>5 r1c6=5 r3c6<>5
r3c8=6 (r3c8<>9) r3c8<>1 r3c9=1 (r3c9<>9) r3c9<>9 r3c3=9 r1c1<>9 r5c1=9 r5c9<>9 r4c9=9 r4c9<>5 r4c7=5 r3c7<>5
r3c8=6 r3c8<>5
r3c8=6 r3c8<>1 r3c9=1 r3c9<>5
Forcing Net Contradiction in r3 => r3c9<>2
r3c9=2 (r3c9<>9) (r3c9<>9) r3c9<>1 r3c8=1 r3c8<>9 r3c3=9 (r1c3<>9 r1c8=9 r1c8<>5) r1c1<>9 r5c1=9 r5c9<>9 r4c9=9 r4c9<>5 r4c7=5 r1c7<>5 r1c6=5 r3c6<>5
r3c9=2 (r3c9<>9) (r3c9<>9) r3c9<>1 r3c8=1 r3c8<>9 r3c3=9 r1c1<>9 r5c1=9 r5c9<>9 r4c9=9 r4c9<>5 r4c7=5 r3c7<>5
r3c9=2 r3c9<>1 r3c8=1 r3c8<>5
r3c9=2 r3c9<>5
Forcing Net Contradiction in r3 => r3c9<>6
r3c9=6 (r3c9<>9) (r3c9<>9) r3c9<>1 r3c8=1 r3c8<>9 r3c3=9 (r1c3<>9 r1c8=9 r1c8<>5) r1c1<>9 r5c1=9 r5c9<>9 r4c9=9 r4c9<>5 r4c7=5 r1c7<>5 r1c6=5 r3c6<>5
r3c9=6 (r3c9<>9) (r3c9<>9) r3c9<>1 r3c8=1 r3c8<>9 r3c3=9 r1c1<>9 r5c1=9 r5c9<>9 r4c9=9 r4c9<>5 r4c7=5 r3c7<>5
r3c9=6 r3c9<>1 r3c8=1 r3c8<>5
r3c9=6 r3c9<>5
Brute Force: r5c8=3
Grouped Discontinuous Nice Loop: 3 r1c3 -3- r2c12 =3= r2c4 -3- r8c4 =3= r7c56 -3- r7c1 =3= r12c1 -3- r1c3 => r1c3<>3
Grouped Discontinuous Nice Loop: 3 r3c2 -3- r2c12 =3= r2c4 -3- r8c4 =3= r7c56 -3- r7c1 =3= r12c1 -3- r3c2 => r3c2<>3
Grouped Discontinuous Nice Loop: 3 r3c3 -3- r2c12 =3= r2c4 -3- r8c4 =3= r7c56 -3- r7c1 =3= r12c1 -3- r3c3 => r3c3<>3
Forcing Chain Contradiction in b9 => r7c8<>8
r7c8=8 r7c8<>1
r7c8=8 r2c8<>8 r2c8=6 r2c9<>6 r7c9=6 r7c9<>1
r7c8=8 r7c8<>7 r9c8=7 r9c8<>1
Forcing Chain Contradiction in b9 => r9c8<>8
r9c8=8 r9c8<>7 r7c8=7 r7c8<>1
r9c8=8 r2c8<>8 r2c8=6 r2c9<>6 r7c9=6 r7c9<>1
r9c8=8 r9c8<>1
Forcing Net Contradiction in r1c1 => r1c3<>6
r1c3=6 (r1c3<>8) r1c4<>6 r2c4=6 r2c8<>6 r2c8=8 (r1c7<>8) r1c8<>8 r1c1=8
r1c3=6 (r3c2<>6 r9c2=6 r9c2<>5 r8c2=5 r8c9<>5) r1c4<>6 r2c4=6 (r2c9<>6) r2c8<>6 r2c8=8 r2c9<>8 r2c9=2 r8c9<>2 r8c9=8 r5c9<>8 r5c9=9 r5c1<>9 r1c1=9
Forcing Net Contradiction in r8 => r7c9<>8
r7c9=8 (r7c9<>6 r2c9=6 r1c8<>6) (r7c9<>6 r2c9=6 r2c8<>6 r2c8=8 r1c8<>8) r5c9<>8 r5c9=9 (r4c9<>9 r4c9=5 r8c9<>5) r5c1<>9 r1c1=9 r1c8<>9 r1c8=5 r8c8<>5 r8c2=5 r8c2<>8
r7c9=8 (r7c9<>6 r2c9=6 r2c8<>6 r2c8=8 r1c7<>8) (r7c9<>6 r2c9=6 r2c8<>6 r2c8=8 r1c8<>8) r5c9<>8 r5c9=9 r5c1<>9 r1c1=9 r1c1<>8 r1c3=8 r8c3<>8
r7c9=8 r8c8<>8
r7c9=8 r8c9<>8
Brute Force: r5c4=2
Locked Candidates Type 2 (Claiming): 4 in r5 => r4c23,r6c23<>4
Finned Swordfish: 2 r268 c239 fr2c1 => r13c3,r3c2<>2
W-Wing: 8/9 in r1c3,r5c9 connected by 9 in r15c1 => r5c3<>8
Almost Locked Set XY-Wing: A=r1c456,r3c56 {234567}, B=r13c7,r2c89,r3c89 {1235689}, C=r3c23 {469}, X,Y=4,9, Z=6 => r1c8<>6
Grouped Discontinuous Nice Loop: 2 r1c5 -2- r3c56 =2= r3c7 =3= r1c7 =6= r1c4 =7= r1c5 => r1c5<>2
Hidden Rectangle: 3/7 in r1c45,r4c45 => r4c4<>3
Forcing Net Verity => r1c4=6
r1c1=8 r1c3<>8 r1c3=9 (r3c3<>9) r5c3<>9 r5c3=4 r3c3<>4 r3c3=6 r3c2<>6 r3c2=4 (r2c1<>4) r2c2<>4 r2c4=4 r2c4<>6 r1c4=6
r2c1=8 r2c8<>8 r2c8=6 r1c7<>6 r1c4=6
r5c1=8 (r5c1<>4 r5c3=4 r3c3<>4) r5c1<>9 r1c1=9 (r1c1<>3 r2c1=3 r2c1<>4) r3c3<>9 r3c3=6 r3c2<>6 r3c2=4 r2c2<>4 r2c4=4 r2c4<>6 r1c4=6
r7c1=8 (r8c2<>8) (r8c3<>8) r5c1<>8 r5c9=8 r8c9<>8 r8c8=8 r2c8<>8 r2c8=6 r1c7<>6 r1c4=6
r9c1=8 (r8c2<>8) (r8c3<>8) r5c1<>8 r5c9=8 r8c9<>8 r8c8=8 r2c8<>8 r2c8=6 r1c7<>6 r1c4=6
Hidden Single: r1c5=7
Hidden Single: r4c4=7
Naked Pair: 3,4 in r28c4 => r6c4<>3, r69c4<>4
Forcing Net Verity => r2c4=4
r1c1=8 r1c3<>8 r1c3=9 (r3c3<>9) r5c3<>9 r5c3=4 r3c3<>4 r3c3=6 r3c2<>6 r3c2=4 (r2c1<>4) r2c2<>4 r2c4=4
r2c1=8 (r2c1<>3) (r2c1<>2) (r2c9<>8) r2c8<>8 r2c8=6 r2c9<>6 r2c9=2 r2c2<>2 r1c1=2 r1c1<>3 r2c2=3 r2c4<>3 r2c4=4
r5c1=8 (r4c2<>8 r4c2=3 r2c2<>3) r5c1<>9 r1c1=9 r1c1<>3 r2c1=3 r2c4<>3 r2c4=4
r7c1=8 (r2c1<>8) (r8c2<>8) (r8c3<>8) r5c1<>8 r5c9=8 (r2c9<>8) r8c9<>8 r8c8=8 r2c8<>8 (r2c8=6 r2c9<>6 r2c9=2 r8c9<>2) r2c2=8 (r6c2<>8) r4c2<>8 r4c2=3 (r8c2<>3) r6c2<>3 r6c2=2 r8c2<>2 r8c3=2 r8c3<>3 r8c4=3 r2c4<>3 r2c4=4
r9c1=8 (r2c1<>8) (r8c2<>8) (r8c3<>8) r5c1<>8 r5c9=8 (r2c9<>8) r8c9<>8 r8c8=8 r2c8<>8 (r2c8=6 r2c9<>6 r2c9=2 r8c9<>2) r2c2=8 (r6c2<>8) r4c2<>8 r4c2=3 (r8c2<>3) r6c2<>3 r6c2=2 r8c2<>2 r8c3=2 r8c3<>3 r8c4=3 r2c4<>3 r2c4=4
Naked Single: r8c4=3
Locked Candidates Type 2 (Claiming): 3 in r2 => r1c1<>3
Almost Locked Set XZ-Rule: A=r2c189 {2368}, B=r79c1,r8c23,r9c2 {234568}, X=3, Z=6 => r2c2<>6
Locked Candidates Type 1 (Pointing): 6 in b1 => r3c7<>6
Naked Triple: 2,3,5 in r3c567 => r3c89<>5
Locked Pair: 1,9 in r3c89 => r1c8,r3c3<>9
Naked Triple: 2,3,8 in r246c2 => r89c2<>2, r89c2<>8
XY-Chain: 5 5- r1c8 -8- r1c3 -9- r5c3 -4- r3c3 -6- r3c2 -4- r8c2 -5 => r8c8<>5
Discontinuous Nice Loop: 8 r4c9 -8- r5c9 -9- r5c3 -4- r3c3 =4= r3c2 -4- r8c2 -5- r8c9 =5= r4c9 => r4c9<>8
Grouped Discontinuous Nice Loop: 8 r2c9 -8- r2c2 =8= r46c2 -8- r5c1 =8= r5c9 -8- r2c9 => r2c9<>8
Discontinuous Nice Loop: 4 r8c3 -4- r8c8 -8- r2c8 -6- r2c9 -2- r8c9 =2= r8c3 => r8c3<>4
Grouped Discontinuous Nice Loop: 8 r5c1 -8- r79c1 =8= r789c3 -8- r1c3 -9- r1c1 =9= r5c1 => r5c1<>8
Hidden Single: r5c9=8
Locked Candidates Type 2 (Claiming): 9 in r5 => r46c3<>9
Empty Rectangle: 8 in b3 (r8c38) => r1c3<>8
Naked Single: r1c3=9
Naked Single: r5c3=4
Full House: r5c1=9
Naked Single: r3c3=6
Naked Single: r3c2=4
Naked Single: r8c2=5
Naked Single: r8c9=2
Naked Single: r9c2=6
Naked Single: r2c9=6
Naked Single: r8c3=8
Full House: r8c8=4
Naked Single: r2c8=8
Naked Single: r7c9=1
Naked Single: r1c8=5
Naked Single: r3c9=9
Full House: r4c9=5
Naked Single: r9c8=7
Naked Single: r3c8=1
Naked Single: r4c7=4
Naked Single: r7c8=6
Full House: r6c8=9
Full House: r6c7=6
Naked Single: r9c3=2
Naked Single: r7c7=8
Full House: r9c7=5
Naked Single: r6c4=1
Full House: r9c4=9
Naked Single: r9c1=4
Naked Single: r6c3=3
Naked Single: r7c1=3
Full House: r7c3=7
Full House: r4c3=1
Naked Single: r9c5=8
Full House: r9c6=1
Naked Single: r4c2=8
Full House: r6c2=2
Full House: r2c2=3
Full House: r2c1=2
Full House: r1c1=8
Naked Single: r6c5=4
Full House: r6c6=8
Naked Single: r4c6=3
Full House: r4c5=9
Naked Single: r7c5=2
Full House: r3c5=3
Full House: r7c6=4
Naked Single: r1c6=2
Full House: r1c7=3
Full House: r3c7=2
Full House: r3c6=5
|
normal_sudoku_746
|
.943...1.1....4938....19.4.96.1..4.2.15.4..934....35617415..3.9.394.1.5....93.1.4
|
694385217157624938328719645963157482815246793472893561741568329239471856586932174
|
Basic 9x9 Sudoku 746
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 9 4 3 . . . 1 .
1 . . . . 4 9 3 8
. . . . 1 9 . 4 .
9 6 . 1 . . 4 . 2
. 1 5 . 4 . . 9 3
4 . . . . 3 5 6 1
7 4 1 5 . . 3 . 9
. 3 9 4 . 1 . 5 .
. . . 9 3 . 1 . 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
694385217157624938328719645963157482815246793472893561741568329239471856586932174 #1 Medium (776)
Hidden Single: r2c7=9
Hidden Single: r2c1=1
Hidden Single: r4c7=4
Hidden Single: r7c2=4
Hidden Single: r8c4=4
Hidden Single: r9c7=1
Hidden Single: r6c9=1
Hidden Single: r7c9=9
Hidden Single: r4c4=1
Hidden Single: r6c1=4
Hidden Single: r9c5=3
Hidden Single: r5c9=3
Hidden Single: r7c7=3
Hidden Single: r4c1=9
Hidden Single: r9c4=9
Hidden Single: r6c5=9
Hidden Single: r4c3=3
Hidden Single: r3c1=3
Locked Candidates Type 1 (Pointing): 2 in b3 => r8c7<>2
Locked Candidates Type 1 (Pointing): 7 in b4 => r6c4<>7
Locked Candidates Type 1 (Pointing): 6 in b9 => r8c15<>6
Locked Candidates Type 1 (Pointing): 6 in b7 => r9c6<>6
Naked Pair: 2,8 in r58c1 => r19c1<>2, r19c1<>8
Locked Candidates Type 1 (Pointing): 8 in b1 => r3c4<>8
Locked Candidates Type 2 (Claiming): 8 in c4 => r4c56,r5c6<>8
Hidden Single: r4c8=8
Full House: r5c7=7
Naked Single: r7c8=2
Full House: r9c8=7
Naked Single: r8c9=6
Full House: r8c7=8
Naked Single: r8c1=2
Full House: r8c5=7
Naked Single: r5c1=8
Naked Single: r4c5=5
Full House: r4c6=7
Hidden Single: r9c6=2
Naked Single: r5c6=6
Full House: r5c4=2
Full House: r6c4=8
Naked Single: r7c6=8
Full House: r1c6=5
Full House: r7c5=6
Naked Single: r1c1=6
Full House: r9c1=5
Naked Single: r1c9=7
Full House: r3c9=5
Naked Single: r2c5=2
Full House: r1c5=8
Full House: r1c7=2
Full House: r3c7=6
Naked Single: r9c2=8
Full House: r9c3=6
Naked Single: r2c3=7
Naked Single: r3c4=7
Full House: r2c4=6
Full House: r2c2=5
Naked Single: r3c2=2
Full House: r3c3=8
Full House: r6c3=2
Full House: r6c2=7
|
normal_sudoku_2192
|
.1..89....8.1.7....6.435....7..9..5.95....47.124573869.913..7.5.4.95213..3..18...
|
312689547485127693769435218678294351953861472124573869291346785847952136536718924
|
Basic 9x9 Sudoku 2192
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 1 . . 8 9 . . .
. 8 . 1 . 7 . . .
. 6 . 4 3 5 . . .
. 7 . . 9 . . 5 .
9 5 . . . . 4 7 .
1 2 4 5 7 3 8 6 9
. 9 1 3 . . 7 . 5
. 4 . 9 5 2 1 3 .
. 3 . . 1 8 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
312689547485127693769435218678294351953861472124573869291346785847952136536718924 #1 Medium (416)
Naked Single: r6c2=2
Naked Single: r3c2=6
Full House: r9c2=3
Naked Single: r6c3=4
Naked Single: r6c9=9
Full House: r6c4=5
Hidden Single: r7c3=1
Hidden Single: r8c5=5
Hidden Single: r2c6=7
Hidden Single: r7c4=3
Hidden Single: r8c4=9
Hidden Single: r4c5=9
Hidden Single: r2c4=1
Hidden Single: r9c4=7
Hidden Single: r4c6=4
Naked Single: r7c6=6
Full House: r5c6=1
Full House: r7c5=4
Hidden Single: r3c8=1
Hidden Single: r4c9=1
Hidden Single: r3c9=8
Naked Single: r8c9=6
Hidden Single: r7c8=8
Full House: r7c1=2
Naked Single: r3c1=7
Naked Single: r8c1=8
Full House: r8c3=7
Hidden Single: r1c9=7
Naked Pair: 2,9 in r39c7 => r124c7<>2, r2c7<>9
Naked Single: r4c7=3
Full House: r5c9=2
Naked Single: r4c1=6
Naked Single: r5c5=6
Full House: r2c5=2
Full House: r1c4=6
Naked Single: r9c9=4
Full House: r2c9=3
Naked Single: r4c3=8
Full House: r4c4=2
Full House: r5c4=8
Full House: r5c3=3
Naked Single: r9c1=5
Full House: r9c3=6
Naked Single: r1c7=5
Naked Single: r2c1=4
Full House: r1c1=3
Naked Single: r1c3=2
Full House: r1c8=4
Naked Single: r2c7=6
Naked Single: r2c8=9
Full House: r2c3=5
Full House: r3c3=9
Full House: r3c7=2
Full House: r9c8=2
Full House: r9c7=9
|
normal_sudoku_138
|
2......87.7..8.6....8..9.1...35.8.9.5...67823.....35....419...8.9.83..4......4...
|
235641987971382654648759312763528491519467823482913576324195768197836245856274139
|
Basic 9x9 Sudoku 138
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
2 . . . . . . 8 7
. 7 . . 8 . 6 . .
. . 8 . . 9 . 1 .
. . 3 5 . 8 . 9 .
5 . . . 6 7 8 2 3
. . . . . 3 5 . .
. . 4 1 9 . . . 8
. 9 . 8 3 . . 4 .
. . . . . 4 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
235641987971382654648759312763528491519467823482913576324195768197836245856274139 #1 Extreme (30132) bf
Brute Force: r5c6=7
Locked Candidates Type 1 (Pointing): 1 in b5 => r1c5<>1
Locked Candidates Type 1 (Pointing): 7 in b8 => r9c1378<>7
Skyscraper: 7 in r7c8,r8c3 (connected by r6c38) => r7c1,r8c7<>7
Discontinuous Nice Loop: 2 r5c4 -2- r5c8 -8- r5c7 =8= r1c7 =9= r1c3 -9- r5c3 =9= r5c4 => r5c4<>2
Grouped Discontinuous Nice Loop: 1 r6c1 -1- r5c23 =1= r5c7 =8= r1c7 =9= r1c3 -9- r2c1 =9= r6c1 => r6c1<>1
Forcing Net Contradiction in c3 => r1c7<>3
r1c7=3 (r1c7<>9 r1c3=9 r2c3<>9) (r2c8<>3) r1c7<>8 r1c8=8 r5c8<>8 r5c8=2 r2c8<>2 r2c8=5 r2c3<>5 r2c3=1
r1c7=3 (r1c7<>9 r1c3=9 r5c3<>9) r1c7<>8 r1c8=8 r5c8<>8 r5c8=2 r5c3<>2 r5c3=1
Forcing Net Contradiction in r2 => r4c1<>6
r4c1=6 (r3c1<>6) r7c1<>6 r7c1=3 r3c1<>3 r3c1=4 r2c1<>4
r4c1=6 (r7c1<>6 r7c1=3 r2c1<>3) (r7c1<>6 r7c1=3 r3c1<>3 r3c1=4 r3c7<>4) (r7c1<>6 r7c1=3 r7c7<>3) r4c1<>7 r4c7=7 r7c7<>7 r7c7=2 r3c7<>2 r3c7=3 r2c8<>3 r2c4=3 r2c4<>4
r4c1=6 (r7c1<>6 r7c1=3 r7c7<>3) r4c1<>7 r4c7=7 r7c7<>7 r7c7=2 (r9c7<>2) (r3c7<>2 r3c7=3 r9c7<>3) r8c7<>2 r8c7=1 r9c7<>1 r9c7=9 r9c9<>9 r2c9=9 r2c9<>4
Forcing Net Contradiction in r3 => r4c7<>2
r4c7=2 (r4c7<>7 r4c1=7 r8c1<>7 r8c1=6 r3c1<>6) (r3c7<>2) (r5c7<>2) (r5c8<>2 r5c8=8 r5c7<>8) r8c7<>2 r8c7=1 r5c7<>1 r5c7=4 r3c7<>4 r3c7=3 r3c1<>3 r3c1=4
r4c7=2 (r4c7<>7 r4c1=7 r8c1<>7 r8c1=6 r3c1<>6) (r3c7<>2) (r5c7<>2) (r5c8<>2 r5c8=8 r5c7<>8) r8c7<>2 r8c7=1 r5c7<>1 r5c7=4 (r3c7<>4) r3c7<>4 r3c7=3 r3c1<>3 r3c1=4 (r3c2<>4) (r3c4<>4) r3c5<>4 r3c9=4
Forcing Net Contradiction in c3 => r5c2<>8
r5c2=8 r5c7<>8 r1c7=8 r1c7<>9 r1c3=9 r1c3<>6
r5c2=8 (r6c2<>8 r6c8=8 r6c8<>7) r5c7<>8 r1c7=8 r1c7<>9 r1c3=9 r2c1<>9 r6c1=9 r6c1<>7 r6c3=7 r6c3<>6
r5c2=8 (r9c2<>8 r9c1=8 r9c1<>3) (r5c7<>8 r1c7=8 r1c7<>9 r9c7=9 r9c7<>3) (r6c1<>8) r6c2<>8 r6c8=8 (r6c8<>6) r6c8<>7 r7c8=7 r7c8<>6 r9c8=6 r9c8<>3 r9c2=3 r7c1<>3 r7c1=6 r8c3<>6
r5c2=8 (r6c1<>8) r6c2<>8 r6c8=8 (r6c8<>6) r6c8<>7 r7c8=7 r7c8<>6 r9c8=6 r9c3<>6
Locked Candidates Type 1 (Pointing): 8 in b4 => r6c8<>8
Grouped Discontinuous Nice Loop: 1 r6c2 -1- r5c23 =1= r5c7 =8= r1c7 =9= r1c3 -9- r2c1 =9= r6c1 =8= r6c2 => r6c2<>1
Forcing Net Contradiction in b9 => r7c8<>2
r7c8=2 r7c8<>7 r7c7=7 r7c7<>3
r7c8=2 r7c8<>3
r7c8=2 r5c8<>2 r5c8=8 r1c8<>8 r1c7=8 r1c7<>9 r9c7=9 r9c7<>3
r7c8=2 (r7c8<>6) r7c8<>7 r6c8=7 r6c8<>6 r9c8=6 r9c8<>3
Forcing Net Contradiction in r2 => r3c4<>4
r3c4=4 (r5c4<>4 r5c4=9 r5c3<>9) (r5c4<>4 r5c4=9 r6c4<>9 r6c4=2 r6c8<>2) (r1c5<>4 r1c5=5 r9c5<>5) r3c4<>7 r3c5=7 r9c5<>7 (r9c4=7 r9c4<>6 r1c4=6 r1c6<>6 r1c6=1 r2c6<>1) r9c5=2 (r9c8<>2) (r7c6<>2) r8c6<>2 r2c6=2 r2c8<>2 r5c8=2 r5c3<>2 r5c3=1 r2c3<>1 r2c1=1 r2c1<>4
r3c4=4 r2c4<>4
r3c4=4 (r1c5<>4 r1c5=5 r1c3<>5) (r1c5<>4 r1c5=5 r1c6<>5) (r3c4<>6) r3c4<>7 r3c5=7 r9c5<>7 r9c4=7 r9c4<>6 r1c4=6 (r1c3<>6) r1c6<>6 r1c6=1 r1c3<>1 r1c3=9 (r2c1<>9) r2c3<>9 r2c9=9 r2c9<>4
Forcing Net Contradiction in r6c8 => r9c5<>2
r9c5=2 (r4c5<>2) r6c5<>2 r6c4=2 r6c8<>2
r9c5=2 (r4c5<>2) (r6c5<>2 r6c4=2 r6c8<>2) (r9c8<>2) (r7c6<>2) r8c6<>2 r2c6=2 r2c8<>2 r5c8=2 r4c9<>2 r4c2=2 r4c2<>6 r4c9=6 r6c8<>6
r9c5=2 (r6c5<>2 r6c4=2 r6c3<>2) (r9c3<>2) (r6c5<>2 r6c4=2 r6c8<>2) (r9c8<>2) (r7c6<>2) r8c6<>2 r2c6=2 r2c8<>2 r5c8=2 r5c3<>2 r8c3=2 r8c3<>7 r6c3=7 r6c8<>7
Brute Force: r5c7=8
Naked Single: r5c8=2
Hidden Single: r1c8=8
Locked Candidates Type 2 (Claiming): 1 in r5 => r4c12,r6c3<>1
Grouped Discontinuous Nice Loop: 1 r8c3 -1- r5c3 -9- r6c1 =9= r2c1 =1= r89c1 -1- r8c3 => r8c3<>1
Grouped Discontinuous Nice Loop: 1 r9c3 -1- r5c3 -9- r6c1 =9= r2c1 =1= r89c1 -1- r9c3 => r9c3<>1
Grouped Discontinuous Nice Loop: 6 r9c9 -6- r79c8 =6= r6c8 =7= r4c7 -7- r4c1 -4- r5c2 -1- r5c3 -9- r1c3 =9= r1c7 -9- r9c7 =9= r9c9 => r9c9<>6
Grouped Discontinuous Nice Loop: 6 r8c3 -6- r8c9 =6= r79c8 -6- r6c8 -7- r6c3 =7= r8c3 => r8c3<>6
Almost Locked Set XZ-Rule: A=r9c3458 {23567}, B=r14789c7 {123479}, X=3, Z=2 => r9c9<>2
Almost Locked Set XY-Wing: A=r9c5 {57}, B=r125c3 {1569}, C=r3c12579 {234567}, X,Y=6,7, Z=5 => r9c3<>5
Finned Franken Swordfish: 4 r25b6 c149 fr4c7 fr5c2 => r4c1<>4
Naked Single: r4c1=7
Hidden Single: r7c7=7
Hidden Single: r6c8=7
Hidden Single: r8c3=7
Locked Candidates Type 1 (Pointing): 6 in b6 => r8c9<>6
Locked Candidates Type 1 (Pointing): 5 in b7 => r13c2<>5
Skyscraper: 5 in r3c5,r8c6 (connected by r38c9) => r12c6,r9c5<>5
Naked Single: r9c5=7
Hidden Single: r3c4=7
Locked Candidates Type 1 (Pointing): 6 in b2 => r1c23<>6
Naked Pair: 2,6 in r9c34 => r9c128<>6, r9c27<>2
Hidden Single: r7c8=6
Naked Single: r7c1=3
Locked Candidates Type 1 (Pointing): 2 in b9 => r8c6<>2
Naked Triple: 1,5,9 in r125c3 => r6c3<>9
XY-Chain: 1 1- r2c6 -2- r7c6 -5- r8c6 -6- r8c1 -1 => r2c1<>1
Locked Candidates Type 2 (Claiming): 1 in c1 => r9c2<>1
W-Wing: 4/9 in r2c1,r5c4 connected by 9 in r6c14 => r2c4<>4
AIC: 4 4- r2c9 =4= r2c1 =9= r6c1 -9- r5c3 -1- r5c2 =1= r1c2 -1- r1c6 -6- r8c6 =6= r8c1 -6- r3c1 -4 => r2c1,r3c79<>4
Naked Single: r2c1=9
Hidden Single: r2c9=4
Naked Single: r1c7=9
Hidden Single: r5c3=9
Naked Single: r5c4=4
Full House: r5c2=1
Hidden Single: r9c9=9
Hidden Single: r6c4=9
Hidden Single: r4c7=4
Locked Candidates Type 1 (Pointing): 2 in b3 => r3c5<>2
Locked Candidates Type 1 (Pointing): 1 in b6 => r8c9<>1
Naked Pair: 2,6 in r4c2,r6c3 => r6c12<>6, r6c2<>2
Bivalue Universal Grave + 1 => r3c2<>3, r3c2<>6
Naked Single: r3c2=4
Naked Single: r1c2=3
Naked Single: r3c1=6
Naked Single: r3c5=5
Naked Single: r6c2=8
Naked Single: r1c4=6
Naked Single: r8c1=1
Naked Single: r1c5=4
Naked Single: r3c9=2
Full House: r3c7=3
Full House: r2c8=5
Full House: r9c8=3
Naked Single: r6c1=4
Full House: r9c1=8
Naked Single: r9c2=5
Naked Single: r1c6=1
Full House: r1c3=5
Full House: r2c3=1
Naked Single: r9c4=2
Full House: r2c4=3
Full House: r2c6=2
Naked Single: r8c7=2
Full House: r9c7=1
Full House: r8c9=5
Full House: r9c3=6
Full House: r7c2=2
Full House: r7c6=5
Full House: r8c6=6
Full House: r6c3=2
Full House: r4c2=6
Naked Single: r6c5=1
Full House: r4c5=2
Full House: r4c9=1
Full House: r6c9=6
|
normal_sudoku_2569
|
.438769.....2914.6.2.345..84.16.95.7...15764.7.54.2....5..24...3....8..4.9..1386.
|
143876952578291436629345718431689527982157643765432189856924371317568294294713865
|
Basic 9x9 Sudoku 2569
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 4 3 8 7 6 9 . .
. . . 2 9 1 4 . 6
. 2 . 3 4 5 . . 8
4 . 1 6 . 9 5 . 7
. . . 1 5 7 6 4 .
7 . 5 4 . 2 . . .
. 5 . . 2 4 . . .
3 . . . . 8 . . 4
. 9 . . 1 3 8 6 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
143876952578291436629345718431689527982157643765432189856924371317568294294713865 #1 Easy (254)
Hidden Single: r3c5=4
Hidden Single: r5c6=7
Naked Single: r2c6=1
Naked Single: r1c6=6
Naked Single: r9c6=3
Full House: r4c6=9
Hidden Single: r4c1=4
Hidden Single: r6c3=5
Hidden Single: r1c4=8
Full House: r1c5=7
Naked Single: r1c3=3
Naked Single: r9c5=1
Naked Single: r8c5=6
Naked Single: r9c1=2
Naked Single: r8c3=7
Naked Single: r9c9=5
Naked Single: r2c3=8
Naked Single: r8c2=1
Naked Single: r9c3=4
Full House: r9c4=7
Naked Single: r2c1=5
Naked Single: r2c2=7
Full House: r2c8=3
Naked Single: r7c3=6
Full House: r7c1=8
Naked Single: r8c7=2
Naked Single: r7c4=9
Full House: r8c4=5
Full House: r8c8=9
Naked Single: r1c1=1
Naked Single: r3c3=9
Full House: r3c1=6
Full House: r5c1=9
Full House: r5c3=2
Naked Single: r1c9=2
Full House: r1c8=5
Naked Single: r5c9=3
Full House: r5c2=8
Naked Single: r6c7=1
Naked Single: r7c9=1
Full House: r6c9=9
Naked Single: r4c2=3
Full House: r6c2=6
Naked Single: r3c7=7
Full House: r3c8=1
Full House: r7c7=3
Full House: r7c8=7
Naked Single: r6c8=8
Full House: r4c8=2
Full House: r4c5=8
Full House: r6c5=3
|
normal_sudoku_3557
|
.3.47..514.15.973....3.1.8424.6..19..7....8....9..5..3.5..1.4..6..25.3.......35.8
|
832476951461589732597321684245638197376192845189745263953817426618254379724963518
|
Basic 9x9 Sudoku 3557
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 3 . 4 7 . . 5 1
4 . 1 5 . 9 7 3 .
. . . 3 . 1 . 8 4
2 4 . 6 . . 1 9 .
. 7 . . . . 8 . .
. . 9 . . 5 . . 3
. 5 . . 1 . 4 . .
6 . . 2 5 . 3 . .
. . . . . 3 5 . 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
832476951461589732597321684245638197376192845189745263953817426618254379724963518 #1 Unfair (1700)
Hidden Single: r2c8=3
Hidden Single: r3c6=1
Hidden Single: r8c7=3
Hidden Single: r4c7=1
Hidden Single: r9c7=5
Hidden Single: r8c5=5
Hidden Single: r2c4=5
Locked Candidates Type 1 (Pointing): 4 in b3 => r5c9<>4
Locked Candidates Type 1 (Pointing): 9 in b9 => r3c9<>9
Naked Triple: 2,6,9 in r3c257 => r3c1<>9, r3c39<>2, r3c39<>6
Naked Single: r3c9=4
Hidden Single: r2c1=4
Empty Rectangle: 8 in b4 (r67c4) => r7c3<>8
XYZ-Wing: 2/4/6 in r5c68,r6c7 => r5c9<>2
XYZ-Wing: 1/7/8 in r4c6,r6c14 => r6c5<>8
Naked Pair: 2,4 in r5c6,r6c5 => r5c5<>2, r5c5<>4
Hidden Pair: 2,4 in r5c68 => r5c8<>6
Finned Swordfish: 6 c369 r157 fr2c9 => r1c7<>6
Multi Colors 1: 6 (r1c3,r5c9,r6c2,r7c6,r9c8) / (r1c6,r5c3,r9c5), (r2c9,r6c7) / (r3c7) => r3c5<>6
Naked Single: r3c5=2
Naked Single: r6c5=4
Naked Single: r5c6=2
Naked Single: r5c8=4
Hidden Single: r8c6=4
Hidden Single: r9c3=4
Locked Candidates Type 1 (Pointing): 8 in b8 => r7c1<>8
Skyscraper: 2 in r2c9,r9c8 (connected by r29c2) => r7c9<>2
Hidden Single: r2c9=2
Naked Single: r1c7=9
Full House: r3c7=6
Full House: r6c7=2
Naked Single: r1c1=8
Naked Single: r3c2=9
Naked Single: r1c6=6
Full House: r1c3=2
Full House: r2c5=8
Full House: r2c2=6
Naked Single: r6c1=1
Naked Single: r4c5=3
Naked Single: r6c2=8
Naked Single: r5c5=9
Full House: r9c5=6
Naked Single: r4c3=5
Naked Single: r6c4=7
Full House: r6c8=6
Naked Single: r8c2=1
Full House: r9c2=2
Naked Single: r5c4=1
Full House: r4c6=8
Full House: r4c9=7
Full House: r5c9=5
Full House: r7c6=7
Naked Single: r3c3=7
Full House: r3c1=5
Naked Single: r5c1=3
Full House: r5c3=6
Naked Single: r9c4=9
Full House: r7c4=8
Naked Single: r8c8=7
Naked Single: r8c9=9
Full House: r8c3=8
Full House: r7c3=3
Full House: r7c9=6
Naked Single: r7c8=2
Full House: r7c1=9
Full House: r9c1=7
Full House: r9c8=1
|
normal_sudoku_297
|
.2..7.65..75.629.11..5.9.27.1..97582.926.517.75.....69.4....2......5..1..3.......
|
924173658375862941186549327613497582492685173758231469847916235269358714531724896
|
Basic 9x9 Sudoku 297
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 2 . . 7 . 6 5 .
. 7 5 . 6 2 9 . 1
1 . . 5 . 9 . 2 7
. 1 . . 9 7 5 8 2
. 9 2 6 . 5 1 7 .
7 5 . . . . . 6 9
. 4 . . . . 2 . .
. . . . 5 . . 1 .
. 3 . . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
924173658375862941186549327613497582492685173758231469847916235269358714531724896 #1 Extreme (3292)
Hidden Single: r2c2=7
Hidden Single: r5c8=7
Hidden Single: r6c9=9
Hidden Single: r3c8=2
Hidden Single: r3c4=5
Hidden Single: r5c6=5
Hidden Single: r4c2=1
Hidden Single: r4c9=2
Hidden Single: r4c7=5
Skyscraper: 8 in r2c4,r5c5 (connected by r25c1) => r3c5,r6c4<>8
2-String Kite: 8 in r2c4,r8c2 (connected by r2c1,r3c2) => r8c4<>8
Turbot Fish: 8 r1c9 =8= r3c7 -8- r3c2 =8= r8c2 => r8c9<>8
Forcing Net Verity => r2c4=8
r5c1=3 (r5c9<>3 r5c9=4 r1c9<>4) (r2c1<>3) (r4c1<>3) r4c3<>3 r4c4=3 r2c4<>3 r2c8=3 r1c9<>3 r1c9=8 (r1c4<>8) r1c6<>8 r2c4=8
r5c1=4 (r5c9<>4 r5c9=3 r1c9<>3) (r2c1<>4) (r4c1<>4) r4c3<>4 r4c4=4 r2c4<>4 r2c8=4 r1c9<>4 r1c9=8 (r1c4<>8) r1c6<>8 r2c4=8
r5c1=8 r2c1<>8 r2c4=8
Finned Franken Swordfish: 3 r25b2 c159 fr1c4 fr1c6 fr2c8 => r1c9<>3
W-Wing: 4/3 in r2c1,r3c5 connected by 3 in r2c8,r3c7 => r3c3<>4
2-String Kite: 4 in r3c5,r9c8 (connected by r2c8,r3c7) => r9c5<>4
Turbot Fish: 4 r3c5 =4= r3c7 -4- r6c7 =4= r5c9 => r5c5<>4
Skyscraper: 4 in r2c8,r5c9 (connected by r25c1) => r1c9<>4
Naked Single: r1c9=8
Naked Pair: 3,4 in r3c57 => r3c3<>3
Naked Pair: 3,4 in r36c7 => r8c7<>3, r89c7<>4
X-Wing: 4 c57 r36 => r6c346<>4
Remote Pair: 3/4 r3c5 -4- r3c7 -3- r6c7 -4- r5c9 => r5c5<>3
Naked Single: r5c5=8
Hidden Single: r6c3=8
Naked Single: r3c3=6
Naked Single: r3c2=8
Full House: r8c2=6
Hidden Single: r4c1=6
Locked Triple: 1,7,9 in r789c3 => r1c3,r789c1<>9
Hidden Single: r1c1=9
Naked Pair: 3,4 in r58c9 => r7c9<>3, r9c9<>4
Hidden Triple: 5,6,8 in r7c169 => r7c6<>1, r7c6<>3
2-String Kite: 3 in r3c5,r7c8 (connected by r2c8,r3c7) => r7c5<>3
Naked Single: r7c5=1
Naked Single: r9c5=2
Hidden Single: r9c3=1
Hidden Single: r6c4=2
Hidden Single: r8c1=2
Hidden Single: r6c6=1
Hidden Single: r1c4=1
Remote Pair: 3/4 r1c6 -4- r1c3 -3- r4c3 -4- r5c1 -3- r5c9 -4- r8c9 => r8c6<>3, r8c6<>4
Naked Single: r8c6=8
Naked Single: r7c6=6
Naked Single: r8c7=7
Naked Single: r7c9=5
Naked Single: r9c6=4
Full House: r1c6=3
Full House: r1c3=4
Full House: r3c5=4
Full House: r2c1=3
Full House: r3c7=3
Full House: r6c5=3
Full House: r2c8=4
Full House: r6c7=4
Full House: r9c7=8
Full House: r4c4=4
Full House: r4c3=3
Full House: r5c1=4
Full House: r5c9=3
Naked Single: r8c3=9
Full House: r7c3=7
Naked Single: r7c1=8
Full House: r9c1=5
Naked Single: r9c9=6
Full House: r8c9=4
Full House: r8c4=3
Naked Single: r9c8=9
Full House: r7c8=3
Full House: r7c4=9
Full House: r9c4=7
|
normal_sudoku_3880
|
.9....1..4....9..7..72...39..6.2.973.8.7.36.....9.6..1....9...5..3..2.96.5.6.....
|
398574162421369587567281439146825973289713654735946821672198345813452796954637218
|
Basic 9x9 Sudoku 3880
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 9 . . . . 1 . .
4 . . . . 9 . . 7
. . 7 2 . . . 3 9
. . 6 . 2 . 9 7 3
. 8 . 7 . 3 6 . .
. . . 9 . 6 . . 1
. . . . 9 . . . 5
. . 3 . . 2 . 9 6
. 5 . 6 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
398574162421369587567281439146825973289713654735946821672198345813452796954637218 #1 Extreme (20788) bf
Hidden Pair: 3,7 in r6c12 => r6c12<>2, r6c1<>5, r6c2<>4
Brute Force: r5c7=6
Hidden Single: r4c7=9
Hidden Single: r1c2=9
Locked Candidates Type 1 (Pointing): 8 in b6 => r6c5<>8
Discontinuous Nice Loop: 6 r1c1 -6- r7c1 =6= r7c2 =2= r2c2 =3= r1c1 => r1c1<>6
Hidden Rectangle: 1/6 in r3c12,r7c12 => r7c1<>1
Discontinuous Nice Loop: 7 r7c1 -7- r6c1 -3- r6c2 =3= r2c2 =2= r7c2 =6= r7c1 => r7c1<>7
Forcing Net Contradiction in c1 => r1c5<>4
r1c5=4 r6c5<>4 r6c5=5 (r5c5<>5 r5c5=1 r3c5<>1) (r5c5<>5 r5c5=1 r4c4<>1) (r5c5<>5 r5c5=1 r4c6<>1) (r4c4<>5) r4c6<>5 r4c1=5 (r3c1<>5 r3c6=5 r3c6<>1) r4c1<>1 r4c2=1 r3c2<>1 r3c1=1
r1c5=4 r6c5<>4 r6c5=5 (r8c5<>5 r8c4=5 r8c4<>1) (r5c5<>5 r5c5=1 r8c5<>1) (r5c5<>5 r5c5=1 r4c4<>1) (r5c5<>5 r5c5=1 r4c6<>1) (r4c4<>5) r4c6<>5 r4c1=5 r4c1<>1 r4c2=1 r8c2<>1 r8c1=1
Forcing Net Contradiction in r3 => r1c5<>5
r1c5=5 r6c5<>5 r6c5=4 r3c5<>4
r1c5=5 (r6c5<>5 r6c5=4 r5c5<>4 r5c5=1 r3c5<>1) (r8c5<>5 r8c4=5 r8c4<>1) (r6c5<>5 r6c5=4 r5c5<>4 r5c5=1 r8c5<>1) (r1c6<>5) r3c6<>5 r4c6=5 r4c1<>5 r4c1=1 (r3c1<>1) r8c1<>1 r8c2=1 r3c2<>1 r3c6=1 r3c6<>4
r1c5=5 (r8c5<>5 r8c4=5 r8c4<>4) r6c5<>5 r6c5=4 (r8c5<>4) (r4c4<>4) r4c6<>4 r4c2=4 r8c2<>4 r8c7=4 r3c7<>4
Forcing Net Contradiction in r3 => r2c5<>5
r2c5=5 r6c5<>5 r6c5=4 r3c5<>4
r2c5=5 (r6c5<>5 r6c5=4 r5c5<>4 r5c5=1 r3c5<>1) (r8c5<>5 r8c4=5 r8c4<>1) (r6c5<>5 r6c5=4 r5c5<>4 r5c5=1 r8c5<>1) (r1c6<>5) r3c6<>5 r4c6=5 r4c1<>5 r4c1=1 (r3c1<>1) r8c1<>1 r8c2=1 r3c2<>1 r3c6=1 r3c6<>4
r2c5=5 (r8c5<>5 r8c4=5 r8c4<>4) r6c5<>5 r6c5=4 (r8c5<>4) (r4c4<>4) r4c6<>4 r4c2=4 r8c2<>4 r8c7=4 r3c7<>4
Forcing Net Contradiction in r3 => r3c5<>5
r3c5=5 r3c5<>4
r3c5=5 (r3c5<>1) (r8c5<>5 r8c4=5 r8c4<>1) (r6c5<>5 r6c5=4 r5c5<>4 r5c5=1 r8c5<>1) (r1c6<>5) r3c6<>5 r4c6=5 r4c1<>5 r4c1=1 (r3c1<>1) r8c1<>1 r8c2=1 r3c2<>1 r3c6=1 r3c6<>4
r3c5=5 (r8c5<>5 r8c4=5 r8c4<>4) r6c5<>5 r6c5=4 (r8c5<>4) (r4c4<>4) r4c6<>4 r4c2=4 r8c2<>4 r8c7=4 r3c7<>4
Forcing Net Contradiction in r3 => r1c1<>5
r1c1=5 (r3c1<>5) (r4c1<>5 r4c1=1 r3c1<>1) r1c1<>3 r6c1=3 r6c2<>3 r2c2=3 r2c2<>2 r7c2=2 r7c2<>6 r7c1=6 r3c1<>6 r3c1=8
r1c1=5 (r4c1<>5 r4c1=1 r5c3<>1 r5c5=1 r3c5<>1) (r4c1<>5 r4c1=1 r5c3<>1 r5c5=1 r5c5<>4 r6c5=4 r3c5<>4) r1c1<>3 r6c1=3 r6c2<>3 r2c2=3 (r2c2<>6) r2c2<>2 r7c2=2 r7c2<>6 r3c2=6 r3c5<>6 r3c5=8
Forcing Net Contradiction in r3 => r8c4<>1
r8c4=1 r8c4<>5 r8c5=5 r6c5<>5 r6c5=4 r3c5<>4
r8c4=1 (r7c6<>1) (r9c6<>1) r8c4<>5 r8c5=5 (r5c5<>5) r6c5<>5 r6c5=4 r5c5<>4 r5c5=1 r4c6<>1 r3c6=1 r3c6<>4
r8c4=1 (r8c4<>4) r8c4<>5 r8c5=5 (r8c5<>4) r6c5<>5 r6c5=4 (r4c4<>4) r4c6<>4 r4c2=4 r8c2<>4 r8c7=4 r3c7<>4
Forcing Net Contradiction in r1 => r4c2=4
r4c2<>4 r4c2=1 (r4c1<>1 r4c1=5 r6c3<>5) (r4c1<>1 r4c1=5 r5c1<>5) (r4c1<>1 r4c1=5 r5c3<>5) (r5c1<>1) r5c3<>1 r5c5=1 r5c5<>5 r5c8=5 (r1c8<>5) (r6c7<>5) r6c8<>5 r6c5=5 r8c5<>5 r8c4=5 r1c4<>5 r1c3=5
r4c2<>4 r4c2=1 (r4c1<>1 r4c1=5 r4c6<>5) (r3c2<>1) (r8c2<>1) (r5c1<>1) r5c3<>1 r5c5=1 (r3c5<>1) r8c5<>1 r8c1=1 r3c1<>1 r3c6=1 r3c6<>5 r1c6=5
Locked Candidates Type 1 (Pointing): 4 in b5 => r389c5<>4
Skyscraper: 4 in r3c6,r8c4 (connected by r38c7) => r1c4,r79c6<>4
Discontinuous Nice Loop: 4 r6c7 -4- r6c5 -5- r8c5 =5= r8c4 =4= r8c7 -4- r6c7 => r6c7<>4
Grouped Discontinuous Nice Loop: 1 r5c3 -1- r4c1 -5- r4c46 =5= r56c5 -5- r8c5 =5= r8c4 =4= r8c7 -4- r9c789 =4= r9c3 =9= r5c3 => r5c3<>1
Locked Candidates Type 1 (Pointing): 1 in b4 => r389c1<>1
Empty Rectangle: 1 in b1 (r8c25) => r2c5<>1
Discontinuous Nice Loop: 8 r7c1 -8- r8c1 -7- r8c2 -1- r3c2 -6- r3c1 =6= r7c1 => r7c1<>8
Discontinuous Nice Loop: 1 r9c3 -1- r8c2 =1= r8c5 =5= r8c4 =4= r7c4 -4- r7c3 =4= r9c3 => r9c3<>1
Discontinuous Nice Loop: 2 r2c3 -2- r6c3 -5- r4c1 -1- r5c1 =1= r5c5 -1- r8c5 =1= r8c2 -1- r7c3 =1= r2c3 => r2c3<>2
Almost Locked Set XZ-Rule: A=r8c1247 {14578}, B=r1c45,r2c45,r3c5 {135678}, X=5, Z=7 => r8c5<>7
Almost Locked Set XZ-Rule: A=r56c5 {145}, B=r79c6,r8c5 {1578}, X=5, Z=1 => r9c5<>1
Forcing Chain Verity => r1c5=7
r3c2=1 r8c2<>1 r8c5=1 r8c5<>5 r8c4=5 r8c4<>4 r7c4=4 r7c4<>3 r9c5=3 r9c5<>7 r1c5=7
r3c5=1 r5c5<>1 r5c1=1 r4c1<>1 r4c1=5 r4c46<>5 r56c5=5 r8c5<>5 r8c4=5 r8c4<>4 r7c4=4 r7c4<>3 r9c5=3 r9c5<>7 r1c5=7
r3c6=1 r3c6<>4 r1c6=4 r1c6<>7 r1c5=7
Hidden Single: r1c8=6
Discontinuous Nice Loop: 2/4/7/8 r7c7 =3= r7c4 =4= r8c4 =5= r8c5 =1= r8c2 -1- r3c2 -6- r3c5 =6= r2c5 =3= r9c5 -3- r9c7 =3= r7c7 => r7c7<>2, r7c7<>4, r7c7<>7, r7c7<>8
Naked Single: r7c7=3
Hidden Single: r9c5=3
Discontinuous Nice Loop: 1 r2c4 -1- r2c3 =1= r7c3 -1- r8c2 -7- r6c2 -3- r2c2 =3= r2c4 => r2c4<>1
Locked Candidates Type 1 (Pointing): 1 in b2 => r3c2<>1
Naked Single: r3c2=6
Hidden Single: r2c5=6
Hidden Single: r7c1=6
XYZ-Wing: 2/5/8 in r16c3,r3c1 => r2c3<>5
Continuous Nice Loop: 1/5/8 4= r7c4 =1= r4c4 -1- r4c1 -5- r3c1 -8- r3c5 =8= r8c5 =5= r8c4 =4= r7c4 =1 => r4c6,r8c5<>1, r5c1<>5, r3c67,r78c4<>8
Hidden Single: r8c2=1
Hidden Single: r2c3=1
Empty Rectangle: 8 in b1 (r19c9) => r9c1<>8
Sashimi Swordfish: 8 c159 r138 fr9c9 => r8c7<>8
X-Wing: 8 r38 c15 => r1c1<>8
Naked Pair: 2,3 in r1c1,r2c2 => r1c3<>2
W-Wing: 8/5 in r1c3,r4c6 connected by 5 in r34c1 => r1c6<>8
W-Wing: 4/5 in r1c6,r3c7 connected by 5 in r1c3,r3c1 => r1c9,r3c6<>4
Hidden Single: r1c6=4
Hidden Single: r3c7=4
Naked Single: r8c7=7
Naked Single: r8c1=8
Naked Single: r3c1=5
Naked Single: r8c5=5
Full House: r8c4=4
Naked Single: r1c3=8
Naked Single: r3c6=1
Full House: r3c5=8
Naked Single: r4c1=1
Naked Single: r6c5=4
Full House: r5c5=1
Naked Single: r7c4=1
Naked Single: r1c9=2
Naked Single: r1c1=3
Full House: r1c4=5
Full House: r2c2=2
Full House: r2c4=3
Full House: r4c4=8
Full House: r4c6=5
Naked Single: r5c9=4
Full House: r9c9=8
Naked Single: r6c1=7
Naked Single: r7c2=7
Full House: r6c2=3
Naked Single: r9c6=7
Full House: r7c6=8
Naked Single: r9c7=2
Naked Single: r7c8=4
Full House: r7c3=2
Full House: r9c8=1
Naked Single: r9c1=9
Full House: r5c1=2
Full House: r9c3=4
Naked Single: r6c3=5
Full House: r5c3=9
Full House: r5c8=5
Naked Single: r6c7=8
Full House: r2c7=5
Full House: r2c8=8
Full House: r6c8=2
|
normal_sudoku_3237
|
9.524867..27.9.8456......92....627.9.927..4687.64.952.2......54.7..24..6.....32.7
|
915248673327691845648357192854162739192735468736489521281976354573824916469513287
|
Basic 9x9 Sudoku 3237
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
9 . 5 2 4 8 6 7 .
. 2 7 . 9 . 8 4 5
6 . . . . . . 9 2
. . . . 6 2 7 . 9
. 9 2 7 . . 4 6 8
7 . 6 4 . 9 5 2 .
2 . . . . . . 5 4
. 7 . . 2 4 . . 6
. . . . . 3 2 . 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
915248673327691845648357192854162739192735468736489521281976354573824916469513287 #1 Hard (1162)
Hidden Single: r1c1=9
Hidden Single: r5c8=6
Hidden Single: r4c9=9
Hidden Single: r5c3=2
Hidden Single: r3c9=2
Hidden Single: r8c5=2
Hidden Single: r1c8=7
Hidden Single: r6c8=2
Hidden Single: r2c9=5
Hidden Single: r8c2=7
Hidden Single: r7c9=4
Hidden Single: r8c9=6
Skyscraper: 4 in r2c8,r5c7 (connected by r25c1) => r3c7,r4c8<>4
Hidden Single: r5c7=4
Hidden Single: r2c8=4
Naked Pair: 1,3 in r1c2,r2c1 => r3c23<>1, r3c23<>3
Remote Pair: 1/3 r1c2 -3- r1c9 -1- r6c9 -3- r4c8 => r4c2<>1, r4c2<>3
Skyscraper: 3 in r2c4,r5c5 (connected by r25c1) => r3c5,r4c4<>3
2-String Kite: 5 in r4c2,r8c4 (connected by r8c1,r9c2) => r4c4<>5
Locked Candidates Type 1 (Pointing): 5 in b5 => r5c1<>5
Naked Pair: 1,3 in r25c1 => r489c1<>1, r48c1<>3
Remote Pair: 1/3 r4c8 -3- r6c9 -1- r1c9 -3- r1c2 -1- r2c1 -3- r5c1 => r4c3<>1, r4c3<>3
Hidden Single: r4c8=3
Full House: r6c9=1
Full House: r1c9=3
Full House: r1c2=1
Full House: r3c7=1
Naked Single: r2c1=3
Naked Single: r5c1=1
Naked Single: r5c6=5
Full House: r5c5=3
Naked Single: r3c6=7
Naked Single: r6c5=8
Full House: r4c4=1
Full House: r6c2=3
Naked Single: r3c5=5
Naked Single: r2c4=6
Full House: r2c6=1
Full House: r3c4=3
Full House: r7c6=6
Naked Single: r9c5=1
Full House: r7c5=7
Naked Single: r7c2=8
Naked Single: r9c8=8
Full House: r8c8=1
Naked Single: r3c2=4
Full House: r3c3=8
Naked Single: r7c4=9
Naked Single: r8c1=5
Naked Single: r4c2=5
Full House: r9c2=6
Naked Single: r4c3=4
Full House: r4c1=8
Full House: r9c1=4
Naked Single: r7c7=3
Full House: r7c3=1
Full House: r8c7=9
Naked Single: r9c4=5
Full House: r8c4=8
Full House: r9c3=9
Full House: r8c3=3
|
normal_sudoku_3437
|
..82...56...35.8.2....6813.74..2..1..816735......1....51..3628.8..5.23.1.2.18..65
|
138294756697351842452768139745829613981673524263415978514936287876542391329187465
|
Basic 9x9 Sudoku 3437
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 8 2 . . . 5 6
. . . 3 5 . 8 . 2
. . . . 6 8 1 3 .
7 4 . . 2 . . 1 .
. 8 1 6 7 3 5 . .
. . . . 1 . . . .
5 1 . . 3 6 2 8 .
8 . . 5 . 2 3 . 1
. 2 . 1 8 . . 6 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
138294756697351842452768139745829613981673524263415978514936287876542391329187465 #1 Extreme (31594) bf
Hidden Single: r2c7=8
Hidden Single: r9c5=8
Hidden Single: r9c4=1
Hidden Single: r7c7=2
Hidden Single: r8c6=2
Hidden Single: r1c8=5
Hidden Single: r7c5=3
Hidden Single: r8c4=5
Naked Triple: 4,7,9 in r357c9 => r46c9<>9, r6c9<>4, r6c9<>7
Brute Force: r5c4=6
Brute Force: r5c3=1
Hidden Single: r4c8=1
Forcing Net Contradiction in r9 => r3c3<>9
r3c3=9 r3c3<>2 r3c1=2 r5c1<>2 r5c1=9 r9c1<>9
r3c3=9 r9c3<>9
r3c3=9 (r3c3<>5) r3c3<>2 r6c3=2 r6c3<>5 r4c3=5 r4c6<>5 r4c6=9 r9c6<>9
r3c3=9 (r3c9<>9) r3c3<>2 r3c1=2 r5c1<>2 r5c1=9 r5c9<>9 r7c9=9 r9c7<>9
Brute Force: r5c5=7
Locked Candidates Type 1 (Pointing): 4 in b5 => r6c78<>4
X-Wing: 7 c49 r37 => r3c23,r7c3<>7
Skyscraper: 4 in r8c5,r9c7 (connected by r1c57) => r8c8,r9c6<>4
W-Wing: 9/7 in r8c8,r9c6 connected by 7 in r7c49 => r8c5,r9c7<>9
Naked Single: r8c5=4
Full House: r1c5=9
Locked Candidates Type 2 (Claiming): 9 in c7 => r5c89,r6c8<>9
Naked Single: r5c9=4
Naked Single: r5c8=2
Full House: r5c1=9
Naked Single: r6c8=7
Naked Single: r8c8=9
Full House: r2c8=4
Naked Single: r7c9=7
Full House: r9c7=4
Naked Single: r1c7=7
Full House: r3c9=9
Naked Single: r7c4=9
Full House: r7c3=4
Full House: r9c6=7
Naked Single: r9c1=3
Full House: r9c3=9
Naked Single: r1c2=3
Naked Single: r3c2=5
Naked Single: r4c4=8
Naked Single: r2c6=1
Naked Single: r3c3=2
Naked Single: r6c2=6
Naked Single: r4c9=3
Full House: r6c9=8
Naked Single: r6c4=4
Full House: r3c4=7
Full House: r1c6=4
Full House: r3c1=4
Full House: r1c1=1
Naked Single: r2c1=6
Full House: r6c1=2
Naked Single: r6c7=9
Full House: r4c7=6
Naked Single: r8c2=7
Full House: r2c2=9
Full House: r2c3=7
Full House: r8c3=6
Naked Single: r4c3=5
Full House: r4c6=9
Full House: r6c6=5
Full House: r6c3=3
|
normal_sudoku_1505
|
6.9.4..155139...6....1.6......29....192.3.65.43..6.2.9986...1..2.1689..33.7.1.896
|
629348715513927468874156932768295341192834657435761289986573124241689573357412896
|
Basic 9x9 Sudoku 1505
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
6 . 9 . 4 . . 1 5
5 1 3 9 . . . 6 .
. . . 1 . 6 . . .
. . . 2 9 . . . .
1 9 2 . 3 . 6 5 .
4 3 . . 6 . 2 . 9
9 8 6 . . . 1 . .
2 . 1 6 8 9 . . 3
3 . 7 . 1 . 8 9 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
629348715513927468874156932768295341192834657435761289986573124241689573357412896 #1 Easy (402)
Naked Single: r8c1=2
Naked Single: r9c1=3
Hidden Single: r5c2=9
Hidden Single: r3c6=6
Hidden Single: r1c8=1
Hidden Single: r9c5=1
Hidden Single: r8c3=1
Hidden Single: r6c9=9
Hidden Single: r8c6=9
Hidden Single: r2c4=9
Hidden Single: r9c7=8
Hidden Single: r5c3=2
Hidden Single: r5c7=6
Hidden Single: r4c2=6
Hidden Single: r3c5=5
Hidden Single: r9c6=2
Naked Single: r7c5=7
Full House: r2c5=2
Hidden Single: r3c3=4
Hidden Single: r3c7=9
Hidden Single: r6c6=1
Hidden Single: r4c9=1
Hidden Single: r8c7=5
Naked Single: r8c2=4
Full House: r8c8=7
Full House: r9c2=5
Full House: r9c4=4
Naked Single: r6c8=8
Naked Single: r6c3=5
Full House: r4c3=8
Full House: r6c4=7
Full House: r4c1=7
Full House: r3c1=8
Naked Single: r5c4=8
Naked Single: r1c4=3
Full House: r7c4=5
Full House: r7c6=3
Naked Single: r5c6=4
Full House: r4c6=5
Full House: r5c9=7
Naked Single: r1c7=7
Naked Single: r3c9=2
Naked Single: r1c2=2
Full House: r1c6=8
Full House: r3c2=7
Full House: r3c8=3
Full House: r2c6=7
Naked Single: r2c7=4
Full House: r2c9=8
Full House: r7c9=4
Full House: r4c7=3
Full House: r4c8=4
Full House: r7c8=2
|
normal_sudoku_3899
|
..3..268.4.6...5...28..6..38..6...7..6547.....3...1456.8136...969.12...53....9.6.
|
953712684476938521128546793814695372265473918739281456581367249697124835342859167
|
Basic 9x9 Sudoku 3899
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 3 . . 2 6 8 .
4 . 6 . . . 5 . .
. 2 8 . . 6 . . 3
8 . . 6 . . . 7 .
. 6 5 4 7 . . . .
. 3 . . . 1 4 5 6
. 8 1 3 6 . . . 9
6 9 . 1 2 . . . 5
3 . . . . 9 . 6 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
953712684476938521128546793814695372265473918739281456581367249697124835342859167 #1 Unfair (1128)
Hidden Single: r1c7=6
Hidden Single: r3c3=8
Hidden Single: r4c4=6
Hidden Single: r6c8=5
Hidden Single: r8c1=6
Hidden Single: r9c8=6
Locked Candidates Type 1 (Pointing): 9 in b1 => r56c1<>9
Locked Candidates Type 1 (Pointing): 8 in b6 => r5c6<>8
Locked Candidates Type 2 (Claiming): 9 in r5 => r4c7<>9
Skyscraper: 4 in r3c5,r7c6 (connected by r37c8) => r1c6,r9c5<>4
2-String Kite: 5 in r1c2,r7c6 (connected by r7c1,r9c2) => r1c6<>5
Finned X-Wing: 5 c24 r19 fr3c4 => r1c5<>5
Finned Swordfish: 7 c249 r129 fr3c4 => r12c6<>7
Naked Single: r1c6=2
Naked Single: r5c6=3
Naked Single: r2c6=8
Naked Single: r4c6=5
Naked Single: r4c5=9
Naked Single: r6c5=8
Full House: r6c4=2
Naked Single: r9c5=5
Naked Single: r6c1=7
Full House: r6c3=9
Hidden Single: r2c5=3
Hidden Single: r4c7=3
Hidden Single: r8c8=3
Hidden Single: r8c7=8
Hidden Single: r7c1=5
Hidden Single: r9c4=8
Hidden Single: r1c2=5
Hidden Single: r5c9=8
Hidden Single: r3c4=5
Hidden Single: r5c1=2
Naked Single: r4c3=4
Full House: r4c2=1
Full House: r4c9=2
Naked Single: r8c3=7
Full House: r8c6=4
Full House: r9c3=2
Full House: r9c2=4
Full House: r2c2=7
Full House: r7c6=7
Naked Single: r2c4=9
Full House: r1c4=7
Naked Single: r2c9=1
Full House: r2c8=2
Naked Single: r7c7=2
Full House: r7c8=4
Naked Single: r1c9=4
Full House: r9c9=7
Full House: r9c7=1
Naked Single: r3c8=9
Full House: r3c7=7
Full House: r5c7=9
Full House: r5c8=1
Naked Single: r1c5=1
Full House: r1c1=9
Full House: r3c1=1
Full House: r3c5=4
|
normal_sudoku_1695
|
.9.1..832.5.283469.3.9..571.7.31.62..124.835..8.7.....32.69...5.6.527....4.83....
|
496175832157283469238946571574319628912468357683752914321694785869527143745831296
|
Basic 9x9 Sudoku 1695
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 9 . 1 . . 8 3 2
. 5 . 2 8 3 4 6 9
. 3 . 9 . . 5 7 1
. 7 . 3 1 . 6 2 .
. 1 2 4 . 8 3 5 .
. 8 . 7 . . . . .
3 2 . 6 9 . . . 5
. 6 . 5 2 7 . . .
. 4 . 8 3 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
496175832157283469238946571574319628912468357683752914321694785869527143745831296 #1 Easy (208)
Naked Single: r1c8=3
Naked Single: r5c2=1
Naked Single: r7c4=6
Naked Single: r8c4=5
Naked Single: r1c9=2
Naked Single: r2c9=9
Full House: r3c7=5
Naked Single: r6c2=8
Full House: r7c2=2
Naked Single: r3c4=9
Full House: r6c4=7
Naked Single: r9c5=3
Naked Single: r2c6=3
Naked Single: r5c9=7
Naked Single: r5c5=6
Full House: r5c1=9
Naked Single: r6c9=4
Naked Single: r9c6=1
Full House: r7c6=4
Naked Single: r9c9=6
Naked Single: r3c5=4
Naked Single: r6c5=5
Full House: r1c5=7
Naked Single: r4c9=8
Full House: r8c9=3
Naked Single: r9c8=9
Naked Single: r3c6=6
Full House: r1c6=5
Naked Single: r4c6=9
Full House: r6c6=2
Naked Single: r6c1=6
Naked Single: r6c8=1
Full House: r6c7=9
Full House: r6c3=3
Naked Single: r8c7=1
Naked Single: r3c3=8
Full House: r3c1=2
Naked Single: r1c1=4
Full House: r1c3=6
Naked Single: r7c8=8
Full House: r8c8=4
Naked Single: r7c7=7
Full House: r7c3=1
Full House: r9c7=2
Naked Single: r8c1=8
Full House: r8c3=9
Naked Single: r4c1=5
Full House: r4c3=4
Naked Single: r2c3=7
Full House: r2c1=1
Full House: r9c1=7
Full House: r9c3=5
|
normal_sudoku_2144
|
.9341..27..7.....15.1..79...75..3...3168.42....9.5.3..138....4675264....964.387.2
|
893415627627389451541267983475923168316874295289156374138792546752641839964538712
|
Basic 9x9 Sudoku 2144
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 9 3 4 1 . . 2 7
. . 7 . . . . . 1
5 . 1 . . 7 9 . .
. 7 5 . . 3 . . .
3 1 6 8 . 4 2 . .
. . 9 . 5 . 3 . .
1 3 8 . . . . 4 6
7 5 2 6 4 . . . .
9 6 4 . 3 8 7 . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
893415627627389451541267983475923168316874295289156374138792546752641839964538712 #1 Easy (282)
Naked Single: r5c2=1
Naked Single: r5c3=6
Hidden Single: r1c3=3
Hidden Single: r9c9=2
Hidden Single: r9c3=4
Hidden Single: r8c5=4
Hidden Single: r3c3=1
Hidden Single: r7c2=3
Hidden Single: r8c1=7
Naked Single: r7c3=8
Full House: r2c3=7
Naked Single: r7c1=1
Full House: r8c2=5
Naked Single: r7c7=5
Naked Single: r9c8=1
Full House: r9c4=5
Naked Single: r8c7=8
Naked Single: r1c7=6
Naked Single: r1c1=8
Full House: r1c6=5
Naked Single: r2c7=4
Full House: r4c7=1
Naked Single: r2c2=2
Naked Single: r2c1=6
Full House: r3c2=4
Full House: r6c2=8
Naked Single: r2c6=9
Naked Single: r6c9=4
Naked Single: r2c4=3
Naked Single: r2c5=8
Full House: r2c8=5
Naked Single: r7c6=2
Naked Single: r8c6=1
Full House: r6c6=6
Naked Single: r6c1=2
Full House: r4c1=4
Naked Single: r3c4=2
Full House: r3c5=6
Naked Single: r6c8=7
Full House: r6c4=1
Naked Single: r4c4=9
Full House: r7c4=7
Full House: r7c5=9
Naked Single: r5c8=9
Naked Single: r4c5=2
Full House: r5c5=7
Full House: r5c9=5
Naked Single: r4c9=8
Full House: r4c8=6
Naked Single: r8c8=3
Full House: r3c8=8
Full House: r3c9=3
Full House: r8c9=9
|
normal_sudoku_5249
|
37...8.2..82.7...1..4...78..67.2..1.84...52.721......64.8.........9......26.8.1..
|
371658924982374561654291783567429318843165297219837456498712635135946872726583149
|
Basic 9x9 Sudoku 5249
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
3 7 . . . 8 . 2 .
. 8 2 . 7 . . . 1
. . 4 . . . 7 8 .
. 6 7 . 2 . . 1 .
8 4 . . . 5 2 . 7
2 1 . . . . . . 6
4 . 8 . . . . . .
. . . 9 . . . . .
. 2 6 . 8 . 1 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
371658924982374561654291783567429318843165297219837456498712635135946872726583149 #1 Extreme (38926) bf
Hidden Single: r1c2=7
Hidden Single: r5c7=2
Hidden Single: r2c3=2
Discontinuous Nice Loop: 7 r8c6 -7- r6c6 =7= r6c4 =8= r6c7 -8- r8c7 =8= r8c9 =2= r8c6 => r8c6<>7
Forcing Net Contradiction in c1 => r3c4<>1
r3c4=1 r3c1<>1
r3c4=1 r3c4<>2 r3c6=2 r8c6<>2 r8c9=2 r8c9<>8 r8c7=8 r6c7<>8 r6c4=8 r5c4<>8 r5c1=8 r5c1<>1
r3c4=1 r3c4<>2 (r7c4=2 r7c4<>7) r3c6=2 r8c6<>2 r8c9=2 r8c9<>8 r8c7=8 r6c7<>8 r6c4=8 r6c4<>7 r9c4=7 r9c1<>7 r8c1=7 r8c1<>1
Brute Force: r6c2=1
Hidden Single: r5c2=4
Locked Candidates Type 1 (Pointing): 3 in b4 => r8c3<>3
Locked Candidates Type 1 (Pointing): 1 in b7 => r8c56<>1
Naked Pair: 3,9 in r5c38 => r5c15<>9, r5c45<>3
Naked Single: r5c1=8
W-Wing: 5/9 in r3c2,r4c1 connected by 9 in r7c2,r9c1 => r23c1<>5
Almost Locked Set XY-Wing: A=r38c2 {359}, B=r2469c6 {34679}, C=r2c1 {69}, X,Y=6,9, Z=3 => r8c6<>3
Forcing Net Contradiction in r7c7 => r3c4=2
r3c4<>2 (r7c4=2 r7c4<>7) r3c6=2 r3c6<>1 r7c6=1 (r7c6<>6) r7c6<>7 r7c8=7 (r7c8<>6) r8c8<>7 r8c1=7 r8c1<>1 r3c1=1 r3c1<>6 r2c1=6 r2c8<>6 r8c8=6 (r8c6<>6) r8c8<>7 r8c1=7 r8c1<>1 r3c1=1 r3c1<>6 r2c1=6 r2c6<>6 r3c6=6 r3c6<>2 r3c4=2
Discontinuous Nice Loop: 9 r7c9 -9- r7c2 =9= r3c2 =5= r1c3 =1= r3c1 -1- r3c6 =1= r7c6 =2= r7c9 => r7c9<>9
Forcing Net Contradiction in r7c7 => r1c5<>6
r1c5=6 (r3c6<>6) (r3c5<>6) r3c6<>6 r3c1=6 r3c1<>1 (r3c6=1 r7c6<>1 r7c4=1 r7c4<>7) r8c1=1 r8c1<>7 r8c8=7 r7c8<>7 r7c6=7 (r7c6<>6) r7c6<>2 r7c9=2 r8c9<>2 r8c6=2 r8c6<>6 r2c6=6 r1c5<>6
Forcing Net Verity => r1c7<>5
r1c5=1 (r5c5<>1 r5c5=6 r3c5<>6) (r3c5<>1) r3c6<>1 r3c1=1 r3c1<>6 r3c6=6 r1c4<>6 r1c7=6 r1c7<>5
r3c5=1 (r1c5<>1) r3c6<>1 r7c6=1 (r7c4<>1) r7c6<>2 r7c9=2 r8c9<>2 r8c6=2 (r8c6<>6) r8c6<>6 r8c7=6 r1c7<>6 r1c4=6 (r2c6<>6) r3c6<>6 r7c6=6 r7c6<>1 r7c5=1 (r7c5<>5) r5c5<>1 (r5c5=6 r8c5<>6) r5c4=1 r1c4<>1 r1c3=1 r8c3<>1 (r8c1=1 r8c1<>7 r8c8=7 r8c8<>6) r8c3=5 (r8c5<>5) (r7c2<>5) r8c2<>5 r3c2=5 r3c5<>5 r1c5=5 r1c7<>5
r5c5=1 r5c4<>1 r5c4=6 r1c4<>6 r1c7=6 r1c7<>5
r7c5=1 (r7c5<>5) (r1c5<>1) r5c5<>1 r5c4=1 r1c4<>1 r1c3=1 r8c3<>1 r8c3=5 (r8c5<>5) (r7c2<>5) r8c2<>5 r3c2=5 r3c5<>5 r1c5=5 r1c7<>5
Forcing Net Contradiction in r7c6 => r3c5<>1
r3c5=1 r3c6<>1 r7c6=1
r3c5=1 (r5c5<>1 r5c5=6 r8c5<>6) (r1c5<>1 r1c3=1 r8c3<>1 r8c1=1 r8c1<>7 r8c8=7 r8c8<>6) r3c6<>1 r7c6=1 r7c6<>2 r7c9=2 r8c9<>2 r8c6=2 (r8c6<>6) r8c6<>6 r8c7=6 r1c7<>6 r1c4=6 (r2c6<>6) r3c6<>6 r7c6=6
Almost Locked Set XZ-Rule: A=r3c259 {3569}, B=r2469c6 {34679}, X=6, Z=3,9 => r3c6<>3, r3c6<>9
Forcing Net Verity => r3c1<>9
r3c1=6 r3c1<>9
r3c5=6 (r3c6<>6) (r5c5<>6 r5c5=1 r7c5<>1 r7c4=1 r7c4<>7) r3c6<>6 r3c6=1 (r1c4<>1) r1c5<>1 r1c3=1 r8c3<>1 r8c1=1 r8c1<>7 r8c8=7 r7c8<>7 r7c6=7 (r7c6<>6) r7c6<>2 r7c9=2 r8c9<>2 r8c6=2 r8c6<>6 r2c6=6 r2c1<>6 r2c1=9 r3c1<>9
r3c6=6 r3c6<>1 r3c1=1 r3c1<>9
Naked Pair: 1,6 in r3c16 => r3c5<>6
Forcing Net Contradiction in r7 => r7c6<>3
r7c6=3 (r7c6<>7) r7c6<>1 r3c6=1 (r1c4<>1) r1c5<>1 r1c3=1 r8c3<>1 r8c1=1 r8c1<>7 r8c8=7 r7c8<>7 r7c4=7 r7c4<>1
r7c6=3 (r7c6<>1 r3c6=1 r1c5<>1 r1c3=1 r8c3<>1 r8c1=1 r8c1<>7 r8c8=7 r8c8<>6) (r7c6<>6) (r7c6<>1 r3c6=1 r3c6<>6) r7c6<>2 r7c9=2 r8c9<>2 r8c6=2 (r8c6<>6) r8c6<>6 r2c6=6 r1c4<>6 r1c7=6 r8c7<>6 r8c5=6 r5c5<>6 r5c5=1 r7c5<>1
r7c6=3 r7c6<>1
Forcing Net Contradiction in r7c7 => r8c1<>5
r8c1=5 (r8c1<>1 r3c1=1 r3c6<>1 r7c6=1 r7c6<>7) (r8c2<>5 r3c2=5 r3c2<>9) r4c1<>5 r4c1=9 (r6c3<>9) (r9c1<>9) r5c3<>9 r5c8=9 (r6c7<>9) (r6c8<>9) r9c8<>9 r9c9=9 r3c9<>9 r3c5=9 r6c5<>9 r6c6=9 r6c6<>7 r9c6=7 r9c1<>7 r8c1=7 r8c1<>5
Forcing Net Contradiction in b9 => r4c7<>5
r4c7=5 r7c7<>5
r4c7=5 r4c1<>5 r4c1=9 (r2c1<>9 r2c1=6 r3c1<>6 r3c1=1 r3c6<>1 r7c6=1 r7c6<>7) (r6c3<>9) (r6c3<>9 r1c3=9 r3c2<>9) (r9c1<>9) r5c3<>9 r5c8=9 (r6c7<>9) (r6c8<>9) r9c8<>9 r9c9=9 r3c9<>9 r3c5=9 r6c5<>9 r6c6=9 r6c6<>7 (r6c4=7 r7c4<>7) r9c6=7 r7c6<>7 r7c8=7 r7c8<>5
r4c7=5 r4c1<>5 r4c1=9 r2c1<>9 r2c1=6 r3c1<>6 r3c1=1 r3c6<>1 r7c6=1 r7c6<>2 r7c9=2 r7c9<>5
r4c7=5 r8c7<>5
r4c7=5 r4c1<>5 r4c1=9 (r6c3<>9) (r6c3<>9 r1c3=9 r3c2<>9) (r9c1<>9) r5c3<>9 r5c8=9 (r6c7<>9) (r6c8<>9) r9c8<>9 r9c9=9 r3c9<>9 r3c5=9 r6c5<>9 r6c6=9 r6c6<>7 (r6c4=7 r7c4<>7) r9c6=7 r7c6<>7 r7c8=7 (r7c8<>6) r8c8<>7 r8c1=7 r8c1<>1 r3c1=1 (r3c6<>1 r7c6=1 r7c6<>7) r3c1<>6 r2c1=6 r2c8<>6 r8c8=6 r8c8<>5
r4c7=5 r4c1<>5 r4c1=9 (r6c3<>9) (r6c3<>9 r1c3=9 r3c2<>9) (r9c1<>9) r5c3<>9 r5c8=9 (r6c7<>9) (r6c8<>9) r9c8<>9 r9c9=9 r3c9<>9 r3c5=9 r6c5<>9 r6c6=9 r6c6<>7 r6c4=7 r6c4<>8 r6c7=8 r8c7<>8 r8c9=8 r8c9<>5
r4c7=5 r4c1<>5 r9c1=5 r9c8<>5
r4c7=5 r4c1<>5 r9c1=5 r9c9<>5
Forcing Net Contradiction in r1c7 => r1c9<>5
r1c9=5 (r1c3<>5) r4c9<>5 r4c1=5 (r9c1<>5 r9c8=5 r7c8<>5 r7c5=5 r7c5<>1) r6c3<>5 r8c3=5 r8c3<>1 r1c3=1 r1c5<>1 r5c5=1 r5c4<>1 r5c4=6 r1c4<>6 r1c7=6
r1c9=5 (r1c3<>5 r3c2=5 r3c2<>9 r7c2=9 r9c1<>9 r2c1=9 r1c3<>9) (r1c9<>9) (r1c3<>5 r3c2=5 r3c2<>9) (r1c3<>5 r3c2=5 r3c2<>9 r7c2=9 r9c1<>9) (r2c8<>5 r2c4=5 r9c4<>5) (r9c9<>5) r4c9<>5 r4c1=5 r9c1<>5 r9c8=5 r9c8<>9 r9c9=9 r3c9<>9 r3c5=9 r1c5<>9 r1c7=9
Forcing Net Contradiction in b8 => r7c6<>6
r7c6=6 (r7c6<>7) r3c6<>6 r3c6=1 (r1c4<>1) r1c5<>1 r1c3=1 r8c3<>1 r8c1=1 r8c1<>7 r8c8=7 r7c8<>7 r7c4=7 r7c4<>5
r7c6=6 (r7c6<>1) (r7c5<>6) r8c5<>6 r5c5=6 r5c4<>6 r5c4=1 r7c4<>1 r7c5=1 r7c5<>5
r7c6=6 r3c6<>6 r3c6=1 (r1c4<>1) r1c5<>1 r1c3=1 r8c3<>1 r8c3=5 r8c5<>5
r7c6=6 (r7c6<>2 r7c9=2 r7c9<>5) r3c6<>6 (r3c1=6 r2c1<>6 r2c1=9 r3c2<>9 r3c2=5 r3c9<>5) (r3c1=6 r2c1<>6 r2c1=9 r4c1<>9 r4c1=5 r4c9<>5) r3c6=1 (r1c4<>1) r1c5<>1 r1c3=1 r8c3<>1 r8c3=5 r8c9<>5 r9c9=5 r9c4<>5
Finned Swordfish: 6 r157 c457 fr7c8 => r8c7<>6
Forcing Net Contradiction in r6c5 => r1c7<>4
r1c7=4 (r1c9<>4 r1c9=9 r9c9<>9) r1c7<>6 r1c4=6 r3c6<>6 r3c1=6 r2c1<>6 r2c1=9 r9c1<>9 r9c8=9 r5c8<>9 r5c8=3 r5c3<>3 r6c3=3 r6c5<>3
r1c7=4 r1c7<>6 r1c4=6 (r2c6<>6) r3c6<>6 (r3c6=1 r1c5<>1 r1c3=1 r8c3<>1 r8c1=1 r8c1<>7 r8c8=7 r8c8<>4) r8c6=6 (r8c6<>4) r8c6<>2 r8c9=2 (r8c9<>4) r8c9<>8 r8c7=8 r8c7<>4 r8c5=4 r6c5<>4
r1c7=4 (r1c9<>4 r1c9=9 r3c9<>9) r1c7<>6 r1c4=6 r3c6<>6 r3c1=6 r2c1<>6 r2c1=9 r3c2<>9 r3c5=9 r6c5<>9
Forcing Net Contradiction in r7c7 => r2c7<>6
r2c7=6 (r2c1<>6 r2c1=9 r3c2<>9 r3c5=9 r3c5<>3) (r2c1<>6 r2c1=9 r3c2<>9 r3c2=5 r8c2<>5 r8c2=3 r8c5<>3) r1c7<>6 r1c4=6 (r3c6<>6 r3c6=1 r7c6<>1) r5c4<>6 r5c4=1 r7c4<>1 r7c5=1 r7c5<>3 r6c5=3 (r4c4<>3) (r4c6<>3) r3c5<>3 r3c9=3 r4c9<>3 r4c7=3 r7c7<>3
r2c7=6 (r2c1<>6 r2c1=9 r3c2<>9 r3c2=5 r3c9<>5 r3c9=3 r7c9<>3) (r2c6<>6) r1c7<>6 r1c4=6 r3c6<>6 r8c6=6 r8c6<>2 r8c9=2 r7c9<>2 r7c9=5 r7c7<>5
r2c7=6 r7c7<>6
r2c7=6 r1c7<>6 r1c7=9 r7c7<>9
Forcing Net Verity => r7c8<>5
r3c9=5 (r2c8<>5 r2c4=5 r9c4<>5) (r9c9<>5) r4c9<>5 r4c1=5 r9c1<>5 r9c8=5 r7c8<>5
r4c9=5 (r3c9<>5) r4c1<>5 r4c1=9 (r4c7<>9) (r5c3<>9 r5c8=9 r6c7<>9) (r5c3<>9) r6c3<>9 r1c3=9 (r1c7<>9) r3c2<>9 r7c2=9 r7c7<>9 r2c7=9 r2c7<>5 r2c8=5 r7c8<>5
r7c9=5 r7c8<>5
r8c9=5 r7c8<>5
r9c9=5 r7c8<>5
Forcing Net Contradiction in r2 => r8c5<>3
r8c5=3 r8c2<>3 r8c2=5 r3c2<>5 r3c2=9 r2c1<>9
r8c5=3 (r8c2<>3 r8c2=5 r9c1<>5 r4c1=5 r4c1<>9) (r9c4<>3) (r9c6<>3) r3c5<>3 r3c9=3 r9c9<>3 r9c8=3 r5c8<>3 r5c8=9 (r4c7<>9) r4c9<>9 r4c6=9 r2c6<>9
r8c5=3 (r8c2<>3 r8c2=5 r9c1<>5 r4c1=5 r4c1<>9 r9c1=9 r9c9<>9) (r9c4<>3) (r9c6<>3) r3c5<>3 r3c9=3 (r3c9<>9) r9c9<>3 r9c8=3 r5c8<>3 r5c8=9 r4c9<>9 r1c9=9 r2c7<>9
r8c5=3 (r9c4<>3) (r9c6<>3) r3c5<>3 r3c9=3 r9c9<>3 r9c8=3 r5c8<>3 r5c8=9 r2c8<>9
Forcing Net Verity => r8c6<>4
r7c4=1 (r7c4<>7) (r1c4<>1) r5c4<>1 r5c5=1 r1c5<>1 r1c3=1 r8c3<>1 r8c1=1 r8c1<>7 r8c8=7 r7c8<>7 r7c6=7 r7c6<>2 r7c9=2 r8c9<>2 r8c6=2 r8c6<>4
r7c5=1 (r1c5<>1) r5c5<>1 (r5c5=6 r8c5<>6) r5c4=1 r1c4<>1 r1c3=1 r8c3<>1 r8c3=5 r8c5<>5 r8c5=4 r8c6<>4
r7c6=1 r7c6<>2 r7c9=2 r8c9<>2 r8c6=2 r8c6<>4
Forcing Net Contradiction in r6c5 => r7c9<>3
r7c9=3 r3c9<>3 r3c5=3 r6c5<>3
r7c9=3 r7c9<>2 r7c6=2 (r8c6<>2 r8c6=6 r8c5<>6) r7c6<>1 r3c6=1 (r1c4<>1) r1c5<>1 r1c3=1 r8c3<>1 r8c3=5 r8c5<>5 r8c5=4 r6c5<>4
r7c9=3 r7c9<>2 r7c6=2 r7c6<>1 r3c6=1 r3c1<>1 r3c1=6 r2c1<>6 r2c1=9 r2c6<>9 r13c5=9 r6c5<>9
Forcing Net Contradiction in c6 => r8c8<>3
r8c8=3 (r5c8<>3 r5c8=9 r2c8<>9) (r5c8<>3 r5c8=9 r7c8<>9) r8c2<>3 (r8c2=5 r3c2<>5 r3c2=9 r2c1<>9) r7c2=3 r7c2<>9 r7c7=9 r2c7<>9 r2c6=9
r8c8=3 (r5c8<>3 r5c8=9 r4c7<>9) (r5c8<>3 r5c8=9 r4c9<>9) (r8c2<>3 r8c2=5 r9c1<>5) r8c8<>7 r8c1=7 r9c1<>7 r9c1=9 r4c1<>9 r4c6=9
Forcing Net Verity => r8c8<>5
r3c9=5 (r2c8<>5 r2c4=5 r9c4<>5) (r9c9<>5) r4c9<>5 r4c1=5 r9c1<>5 r9c8=5 r8c8<>5
r4c9=5 (r3c9<>5) r4c1<>5 r4c1=9 (r4c7<>9) (r5c3<>9 r5c8=9 r6c7<>9) (r5c3<>9) r6c3<>9 r1c3=9 (r1c7<>9) r3c2<>9 r7c2=9 r7c7<>9 r2c7=9 r2c7<>5 r2c8=5 r8c8<>5
r7c9=5 r8c8<>5
r8c9=5 r8c8<>5
r9c9=5 r8c8<>5
Brute Force: r6c4=8
Hidden Single: r6c6=7
Naked Triple: 1,2,6 in r378c6 => r2c6<>6
Empty Rectangle: 3 in b5 (r3c59) => r4c9<>3
Finned Swordfish: 9 c169 r249 fr1c9 fr3c9 => r2c78<>9
Discontinuous Nice Loop: 1 r7c4 -1- r7c6 =1= r3c6 -1- r3c1 =1= r8c1 =7= r8c8 -7- r7c8 =7= r7c4 => r7c4<>1
Grouped Discontinuous Nice Loop: 4 r4c9 =8= r8c9 =2= r8c6 =6= r3c6 -6- r3c1 =6= r2c1 =9= r2c6 -9- r4c6 =9= r6c5 =4= r4c46 -4- r4c9 => r4c9<>4
Grouped Discontinuous Nice Loop: 9 r4c9 -9- r4c6 =9= r2c6 -9- r2c1 -6- r2c8 =6= r1c7 =9= r13c9 -9- r4c9 => r4c9<>9
Hidden Rectangle: 5/8 in r4c79,r8c79 => r8c7<>5
Sashimi Swordfish: 9 r249 c167 fr9c8 fr9c9 => r7c7<>9
Discontinuous Nice Loop: 3 r8c7 -3- r8c2 -5- r9c1 =5= r4c1 -5- r4c9 -8- r4c7 =8= r8c7 => r8c7<>3
Grouped AIC: 9 9- r2c1 -6- r2c8 =6= r1c7 =9= r46c7 -9- r5c8 =9= r5c3 -9 => r1c3,r4c1<>9
Naked Single: r4c1=5
Naked Single: r4c9=8
Hidden Single: r8c7=8
Uniqueness Test 1: 3/9 in r5c38,r6c38 => r6c8<>3, r6c8<>9
Finned Swordfish: 5 r269 c478 fr9c9 => r7c7<>5
Sue de Coq: r46c7 - {3459} (r17c7 - {369}, r6c8 - {45}) => r2c7<>3
Discontinuous Nice Loop: 3/5/6 r7c4 =7= r7c8 =9= r7c2 -9- r9c1 -7- r9c4 =7= r7c4 => r7c4<>3, r7c4<>5, r7c4<>6
Naked Single: r7c4=7
Empty Rectangle: 3 in b8 (r3c59) => r9c9<>3
XYZ-Wing: 3/6/9 in r57c8,r7c7 => r9c8<>3
Locked Candidates Type 2 (Claiming): 3 in r9 => r7c5<>3
Finned Swordfish: 3 r249 c468 fr4c7 => r5c8<>3
Naked Single: r5c8=9
Naked Single: r5c3=3
Full House: r6c3=9
Hidden Single: r4c6=9
Hidden Single: r1c7=9
Naked Single: r1c9=4
Naked Single: r2c7=5
Naked Single: r3c9=3
Full House: r2c8=6
Naked Single: r2c1=9
Naked Single: r7c8=3
Naked Single: r3c2=5
Naked Single: r9c1=7
Naked Single: r7c7=6
Naked Single: r1c3=1
Full House: r3c1=6
Full House: r8c1=1
Full House: r8c3=5
Naked Single: r3c5=9
Full House: r3c6=1
Naked Single: r7c2=9
Full House: r8c2=3
Naked Single: r1c5=5
Full House: r1c4=6
Naked Single: r8c9=2
Naked Single: r7c6=2
Naked Single: r7c5=1
Full House: r7c9=5
Full House: r9c9=9
Naked Single: r5c4=1
Full House: r5c5=6
Naked Single: r8c6=6
Naked Single: r9c8=4
Full House: r8c8=7
Full House: r8c5=4
Full House: r6c8=5
Full House: r6c5=3
Full House: r4c4=4
Full House: r6c7=4
Full House: r4c7=3
Naked Single: r9c6=3
Full House: r2c6=4
Full House: r2c4=3
Full House: r9c4=5
|
normal_sudoku_5719
|
46.15...22.16..5...5..24....7.2.165.18674592352..6...171.4.62.5.45.72...6.251....
|
467159382231687594859324716974231658186745923523968471718496235345872169692513847
|
Basic 9x9 Sudoku 5719
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
4 6 . 1 5 . . . 2
2 . 1 6 . . 5 . .
. 5 . . 2 4 . . .
. 7 . 2 . 1 6 5 .
1 8 6 7 4 5 9 2 3
5 2 . . 6 . . . 1
7 1 . 4 . 6 2 . 5
. 4 5 . 7 2 . . .
6 . 2 5 1 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
467159382231687594859324716974231658186745923523968471718496235345872169692513847 #1 Extreme (24150) bf
Hidden Single: r1c5=5
Hidden Single: r5c1=1
Hidden Single: r4c8=5
Hidden Single: r5c3=6
Hidden Single: r7c6=6
Hidden Single: r8c3=5
Hidden Single: r4c6=1
Hidden Single: r9c4=5
Hidden Single: r7c4=4
Hidden Pair: 1,6 in r38c8 => r38c8<>3, r3c8<>7, r38c8<>8, r38c8<>9
Brute Force: r5c4=7
Brute Force: r5c2=8
Full House: r5c8=2
Hidden Single: r6c2=2
Hidden Single: r4c4=2
Hidden Single: r1c9=2
Hidden Single: r7c7=2
Finned Franken Swordfish: 3 c25b4 r247 fr6c3 fr9c2 => r7c3<>3
W-Wing: 9/3 in r2c2,r4c1 connected by 3 in r8c1,r9c2 => r3c1<>9
Sashimi Swordfish: 9 c125 r247 fr8c1 fr9c2 => r7c3<>9
Naked Single: r7c3=8
Hidden Single: r3c1=8
2-String Kite: 8 in r4c9,r8c4 (connected by r4c5,r6c4) => r8c9<>8
Discontinuous Nice Loop: 8 r2c8 -8- r2c5 =8= r4c5 -8- r4c9 -4- r2c9 =4= r2c8 => r2c8<>8
Forcing Chain Contradiction in r9c6 => r2c5<>3
r2c5=3 r2c2<>3 r9c2=3 r9c6<>3
r2c5=3 r2c5<>8 r12c6=8 r9c6<>8
r2c5=3 r7c5<>3 r7c5=9 r9c6<>9
Skyscraper: 3 in r7c5,r8c1 (connected by r4c15) => r8c4<>3
W-Wing: 9/3 in r7c8,r9c2 connected by 3 in r8c17 => r9c89<>9
Discontinuous Nice Loop: 3 r3c7 -3- r3c4 =3= r6c4 -3- r4c5 =3= r7c5 =9= r7c8 -9- r8c9 -6- r8c8 -1- r8c7 =1= r3c7 => r3c7<>3
Discontinuous Nice Loop: 3 r2c6 -3- r3c4 =3= r3c3 =7= r1c3 -7- r1c6 =7= r2c6 => r2c6<>3
Discontinuous Nice Loop: 9 r4c3 -9- r4c1 -3- r8c1 =3= r9c2 -3- r2c2 =3= r2c8 =4= r2c9 -4- r4c9 =4= r4c3 => r4c3<>9
Forcing Chain Contradiction in r1 => r2c2=3
r2c2<>3 r2c2=9 r1c3<>9
r2c2<>3 r2c2=9 r9c2<>9 r9c6=9 r1c6<>9
r2c2<>3 r2c8=3 r7c8<>3 r7c8=9 r1c8<>9
Full House: r9c2=9
Full House: r8c1=3
Full House: r4c1=9
Hidden Single: r3c4=3
2-String Kite: 9 in r2c5,r8c9 (connected by r7c5,r8c4) => r2c9<>9
Naked Triple: 4,7,8 in r249c9 => r3c9<>7
W-Wing: 8/9 in r2c5,r6c4 connected by 9 in r7c5,r8c4 => r4c5<>8
Naked Single: r4c5=3
Naked Single: r4c3=4
Full House: r4c9=8
Full House: r6c3=3
Naked Single: r7c5=9
Full House: r2c5=8
Full House: r7c8=3
Naked Single: r8c4=8
Full House: r6c4=9
Full House: r9c6=3
Full House: r6c6=8
Naked Single: r8c7=1
Naked Single: r3c7=7
Naked Single: r8c8=6
Full House: r8c9=9
Naked Single: r2c9=4
Naked Single: r3c3=9
Full House: r1c3=7
Naked Single: r6c7=4
Full House: r6c8=7
Naked Single: r3c8=1
Full House: r3c9=6
Full House: r9c9=7
Naked Single: r2c8=9
Full House: r2c6=7
Full House: r1c6=9
Naked Single: r9c7=8
Full House: r1c7=3
Full House: r1c8=8
Full House: r9c8=4
|
normal_sudoku_4486
|
.1683..7553...7...8475.16..35.7.6.18.7815....6.14..75.78.....4..6..7..9...5.....7
|
916832475532647189847591623354726918278159364691483752789315246463278591125964837
|
Basic 9x9 Sudoku 4486
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 1 6 8 3 . . 7 5
5 3 . . . 7 . . .
8 4 7 5 . 1 6 . .
3 5 . 7 . 6 . 1 8
. 7 8 1 5 . . . .
6 . 1 4 . . 7 5 .
7 8 . . . . . 4 .
. 6 . . 7 . . 9 .
. . 5 . . . . . 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
916832475532647189847591623354726918278159364691483752789315246463278591125964837 #1 Extreme (12330) bf
Hidden Single: r1c3=6
Hidden Single: r6c3=1
Hidden Single: r9c9=7
Hidden Single: r2c1=5
Hidden Single: r6c8=5
Hidden Single: r5c3=8
Hidden Single: r3c4=5
Hidden Single: r4c2=5
Hidden Single: r4c4=7
Hidden Single: r5c2=7
Hidden Single: r2c6=7
Hidden Pair: 5,8 in r8c67 => r8c67<>2, r8c67<>3, r8c6<>4, r8c7<>1
Brute Force: r6c4=4
Locked Candidates Type 1 (Pointing): 3 in b5 => r79c6<>3
Locked Candidates Type 1 (Pointing): 4 in b8 => r9c12<>4
Hidden Single: r3c2=4
Naked Pair: 2,9 in r34c5 => r2679c5<>2, r2679c5<>9
Naked Single: r6c5=8
AIC: 1 1- r2c7 =1= r2c9 =4= r5c9 -4- r5c1 =4= r8c1 =1= r8c9 -1 => r2c9,r79c7<>1
Hidden Single: r2c7=1
Hidden Single: r2c8=8
AIC: 1/6 1- r7c5 -6- r2c5 -4- r2c9 =4= r5c9 =6= r7c9 -6 => r7c9<>1, r7c5<>6
Naked Single: r7c5=1
Hidden Single: r8c9=1
Hidden Single: r9c1=1
Empty Rectangle: 9 in b3 (r15c1) => r5c9<>9
W-Wing: 2/9 in r2c3,r6c2 connected by 9 in r15c1 => r4c3<>2
Sashimi X-Wing: 2 r34 c57 fr3c8 fr3c9 => r1c7<>2
Turbot Fish: 2 r1c6 =2= r1c1 -2- r5c1 =2= r6c2 => r6c6<>2
W-Wing: 4/9 in r1c7,r4c3 connected by 9 in r15c1 => r4c7<>4
Hidden Single: r4c3=4
Hidden Single: r8c1=4
Skyscraper: 9 in r3c9,r4c7 (connected by r34c5) => r1c7,r6c9<>9
Naked Single: r1c7=4
Hidden Single: r9c6=4
Naked Single: r9c5=6
Naked Single: r2c5=4
Hidden Single: r5c9=4
Hidden Single: r9c7=8
Naked Single: r8c7=5
Naked Single: r8c6=8
Hidden Single: r2c4=6
Hidden Single: r7c9=6
Hidden Single: r5c8=6
Hidden Single: r7c6=5
X-Wing: 2 c16 r15 => r5c7<>2
Remote Pair: 9/2 r4c7 -2- r4c5 -9- r3c5 -2- r1c6 -9- r1c1 -2- r5c1 => r5c7<>9
Naked Single: r5c7=3
Naked Single: r6c9=2
Full House: r4c7=9
Full House: r7c7=2
Full House: r4c5=2
Full House: r9c8=3
Full House: r3c5=9
Full House: r3c8=2
Full House: r1c6=2
Full House: r3c9=3
Full House: r2c9=9
Full House: r1c1=9
Full House: r2c3=2
Full House: r5c1=2
Full House: r6c2=9
Full House: r5c6=9
Full House: r6c6=3
Full House: r9c2=2
Full House: r9c4=9
Naked Single: r8c3=3
Full House: r7c3=9
Full House: r7c4=3
Full House: r8c4=2
|
normal_sudoku_1409
|
74..9.3511....3.866.3..1..28....2..3.....781...7....2.5..12..3...1...2.5236..51..
|
742698351159243786683751942864912573925367814317584629598126437471839265236475198
|
Basic 9x9 Sudoku 1409
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
7 4 . . 9 . 3 5 1
1 . . . . 3 . 8 6
6 . 3 . . 1 . . 2
8 . . . . 2 . . 3
. . . . . 7 8 1 .
. . 7 . . . . 2 .
5 . . 1 2 . . 3 .
. . 1 . . . 2 . 5
2 3 6 . . 5 1 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
742698351159243786683751942864912573925367814317584629598126437471839265236475198 #1 Extreme (23780) bf
Locked Candidates Type 1 (Pointing): 3 in b8 => r8c78<>3
Brute Force: r5c6=7
Finned Franken Swordfish: 7 c19b8 r189 fr7c9 => r8c78,r9c78<>7
Brute Force: r5c8=1
Locked Pair: 4,9 in r56c9 => r4c78,r6c7,r79c9<>4, r4c78,r6c7,r79c9<>9
Grouped Discontinuous Nice Loop: 2 r1c1 -2- r9c1 =2= r9c7 =1= r9c9 =8= r7c9 -8- r7c23 =8= r8c2 =2= r89c1 -2- r1c1 => r1c1<>2
Naked Triple: 1,3,7 in r1c179 => r1c3<>3, r1c4<>7
Grouped Discontinuous Nice Loop: 2 r5c1 -2- r9c1 =2= r9c7 =1= r9c9 =8= r7c9 -8- r7c23 =8= r8c2 =2= r89c1 -2- r5c1 => r5c1<>2
Locked Candidates Type 2 (Claiming): 2 in c1 => r8c2<>2
Uniqueness Test 2: 4/9 in r5c19,r6c19 => r1c1,r5c3<>3
Naked Single: r1c1=7
Naked Single: r1c9=1
Naked Single: r1c7=3
Hidden Single: r3c3=3
Hidden Single: r9c7=1
Hidden Single: r7c8=3
Hidden Single: r9c1=2
Hidden Single: r8c7=2
Locked Candidates Type 2 (Claiming): 7 in c9 => r7c7<>7
Finned X-Wing: 6 c58 r48 fr5c5 fr6c5 => r4c4<>6
Finned Swordfish: 4 c169 r568 fr7c6 => r8c45<>4
Finned Swordfish: 9 c169 r568 fr7c6 => r8c4<>9
Sue de Coq: r7c23 - {4789} (r7c9 - {78}, r8c1 - {49}) => r8c2<>9, r7c6<>8
Grouped Discontinuous Nice Loop: 6 r4c5 -6- r4c8 =6= r8c8 -6- r7c7 =6= r7c6 -6- r1c6 -8- r1c3 -2- r5c3 =2= r5c2 =6= r5c45 -6- r4c5 => r4c5<>6
Grouped Discontinuous Nice Loop: 5 r6c2 -5- r6c7 -6- r4c78 =6= r4c2 =1= r6c2 => r6c2<>5
Grouped Discontinuous Nice Loop: 9 r7c7 =6= r7c6 -6- r1c6 -8- r1c3 =8= r7c3 =4= r8c1 =9= r7c23 -9- r7c7 => r7c7<>9
Locked Candidates Type 1 (Pointing): 9 in b9 => r3c8<>9
Finned Jellyfish: 9 r2347 c2347 fr7c6 => r9c4<>9
Hidden Single: r9c8=9
Locked Candidates Type 1 (Pointing): 9 in b8 => r6c6<>9
Locked Candidates Type 2 (Claiming): 4 in r9 => r78c6<>4
Hidden Single: r6c6=4
Naked Single: r6c9=9
Naked Single: r5c9=4
Naked Single: r6c1=3
Naked Single: r5c1=9
Full House: r8c1=4
Naked Single: r8c8=6
Naked Single: r4c8=7
Full House: r3c8=4
Naked Single: r7c7=4
Hidden Single: r4c3=4
Hidden Single: r4c4=9
Hidden Single: r8c6=9
Naked Single: r7c6=6
Full House: r1c6=8
Naked Single: r1c3=2
Full House: r1c4=6
Naked Single: r5c3=5
Naked Single: r2c3=9
Full House: r7c3=8
Naked Single: r5c4=3
Naked Single: r2c2=5
Full House: r3c2=8
Naked Single: r2c7=7
Full House: r3c7=9
Naked Single: r7c9=7
Full House: r7c2=9
Full House: r8c2=7
Full House: r9c9=8
Naked Single: r5c5=6
Full House: r5c2=2
Naked Single: r2c5=4
Full House: r2c4=2
Naked Single: r8c4=8
Full House: r8c5=3
Naked Single: r9c5=7
Full House: r9c4=4
Naked Single: r6c4=5
Full House: r3c4=7
Full House: r3c5=5
Naked Single: r4c5=1
Full House: r6c5=8
Naked Single: r6c7=6
Full House: r4c7=5
Full House: r4c2=6
Full House: r6c2=1
|
normal_sudoku_1461
|
....19.46...4..2.3...2.391....6.1.922..397154.9..4236.8.5.2..3.....3.4...3.1...2.
|
328719546619485273457263918743651892286397154591842367865924731172536489934178625
|
Basic 9x9 Sudoku 1461
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . 1 9 . 4 6
. . . 4 . . 2 . 3
. . . 2 . 3 9 1 .
. . . 6 . 1 . 9 2
2 . . 3 9 7 1 5 4
. 9 . . 4 2 3 6 .
8 . 5 . 2 . . 3 .
. . . . 3 . 4 . .
. 3 . 1 . . . 2 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
328719546619485273457263918743651892286397154591842367865924731172536489934178625 #1 Extreme (25768) bf
Hidden Single: r4c9=2
Hidden Single: r2c9=3
Hidden Single: r5c4=3
Hidden Single: r4c6=1
Hidden Single: r7c5=2
Hidden Single: r5c9=4
Hidden Single: r5c5=9
Brute Force: r5c6=7
Forcing Net Verity => r8c9<>7
r8c4=5 (r6c4<>5 r6c4=8 r6c9<>8) (r8c8<>5) (r8c6<>5) r9c6<>5 r2c6=5 r2c8<>5 r5c8=5 r6c9<>5 r6c9=7 r8c9<>7
r8c4=7 r8c9<>7
r8c4=8 (r6c4<>8 r6c4=5 r6c9<>5) (r8c8<>8) (r8c6<>8) r9c6<>8 r2c6=8 r2c8<>8 r5c8=8 r6c9<>8 r6c9=7 r8c9<>7
r8c4=9 r7c4<>9 r7c9=9 r7c9<>1 r7c2=1 (r8c1<>1) (r8c2<>1) r8c3<>1 r8c9=1 r8c9<>7
Forcing Net Verity => r9c7<>7
r1c4=5 (r1c7<>5) r6c4<>5 r4c5=5 r4c7<>5 r9c7=5 r9c7<>7
r1c4=7 (r2c5<>7) r3c5<>7 r9c5=7 r9c7<>7
r1c4=8 (r1c7<>8) r6c4<>8 r4c5=8 r4c7<>8 r9c7=8 r9c7<>7
Brute Force: r5c8=5
Locked Candidates Type 2 (Claiming): 8 in r5 => r4c23,r6c3<>8
Finned X-Wing: 8 c68 r28 fr9c6 => r8c4<>8
2-String Kite: 8 in r1c4,r4c7 (connected by r4c5,r6c4) => r1c7<>8
W-Wing: 7/8 in r6c9,r8c8 connected by 8 in r49c7 => r79c9<>7
Discontinuous Nice Loop: 5 r1c1 -5- r1c7 -7- r4c7 -8- r4c5 -5- r6c4 =5= r6c1 -5- r1c1 => r1c1<>5
Hidden Rectangle: 3/7 in r1c13,r4c13 => r4c3<>7
Grouped Discontinuous Nice Loop: 8 r2c2 -8- r2c8 =8= r3c9 -8- r6c9 =8= r6c4 -8- r1c4 =8= r1c23 -8- r2c2 => r2c2<>8
Grouped Discontinuous Nice Loop: 8 r2c3 -8- r2c8 =8= r3c9 -8- r6c9 =8= r6c4 -8- r1c4 =8= r1c23 -8- r2c3 => r2c3<>8
Almost Locked Set Chain: 5- r1c47 {578} -8- r6c134 {1578} -7- r6c9 {78} -8- r14c7 {578} -5 => r1c2<>5
Forcing Chain Contradiction in b2 => r2c5<>5
r2c5=5 r4c5<>5 r4c5=8 r6c4<>8 r1c4=8 r1c4<>7
r2c5=5 r2c5<>7
r2c5=5 r4c5<>5 r4c5=8 r4c7<>8 r4c7=7 r6c9<>7 r3c9=7 r3c5<>7
Forcing Chain Contradiction in r1c4 => r2c6<>8
r2c6=8 r2c8<>8 r2c8=7 r1c7<>7 r1c7=5 r1c4<>5
r2c6=8 r89c6<>8 r9c5=8 r9c5<>7 r78c4=7 r1c4<>7
r2c6=8 r1c4<>8
Locked Candidates Type 2 (Claiming): 8 in c6 => r9c5<>8
Discontinuous Nice Loop: 6 r7c6 -6- r7c7 -7- r8c8 -8- r8c6 =8= r9c6 =4= r7c6 => r7c6<>6
Naked Single: r7c6=4
Almost Locked Set XZ-Rule: A=r7c279 {1679}, B=r9c5679 {56789}, X=9, Z=7 => r7c4<>7
Naked Single: r7c4=9
Naked Single: r7c9=1
Skyscraper: 7 in r1c4,r2c8 (connected by r8c48) => r1c7,r2c5<>7
Naked Single: r1c7=5
Naked Pair: 7,8 in r36c9 => r89c9<>8
Jellyfish: 8 r2489 c5678 => r3c5<>8
2-String Kite: 7 in r2c8,r7c2 (connected by r7c7,r8c8) => r2c2<>7
W-Wing: 7/8 in r1c4,r3c9 connected by 8 in r2c58 => r3c5<>7
Hidden Single: r9c5=7
Naked Single: r8c4=5
Naked Single: r6c4=8
Full House: r1c4=7
Full House: r4c5=5
Naked Single: r8c9=9
Naked Single: r6c9=7
Full House: r4c7=8
Naked Single: r1c1=3
Naked Single: r3c5=6
Full House: r2c5=8
Full House: r2c6=5
Naked Single: r9c9=5
Full House: r3c9=8
Full House: r2c8=7
Full House: r8c8=8
Naked Single: r6c3=1
Full House: r6c1=5
Naked Single: r9c7=6
Full House: r7c7=7
Full House: r7c2=6
Naked Single: r8c6=6
Full House: r9c6=8
Naked Single: r2c2=1
Naked Single: r5c2=8
Full House: r5c3=6
Naked Single: r1c2=2
Full House: r1c3=8
Naked Single: r2c3=9
Full House: r2c1=6
Naked Single: r8c2=7
Naked Single: r9c3=4
Full House: r9c1=9
Naked Single: r4c2=4
Full House: r3c2=5
Naked Single: r8c1=1
Full House: r8c3=2
Naked Single: r3c3=7
Full House: r4c3=3
Full House: r4c1=7
Full House: r3c1=4
|
normal_sudoku_1678
|
29.485....5.271..81..69325..13.29.......34.92.29..68....13625...3.957.....2148...
|
297485316356271948148693257713829465685734192429516873971362584834957621562148739
|
Basic 9x9 Sudoku 1678
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
2 9 . 4 8 5 . . .
. 5 . 2 7 1 . . 8
1 . . 6 9 3 2 5 .
. 1 3 . 2 9 . . .
. . . . 3 4 . 9 2
. 2 9 . . 6 8 . .
. . 1 3 6 2 5 . .
. 3 . 9 5 7 . . .
. . 2 1 4 8 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
297485316356271948148693257713829465685734192429516873971362584834957621562148739 #1 Hard (1134)
Naked Single: r3c5=9
Naked Single: r3c6=3
Naked Single: r2c6=1
Naked Single: r1c6=5
Full House: r1c4=4
Hidden Single: r5c9=2
Hidden Single: r1c1=2
Hidden Single: r6c3=9
Naked Single: r6c6=6
Naked Single: r9c6=8
Naked Single: r7c4=3
Naked Single: r7c6=2
Full House: r4c6=9
Naked Single: r7c5=6
Full House: r8c5=5
Naked Single: r4c5=2
Full House: r6c5=1
Hidden Single: r2c7=9
Hidden Single: r9c1=5
Hidden Single: r5c7=1
Hidden Single: r2c1=3
Hidden Single: r8c8=2
Hidden Single: r5c3=5
Hidden Single: r9c9=9
Hidden Single: r7c1=9
Hidden Single: r8c9=1
Hidden Single: r1c8=1
Hidden Single: r7c8=8
Locked Candidates Type 1 (Pointing): 6 in b1 => r8c3<>6
Locked Candidates Type 1 (Pointing): 4 in b4 => r8c1<>4
Locked Candidates Type 1 (Pointing): 6 in b6 => r4c1<>6
Locked Candidates Type 1 (Pointing): 7 in b7 => r35c2<>7
Naked Pair: 4,7 in r37c9 => r146c9<>7, r46c9<>4
X-Wing: 4 c29 r37 => r3c3<>4
W-Wing: 6/4 in r2c8,r8c7 connected by 4 in r28c3 => r1c7,r9c8<>6
Locked Candidates Type 1 (Pointing): 6 in b9 => r4c7<>6
W-Wing: 3/7 in r1c7,r9c8 connected by 7 in r37c9 => r9c7<>3
Hidden Single: r9c8=3
Hidden Single: r1c7=3
Naked Single: r1c9=6
Full House: r1c3=7
Naked Single: r2c8=4
Full House: r2c3=6
Full House: r3c9=7
Naked Single: r4c9=5
Naked Single: r3c3=8
Full House: r3c2=4
Full House: r8c3=4
Naked Single: r6c8=7
Full House: r4c8=6
Naked Single: r7c9=4
Full House: r6c9=3
Full House: r7c2=7
Full House: r4c7=4
Naked Single: r8c7=6
Full House: r8c1=8
Full House: r9c2=6
Full House: r9c7=7
Full House: r5c2=8
Naked Single: r6c1=4
Full House: r6c4=5
Naked Single: r4c1=7
Full House: r4c4=8
Full House: r5c4=7
Full House: r5c1=6
|
normal_sudoku_2710
|
..1746.327.2..3.4..43...6.72.9.5847.5371249864........32....19.6.....7.4......36.
|
951746832762813549843295617219658473537124986486379251325467198698531724174982365
|
Basic 9x9 Sudoku 2710
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 1 7 4 6 . 3 2
7 . 2 . . 3 . 4 .
. 4 3 . . . 6 . 7
2 . 9 . 5 8 4 7 .
5 3 7 1 2 4 9 8 6
4 . . . . . . . .
3 2 . . . . 1 9 .
6 . . . . . 7 . 4
. . . . . . 3 6 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
951746832762813549843295617219658473537124986486379251325467198698531724174982365 #1 Easy (364)
Naked Single: r5c1=5
Hidden Single: r1c4=7
Hidden Single: r3c3=3
Hidden Single: r4c1=2
Hidden Single: r2c8=4
Hidden Single: r1c8=3
Hidden Single: r8c7=7
Hidden Single: r3c7=6
Naked Single: r4c7=4
Naked Single: r4c6=8
Naked Single: r5c7=9
Naked Single: r5c9=6
Naked Single: r5c3=7
Full House: r5c6=4
Hidden Single: r2c2=6
Naked Single: r4c2=1
Naked Single: r4c9=3
Full House: r4c4=6
Naked Single: r6c2=8
Full House: r6c3=6
Hidden Single: r9c1=1
Hidden Single: r6c7=2
Hidden Single: r8c8=2
Hidden Single: r2c9=9
Hidden Single: r9c2=7
Hidden Single: r1c2=5
Full House: r8c2=9
Naked Single: r1c7=8
Full House: r1c1=9
Full House: r2c7=5
Full House: r3c1=8
Full House: r3c8=1
Full House: r6c8=5
Full House: r6c9=1
Naked Single: r2c4=8
Full House: r2c5=1
Naked Single: r3c5=9
Naked Single: r9c5=8
Naked Single: r8c5=3
Naked Single: r9c9=5
Full House: r7c9=8
Naked Single: r6c5=7
Full House: r7c5=6
Naked Single: r8c4=5
Naked Single: r9c3=4
Naked Single: r6c6=9
Full House: r6c4=3
Naked Single: r3c4=2
Full House: r3c6=5
Naked Single: r7c4=4
Full House: r9c4=9
Full House: r9c6=2
Naked Single: r7c6=7
Full House: r8c6=1
Full House: r8c3=8
Full House: r7c3=5
|
normal_sudoku_134
|
..214...9..65.......49..18.745296831..3714...2.1385.4..18........9...7..437629518
|
852143679196578423374962185745296831983714256261385947618457392529831764437629518
|
Basic 9x9 Sudoku 134
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 2 1 4 . . . 9
. . 6 5 . . . . .
. . 4 9 . . 1 8 .
7 4 5 2 9 6 8 3 1
. . 3 7 1 4 . . .
2 . 1 3 8 5 . 4 .
. 1 8 . . . . . .
. . 9 . . . 7 . .
4 3 7 6 2 9 5 1 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
852143679196578423374962185745296831983714256261385947618457392529831764437629518 #1 Easy (238)
Naked Single: r4c3=5
Naked Single: r6c3=1
Naked Single: r4c6=6
Naked Single: r9c1=4
Naked Single: r9c8=1
Full House: r9c9=8
Naked Single: r1c3=2
Full House: r3c3=4
Naked Single: r4c5=9
Full House: r5c4=7
Naked Single: r4c8=3
Full House: r4c7=8
Naked Single: r3c4=9
Naked Single: r7c4=4
Full House: r8c4=8
Hidden Single: r2c1=1
Hidden Single: r6c9=7
Hidden Single: r8c2=2
Naked Single: r8c8=6
Naked Single: r8c1=5
Full House: r7c1=6
Naked Single: r3c1=3
Naked Single: r8c5=3
Naked Single: r1c1=8
Full House: r5c1=9
Naked Single: r2c5=7
Naked Single: r7c6=7
Naked Single: r8c6=1
Full House: r8c9=4
Full House: r7c5=5
Full House: r3c5=6
Naked Single: r6c2=6
Full House: r5c2=8
Full House: r6c7=9
Naked Single: r1c6=3
Naked Single: r2c2=9
Naked Single: r2c8=2
Naked Single: r3c6=2
Full House: r2c6=8
Naked Single: r1c7=6
Naked Single: r2c9=3
Full House: r2c7=4
Naked Single: r3c9=5
Full House: r1c8=7
Full House: r3c2=7
Full House: r1c2=5
Naked Single: r5c8=5
Full House: r7c8=9
Naked Single: r5c7=2
Full House: r5c9=6
Full House: r7c9=2
Full House: r7c7=3
|
normal_sudoku_2806
|
.6....34....5...2.2..4.36.1..6..21.882...543..1.9...7............387.....8...17.3
|
169287345348516927275493681936742158827165439514938276751329864693874512482651793
|
Basic 9x9 Sudoku 2806
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 6 . . . . 3 4 .
. . . 5 . . . 2 .
2 . . 4 . 3 6 . 1
. . 6 . . 2 1 . 8
8 2 . . . 5 4 3 .
. 1 . 9 . . . 7 .
. . . . . . . . .
. . 3 8 7 . . . .
. 8 . . . 1 7 . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
169287345348516927275493681936742158827165439514938276751329864693874512482651793 #1 Extreme (37976) bf
Locked Candidates Type 2 (Claiming): 2 in r8 => r7c789,r9c8<>2
Forcing Net Contradiction in r9 => r2c2<>7
r2c2=7 (r3c3<>7 r3c4=7 r4c4<>7 r4c1=7 r7c1<>7 r7c3=7 r7c3<>2) r2c2<>3 r2c1=3 r6c1<>3 r6c5=3 r7c5<>3 r7c4=3 (r7c4<>6) (r7c4<>2) r7c4<>2 r7c5=2 r9c4<>2 r1c4=2 r1c4<>1 r5c4=1 r5c4<>6 r9c4=6
r2c2=7 (r2c2<>3 r4c2=3 r4c8<>3) r2c9<>7 r1c9=7 r1c9<>5 r3c8=5 (r9c8<>5) r4c8<>5 r4c8=9 r9c8<>9 r9c8=6
Brute Force: r5c7=4
Brute Force: r5c8=3
Locked Candidates Type 1 (Pointing): 6 in b6 => r78c9<>6
Forcing Chain Verity => r1c9<>2
r8c1=6 r8c1<>1 r8c8=1 r8c8<>2 r2c8=2 r1c9<>2
r8c6=6 r2c6<>6 r2c5=6 r2c5<>2 r1c45=2 r1c9<>2
r8c8=6 r8c8<>2 r2c8=2 r1c9<>2
Locked Candidates Type 1 (Pointing): 2 in b3 => r2c5<>2
Forcing Chain Verity => r2c7<>2
r8c1=6 r8c1<>1 r8c8=1 r8c8<>2 r2c8=2 r2c7<>2
r8c6=6 r79c4<>6 r5c4=6 r5c9<>6 r6c9=6 r6c9<>2 r6c7=2 r2c7<>2
r8c8=6 r8c8<>2 r2c8=2 r2c7<>2
XYZ-Wing: 5/8/9 in r2c7,r34c8 => r2c8<>9
Forcing Chain Verity => r8c8<>5
r8c1=6 r8c1<>1 r8c8=1 r8c8<>5
r8c6=6 r79c4<>6 r5c4=6 r5c9<>6 r6c9=6 r6c9<>2 r6c7=2 r6c7<>5 r78c7=5 r8c8<>5
r8c8=6 r8c8<>5
Brute Force: r5c6=5
Locked Candidates Type 1 (Pointing): 7 in b5 => r13c4<>7
Naked Single: r3c4=4
Locked Candidates Type 2 (Claiming): 7 in r3 => r1c13,r2c13<>7
Discontinuous Nice Loop: 5 r9c8 -5- r9c5 =5= r7c5 =3= r7c4 -3- r4c4 -7- r5c4 =7= r5c3 =9= r5c9 -9- r4c8 -5- r9c8 => r9c8<>5
Discontinuous Nice Loop: 2 r7c4 -2- r9c4 -6- r9c8 -9- r4c8 =9= r5c9 -9- r5c3 -7- r5c4 =7= r4c4 =3= r7c4 => r7c4<>2
Discontinuous Nice Loop: 6 r7c1 -6- r7c4 -3- r4c4 -7- r4c1 =7= r7c1 => r7c1<>6
Discontinuous Nice Loop: 2 r2c9 -2- r2c8 =2= r8c8 =1= r8c1 =6= r9c1 -6- r9c8 -9- r4c8 -5- r3c8 =5= r1c9 =7= r2c9 => r2c9<>2
Hidden Single: r2c8=2
Hidden Rectangle: 7/9 in r1c69,r2c69 => r1c6<>9
Hidden Rectangle: 2/5 in r6c79,r8c79 => r8c9<>5
Discontinuous Nice Loop: 4 r7c3 -4- r7c9 =4= r8c9 =2= r8c7 -2- r6c7 -5- r6c3 -4- r7c3 => r7c3<>4
Discontinuous Nice Loop: 4 r7c5 -4- r7c9 =4= r8c9 =2= r6c9 =6= r5c9 =9= r5c3 =7= r5c4 -7- r4c4 -3- r7c4 =3= r7c5 => r7c5<>4
Discontinuous Nice Loop: 7 r7c3 -7- r7c1 =7= r4c1 -7- r4c4 -3- r7c4 =3= r7c5 =2= r7c3 => r7c3<>7
Discontinuous Nice Loop: 9 r8c8 -9- r9c8 -6- r9c1 =6= r8c1 =1= r8c8 => r8c8<>9
Grouped Discontinuous Nice Loop: 9 r1c5 -9- r3c5 -8- r3c8 =8= r7c8 =6= r7c456 -6- r9c4 -2- r1c4 =2= r1c5 => r1c5<>9
Finned X-Wing: 9 r15 c39 fr1c1 => r23c3<>9
Grouped Discontinuous Nice Loop: 9 r2c2 -9- r1c13 =9= r1c9 -9- r5c9 =9= r5c3 =7= r5c4 -7- r4c4 -3- r4c2 =3= r2c2 => r2c2<>9
Grouped Discontinuous Nice Loop: 4 r7c1 -4- r9c13 =4= r9c5 -4- r4c5 -3- r4c4 -7- r4c1 =7= r7c1 => r7c1<>4
Grouped Discontinuous Nice Loop: 4 r7c2 -4- r7c9 =4= r8c9 =2= r8c7 =5= r7c789 -5- r7c5 =5= r9c5 =4= r9c13 -4- r7c2 => r7c2<>4
Almost Locked Set Chain: 9- r2c7 {89} -8- r7c12345679 {123456789} -6- r19c4 {126} -1- r1c13,r3c23 {15789} -9 => r2c1<>9
Almost Locked Set Chain: 8- r3c58 {589} -5- r4c8 {59} -9- r5c459 {1679} -7- r125679c3 {1245789} -8 => r3c3<>8
Sue de Coq: r1c13 - {1589} (r1c45 - {128}, r3c23 - {579}) => r1c6<>8
Naked Single: r1c6=7
Hidden Single: r2c9=7
AIC: 4 4- r4c5 -3- r4c4 -7- r5c4 =7= r5c3 -7- r3c3 -5- r6c3 -4 => r4c12,r6c56<>4
Hidden Single: r4c5=4
Locked Candidates Type 2 (Claiming): 4 in r9 => r8c12<>4
Hidden Single: r2c2=4
Hidden Single: r2c1=3
Hidden Single: r4c2=3
Naked Single: r4c4=7
Hidden Single: r6c5=3
Hidden Single: r7c4=3
Hidden Single: r7c1=7
Hidden Single: r5c3=7
Naked Single: r3c3=5
Naked Single: r6c3=4
Naked Single: r6c1=5
Full House: r4c1=9
Full House: r4c8=5
Naked Single: r6c7=2
Naked Single: r1c1=1
Naked Single: r6c9=6
Full House: r5c9=9
Full House: r6c6=8
Naked Single: r1c4=2
Naked Single: r2c3=8
Naked Single: r8c1=6
Full House: r9c1=4
Naked Single: r1c9=5
Naked Single: r1c5=8
Full House: r1c3=9
Full House: r3c2=7
Naked Single: r9c4=6
Full House: r5c4=1
Full House: r5c5=6
Naked Single: r2c7=9
Full House: r3c8=8
Full House: r3c5=9
Naked Single: r8c8=1
Naked Single: r7c9=4
Full House: r8c9=2
Naked Single: r9c3=2
Full House: r7c3=1
Naked Single: r9c8=9
Full House: r9c5=5
Full House: r7c8=6
Naked Single: r2c5=1
Full House: r2c6=6
Full House: r7c5=2
Naked Single: r8c7=5
Full House: r7c7=8
Naked Single: r7c6=9
Full House: r7c2=5
Full House: r8c2=9
Full House: r8c6=4
|
normal_sudoku_2895
|
36....59....35...25.8.9..4.....1...4..183.9.56.57.9.1..5......6..6.8..791..96245.
|
362478591794351682518296347983615724271834965645729813859147236426583179137962458
|
Basic 9x9 Sudoku 2895
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
3 6 . . . . 5 9 .
. . . 3 5 . . . 2
5 . 8 . 9 . . 4 .
. . . . 1 . . . 4
. . 1 8 3 . 9 . 5
6 . 5 7 . 9 . 1 .
. 5 . . . . . . 6
. . 6 . 8 . . 7 9
1 . . 9 6 2 4 5 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
362478591794351682518296347983615724271834965645729813859147236426583179137962458 #1 Extreme (11916) bf
Brute Force: r5c5=3
Grouped Discontinuous Nice Loop: 2 r4c1 -2- r4c4 =2= r6c5 =4= r5c6 =6= r5c8 =2= r5c12 -2- r4c1 => r4c1<>2
Grouped Discontinuous Nice Loop: 2 r4c2 -2- r4c4 =2= r6c5 =4= r5c6 =6= r5c8 =2= r5c12 -2- r4c2 => r4c2<>2
Grouped Discontinuous Nice Loop: 2 r4c3 -2- r4c4 =2= r6c5 =4= r5c6 =6= r5c8 =2= r5c12 -2- r4c3 => r4c3<>2
Sashimi Swordfish: 2 c358 r167 fr4c8 fr5c8 => r6c7<>2
Grouped Continuous Nice Loop: 5 6= r5c6 =4= r6c5 =2= r4c4 -2- r4c78 =2= r5c8 =6= r5c6 =4 => r5c68,r6c5<>5
Locked Candidates Type 1 (Pointing): 5 in b5 => r4c138<>5
Hidden Single: r9c8=5
Hidden Single: r2c5=5
Hidden Single: r6c3=5
Hidden Single: r3c1=5
Hidden Single: r9c5=6
Naked Single: r9c4=9
Hidden Single: r5c9=5
Hidden Single: r8c9=9
Hidden Single: r4c7=7
Locked Pair: 3,8 in r6c79 => r4c8,r6c2<>3, r4c8,r6c2<>8
Hidden Single: r7c8=3
Naked Single: r9c9=8
Naked Single: r6c9=3
Naked Single: r6c7=8
Hidden Single: r8c6=3
Hidden Single: r2c8=8
Hidden Single: r1c6=8
Hidden Single: r7c1=8
Naked Single: r4c1=9
Naked Single: r4c3=3
Naked Single: r4c2=8
Naked Single: r9c3=7
Full House: r9c2=3
Hidden Single: r3c7=3
Hidden Single: r8c4=5
Hidden Single: r4c6=5
Hidden Single: r7c3=9
Naked Single: r2c3=4
Full House: r1c3=2
Naked Single: r2c1=7
Naked Single: r3c2=1
Full House: r2c2=9
Naked Single: r3c9=7
Full House: r1c9=1
Full House: r2c7=6
Full House: r2c6=1
Naked Single: r3c6=6
Full House: r3c4=2
Naked Single: r1c4=4
Full House: r1c5=7
Naked Single: r5c6=4
Full House: r7c6=7
Naked Single: r4c4=6
Full House: r7c4=1
Full House: r7c5=4
Full House: r6c5=2
Full House: r4c8=2
Full House: r7c7=2
Full House: r6c2=4
Full House: r5c8=6
Full House: r8c7=1
Naked Single: r5c1=2
Full House: r5c2=7
Full House: r8c2=2
Full House: r8c1=4
|
normal_sudoku_3208
|
1..7.549..4.....75....4..1..2...4...5.382714.4...5..279.4.7.2.12..59.7.4.7.4.2.6.
|
132785496649231875857649312721964583563827149498153627984376251216598734375412968
|
Basic 9x9 Sudoku 3208
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
1 . . 7 . 5 4 9 .
. 4 . . . . . 7 5
. . . . 4 . . 1 .
. 2 . . . 4 . . .
5 . 3 8 2 7 1 4 .
4 . . . 5 . . 2 7
9 . 4 . 7 . 2 . 1
2 . . 5 9 . 7 . 4
. 7 . 4 . 2 . 6 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
132785496649231875857649312721964583563827149498153627984376251216598734375412968 #1 Extreme (18836) bf
Hidden Single: r2c8=7
Hidden Single: r1c7=4
Hidden Single: r7c3=4
Locked Candidates Type 1 (Pointing): 2 in b3 => r5c9<>2
Hidden Pair: 4,7 in r45c6 => r4c6<>1, r4c6<>3, r45c6<>6, r45c6<>9
Discontinuous Nice Loop: 6 r4c7 -6- r5c9 -9- r9c9 =9= r9c7 =5= r4c7 => r4c7<>6
Forcing Chain Contradiction in c3 => r4c1<>5
r4c1=5 r4c78<>5 r5c8=5 r5c8<>4 r5c6=4 r5c6<>7 r5c1=7 r3c1<>7 r3c3=7 r3c3<>5
r4c1=5 r4c3<>5
r4c1=5 r4c7<>5 r9c7=5 r9c3<>5
Brute Force: r5c1=5
Hidden Single: r5c6=7
Naked Single: r4c6=4
Hidden Single: r5c8=4
Hidden Single: r5c5=2
Hidden Single: r6c8=2
Discontinuous Nice Loop: 9 r3c2 -9- r5c2 =9= r5c9 -9- r9c9 =9= r9c7 =5= r9c3 -5- r3c3 =5= r3c2 => r3c2<>9
Locked Candidates Type 1 (Pointing): 9 in b1 => r46c3<>9
Grouped Discontinuous Nice Loop: 1 r4c5 -1- r9c5 =1= r9c3 =5= r3c3 =9= r2c3 =2= r2c4 =1= r46c4 -1- r4c5 => r4c5<>1
Discontinuous Nice Loop: 1 r2c4 -1- r4c4 =1= r4c3 =7= r3c3 =9= r2c3 =2= r2c4 => r2c4<>1
Locked Candidates Type 2 (Claiming): 1 in c4 => r6c6<>1
Discontinuous Nice Loop: 9 r2c6 -9- r2c3 =9= r3c3 =5= r9c3 =1= r9c5 -1- r2c5 =1= r2c6 => r2c6<>9
Hidden Pair: 2,9 in r2c34 => r2c34<>6, r2c3<>8, r2c4<>3
Forcing Chain Contradiction in c1 => r2c6<>6
r2c6=6 r2c1<>6
r2c6=6 r2c6<>1 r2c5=1 r9c5<>1 r9c3=1 r9c3<>5 r3c3=5 r3c3<>7 r3c1=7 r3c1<>6
r2c6=6 r12c5<>6 r4c5=6 r4c1<>6
Grouped Discontinuous Nice Loop: 6 r3c9 -6- r3c46 =6= r12c5 -6- r4c5 -3- r4c789 =3= r6c7 =6= r23c7 -6- r3c9 => r3c9<>6
Forcing Chain Contradiction in r1 => r3c6<>6
r3c6=6 r12c5<>6 r4c5=6 r4c1<>6 r23c1=6 r1c2<>6
r3c6=6 r12c5<>6 r4c5=6 r4c1<>6 r23c1=6 r1c3<>6
r3c6=6 r1c5<>6
r3c6=6 r3c6<>9 r6c6=9 r6c2<>9 r5c2=9 r5c2<>6 r5c9=6 r1c9<>6
Grouped AIC: 3 3- r4c5 -6- r6c6 =6= r78c6 -6- r7c4 -3 => r46c4,r9c5<>3
Grouped Discontinuous Nice Loop: 3 r7c2 -3- r7c4 =3= r3c4 -3- r12c5 =3= r4c5 -3- r4c8 =3= r78c8 -3- r9c79 =3= r9c1 -3- r7c2 => r7c2<>3
Almost Locked Set XY-Wing: A=r236c7 {3689}, B=r7c2,r89c3,r9c1 {13568}, C=r4c135789 {1356789}, X,Y=1,9, Z=3 => r9c7<>3
Forcing Chain Verity => r2c3=9
r2c1=3 r9c1<>3 r9c9=3 r78c8<>3 r4c8=3 r4c5<>3 r6c6=3 r6c6<>9 r3c6=9 r3c3<>9 r2c3=9
r2c5=3 r4c5<>3 r6c6=3 r6c6<>9 r3c6=9 r3c3<>9 r2c3=9
r2c6=3 r2c6<>1 r2c5=1 r9c5<>1 r9c3=1 r9c3<>5 r3c3=5 r3c3<>9 r2c3=9
r2c7=3 r6c7<>3 r6c6=3 r6c6<>9 r3c6=9 r3c3<>9 r2c3=9
Naked Single: r2c4=2
Forcing Chain Contradiction in r2 => r7c4=3
r7c4<>3 r3c4=3 r12c5<>3 r4c5=3 r4c8<>3 r78c8=3 r9c9<>3 r9c1=3 r2c1<>3
r7c4<>3 r3c4=3 r2c5<>3
r7c4<>3 r3c4=3 r2c6<>3
r7c4<>3 r78c6=3 r6c6<>3 r6c7=3 r2c7<>3
Locked Candidates Type 1 (Pointing): 6 in b8 => r6c6<>6
Discontinuous Nice Loop: 6 r4c9 -6- r4c5 -3- r6c6 -9- r6c2 =9= r5c2 =6= r5c9 -6- r4c9 => r4c9<>6
Forcing Chain Contradiction in r1 => r8c8=3
r8c8<>3 r4c8=3 r4c5<>3 r4c5=6 r4c1<>6 r23c1=6 r1c2<>6
r8c8<>3 r4c8=3 r4c5<>3 r4c5=6 r4c1<>6 r23c1=6 r1c3<>6
r8c8<>3 r4c8=3 r4c5<>3 r4c5=6 r1c5<>6
r8c8<>3 r8c2=3 r8c2<>1 r6c2=1 r6c2<>9 r5c2=9 r5c2<>6 r5c9=6 r1c9<>6
Hidden Single: r9c1=3
Finned X-Wing: 3 r26 c67 fr2c5 => r3c6<>3
Discontinuous Nice Loop: 6 r2c5 -6- r4c5 -3- r6c6 =3= r2c6 =1= r2c5 => r2c5<>6
Sashimi X-Wing: 6 c15 r14 fr2c1 fr3c1 => r1c23<>6
Hidden Rectangle: 2/8 in r1c39,r3c39 => r3c9<>8
Continuous Nice Loop: 1/6/8 1= r2c6 =3= r6c6 -3- r4c5 -6- r1c5 =6= r1c9 -6- r5c9 -9- r5c2 =9= r6c2 =1= r8c2 -1- r8c6 =1= r2c6 =3 => r8c3<>1, r6c2<>6, r2c6,r6c2<>8
Empty Rectangle: 8 in b3 (r6c37) => r1c3<>8
Naked Single: r1c3=2
Hidden Single: r3c9=2
Finned Jellyfish: 8 r1269 c3579 fr1c2 fr2c1 => r3c3<>8
Sue de Coq: r6c46 - {1369} (r6c2 - {19}, r4c5 - {36}) => r4c4<>6, r6c3<>1, r6c7<>9
Naked Pair: 6,8 in r68c3 => r34c3<>6, r49c3<>8
Naked Triple: 3,6,8 in r236c7 => r4c7<>3, r49c7<>8
2-String Kite: 6 in r3c4,r4c1 (connected by r4c5,r6c4) => r3c1<>6
Sashimi Swordfish: 6 r124 c157 fr1c9 => r3c7<>6
Skyscraper: 6 in r4c1,r6c7 (connected by r2c17) => r6c3<>6
Naked Single: r6c3=8
Naked Single: r8c3=6
Hidden Single: r7c6=6
Locked Candidates Type 1 (Pointing): 8 in b7 => r13c2<>8
Naked Single: r1c2=3
Hidden Single: r4c9=3
Naked Single: r4c5=6
Naked Single: r6c7=6
Naked Single: r1c5=8
Full House: r1c9=6
Naked Single: r4c1=7
Naked Single: r5c9=9
Full House: r5c2=6
Full House: r9c9=8
Naked Single: r3c6=9
Naked Single: r9c5=1
Full House: r2c5=3
Full House: r8c6=8
Full House: r8c2=1
Naked Single: r3c1=8
Full House: r2c1=6
Naked Single: r4c3=1
Full House: r6c2=9
Naked Single: r4c7=5
Full House: r4c8=8
Full House: r7c8=5
Full House: r4c4=9
Full House: r9c7=9
Full House: r9c3=5
Full House: r7c2=8
Full House: r3c2=5
Full House: r3c3=7
Naked Single: r3c4=6
Full House: r2c6=1
Full House: r6c6=3
Full House: r2c7=8
Full House: r3c7=3
Full House: r6c4=1
|
normal_sudoku_1982
|
.26.75981.5..8.....8.9..4..27...9....49....12.632...9..3.8971..718546329.9.132.6.
|
426375981951684273387921456275419638849763512163258794632897145718546329594132867
|
Basic 9x9 Sudoku 1982
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 2 6 . 7 5 9 8 1
. 5 . . 8 . . . .
. 8 . 9 . . 4 . .
2 7 . . . 9 . . .
. 4 9 . . . . 1 2
. 6 3 2 . . . 9 .
. 3 . 8 9 7 1 . .
7 1 8 5 4 6 3 2 9
. 9 . 1 3 2 . 6 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
426375981951684273387921456275419638849763512163258794632897145718546329594132867 #1 Easy (314)
Naked Single: r8c2=1
Naked Single: r8c4=5
Naked Single: r4c2=7
Full House: r7c2=3
Naked Single: r8c8=2
Full House: r8c3=8
Naked Single: r9c5=3
Full House: r7c5=9
Naked Single: r1c5=7
Naked Single: r1c7=9
Hidden Single: r4c6=9
Hidden Single: r7c7=1
Hidden Single: r3c5=2
Hidden Single: r7c1=6
Hidden Single: r2c7=2
Hidden Single: r7c3=2
Hidden Single: r5c4=7
Hidden Single: r2c1=9
Hidden Single: r3c9=6
Hidden Single: r2c4=6
Hidden Single: r5c6=3
Naked Single: r3c6=1
Naked Single: r4c4=4
Full House: r1c4=3
Full House: r2c6=4
Full House: r6c6=8
Full House: r1c1=4
Naked Single: r3c1=3
Naked Single: r3c3=7
Full House: r2c3=1
Full House: r3c8=5
Naked Single: r9c1=5
Full House: r9c3=4
Full House: r4c3=5
Naked Single: r4c8=3
Naked Single: r7c8=4
Full House: r2c8=7
Full House: r7c9=5
Full House: r2c9=3
Naked Single: r5c1=8
Full House: r6c1=1
Naked Single: r4c9=8
Naked Single: r6c5=5
Naked Single: r4c7=6
Full House: r4c5=1
Full House: r5c5=6
Full House: r5c7=5
Naked Single: r9c9=7
Full House: r6c9=4
Full House: r6c7=7
Full House: r9c7=8
|
normal_sudoku_1331
|
...7.82.9.78..9..129..14...7691.3.28.84972.3..23..69....2.95...8..4.7592957..1.6.
|
416738259378529641295614783769153428584972136123846975642395817831467592957281364
|
Basic 9x9 Sudoku 1331
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . 7 . 8 2 . 9
. 7 8 . . 9 . . 1
2 9 . . 1 4 . . .
7 6 9 1 . 3 . 2 8
. 8 4 9 7 2 . 3 .
. 2 3 . . 6 9 . .
. . 2 . 9 5 . . .
8 . . 4 . 7 5 9 2
9 5 7 . . 1 . 6 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
416738259378529641295614783769153428584972136123846975642395817831467592957281364 #1 Hard (454)
Naked Single: r5c6=2
Naked Single: r4c6=3
Naked Single: r2c6=9
Naked Single: r8c6=7
Full House: r1c6=8
Hidden Single: r4c3=9
Hidden Single: r9c1=9
Hidden Single: r8c8=9
Hidden Single: r4c8=2
Hidden Single: r7c3=2
Hidden Single: r6c2=2
Hidden Single: r1c9=9
Hidden Single: r8c7=5
Naked Single: r4c7=4
Full House: r4c5=5
Naked Single: r6c4=8
Full House: r6c5=4
Hidden Single: r9c9=4
Hidden Single: r9c5=8
Naked Single: r9c7=3
Full House: r9c4=2
Naked Single: r2c7=6
Naked Single: r7c9=7
Naked Single: r5c7=1
Naked Single: r6c9=5
Naked Single: r5c1=5
Full House: r5c9=6
Full House: r3c9=3
Full House: r6c1=1
Full House: r6c8=7
Naked Single: r7c7=8
Full House: r3c7=7
Full House: r7c8=1
Hidden Single: r2c5=2
Hidden Single: r3c8=8
Skyscraper: 6 in r3c3,r7c1 (connected by r37c4) => r1c1,r8c3<>6
Naked Single: r8c3=1
Naked Single: r8c2=3
Full House: r8c5=6
Full House: r1c5=3
Full House: r7c4=3
Naked Single: r7c2=4
Full House: r1c2=1
Full House: r7c1=6
Naked Single: r1c1=4
Full House: r2c1=3
Naked Single: r2c4=5
Full House: r2c8=4
Full House: r1c8=5
Full House: r3c4=6
Full House: r1c3=6
Full House: r3c3=5
|
normal_sudoku_825
|
2....9.3....2..9....9.4...6.....5.1.526391..731....5...4...7..86...8......89.4...
|
261859734473216985859743126984675312526391847317428569142537698695182473738964251
|
Basic 9x9 Sudoku 825
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
2 . . . . 9 . 3 .
. . . 2 . . 9 . .
. . 9 . 4 . . . 6
. . . . . 5 . 1 .
5 2 6 3 9 1 . . 7
3 1 . . . . 5 . .
. 4 . . . 7 . . 8
6 . . . 8 . . . .
. . 8 9 . 4 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
261859734473216985859743126984675312526391847317428569142537698695182473738964251 #1 Extreme (29834) bf
Hidden Single: r1c6=9
Locked Candidates Type 1 (Pointing): 9 in b4 => r4c9<>9
Brute Force: r5c4=3
Hidden Single: r5c6=1
Forcing Chain Contradiction in r7 => r6c3<>2
r6c3=2 r7c3<>2
r6c3=2 r6c6<>2 r8c6=2 r7c5<>2
r6c3=2 r5c2<>2 r5c78=2 r46c9<>2 r89c9=2 r7c7<>2
r6c3=2 r5c2<>2 r5c78=2 r46c9<>2 r89c9=2 r7c8<>2
Forcing Net Contradiction in r7 => r4c1<>7
r4c1=7 (r4c3<>7) r6c3<>7 r6c3=4 r4c3<>4 r4c3=2 r7c3<>2
r4c1=7 (r4c1<>8) (r4c1<>9 r4c2=9 r4c2<>8) r6c3<>7 r6c3=4 r6c4<>4 r4c4=4 r4c4<>8 r4c7=8 (r1c7<>8) r4c7<>6 r6c8=6 r6c6<>6 r2c6=6 (r1c4<>6) r1c5<>6 r1c2=6 r1c2<>8 r1c4=8 r3c6<>8 r3c6=3 r8c6<>3 r8c6=2 r7c5<>2
r4c1=7 (r4c3<>7) r6c3<>7 r6c3=4 r4c3<>4 r4c3=2 r5c2<>2 r5c78=2 r46c9<>2 r89c9=2 r7c7<>2
r4c1=7 (r4c3<>7) r6c3<>7 r6c3=4 r4c3<>4 r4c3=2 r5c2<>2 r5c78=2 r46c9<>2 r89c9=2 r7c8<>2
Forcing Net Contradiction in c7 => r1c3<>7
r1c3=7 (r6c3<>7 r6c3=4 r4c3<>4 r4c3=2 r4c9<>2) (r6c3<>7 r6c3=4 r4c3<>4 r4c3=2 r5c2<>2) (r1c2<>7) (r2c2<>7) (r3c2<>7) (r2c1<>7) r3c1<>7 r9c1=7 (r8c2<>7) r9c2<>7 r4c2=7 (r4c2<>2) r4c2<>9 (r4c1=9 r7c1<>9 r7c8=9 r6c8<>9 r6c9=9 r6c9<>2) r8c2=9 r8c2<>2 r9c2=2 r9c9<>2 r8c9=2 r8c6<>2 (r8c6=3 r3c6<>3 r3c6=8 r1c4<>8) r6c6=2 r6c6<>6 r2c6=6 (r1c4<>6) r1c5<>6 r1c2=6 r1c2<>8 r1c7=8
r1c3=7 (r6c3<>7 r6c3=4 r6c4<>4 r4c4=4 r4c4<>8) (r1c2<>7) (r2c2<>7) (r3c2<>7) (r2c1<>7) r3c1<>7 r9c1=7 (r8c2<>7) r9c2<>7 r4c2=7 (r4c2<>8) r4c2<>9 r4c1=9 r4c1<>8 r4c7=8
Forcing Net Contradiction in c7 => r2c3<>7
r2c3=7 (r6c3<>7 r6c3=4 r4c3<>4 r4c3=2 r4c9<>2) (r6c3<>7 r6c3=4 r4c3<>4 r4c3=2 r5c2<>2) (r1c2<>7) (r2c2<>7) (r3c2<>7) (r2c1<>7) r3c1<>7 r9c1=7 (r8c2<>7) r9c2<>7 r4c2=7 (r4c2<>2) r4c2<>9 (r4c1=9 r7c1<>9 r7c8=9 r6c8<>9 r6c9=9 r6c9<>2) r8c2=9 r8c2<>2 r9c2=2 r9c9<>2 r8c9=2 r8c6<>2 (r8c6=3 r3c6<>3 r3c6=8 r1c4<>8) r6c6=2 r6c6<>6 r2c6=6 (r1c4<>6) r1c5<>6 r1c2=6 r1c2<>8 r1c7=8
r2c3=7 (r6c3<>7 r6c3=4 r6c4<>4 r4c4=4 r4c4<>8) (r1c2<>7) (r2c2<>7) (r3c2<>7) (r2c1<>7) r3c1<>7 r9c1=7 (r8c2<>7) r9c2<>7 r4c2=7 (r4c2<>8) r4c2<>9 r4c1=9 r4c1<>8 r4c7=8
Forcing Net Contradiction in c7 => r4c2<>7
r4c2=7 (r4c2<>9 r4c1=9 r7c1<>9 r7c8=9 r6c8<>9 r6c9=9 r6c9<>2) (r4c2<>2) (r4c2<>9 r8c2=9 r8c2<>2) (r4c3<>7) r6c3<>7 r6c3=4 r4c3<>4 r4c3=2 (r4c9<>2) r5c2<>2 r9c2=2 r9c9<>2 r8c9=2 r8c6<>2 (r8c6=3 r3c6<>3 r3c6=8 r1c4<>8) r6c6=2 r6c6<>6 r2c6=6 (r1c4<>6) r1c5<>6 r1c2=6 r1c2<>8 r1c7=8
r4c2=7 (r4c2<>8) (r4c2<>9 r4c1=9 r4c1<>8) r6c3<>7 r6c3=4 r6c4<>4 r4c4=4 r4c4<>8 r4c7=8
Locked Candidates Type 1 (Pointing): 7 in b4 => r8c3<>7
Forcing Net Contradiction in c9 => r4c7<>4
r4c7=4 r4c7<>3 r4c9=3 r4c9<>2
r4c7=4 r4c7<>6 r6c8=6 r6c8<>9 r6c9=9 r6c9<>2
r4c7=4 (r4c4<>4 r6c4=4 r6c4<>8) r4c7<>6 r6c8=6 r6c8<>8 r6c6=8 r6c6<>2 r8c6=2 r8c9<>2
r4c7=4 (r5c8<>4 r5c1=4 r5c1<>5 r5c2=5 r5c2<>2) (r4c4<>4 r6c4=4 r6c3<>4 r6c3=7 r4c3<>7 r4c3=2 r4c2<>2) (r4c4<>4 r6c4=4 r6c4<>8) r4c7<>6 r6c8=6 r6c8<>8 r6c6=8 r6c6<>2 r8c6=2 r8c2<>2 r9c2=2 r9c9<>2
Forcing Net Contradiction in r7 => r4c9<>4
r4c9=4 (r4c3<>4) r4c4<>4 r6c4=4 r6c3<>4 r6c3=7 r4c3<>7 r4c3=2 r7c3<>2
r4c9=4 (r4c4<>4 r6c4=4 r6c3<>4 r6c3=7 r6c5<>7) r4c9<>3 r4c7=3 r4c7<>6 r6c8=6 r6c5<>6 r6c5=2 r7c5<>2
r4c9=4 (r5c7<>4) r5c8<>4 r5c1=4 r5c1<>5 r5c2=5 r5c2<>2 r5c78=2 r46c9<>2 r89c9=2 r7c7<>2
r4c9=4 (r5c7<>4) r5c8<>4 r5c1=4 r5c1<>5 r5c2=5 r5c2<>2 r5c78=2 r46c9<>2 r89c9=2 r7c8<>2
Forcing Net Verity => r7c3<>1
r7c3=2 r7c3<>1
r7c5=2 r8c6<>2 r8c6=3 (r8c3<>3) r3c6<>3 r3c2=3 r2c3<>3 r7c3=3 r7c3<>1
r7c7=2 (r7c3<>2) (r5c7<>2) r3c7<>2 r3c8=2 r5c8<>2 r5c2=2 r4c3<>2 r8c3=2 (r8c3<>3) r8c6<>2 r8c6=3 r3c6<>3 r3c2=3 r2c3<>3 r7c3=3 r7c3<>1
r7c8=2 (r7c3<>2) (r5c8<>2) r3c8<>2 r3c7=2 r5c7<>2 r5c2=2 r4c3<>2 r8c3=2 (r8c3<>3) r8c6<>2 r8c6=3 r3c6<>3 r3c2=3 r2c3<>3 r7c3=3 r7c3<>1
Forcing Net Verity => r7c3<>5
r7c3=2 r7c3<>5
r7c5=2 r8c6<>2 r8c6=3 (r8c3<>3) r3c6<>3 r3c2=3 r2c3<>3 r7c3=3 r7c3<>5
r7c7=2 (r7c3<>2) (r5c7<>2) r3c7<>2 r3c8=2 r5c8<>2 r5c2=2 r4c3<>2 r8c3=2 (r8c3<>3) r8c6<>2 r8c6=3 r3c6<>3 r3c2=3 r2c3<>3 r7c3=3 r7c3<>5
r7c8=2 (r7c3<>2) (r5c8<>2) r3c8<>2 r3c7=2 r5c7<>2 r5c2=2 r4c3<>2 r8c3=2 (r8c3<>3) r8c6<>2 r8c6=3 r3c6<>3 r3c2=3 r2c3<>3 r7c3=3 r7c3<>5
Forcing Net Contradiction in r3 => r8c2<>5
r8c2=5 (r8c4<>5 r8c4=1 r9c5<>1) (r8c4<>5 r8c4=1 r7c4<>1) (r8c4<>5 r8c4=1 r7c5<>1) r8c2<>9 r4c2=9 r4c1<>9 r7c1=9 r7c1<>1 r7c7=1 (r9c7<>1) r9c9<>1 r9c1=1 r3c1<>1
r8c2=5 r8c4<>5 r8c4=1 r3c4<>1
r8c2=5 (r8c4<>5 r8c4=1 r7c4<>1) (r8c4<>5 r8c4=1 r7c5<>1) r8c2<>9 r4c2=9 r4c1<>9 r7c1=9 r7c1<>1 r7c7=1 r3c7<>1
Forcing Net Contradiction in b7 => r8c7<>2
r8c7=2 r8c6<>2 r8c6=3 (r8c3<>3) r3c6<>3 r3c2=3 r2c3<>3 r7c3=3 r7c3<>2
r8c7=2 r8c2<>2
r8c7=2 r8c3<>2
r8c7=2 (r5c7<>2) r3c7<>2 r3c8=2 r5c8<>2 r5c2=2 r9c2<>2
Forcing Net Contradiction in b7 => r8c8<>2
r8c8=2 r8c6<>2 r8c6=3 (r8c3<>3) r3c6<>3 r3c2=3 r2c3<>3 r7c3=3 r7c3<>2
r8c8=2 r8c2<>2
r8c8=2 r8c3<>2
r8c8=2 (r5c8<>2) r3c8<>2 r3c7=2 r5c7<>2 r5c2=2 r9c2<>2
Brute Force: r5c2=2
Hidden Single: r5c1=5
Locked Pair: 4,7 in r46c3 => r12c3,r4c1<>4
Hidden Single: r2c1=4
Locked Candidates Type 1 (Pointing): 8 in b4 => r4c47<>8
Locked Candidates Type 1 (Pointing): 8 in b5 => r6c8<>8
Locked Candidates Type 2 (Claiming): 4 in r5 => r6c89<>4
Uniqueness Test 4: 4/7 in r4c34,r6c34 => r46c4<>7
Locked Candidates Type 1 (Pointing): 7 in b5 => r12c5<>7
2-String Kite: 7 in r2c8,r9c1 (connected by r2c2,r3c1) => r9c8<>7
Discontinuous Nice Loop: 6 r6c5 -6- r4c4 -4- r4c3 -7- r4c5 =7= r6c5 => r6c5<>6
Finned Franken Swordfish: 5 r37b7 c248 fr7c5 fr8c3 => r8c4<>5
Naked Single: r8c4=1
Locked Candidates Type 1 (Pointing): 1 in b7 => r3c1<>1
Hidden Single: r3c7=1
Naked Single: r2c9=5
Naked Single: r1c9=4
Hidden Single: r9c9=1
Naked Single: r9c1=7
Naked Single: r3c1=8
Naked Single: r3c6=3
Naked Single: r4c1=9
Full House: r7c1=1
Naked Single: r8c6=2
Naked Single: r4c2=8
Hidden Single: r3c8=2
Hidden Single: r8c2=9
Naked Single: r8c9=3
Naked Single: r4c9=2
Full House: r6c9=9
Naked Single: r8c3=5
Naked Single: r6c8=6
Naked Single: r1c3=1
Naked Single: r9c2=3
Full House: r7c3=2
Naked Single: r4c7=3
Naked Single: r6c6=8
Full House: r2c6=6
Naked Single: r9c8=5
Naked Single: r2c3=3
Naked Single: r7c7=6
Naked Single: r6c4=4
Naked Single: r1c5=5
Naked Single: r2c2=7
Naked Single: r2c5=1
Full House: r2c8=8
Full House: r1c7=7
Naked Single: r7c8=9
Naked Single: r9c5=6
Full House: r9c7=2
Naked Single: r7c4=5
Full House: r7c5=3
Naked Single: r4c4=6
Naked Single: r6c3=7
Full House: r4c3=4
Full House: r4c5=7
Full House: r6c5=2
Naked Single: r3c4=7
Full House: r3c2=5
Full House: r1c2=6
Full House: r1c4=8
Naked Single: r5c8=4
Full House: r5c7=8
Full House: r8c7=4
Full House: r8c8=7
|
normal_sudoku_291
|
.942..65.85...62.92.6.5..48..8.75.2...2.348955..8......25...98.48.59..62......5.4
|
394218657857346219216957348948675123672134895531829476725463981483591762169782534
|
Basic 9x9 Sudoku 291
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 9 4 2 . . 6 5 .
8 5 . . . 6 2 . 9
2 . 6 . 5 . . 4 8
. . 8 . 7 5 . 2 .
. . 2 . 3 4 8 9 5
5 . . 8 . . . . .
. 2 5 . . . 9 8 .
4 8 . 5 9 . . 6 2
. . . . . . 5 . 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
394218657857346219216957348948675123672134895531829476725463981483591762169782534 #1 Extreme (21688) bf
Hidden Single: r1c8=5
Hidden Single: r3c1=2
Hidden Single: r4c6=5
Hidden Single: r8c8=6
Hidden Single: r7c3=5
Hidden Single: r2c2=5
Hidden Single: r7c7=9
Hidden Pair: 2,8 in r9c56 => r9c56<>1, r9c5<>6, r9c6<>3, r9c6<>7
Brute Force: r5c6=4
Hidden Single: r5c3=2
Hidden Single: r4c8=2
Hidden Single: r5c7=8
Hidden Single: r4c3=8
Locked Candidates Type 1 (Pointing): 7 in b6 => r6c23<>7
Hidden Rectangle: 1/4 in r2c45,r7c45 => r7c4<>1
Discontinuous Nice Loop: 1 r3c6 -1- r1c5 -8- r1c6 =8= r9c6 =2= r6c6 =9= r3c6 => r3c6<>1
Forcing Chain Contradiction in c4 => r9c1<>7
r9c1=7 r89c3<>7 r2c3=7 r2c4<>7
r9c1=7 r9c1<>9 r4c1=9 r4c4<>9 r3c4=9 r3c4<>7
r9c1=7 r9c1<>9 r9c3=9 r6c3<>9 r6c6=9 r6c6<>2 r6c5=2 r6c5<>6 r7c5=6 r7c5<>4 r7c4=4 r7c4<>7
r9c1=7 r9c4<>7
Brute Force: r6c3=1
Hidden Single: r5c4=1
Hidden Single: r6c6=9
Naked Single: r4c4=6
Full House: r6c5=2
Naked Single: r9c5=8
Naked Single: r1c5=1
Naked Single: r9c6=2
Naked Single: r2c5=4
Full House: r7c5=6
Hidden Single: r9c3=9
Hidden Single: r4c1=9
Hidden Single: r3c4=9
Hidden Single: r6c9=6
Hidden Single: r1c6=8
Hidden Single: r3c2=1
Hidden Single: r2c8=1
Hidden Single: r7c4=4
Hidden Single: r9c1=1
Hidden Single: r9c2=6
Naked Single: r5c2=7
Full House: r5c1=6
X-Wing: 7 c19 r17 => r7c6<>7
Remote Pair: 3/7 r3c7 -7- r1c9 -3- r1c1 -7- r7c1 -3- r8c3 -7- r2c3 -3- r2c4 -7- r9c4 -3- r9c8 -7- r6c8 => r46c7,r7c9,r8c6<>3, r6c7,r7c9,r8c6<>7
Naked Single: r6c7=4
Naked Single: r7c9=1
Naked Single: r8c6=1
Naked Single: r4c7=1
Naked Single: r6c2=3
Full House: r4c2=4
Full House: r4c9=3
Full House: r6c8=7
Full House: r1c9=7
Full House: r9c8=3
Full House: r1c1=3
Full House: r3c7=3
Full House: r8c7=7
Full House: r9c4=7
Full House: r7c6=3
Full House: r2c3=7
Full House: r7c1=7
Full House: r3c6=7
Full House: r8c3=3
Full House: r2c4=3
|
normal_sudoku_2376
|
3728965149..45...71..372.8....64...56...1.....1.7.5.......8...2.61...4..238964751
|
372896514986451237145372689823649175657218943419735826594187362761523498238964751
|
Basic 9x9 Sudoku 2376
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
3 7 2 8 9 6 5 1 4
9 . . 4 5 . . . 7
1 . . 3 7 2 . 8 .
. . . 6 4 . . . 5
6 . . . 1 . . . .
. 1 . 7 . 5 . . .
. . . . 8 . . . 2
. 6 1 . . . 4 . .
2 3 8 9 6 4 7 5 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
372896514986451237145372689823649175657218943419735826594187362761523498238964751 #1 Easy (256)
Naked Single: r1c5=9
Naked Single: r9c5=6
Hidden Single: r3c5=7
Hidden Single: r3c1=1
Naked Single: r3c4=3
Hidden Single: r4c4=6
Hidden Single: r9c9=1
Naked Single: r9c4=9
Naked Single: r9c6=4
Full House: r9c3=8
Naked Single: r1c3=2
Naked Single: r1c8=1
Full House: r1c4=8
Full House: r2c6=1
Naked Single: r2c2=8
Naked Single: r2c3=6
Naked Single: r5c4=2
Naked Single: r6c5=3
Full House: r8c5=2
Naked Single: r8c4=5
Full House: r7c4=1
Naked Single: r8c1=7
Naked Single: r4c1=8
Naked Single: r8c6=3
Full House: r7c6=7
Naked Single: r4c6=9
Full House: r5c6=8
Naked Single: r6c1=4
Full House: r7c1=5
Naked Single: r8c8=9
Full House: r8c9=8
Naked Single: r4c2=2
Naked Single: r6c3=9
Naked Single: r5c2=5
Naked Single: r6c9=6
Naked Single: r7c3=4
Full House: r7c2=9
Full House: r3c2=4
Full House: r3c3=5
Naked Single: r3c9=9
Full House: r3c7=6
Full House: r5c9=3
Naked Single: r6c8=2
Full House: r6c7=8
Naked Single: r7c7=3
Full House: r7c8=6
Naked Single: r4c7=1
Naked Single: r4c8=7
Full House: r4c3=3
Full House: r5c3=7
Naked Single: r5c7=9
Full House: r2c7=2
Full House: r2c8=3
Full House: r5c8=4
|
normal_sudoku_5286
|
..52....8.78..31..4.......3.83..2..9....65...5..3...1....72.......6..9.7.67..9.8.
|
135276498278943165496581723683412579719865342542397816954728631821634957367159284
|
Basic 9x9 Sudoku 5286
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 5 2 . . . . 8
. 7 8 . . 3 1 . .
4 . . . . . . . 3
. 8 3 . . 2 . . 9
. . . . 6 5 . . .
5 . . 3 . . . 1 .
. . . 7 2 . . . .
. . . 6 . . 9 . 7
. 6 7 . . 9 . 8 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
135276498278943165496581723683412579719865342542397816954728631821634957367159284 #1 Extreme (23848) bf
Brute Force: r5c6=5
Forcing Net Contradiction in r6 => r4c1<>1
r4c1=1 r4c1<>6 r6c3=6
r4c1=1 (r9c1<>1) (r5c1<>1) (r5c2<>1) r5c3<>1 r5c4=1 (r5c4<>8 r3c4=8 r3c5<>8) r5c4<>9 r6c5=9 r6c5<>8 r8c5=8 r8c5<>3 r9c5=3 r9c1<>3 r9c1=2 (r2c1<>2) (r8c1<>2) (r8c2<>2) r8c3<>2 r8c8=2 r2c8<>2 r2c9=2 (r6c9<>2) r5c9<>2 r5c9=4 r6c9<>4 r6c9=6
Locked Candidates Type 1 (Pointing): 1 in b4 => r5c4<>1
Forcing Net Verity => r1c6<>7
r5c4=8 (r6c6<>8 r6c7=8 r6c7<>7) r5c4<>9 r6c5=9 r6c5<>7 r6c6=7 r1c6<>7
r5c7=8 (r5c7<>7) r5c7<>3 r5c8=3 r5c8<>7 r5c1=7 r4c1<>7 r4c1=6 r6c3<>6 r3c3=6 r3c6<>6 r1c6=6 r1c6<>7
Forcing Net Contradiction in c9 => r4c5<>7
r4c5=7 (r6c5<>7) r6c6<>7 r6c7=7 (r6c7<>2) (r6c7<>6 r6c9=6 r6c9<>2) r6c7<>8 r5c7=8 (r5c7<>2) r5c7<>3 r5c8=3 r5c8<>2 r5c9=2
r4c5=7 (r4c5<>4) (r4c5<>1 r4c4=1 r4c4<>4) r6c6<>7 (r6c7=7 r1c7<>7) r3c6=7 (r3c7<>7) r3c6<>6 r1c6=6 r1c7<>6 (r7c7=6 r7c7<>3 r9c7=3 r9c7<>2) r1c7=4 r4c7<>4 (r4c7=5 r3c7<>5) r4c8=4 r5c9<>4 r5c9=2 r6c9<>2 r6c9=6 (r2c9<>6 r2c8=6 r2c8<>2) (r6c9<>4) r6c3<>6 r3c3=6 r3c7<>6 r3c7=2 r2c9<>2 r2c1=2 r9c1<>2 r9c9=2
Locked Pair: 1,4 in r4c45 => r4c78,r5c4,r6c56<>4
Locked Candidates Type 1 (Pointing): 7 in b5 => r6c7<>7
Forcing Chain Contradiction in r6c9 => r7c9<>4
r7c9=4 r5c9<>4 r5c9=2 r6c9<>2
r7c9=4 r6c9<>4
r7c9=4 r9c79<>4 r9c45=4 r78c6<>4 r1c6=4 r1c6<>6 r3c6=6 r3c3<>6 r6c3=6 r6c9<>6
Forcing Net Verity => r7c8<>4
r1c7=4 r1c6<>4 r78c6=4 r9c45<>4 r9c79=4 r7c8<>4
r1c8=4 r7c8<>4
r2c8=4 r7c8<>4
r2c9=4 (r2c9<>6) (r6c9<>4) r5c9<>4 r5c9=2 r6c9<>2 r6c9=6 (r4c7<>6) r4c8<>6 r4c1=6 (r1c1<>6) r2c1<>6 r2c8=6 (r1c7<>6) r1c8<>6 r1c6=6 r1c6<>4 r78c6=4 r9c45<>4 r9c79=4 r7c8<>4
Forcing Net Verity => r8c8<>4
r1c7=4 r1c6<>4 r78c6=4 r9c45<>4 r9c79=4 r8c8<>4
r1c8=4 r8c8<>4
r2c8=4 r8c8<>4
r2c9=4 (r2c9<>6) (r6c9<>4) r5c9<>4 r5c9=2 r6c9<>2 r6c9=6 (r4c7<>6) r4c8<>6 r4c1=6 (r1c1<>6) r2c1<>6 r2c8=6 (r1c7<>6) r1c8<>6 r1c6=6 r1c6<>4 r78c6=4 r9c45<>4 r9c79=4 r8c8<>4
Forcing Net Verity => r9c4<>4
r2c5=4 r4c5<>4 r4c4=4 r9c4<>4
r2c5=5 (r2c4<>5) r3c4<>5 r9c4=5 r9c4<>4
r2c5=9 (r2c4<>9) r3c4<>9 r5c4=9 r5c4<>8 r5c7=8 (r5c7<>7) r5c7<>3 r5c8=3 r5c8<>7 r5c1=7 r4c1<>7 r4c1=6 r6c3<>6 r3c3=6 r3c6<>6 r1c6=6 r1c6<>4 r78c6=4 r9c4<>4
Forcing Net Contradiction in r3 => r1c8<>6
r1c8=6 (r7c8<>6) (r4c8<>6) (r2c8<>6) r2c9<>6 r2c1=6 r4c1<>6 r4c1=7 r4c8<>7 r4c8=5 r7c8<>5 r7c8=3 r5c8<>3 r5c7=3 r5c7<>8 r5c4=8 r3c4<>8
r1c8=6 (r7c8<>6) (r4c8<>6) (r2c8<>6) r2c9<>6 r2c1=6 r4c1<>6 r4c7=6 r7c7<>6 r7c9=6 (r7c9<>5) r7c9<>1 r9c9=1 (r9c4<>1 r9c4=5 r3c4<>5) r9c9<>5 r2c9=5 (r3c7<>5) r3c8<>5 r3c5=5 r3c5<>8
r1c8=6 r1c6<>6 r3c6=6 r3c6<>8
Forcing Net Verity => r8c5<>4
r9c1=1 (r9c4<>1 r9c4=5 r9c9<>5) r9c9<>1 r7c9=1 (r7c9<>6) r7c9<>5 r2c9=5 (r2c9<>6) r2c9<>6 r6c9=6 (r4c7<>6) r4c8<>6 r4c1=6 (r1c1<>6) r2c1<>6 r2c8=6 r1c7<>6 r1c6=6 r1c6<>4 r78c6=4 r8c5<>4
r9c1=2 (r2c1<>2) (r8c1<>2) (r8c2<>2) r8c3<>2 r8c8=2 r2c8<>2 r2c9=2 (r2c9<>6) (r6c9<>2) r5c9<>2 r5c9=4 r6c9<>4 r6c9=6 (r4c7<>6) r4c8<>6 r4c1=6 (r1c1<>6) r2c1<>6 r2c8=6 r1c7<>6 r1c6=6 r1c6<>4 r78c6=4 r8c5<>4
r9c1=3 r9c5<>3 r8c5=3 r8c5<>4
Forcing Net Contradiction in r1c7 => r9c5<>1
r9c5=1 (r9c4<>1 r9c4=5 r3c4<>5) (r4c5<>1 r4c4=1 r3c4<>1) (r4c5<>1 r4c5=4 r2c5<>4) (r9c4<>1 r9c4=5 r9c9<>5) r9c9<>1 r7c9=1 r7c9<>5 r2c9=5 r2c5<>5 r2c5=9 r3c4<>9 r3c4=8 r5c4<>8 r5c7=8 r5c7<>3 r5c8=3 r5c8<>4 r12c8=4 r1c7<>4
r9c5=1 (r9c4<>1 r9c4=5 r9c9<>5) r9c9<>1 r7c9=1 (r7c9<>6) r7c9<>5 r2c9=5 (r2c9<>6) r2c9<>6 r6c9=6 (r4c7<>6) r4c8<>6 r4c1=6 r2c1<>6 r2c8=6 r1c7<>6
r9c5=1 (r1c5<>1) (r4c5<>1 r4c5=4 r1c5<>4) (r4c5<>1 r4c5=4 r2c5<>4) (r9c4<>1 r9c4=5 r9c9<>5) r9c9<>1 r7c9=1 r7c9<>5 r2c9=5 r2c5<>5 r2c5=9 r1c5<>9 r1c5=7 r1c7<>7
Forcing Net Contradiction in c7 => r6c7<>4
r6c7=4 r6c7<>8 r5c7=8 r5c7<>3
r6c7=4 (r6c9<>4) r5c9<>4 r5c9=2 r6c9<>2 r6c9=6 (r7c9<>6) (r2c9<>6) (r4c7<>6) r4c8<>6 r4c1=6 r2c1<>6 r2c8=6 r7c8<>6 r7c7=6 r7c7<>3
r6c7=4 (r9c7<>4 r9c9=4 r9c5<>4) (r6c7<>8 r5c7=8 r5c4<>8 r5c4=9 r2c4<>9) (r9c7<>4 r9c9=4 r2c9<>4) (r6c9<>4) r5c9<>4 r5c9=2 (r2c9<>2) r6c9<>2 r6c9=6 r2c9<>6 r2c9=5 r2c4<>5 r2c4=4 r4c4<>4 r4c4=1 r9c4<>1 r9c4=5 r9c5<>5 r9c5=3 r9c7<>3
Forcing Net Verity => r9c7<>5
r9c1=1 r9c4<>1 r9c4=5 r9c7<>5
r9c1=2 (r2c1<>2) (r8c1<>2) (r8c2<>2) r8c3<>2 r8c8=2 r2c8<>2 r2c9=2 r2c9<>5 r79c9=5 r9c7<>5
r9c1=3 r9c5<>3 r8c5=3 r8c5<>5 r9c45=5 r9c7<>5
Forcing Net Contradiction in r3c7 => r4c7<>7
r4c7=7 (r1c7<>7) r4c1<>7 r4c1=6 r6c3<>6 r3c3=6 r3c6<>6 r1c6=6 r1c7<>6 r1c7=4 (r9c7<>4) (r1c8<>4) r2c8<>4 r5c8=4 r5c8<>3 r5c7=3 r9c7<>3 r9c7=2 r3c7<>2
r4c7=7 (r1c7<>7) r4c1<>7 r4c1=6 r6c3<>6 r3c3=6 r3c6<>6 r1c6=6 r1c7<>6 r1c7=4 (r2c9<>4) (r1c8<>4) r2c8<>4 r5c8=4 (r5c9<>4) r6c9<>4 r9c9=4 (r9c9<>5) r9c9<>1 r7c9=1 r7c9<>5 r2c9=5 r3c7<>5
r4c7=7 r4c1<>7 r4c1=6 r6c3<>6 r3c3=6 r3c7<>6
r4c7=7 r3c7<>7
Forcing Net Contradiction in r3 => r1c8<>7
r1c8=7 (r1c7<>7) r3c7<>7 r5c7=7 r5c7<>8 r5c4=8 r3c4<>8
r1c8=7 (r3c7<>7) (r3c8<>7) (r1c7<>7) r3c7<>7 r5c7=7 r5c7<>8 r5c4=8 r6c6<>8 r6c6=7 r3c6<>7 r3c5=7 r3c5<>8
r1c8=7 (r1c7<>7) (r1c8<>4) (r1c7<>7) r3c7<>7 r5c7=7 r5c7<>3 r5c8=3 r5c8<>4 r2c8=4 r1c7<>4 r1c7=6 r1c6<>6 r3c6=6 r3c6<>8
Forcing Net Contradiction in c9 => r1c6<>4
r1c6=4 (r1c7<>4) (r1c5<>4) (r1c8<>4 r1c8=9 r1c5<>9) r2c4<>4 r4c4=4 r4c5<>4 r4c5=1 r1c5<>1 r1c5=7 r1c7<>7 r1c7=6 r2c9<>6
r1c6=4 r1c6<>6 r3c6=6 r3c3<>6 r6c3=6 r6c9<>6
r1c6=4 (r2c5<>4) (r2c4<>4) (r1c5<>4) (r2c5<>4) r2c4<>4 r4c4=4 r4c5<>4 r9c5=4 (r9c5<>5) r9c5<>3 r8c5=3 r8c5<>5 r9c4=5 (r2c4<>5) r2c4<>5 r2c4=9 r2c5<>9 r2c5=5 (r2c9<>5) r3c4<>5 r9c4=5 (r2c4<>5) r9c9<>5 r7c9=5 r7c9<>6
Locked Candidates Type 2 (Claiming): 4 in c6 => r9c5<>4
Locked Candidates Type 2 (Claiming): 4 in r9 => r7c7<>4
Forcing Net Verity => r1c6=6
r6c9=2 (r5c7<>2) (r6c7<>2) r5c9<>2 r5c9=4 r9c9<>4 r9c7=4 (r9c7<>2) r9c7<>2 r3c7=2 (r2c8<>2) (r3c8<>2) (r2c8<>2) r2c9<>2 r2c1=2 r9c1<>2 r9c9=2 r8c8<>2 r5c8=2 (r6c9<>2) r5c9<>2 r5c9=4 r6c9<>4 r6c9=6 r6c3<>6 r3c3=6 r3c6<>6 r1c6=6
r6c9=4 (r6c9<>2) r5c9<>4 r5c9=2 r6c7<>2 r6c3=2 r6c3<>6 r3c3=6 r3c6<>6 r1c6=6
r6c9=6 (r2c9<>6) (r4c7<>6) r4c8<>6 r4c1=6 (r1c1<>6) r2c1<>6 r2c8=6 r1c7<>6 r1c6=6
Grouped Discontinuous Nice Loop: 7 r5c7 -7- r1c7 -4- r12c8 =4= r5c8 =3= r5c7 => r5c7<>7
Locked Candidates Type 1 (Pointing): 7 in b6 => r3c8<>7
Forcing Chain Contradiction in r7c7 => r3c7<>5
r3c7=5 r4c7<>5 r4c8=5 r4c8<>7 r5c8=7 r5c8<>3 r5c7=3 r7c7<>3
r3c7=5 r7c7<>5
r3c7=5 r4c7<>5 r4c7=6 r7c7<>6
Forcing Chain Contradiction in r3c7 => r4c7=5
r4c7<>5 r4c7=6 r4c1<>6 r2c1=6 r2c1<>2 r2c89=2 r3c7<>2
r4c7<>5 r4c7=6 r3c7<>6
r4c7<>5 r4c8=5 r4c8<>7 r5c8=7 r5c8<>4 r12c8=4 r1c7<>4 r1c7=7 r3c7<>7
2-String Kite: 6 in r3c3,r4c8 (connected by r4c1,r6c3) => r3c8<>6
Discontinuous Nice Loop: 1/2/9 r3c3 =6= r3c7 -6- r7c7 -3- r5c7 =3= r5c8 =7= r5c1 -7- r4c1 -6- r2c1 =6= r3c3 => r3c3<>1, r3c3<>2, r3c3<>9
Naked Single: r3c3=6
Hidden Single: r4c1=6
Naked Single: r4c8=7
Hidden Single: r5c1=7
AIC: 2 2- r3c7 -7- r1c7 -4- r9c7 =4= r9c9 -4- r5c9 -2 => r2c9,r56c7<>2
2-String Kite: 2 in r2c1,r9c7 (connected by r2c8,r3c7) => r9c1<>2
Locked Candidates Type 1 (Pointing): 2 in b7 => r8c8<>2
Naked Triple: 3,5,6 in r7c78,r8c8 => r79c9<>5, r7c9<>6, r9c7<>3
Naked Single: r7c9=1
Hidden Single: r2c9=5
Hidden Single: r2c8=6
Hidden Single: r6c9=6
Naked Single: r6c7=8
Naked Single: r6c6=7
Naked Single: r6c5=9
Naked Single: r2c5=4
Naked Single: r5c4=8
Naked Single: r2c4=9
Full House: r2c1=2
Naked Single: r4c5=1
Full House: r4c4=4
Naked Single: r1c5=7
Naked Single: r1c7=4
Naked Single: r1c8=9
Naked Single: r5c7=3
Naked Single: r9c7=2
Naked Single: r3c8=2
Full House: r3c7=7
Full House: r7c7=6
Naked Single: r9c9=4
Full House: r5c9=2
Full House: r5c8=4
Hidden Single: r7c1=9
Naked Single: r7c3=4
Naked Single: r6c3=2
Full House: r6c2=4
Naked Single: r7c6=8
Naked Single: r8c3=1
Full House: r5c3=9
Full House: r5c2=1
Naked Single: r3c6=1
Full House: r8c6=4
Naked Single: r9c1=3
Naked Single: r1c2=3
Full House: r1c1=1
Full House: r3c2=9
Full House: r8c1=8
Naked Single: r3c4=5
Full House: r3c5=8
Full House: r9c4=1
Full House: r9c5=5
Full House: r8c5=3
Naked Single: r7c2=5
Full House: r7c8=3
Full House: r8c8=5
Full House: r8c2=2
|
normal_sudoku_5423
|
..2943..8186572.....3186.7..19..578.......9..6...9...4265.....7.31.67.5...425.6..
|
752943168186572349493186275319425786547638921628791534265314897931867452874259613
|
Basic 9x9 Sudoku 5423
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 2 9 4 3 . . 8
1 8 6 5 7 2 . . .
. . 3 1 8 6 . 7 .
. 1 9 . . 5 7 8 .
. . . . . . 9 . .
6 . . . 9 . . . 4
2 6 5 . . . . . 7
. 3 1 . 6 7 . 5 .
. . 4 2 5 . 6 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
752943168186572349493186275319425786547638921628791534265314897931867452874259613 #1 Hard (1476)
Naked Single: r4c3=9
Naked Single: r2c3=6
Hidden Single: r7c2=6
Hidden Single: r7c3=5
Hidden Single: r8c3=1
Hidden Single: r7c9=7
Locked Candidates Type 1 (Pointing): 2 in b2 => r56c6<>2
Locked Candidates Type 1 (Pointing): 8 in b7 => r5c1<>8
Locked Candidates Type 1 (Pointing): 3 in b8 => r7c78<>3
Locked Candidates Type 2 (Claiming): 7 in c3 => r5c12,r6c2<>7
Naked Pair: 4,6 in r18c5 => r457c5<>4, r45c5<>6
Skyscraper: 6 in r3c6,r4c4 (connected by r34c9) => r1c4,r5c6<>6
Hidden Single: r3c6=6
Naked Single: r1c5=4
Naked Single: r1c4=9
Full House: r2c6=2
Naked Single: r8c5=6
Hidden Single: r1c8=6
Hidden Single: r1c7=1
Locked Candidates Type 1 (Pointing): 4 in b1 => r3c7<>4
Locked Candidates Type 1 (Pointing): 9 in b1 => r3c9<>9
Locked Candidates Type 1 (Pointing): 5 in b3 => r3c12<>5
Locked Candidates Type 2 (Claiming): 2 in c8 => r45c9,r6c7<>2
Hidden Single: r4c5=2
Skyscraper: 1 in r7c5,r9c9 (connected by r5c59) => r7c8,r9c6<>1
Naked Triple: 7,8,9 in r9c126 => r9c89<>9
Naked Triple: 1,2,3 in r569c8 => r2c8<>3
W-Wing: 3/1 in r5c5,r9c8 connected by 1 in r6c68 => r5c8<>3
Uniqueness Test 4: 7/8 in r5c34,r6c34 => r56c4<>8
Locked Candidates Type 1 (Pointing): 8 in b5 => r79c6<>8
Naked Single: r9c6=9
Naked Single: r9c2=7
Naked Single: r1c2=5
Full House: r1c1=7
Naked Single: r9c1=8
Full House: r8c1=9
Naked Single: r6c2=2
Naked Single: r3c1=4
Full House: r3c2=9
Full House: r5c2=4
Naked Single: r8c9=2
Naked Single: r4c1=3
Full House: r5c1=5
Naked Single: r3c9=5
Full House: r3c7=2
Naked Single: r4c9=6
Full House: r4c4=4
Naked Single: r8c4=8
Full House: r8c7=4
Naked Single: r7c4=3
Naked Single: r2c7=3
Naked Single: r7c7=8
Full House: r6c7=5
Naked Single: r7c8=9
Naked Single: r6c4=7
Full House: r5c4=6
Naked Single: r7c5=1
Full House: r5c5=3
Full House: r7c6=4
Naked Single: r2c9=9
Full House: r2c8=4
Naked Single: r6c3=8
Full House: r5c3=7
Naked Single: r5c9=1
Full House: r9c9=3
Full House: r9c8=1
Naked Single: r6c6=1
Full House: r5c6=8
Full House: r5c8=2
Full House: r6c8=3
|
normal_sudoku_550
|
..9.8.6.......94...6352...9.....3.6...6.5.3..381.7.295175.4.9..234..58..69813.5..
|
429781653517369428863524179952813764746952381381476295175248936234695817698137542
|
Basic 9x9 Sudoku 550
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 9 . 8 . 6 . .
. . . . . 9 4 . .
. 6 3 5 2 . . . 9
. . . . . 3 . 6 .
. . 6 . 5 . 3 . .
3 8 1 . 7 . 2 9 5
1 7 5 . 4 . 9 . .
2 3 4 . . 5 8 . .
6 9 8 1 3 . 5 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
429781653517369428863524179952813764746952381381476295175248936234695817698137542 #1 Extreme (2484)
Naked Single: r8c3=4
Naked Single: r8c2=3
Hidden Single: r9c1=6
Naked Single: r9c5=3
Hidden Single: r7c7=9
Hidden Single: r1c7=6
Hidden Single: r5c7=3
Hidden Single: r6c1=3
Locked Candidates Type 1 (Pointing): 5 in b7 => r246c3<>5
Naked Single: r6c3=1
Hidden Single: r6c9=5
Hidden Single: r9c7=5
Naked Single: r9c3=8
Full House: r7c3=5
Locked Candidates Type 2 (Claiming): 4 in r6 => r45c4,r5c6<>4
Skyscraper: 1 in r2c5,r3c7 (connected by r4c57) => r2c89,r3c6<>1
Locked Candidates Type 2 (Claiming): 1 in r3 => r1c89<>1
Skyscraper: 7 in r2c3,r3c7 (connected by r4c37) => r2c89,r3c1<>7
W-Wing: 7/1 in r4c7,r8c8 connected by 1 in r3c78 => r5c8<>7
Sue de Coq: r4c123 - {24579} (r4c57 - {179}, r5c2 - {24}) => r5c1<>4, r4c4<>9, r4c9<>1, r4c9<>7
AIC: 4 4- r3c6 -7- r3c7 =7= r4c7 -7- r4c3 -2- r4c4 -8- r7c4 =8= r7c6 =6= r6c6 =4= r6c4 -4 => r1c4,r6c6<>4
Naked Single: r6c6=6
Full House: r6c4=4
AIC: 8 8- r4c4 -2- r4c3 -7- r4c7 -1- r4c5 =1= r5c6 =8= r7c6 -8 => r5c6,r7c4<>8
Hidden Single: r7c6=8
XY-Chain: 4 4- r4c9 -8- r4c4 -2- r7c4 -6- r8c5 -9- r4c5 -1- r5c6 -2- r5c2 -4 => r4c12,r5c89<>4
Hidden Single: r4c9=4
Hidden Single: r5c2=4
Hidden Single: r9c8=4
Hidden Single: r4c4=8
Naked Triple: 1,7,8 in r358c8 => r1c8<>7, r2c8<>8
2-String Kite: 7 in r3c8,r9c6 (connected by r8c8,r9c9) => r3c6<>7
Naked Single: r3c6=4
Naked Single: r3c1=8
Hidden Single: r1c1=4
Hidden Single: r2c9=8
Hidden Single: r5c8=8
Locked Candidates Type 1 (Pointing): 7 in b1 => r2c4<>7
Locked Candidates Type 1 (Pointing): 7 in b2 => r1c9<>7
W-Wing: 1/7 in r1c6,r5c9 connected by 7 in r9c69 => r5c6<>1
Naked Single: r5c6=2
Naked Single: r5c4=9
Full House: r4c5=1
Naked Single: r9c6=7
Full House: r1c6=1
Full House: r9c9=2
Naked Single: r5c1=7
Full House: r5c9=1
Full House: r4c7=7
Full House: r3c7=1
Full House: r3c8=7
Naked Single: r2c5=6
Full House: r8c5=9
Naked Single: r8c4=6
Full House: r7c4=2
Naked Single: r1c9=3
Naked Single: r7c8=3
Full House: r7c9=6
Full House: r8c9=7
Full House: r8c8=1
Naked Single: r2c1=5
Full House: r4c1=9
Naked Single: r4c3=2
Full House: r2c3=7
Full House: r4c2=5
Naked Single: r2c4=3
Full House: r1c4=7
Naked Single: r1c2=2
Full House: r1c8=5
Full House: r2c8=2
Full House: r2c2=1
|
normal_sudoku_1900
|
4..9...8...9..7..4......97.1.287.3.5.6..3.2.......281...1..4.5.2..5....8935768421
|
476953182319287564528641973192876345864135297753492816681324759247519638935768421
|
Basic 9x9 Sudoku 1900
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
4 . . 9 . . . 8 .
. . 9 . . 7 . . 4
. . . . . . 9 7 .
1 . 2 8 7 . 3 . 5
. 6 . . 3 . 2 . .
. . . . . 2 8 1 .
. . 1 . . 4 . 5 .
2 . . 5 . . . . 8
9 3 5 7 6 8 4 2 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
476953182319287564528641973192876345864135297753492816681324759247519638935768421 #1 Extreme (1920)
Naked Single: r9c8=2
Hidden Single: r9c3=5
Hidden Single: r9c6=8
Sue de Coq: r78c7 - {1367} (r4c7 - {36}, r9c9 - {17}) => r7c9<>7, r126c7<>3, r126c7<>6
Empty Rectangle: 6 in b3 (r6c49) => r2c4<>6
Turbot Fish: 6 r2c8 =6= r2c1 -6- r7c1 =6= r8c3 => r8c8<>6
Naked Triple: 1,3,9 in r8c568 => r8c7<>1, r8c7<>3
Hidden Single: r9c9=1
Full House: r9c4=7
Locked Candidates Type 1 (Pointing): 7 in b9 => r56c7<>7
Naked Single: r6c7=8
Naked Single: r5c7=2
AIC: 1 1- r4c1 -3- r4c7 =3= r7c7 -3- r8c8 -9- r5c8 -4- r5c4 -1 => r4c6,r5c1<>1
AIC: 3 3- r4c7 -6- r8c7 -7- r8c2 -4- r4c2 =4= r4c8 -4- r5c8 -9- r8c8 -3 => r4c8,r7c7<>3
Hidden Single: r4c7=3
Naked Single: r4c1=1
Locked Candidates Type 2 (Claiming): 6 in c7 => r7c9<>6
2-String Kite: 3 in r2c8,r7c4 (connected by r7c9,r8c8) => r2c4<>3
Hidden Pair: 3,6 in r2c18 => r2c1<>5, r2c1<>8
XY-Wing: 6/9/4 in r4c26,r6c4 => r6c23<>4
Locked Candidates Type 2 (Claiming): 4 in r6 => r5c4<>4
Naked Single: r5c4=1
Naked Single: r2c4=2
Naked Single: r7c4=3
Naked Single: r7c9=9
Naked Single: r5c9=7
Naked Single: r7c5=2
Naked Single: r8c8=3
Naked Single: r6c9=6
Naked Single: r2c8=6
Naked Single: r6c4=4
Full House: r3c4=6
Naked Single: r2c1=3
Naked Single: r3c3=8
Naked Single: r3c1=5
Naked Single: r5c3=4
Naked Single: r2c2=1
Naked Single: r5c1=8
Naked Single: r6c1=7
Full House: r7c1=6
Naked Single: r4c2=9
Naked Single: r5c8=9
Full House: r4c8=4
Full House: r4c6=6
Full House: r5c6=5
Full House: r6c5=9
Naked Single: r2c7=5
Full House: r2c5=8
Naked Single: r3c2=2
Naked Single: r6c3=3
Full House: r6c2=5
Naked Single: r7c7=7
Full House: r7c2=8
Full House: r8c7=6
Full House: r1c7=1
Naked Single: r8c3=7
Full House: r1c3=6
Full House: r1c2=7
Full House: r8c2=4
Naked Single: r8c5=1
Full House: r8c6=9
Naked Single: r3c9=3
Full House: r1c9=2
Naked Single: r1c5=5
Full House: r1c6=3
Full House: r3c5=4
Full House: r3c6=1
|
normal_sudoku_375
|
..98...54.4...5.......943...7.5..4....4.8..25......6.719.2..54.42.95..6...5..8.92
|
769832154843165279251794386976521438314687925582349617198276543427953861635418792
|
Basic 9x9 Sudoku 375
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 9 8 . . . 5 4
. 4 . . . 5 . . .
. . . . 9 4 3 . .
. 7 . 5 . . 4 . .
. . 4 . 8 . . 2 5
. . . . . . 6 . 7
1 9 . 2 . . 5 4 .
4 2 . 9 5 . . 6 .
. . 5 . . 8 . 9 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
769832154843165279251794386976521438314687925582349617198276543427953861635418792 #1 Extreme (3100)
Hidden Single: r4c7=4
Hidden Single: r2c6=5
Hidden Single: r8c1=4
Hidden Single: r7c7=5
Hidden Single: r7c2=9
Hidden Single: r2c2=4
Locked Candidates Type 1 (Pointing): 8 in b7 => r2346c3<>8
Locked Candidates Type 1 (Pointing): 3 in b9 => r4c9<>3
Locked Candidates Type 1 (Pointing): 7 in b9 => r12c7<>7
Locked Candidates Type 2 (Claiming): 2 in r3 => r12c1,r2c3<>2
Naked Triple: 1,3,6 in r159c2 => r36c2<>1, r3c2<>6, r6c2<>3
Uniqueness Test 4: 5/8 in r3c12,r6c12 => r36c1<>8
2-String Kite: 8 in r2c1,r6c8 (connected by r4c1,r6c2) => r2c8<>8
Discontinuous Nice Loop: 7 r2c5 -7- r2c8 -1- r1c7 -2- r2c7 =2= r2c5 => r2c5<>7
Grouped Discontinuous Nice Loop: 1 r2c9 -1- r8c9 =1= r89c7 -1- r5c7 -9- r2c7 =9= r2c9 => r2c9<>1
Grouped Discontinuous Nice Loop: 1 r3c9 -1- r8c9 =1= r89c7 -1- r5c7 -9- r2c7 =9= r2c9 =6= r3c9 => r3c9<>1
Grouped Discontinuous Nice Loop: 7 r3c3 =2= r3c1 =5= r3c2 =8= r2c1 -8- r2c7 =8= r8c7 =7= r9c7 -7- r9c1 =7= r123c1 -7- r3c3 => r3c3<>7
Almost Locked Set XZ-Rule: A=r12459c1 {236789}, B=r46c3,r5c2 {1236}, X=2, Z=3 => r6c1<>3
Almost Locked Set XZ-Rule: A=r1259c1 {36789}, B=r1589c7 {12789}, X=9, Z=8 => r2c7<>8
Hidden Single: r8c7=8
Naked Single: r7c9=3
Naked Single: r8c9=1
Full House: r9c7=7
Hidden Single: r7c3=8
Hidden Single: r8c3=7
Full House: r8c6=3
Locked Candidates Type 1 (Pointing): 6 in b7 => r9c45<>6
Uniqueness Test 3: 3/6 in r5c12,r9c12 => r5c46<>1, r5c6<>9
Naked Pair: 6,7 in r57c6 => r14c6<>6, r1c6<>7
Naked Pair: 1,2 in r1c67 => r1c25<>1, r1c5<>2
Hidden Single: r5c2=1
Naked Single: r5c7=9
Naked Single: r4c9=8
Naked Single: r3c9=6
Full House: r2c9=9
Hidden Single: r2c1=8
Naked Single: r3c2=5
Naked Single: r6c2=8
Hidden Single: r3c8=8
Hidden Single: r6c1=5
Hidden Single: r2c8=7
Hidden Single: r6c6=9
Hidden Single: r4c1=9
Hidden Single: r3c1=2
Naked Single: r3c3=1
Full House: r3c4=7
Hidden Single: r1c1=7
Hidden Single: r7c5=7
Full House: r7c6=6
Naked Single: r5c6=7
Remote Pair: 3/6 r1c5 -6- r1c2 -3- r9c2 -6- r9c1 -3- r5c1 -6- r5c4 => r2c4,r46c5<>3, r2c4,r4c5<>6
Naked Single: r2c4=1
Naked Single: r1c6=2
Full House: r4c6=1
Naked Single: r2c7=2
Full House: r1c7=1
Naked Single: r9c4=4
Full House: r9c5=1
Naked Single: r4c5=2
Naked Single: r4c8=3
Full House: r4c3=6
Full House: r6c8=1
Naked Single: r6c4=3
Full House: r5c4=6
Full House: r6c5=4
Full House: r5c1=3
Full House: r6c3=2
Full House: r2c3=3
Full House: r9c1=6
Full House: r1c2=6
Full House: r2c5=6
Full House: r9c2=3
Full House: r1c5=3
|
normal_sudoku_1071
|
5...8...9..1..2....9.5.3...81.2.......5.71..876.....4..5..6...71......3...7..94..
|
534687129671492583298513674813246795425971368769835241952364817146758932387129456
|
Basic 9x9 Sudoku 1071
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
5 . . . 8 . . . 9
. . 1 . . 2 . . .
. 9 . 5 . 3 . . .
8 1 . 2 . . . . .
. . 5 . 7 1 . . 8
7 6 . . . . . 4 .
. 5 . . 6 . . . 7
1 . . . . . . 3 .
. . 7 . . 9 4 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
534687129671492583298513674813246795425971368769835241952364817146758932387129456 #1 Extreme (27540) bf
Finned X-Wing: 7 r36 c17 fr3c8 => r12c7<>7
Brute Force: r5c6=1
Hidden Single: r4c2=1
Hidden Single: r6c1=7
Locked Candidates Type 2 (Claiming): 7 in r3 => r12c8<>7
2-String Kite: 9 in r5c1,r8c7 (connected by r7c1,r8c3) => r5c7<>9
Almost Locked Set XZ-Rule: A=r2346c5 {13459}, B=r67c6 {458}, X=5, Z=4 => r8c5<>4
Forcing Net Contradiction in r3 => r3c7<>1
r3c7=1 r3c5<>1 r9c5=1 (r9c5<>5) r9c5<>2 r8c5=2 (r8c9<>2) r8c5<>5 r8c6=5 r8c9<>5 r8c9=6 (r9c8<>6) r9c9<>6 r9c1=6 r3c1<>6
r3c7=1 (r3c7<>8) r3c7<>7 r3c8=7 r3c8<>8 r3c3=8 r3c3<>6
r3c7=1 r3c7<>6
r3c7=1 r3c7<>7 r3c8=7 r3c8<>6
r3c7=1 r3c5<>1 r9c5=1 (r9c5<>5) r9c5<>2 r8c5=2 (r8c9<>2) r8c5<>5 r8c6=5 r8c9<>5 r8c9=6 r3c9<>6
Forcing Net Contradiction in r3 => r3c8<>1
r3c8=1 r3c5<>1 r9c5=1 (r9c5<>5) r9c5<>2 r8c5=2 (r8c9<>2) r8c5<>5 r8c6=5 r8c9<>5 r8c9=6 (r9c8<>6) r9c9<>6 r9c1=6 r3c1<>6
r3c8=1 (r3c8<>8) r3c8<>7 r3c7=7 r3c7<>8 r3c3=8 r3c3<>6
r3c8=1 r3c8<>7 r3c7=7 r3c7<>6
r3c8=1 r3c8<>6
r3c8=1 r3c5<>1 r9c5=1 (r9c5<>5) r9c5<>2 r8c5=2 (r8c9<>2) r8c5<>5 r8c6=5 r8c9<>5 r8c9=6 r3c9<>6
Forcing Net Contradiction in r7c7 => r3c8<>8
r3c8=8 (r9c8<>8) (r2c7<>8) r2c8<>8 r2c2=8 r9c2<>8 r9c4=8 (r8c4<>8) r7c6<>8 r7c6=4 r8c4<>4 r8c4=7 r2c4<>7 r2c2=7 r2c2<>8 r3c3=8 r3c8<>8
Forcing Net Contradiction in c2 => r4c5<>5
r4c5=5 (r4c5<>4) r6c6<>5 r6c6=8 r7c6<>8 r7c6=4 (r1c6<>4) r4c6<>4 r4c3=4 (r1c3<>4) (r5c1<>4) r5c2<>4 r5c4=4 r1c4<>4 r1c2=4
r4c5=5 (r4c5<>4) r6c6<>5 (r8c6=5 r8c6<>4) r6c6=8 r7c6<>8 r7c6=4 (r8c4<>4) r4c6<>4 r4c3=4 r8c3<>4 r8c2=4
Forcing Net Contradiction in c3 => r6c7<>9
r6c7=9 (r4c7<>9) (r4c8<>9) r8c7<>9 r8c3=9 r4c3<>9 r4c5=9 r2c5<>9 r2c4=9 r2c4<>6 r1c46=6 r1c3<>6
r6c7=9 (r4c7<>9) (r4c8<>9) r8c7<>9 r8c3=9 r4c3<>9 r4c5=9 r2c5<>9 r2c4=9 r2c4<>7 r2c2=7 r2c2<>8 r3c3=8 r3c3<>6
r6c7=9 r8c7<>9 r8c3=9 r8c3<>6
Forcing Net Verity => r6c4<>3
r4c5=9 (r4c5<>4) (r2c5<>9 r2c5=4 r2c1<>4) (r2c5<>9 r2c5=4 r2c9<>4 r3c9=4 r3c1<>4) (r4c7<>9) r4c8<>9 r5c8=9 r5c1<>9 r7c1=9 r7c1<>4 r5c1=4 r4c3<>4 r4c6=4 r7c6<>4 r7c6=8 r6c6<>8 r6c4=8 r6c4<>3
r5c4=9 (r5c1<>9 r7c1=9 r7c1<>3) (r6c5<>9 r6c3=9 r4c3<>9) (r5c4<>4) r5c4<>6 r4c6=6 r4c6<>4 r4c5=4 r4c3<>4 r4c3=3 r7c3<>3 r7c4=3 r6c4<>3
r6c4=9 r6c4<>3
r6c5=9 (r4c5<>9) r2c5<>9 r2c5=4 r4c5<>4 r4c5=3 r6c4<>3
Forcing Net Verity => r3c3<>2
r3c3=8 r3c3<>2
r7c3=8 (r7c6<>8 r7c6=4 r4c6<>4) (r7c6<>8 r7c6=4 r1c6<>4) r3c3<>8 r3c7=8 (r2c7<>8) r2c8<>8 r2c2=8 r2c2<>7 r2c4=7 r1c6<>7 r1c6=6 r4c6<>6 r4c6=5 (r6c5<>5) r6c6<>5 r6c6=8 r6c4<>8 r6c4=9 (r6c3<>9) r6c5<>9 r6c5=3 r6c3<>3 r6c3=2 r3c3<>2
r8c3=8 (r3c3<>8 r3c7=8 r3c7<>6) (r8c3<>6 r9c1=6 r3c1<>6) (r3c3<>8 r3c7=8 r3c7<>7 r3c8=7 r3c8<>6) (r8c3<>6) r8c3<>9 r8c7=9 r8c7<>6 r8c9=6 r3c9<>6 r3c3=6 r3c3<>2
Forcing Net Contradiction in r8 => r7c4<>4
r7c4=4 (r8c4<>4) r7c6<>4 r7c6=8 r8c4<>8 r8c4=7
r7c4=4 (r8c6<>4) r7c6<>4 r7c6=8 (r8c6<>8) r6c6<>8 r6c6=5 r8c6<>5 r8c6=7
Forcing Net Contradiction in c1 => r3c5=1
r3c5<>1 r3c5=4 r3c9<>4 r2c9=4 r2c1<>4
r3c5<>1 r3c5=4 r3c1<>4
r3c5<>1 (r3c5=4 r1c4<>4) (r3c5=4 r2c4<>4) r9c5=1 (r9c5<>5) r9c5<>2 r8c5=2 r8c5<>5 r6c5=5 (r4c6<>5) r6c6<>5 r8c6=5 r8c6<>7 r8c4=7 r8c4<>4 r5c4=4 r5c1<>4
r3c5<>1 r9c5=1 (r9c5<>5) r9c5<>2 r8c5=2 r8c5<>5 r6c5=5 r6c6<>5 r6c6=8 r7c6<>8 r7c6=4 r7c1<>4
Forcing Net Contradiction in r1 => r8c3<>8
r8c3=8 r3c3<>8 r3c7=8 (r2c7<>8) r2c8<>8 r2c2=8 r2c2<>7 r2c4=7 (r1c4<>7) r1c6<>7 r1c2=7 r1c2<>3
r8c3=8 r3c3<>8 r3c7=8 (r2c7<>8) r2c8<>8 r2c2=8 r2c2<>7 r2c4=7 (r8c4<>7 r8c4=4 r8c2<>4 r5c2=4 r4c3<>4) (r8c4<>7 r8c4=4 r7c6<>4) (r8c4<>7 r8c4=4 r8c6<>4) r2c4<>9 r2c5=9 (r6c5<>9) r2c5<>4 r4c5=4 r4c6<>4 r1c6=4 r7c6<>4 r7c6=8 r6c6<>8 r6c4=8 r6c4<>9 r6c3=9 r4c3<>9 r4c3=3 r1c3<>3
r8c3=8 r3c3<>8 r3c7=8 (r2c7<>8) r2c8<>8 r2c2=8 r2c2<>7 r2c4=7 (r2c4<>9) (r8c4<>7 r8c4=4 r7c6<>4) (r8c4<>7 r8c4=4 r8c6<>4) r2c4<>9 r2c5=9 r2c5<>4 r4c5=4 r4c6<>4 r1c6=4 r7c6<>4 r7c6=8 r6c6<>8 (r6c6=5 r6c5<>5 r6c5=3 r6c9<>3) r6c4=8 r6c4<>9 r5c4=9 r2c4<>9 r2c5=9 r2c5<>4 r4c5=4 r4c3<>4 r4c3=3 (r4c3<>9) r4c9<>3 r2c9=3 r1c7<>3
Forcing Net Contradiction in c7 => r1c6<>4
r1c6=4 (r2c5<>4 r2c5=9 r2c4<>9) r7c6<>4 r7c6=8 r6c6<>8 (r6c6=5 r6c7<>5) r6c4=8 r6c4<>9 (r6c3=9 r8c3<>9 r8c7=9 r8c7<>5) r5c4=9 (r5c8<>9) r5c1<>9 r7c1=9 r7c8<>9 r4c8=9 r4c8<>7 r4c7=7 r4c7<>5 r2c7=5 r2c7<>8
r1c6=4 r7c6<>4 r7c6=8 r7c3<>8 r3c3=8 r3c7<>8
r1c6=4 r7c6<>4 r7c6=8 r7c7<>8
r1c6=4 (r2c5<>4 r2c5=9 r6c5<>9) r7c6<>4 r7c6=8 r6c6<>8 r6c4=8 r6c4<>9 r6c3=9 r8c3<>9 r8c7=9 r8c7<>8
Forcing Net Contradiction in r7 => r2c2<>3
r2c2=3 r2c2<>7 r2c4=7 (r8c4<>7 r8c6=7 r8c6<>4) r2c4<>9 r2c5=9 r2c5<>4 r4c5=4 r4c6<>4 r7c6=4 r7c1<>4 r7c3=4
r2c2=3 r2c2<>7 r2c4=7 (r8c4<>7 r8c6=7 r8c6<>4) r2c4<>9 r2c5=9 r2c5<>4 r4c5=4 r4c6<>4 r7c6=4
Forcing Net Contradiction in r8 => r2c2<>4
r2c2=4 (r2c2<>8 r3c3=8 r3c3<>6) r2c2<>7 r2c4=7 r1c6<>7 r1c6=6 r1c3<>6 r8c3=6
r2c2=4 (r8c2<>4) (r1c3<>4 r1c4=4 r8c4<>4) r2c2<>7 r2c4=7 r8c4<>7 r8c4=8 r8c2<>8 r8c2=2 (r8c9<>2) r8c5<>2 r8c5=5 r8c9<>5 r8c9=6
Forcing Net Contradiction in c3 => r8c7<>8
r8c7=8 (r3c7<>8 r3c3=8 r3c3<>6) r8c7<>9 r8c3=9 r8c3<>6 r1c3=6 r1c3<>4
r8c7=8 r3c7<>8 r3c3=8 r3c3<>4
r8c7=8 (r3c7<>8 r3c3=8 r3c3<>6) r8c7<>9 r8c3=9 r8c3<>6 r1c3=6 (r1c4<>6) r1c6<>6 r1c6=7 r1c4<>7 r1c4=4 r2c5<>4 r4c5=4 r4c3<>4
r8c7=8 (r3c7<>8 r3c3=8 r3c3<>6) r8c7<>9 r8c3=9 (r6c3<>9) r8c3<>6 r1c3=6 (r1c4<>6) r1c6<>6 r4c6=6 r5c4<>6 r2c4=6 r2c4<>9 r2c5=9 r6c5<>9 r6c4=9 r6c4<>8 r6c6=8 r7c6<>8 r7c6=4 r7c3<>4
r8c7=8 r8c7<>9 r8c3=9 r8c3<>4
Forcing Net Contradiction in c9 => r7c4<>8
r7c4=8 (r7c8<>8 r9c8=8 r2c8<>8 r2c7=8 r2c7<>3) (r7c4<>3) r7c4<>1 r9c4=1 r9c4<>3 r5c4=3 (r5c2<>3) (r4c5<>3) r6c5<>3 r9c5=3 r9c2<>3 r1c2=3 r2c1<>3 r2c9=3
r7c4=8 (r7c3<>8 r3c3=8 r2c2<>8 r2c2=7 r1c2<>7 r1c6=7 r1c6<>6 r4c6=6 r4c9<>6) (r7c8<>8 r9c8=8 r9c8<>5) (r7c4<>3) r7c4<>1 r9c4=1 r9c4<>3 r5c4=3 (r4c5<>3) r6c5<>3 r9c5=3 r9c5<>5 r9c9=5 r4c9<>5 r4c9=3
Forcing Net Contradiction in c9 => r5c4<>3
r5c4=3 (r6c5<>3 r9c5=3 r9c5<>2 r8c5=2 r8c3<>2) (r9c4<>3) r7c4<>3 r7c4=1 r9c4<>1 r9c4=8 (r9c2<>8 r9c2=2 r7c1<>2) (r9c2<>8 r9c2=2 r9c1<>2) (r9c2<>8 r9c2=2 r7c3<>2) (r7c6<>8 r7c6=4 r8c4<>4) (r7c6<>8 r7c6=4 r8c6<>4) (r8c4<>8) r8c6<>8 r8c2=8 (r7c3<>8 r3c3=8 r3c3<>6) r8c2<>4 r8c3=4 r8c3<>6 r1c3=6 r1c3<>2 r6c3=2 r5c1<>2 r3c1=2 r3c9<>2
r5c4=3 (r6c5<>3 r9c5=3 r9c5<>2 r8c5=2 r8c3<>2) (r9c4<>3) r7c4<>3 r7c4=1 r9c4<>1 r9c4=8 (r9c2<>8 r9c2=2 r7c3<>2) (r7c6<>8 r7c6=4 r8c4<>4) (r7c6<>8 r7c6=4 r8c6<>4) (r8c4<>8) r8c6<>8 r8c2=8 (r7c3<>8 r3c3=8 r3c3<>6) r8c2<>4 r8c3=4 r8c3<>6 r1c3=6 r1c3<>2 r6c3=2 r6c9<>2
r5c4=3 (r4c5<>3) r6c5<>3 r9c5=3 r9c5<>2 r8c5=2 r8c9<>2
r5c4=3 (r6c5<>3 r9c5=3 r9c2<>3) (r9c4<>3) r7c4<>3 r7c4=1 r9c4<>1 r9c4=8 r9c2<>8 r9c2=2 r9c9<>2
Locked Candidates Type 1 (Pointing): 3 in b5 => r9c5<>3
Locked Pair: 2,5 in r89c5 => r6c5,r8c6<>5
Naked Triple: 4,7,8 in r78c6,r8c4 => r9c4<>8
Forcing Net Contradiction in c1 => r1c3<>6
r1c3=6 (r1c4<>6) r1c6<>6 (r4c6=6 r5c4<>6 r2c4=6 r2c4<>9 r2c5=9 r4c5<>9) (r4c6=6 r5c4<>6) r1c6=7 r1c4<>7 r1c4=4 r5c4<>4 r5c4=9 (r6c4<>9 r6c3=9 r4c3<>9) r6c5<>9 r6c5=3 (r6c9<>3) r4c5<>3 r4c5=4 r4c3<>4 r4c3=3 r4c9<>3 r2c9=3 r2c1<>3
r1c3=6 (r1c4<>6) r1c6<>6 (r4c6=6 r5c4<>6 r2c4=6 r2c4<>9 r2c5=9 r4c5<>9) (r4c6=6 r5c4<>6) r1c6=7 r1c4<>7 r1c4=4 r5c4<>4 r5c4=9 (r6c4<>9 r6c3=9 r4c3<>9) r6c5<>9 r6c5=3 r4c5<>3 r4c5=4 r4c3<>4 r4c3=3 r5c1<>3
r1c3=6 (r1c4<>6) r1c6<>6 (r4c6=6 r5c4<>6) r1c6=7 r1c4<>7 r1c4=4 r5c4<>4 r5c4=9 r5c1<>9 r7c1=9 r7c1<>3
r1c3=6 (r2c1<>6) r3c1<>6 r9c1=6 r9c1<>3
Discontinuous Nice Loop: 9 r4c7 -9- r8c7 =9= r8c3 =6= r3c3 =8= r3c7 =7= r4c7 => r4c7<>9
Locked Candidates Type 1 (Pointing): 9 in b6 => r7c8<>9
Forcing Net Contradiction in c9 => r7c6=4
r7c6<>4 r7c6=8 (r6c6<>8 r6c4=8 r6c4<>9) (r6c6<>8 r6c6=5 r6c7<>5) (r7c8<>8 r9c8=8 r2c8<>8 r2c7=8 r2c7<>5) r7c3<>8 r3c3=8 r3c3<>6 r8c3=6 r8c3<>9 r8c7=9 r8c7<>5 r4c7=5 r4c7<>7 r4c8=7 r4c8<>9 r5c8=9 r5c4<>9 r2c4=9 r2c5<>9 r2c5=4 r2c9<>4 r3c9=4 r3c9<>2
r7c6<>4 r7c6=8 (r7c8<>8 r9c8=8 r9c8<>6) r7c3<>8 r3c3=8 r3c3<>6 r8c3=6 r9c1<>6 r9c9=6 r9c9<>1 r6c9=1 r6c9<>2
r7c6<>4 r7c6=8 (r7c8<>8 r9c8=8 r9c8<>5) (r7c8<>8 r9c8=8 r9c8<>6) r7c3<>8 r3c3=8 r3c3<>6 r8c3=6 (r8c3<>9 r8c7=9 r8c7<>5) r9c1<>6 r9c9=6 r9c9<>5 r9c5=5 r8c5<>5 r8c9=5 r8c9<>2
r7c6<>4 r7c6=8 (r7c8<>8 r9c8=8 r9c8<>6) r7c3<>8 r3c3=8 r3c3<>6 r8c3=6 r9c1<>6 r9c9=6 r9c9<>2
Locked Candidates Type 1 (Pointing): 8 in b8 => r8c2<>8
Finned Swordfish: 4 r148 c235 fr1c4 => r2c5<>4
Naked Single: r2c5=9
Naked Single: r6c5=3
Naked Single: r4c5=4
Discontinuous Nice Loop: 2/5/6 r8c7 =9= r8c3 =4= r8c2 -4- r5c2 =4= r5c1 =9= r7c1 -9- r7c7 =9= r8c7 => r8c7<>2, r8c7<>5, r8c7<>6
Naked Single: r8c7=9
Discontinuous Nice Loop: 2/3 r7c1 =9= r7c3 =8= r3c3 =6= r8c3 =4= r8c2 -4- r5c2 =4= r5c1 =9= r7c1 => r7c1<>2, r7c1<>3
Naked Single: r7c1=9
Discontinuous Nice Loop: 4 r1c2 -4- r8c2 =4= r8c3 =6= r3c3 =8= r2c2 =7= r1c2 => r1c2<>4
Discontinuous Nice Loop: 5 r4c7 -5- r4c6 -6- r5c4 -9- r5c8 =9= r4c8 =7= r4c7 => r4c7<>5
Discontinuous Nice Loop: 2 r5c1 -2- r6c3 -9- r6c4 -8- r8c4 -7- r2c4 =7= r2c2 =8= r3c3 =6= r8c3 =4= r8c2 -4- r5c2 =4= r5c1 => r5c1<>2
Discontinuous Nice Loop: 4 r3c1 -4- r5c1 =4= r5c2 -4- r8c2 -2- r9c1 =2= r3c1 => r3c1<>4
Discontinuous Nice Loop: 5 r4c8 -5- r4c6 -6- r5c4 -9- r5c8 =9= r4c8 => r4c8<>5
Discontinuous Nice Loop: 2 r1c3 -2- r6c3 -9- r6c4 -8- r6c6 -5- r6c7 =5= r2c7 -5- r2c8 =5= r9c8 -5- r9c5 -2- r9c1 =2= r3c1 -2- r1c3 => r1c3<>2
Finned Swordfish: 2 r157 c278 fr7c3 => r89c2<>2
Naked Single: r8c2=4
Hidden Single: r5c1=4
Sue de Coq: r1c23 - {2347} (r1c46 - {467}, r23c1 - {236}) => r1c78,r3c3<>6
Hidden Single: r8c3=6
Locked Candidates Type 2 (Claiming): 6 in r1 => r2c4<>6
W-Wing: 3/2 in r5c2,r9c1 connected by 2 in r67c3 => r9c2<>3
Naked Single: r9c2=8
Naked Single: r2c2=7
Naked Single: r2c4=4
Hidden Single: r3c3=8
Hidden Single: r1c3=4
Hidden Single: r3c9=4
X-Wing: 3 r15 c27 => r24c7<>3
Uniqueness Test 1: 2/5 in r8c59,r9c59 => r9c9<>2, r9c9<>5
Skyscraper: 2 in r7c3,r8c9 (connected by r6c39) => r7c78<>2
Hidden Single: r7c3=2
Full House: r9c1=3
Naked Single: r6c3=9
Full House: r4c3=3
Full House: r5c2=2
Full House: r1c2=3
Naked Single: r2c1=6
Full House: r3c1=2
Naked Single: r9c4=1
Naked Single: r6c4=8
Naked Single: r7c4=3
Naked Single: r9c9=6
Naked Single: r6c6=5
Naked Single: r8c4=7
Naked Single: r4c9=5
Naked Single: r4c6=6
Full House: r5c4=9
Full House: r1c4=6
Full House: r1c6=7
Full House: r8c6=8
Naked Single: r2c9=3
Naked Single: r8c9=2
Full House: r6c9=1
Full House: r8c5=5
Full House: r6c7=2
Full House: r9c5=2
Full House: r9c8=5
Naked Single: r4c7=7
Full House: r4c8=9
Naked Single: r5c8=6
Full House: r5c7=3
Naked Single: r1c7=1
Full House: r1c8=2
Naked Single: r2c8=8
Full House: r2c7=5
Naked Single: r3c7=6
Full House: r3c8=7
Full House: r7c7=8
Full House: r7c8=1
|
normal_sudoku_1383
|
..13...9.2459761..7.9841.52..7...8......879..18...9.4735819......263.5.16147....9
|
861325794245976138739841652497213865526487913183569247358192476972634581614758329
|
Basic 9x9 Sudoku 1383
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 1 3 . . . 9 .
2 4 5 9 7 6 1 . .
7 . 9 8 4 1 . 5 2
. . 7 . . . 8 . .
. . . . 8 7 9 . .
1 8 . . . 9 . 4 7
3 5 8 1 9 . . . .
. . 2 6 3 . 5 . 1
6 1 4 7 . . . . 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
861325794245976138739841652497213865526487913183569247358192476972634581614758329 #1 Easy (264)
Naked Single: r3c4=8
Naked Single: r9c2=1
Naked Single: r9c3=4
Hidden Single: r6c2=8
Hidden Single: r7c4=1
Hidden Single: r2c7=1
Hidden Single: r5c6=7
Naked Single: r2c6=6
Naked Single: r2c5=7
Hidden Single: r1c8=9
Hidden Single: r3c3=9
Naked Single: r3c1=7
Naked Single: r1c1=8
Naked Single: r1c2=6
Full House: r3c2=3
Full House: r3c7=6
Naked Single: r8c1=9
Full House: r8c2=7
Naked Single: r1c9=4
Naked Single: r5c2=2
Full House: r4c2=9
Naked Single: r8c8=8
Full House: r8c6=4
Naked Single: r1c7=7
Naked Single: r7c9=6
Naked Single: r2c8=3
Full House: r2c9=8
Naked Single: r7c6=2
Naked Single: r9c8=2
Naked Single: r1c6=5
Full House: r1c5=2
Naked Single: r7c7=4
Full House: r7c8=7
Full House: r9c7=3
Full House: r6c7=2
Naked Single: r9c5=5
Full House: r9c6=8
Full House: r4c6=3
Naked Single: r6c4=5
Naked Single: r6c5=6
Full House: r4c5=1
Full House: r6c3=3
Full House: r5c3=6
Naked Single: r4c9=5
Full House: r5c9=3
Naked Single: r5c4=4
Full House: r4c4=2
Naked Single: r4c8=6
Full House: r5c8=1
Full House: r4c1=4
Full House: r5c1=5
|
normal_sudoku_6311
|
.3..16.7..6.7..53......8..165.8.1..3.1.6..745..2...1....6...41......9....8.16...7
|
835216974261794538794538621657841293918623745342975186526387419173459862489162357
|
Basic 9x9 Sudoku 6311
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 3 . . 1 6 . 7 .
. 6 . 7 . . 5 3 .
. . . . . 8 . . 1
6 5 . 8 . 1 . . 3
. 1 . 6 . . 7 4 5
. . 2 . . . 1 . .
. . 6 . . . 4 1 .
. . . . . 9 . . .
. 8 . 1 6 . . . 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
835216974261794538794538621657841293918623745342975186526387419173459862489162357 #1 Extreme (14994) bf
Hidden Single: r6c7=1
Brute Force: r5c8=4
Locked Pair: 2,9 in r4c78 => r4c35,r6c89<>9, r4c5<>2
Locked Candidates Type 1 (Pointing): 8 in b6 => r6c1<>8
Uniqueness Test 2: 2/9 in r3c78,r4c78 => r1c79,r2c9,r3c2<>6
Hidden Single: r1c6=6
Hidden Single: r2c2=6
Forcing Chain Contradiction in r9c6 => r8c4<>3
r8c4=3 r7c456<>3 r7c1=3 r6c1<>3 r5c13=3 r5c6<>3 r5c6=2 r9c6<>2
r8c4=3 r9c6<>3
r8c4=3 r7c456<>3 r7c1=3 r6c1<>3 r5c13=3 r5c6<>3 r5c6=2 r2c6<>2 r2c6=4 r9c6<>4
r8c4=3 r7c456<>3 r7c1=3 r7c1<>5 r7c456=5 r9c6<>5
Forcing Chain Contradiction in r9c6 => r8c5<>3
r8c5=3 r7c456<>3 r7c1=3 r6c1<>3 r5c13=3 r5c6<>3 r5c6=2 r9c6<>2
r8c5=3 r9c6<>3
r8c5=3 r7c456<>3 r7c1=3 r6c1<>3 r5c13=3 r5c6<>3 r5c6=2 r2c6<>2 r2c6=4 r9c6<>4
r8c5=3 r7c456<>3 r7c1=3 r7c1<>5 r7c456=5 r9c6<>5
Forcing Net Contradiction in r9c6 => r1c7<>2
r1c7=2 (r3c8<>2) (r3c7<>2) r4c7<>2 r4c7=9 r3c7<>9 r3c7=6 r3c8<>6 r3c8=9 (r3c2<>9) (r1c9<>9) r2c9<>9 r7c9=9 r7c2<>9 r6c2=9 (r5c1<>9) r5c3<>9 r5c5=9 r5c5<>2 r5c6=2 r9c6<>2
r1c7=2 (r9c7<>2) r4c7<>2 r4c7=9 r9c7<>9 r9c7=3 r9c6<>3
r1c7=2 (r3c8<>2) (r3c7<>2) r4c7<>2 r4c7=9 r3c7<>9 r3c7=6 r3c8<>6 r3c8=9 (r3c2<>9) (r1c9<>9) r2c9<>9 r7c9=9 r7c2<>9 r6c2=9 (r5c1<>9) r5c3<>9 r5c5=9 r5c5<>2 r5c6=2 r2c6<>2 r2c6=4 r9c6<>4
r1c7=2 (r3c8<>2) (r3c7<>2) r4c7<>2 (r4c8=2 r9c8<>2) r4c7=9 r3c7<>9 r3c7=6 r3c8<>6 r3c8=9 r9c8<>9 r9c8=5 r9c6<>5
Forcing Net Verity => r1c9<>2
r1c7=9 (r3c8<>9) (r3c7<>9) r4c7<>9 r4c7=2 r3c7<>2 r3c7=6 r3c8<>6 r3c8=2 r1c9<>2
r1c9=9 r1c9<>2
r2c9=9 r2c9<>4 r1c9=4 r1c9<>2
r3c7=9 (r3c2<>9) (r1c9<>9) r2c9<>9 r7c9=9 r7c2<>9 r6c2=9 (r5c1<>9) r5c3<>9 r5c5=9 r5c5<>2 r5c6=2 r2c6<>2 r2c6=4 r2c9<>4 r1c9=4 r1c9<>2
r3c8=9 (r3c2<>9) (r1c9<>9) r2c9<>9 r7c9=9 r7c2<>9 r6c2=9 (r5c1<>9) r5c3<>9 r5c5=9 r5c5<>2 r5c6=2 r2c6<>2 r2c6=4 r2c9<>4 r1c9=4 r1c9<>2
Discontinuous Nice Loop: 4 r1c1 -4- r1c9 =4= r2c9 -4- r2c6 -2- r1c4 =2= r1c1 => r1c1<>4
Forcing Chain Contradiction in r9 => r1c9=4
r1c9<>4 r2c9=4 r2c9<>2 r3c78=2 r3c2<>2 r123c1=2 r9c1<>2
r1c9<>4 r2c9=4 r2c6<>4 r2c6=2 r9c6<>2
r1c9<>4 r2c9=4 r2c9<>2 r78c9=2 r9c7<>2
r1c9<>4 r2c9=4 r2c9<>2 r78c9=2 r9c8<>2
Forcing Chain Contradiction in r9 => r2c6=4
r2c6<>4 r2c6=2 r1c4<>2 r1c1=2 r9c1<>2
r2c6<>4 r2c6=2 r9c6<>2
r2c6<>4 r2c6=2 r2c9<>2 r78c9=2 r9c7<>2
r2c6<>4 r2c6=2 r2c9<>2 r78c9=2 r9c8<>2
Locked Candidates Type 1 (Pointing): 4 in b8 => r8c123<>4
Discontinuous Nice Loop: 2 r7c5 -2- r2c5 -9- r2c9 =9= r7c9 =8= r7c5 => r7c5<>2
Forcing Chain Contradiction in r9 => r2c5=9
r2c5<>9 r2c5=2 r1c4<>2 r1c1=2 r9c1<>2
r2c5<>9 r2c5=2 r5c5<>2 r5c6=2 r9c6<>2
r2c5<>9 r2c5=2 r2c9<>2 r78c9=2 r9c7<>2
r2c5<>9 r2c5=2 r2c9<>2 r78c9=2 r9c8<>2
Hidden Single: r7c9=9
Hidden Single: r6c4=9
Hidden Single: r7c5=8
Hidden Single: r3c2=9
Hidden Single: r8c4=4
Hidden Single: r1c7=9
Naked Single: r4c7=2
Naked Single: r3c7=6
Naked Single: r4c8=9
Naked Single: r9c7=3
Full House: r8c7=8
Naked Single: r3c8=2
Full House: r2c9=8
Naked Single: r9c8=5
Naked Single: r2c3=1
Full House: r2c1=2
Naked Single: r6c9=6
Full House: r6c8=8
Full House: r8c8=6
Full House: r8c9=2
Naked Single: r9c6=2
Naked Single: r8c2=7
Naked Single: r5c6=3
Naked Single: r6c2=4
Full House: r7c2=2
Naked Single: r8c5=5
Naked Single: r5c5=2
Naked Single: r4c3=7
Full House: r4c5=4
Naked Single: r3c5=3
Full House: r6c5=7
Full House: r6c6=5
Full House: r7c6=7
Full House: r7c4=3
Full House: r6c1=3
Full House: r7c1=5
Naked Single: r8c3=3
Full House: r8c1=1
Naked Single: r3c4=5
Full House: r1c4=2
Naked Single: r1c1=8
Full House: r1c3=5
Naked Single: r3c3=4
Full House: r3c1=7
Naked Single: r5c1=9
Full House: r5c3=8
Full House: r9c3=9
Full House: r9c1=4
|
normal_sudoku_2398
|
..856.4.2...2....12...1.5......56.28..517264..2.84...5...78..5.9.362581....4....6
|
318567492459238761276914583794356128835172649621849375162783954943625817587491236
|
Basic 9x9 Sudoku 2398
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 8 5 6 . 4 . 2
. . . 2 . . . . 1
2 . . . 1 . 5 . .
. . . . 5 6 . 2 8
. . 5 1 7 2 6 4 .
. 2 . 8 4 . . . 5
. . . 7 8 . . 5 .
9 . 3 6 2 5 8 1 .
. . . 4 . . . . 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
318567492459238761276914583794356128835172649621849375162783954943625817587491236 #1 Extreme (22094) bf
Hidden Single: r6c9=5
Hidden Single: r8c5=2
Hidden Single: r5c8=4
Hidden Single: r2c4=2
Hidden Single: r1c4=5
Naked Triple: 3,7,9 in r1c6,r2c5,r3c4 => r23c6<>3, r23c6<>7, r23c6<>9
Naked Triple: 3,7,9 in r1c8,r2c7,r3c9 => r23c8<>3, r23c8<>7, r23c8<>9
Brute Force: r5c4=1
Brute Force: r5c5=7
Finned X-Wing: 7 c49 r37 fr8c9 => r7c7<>7
Forcing Net Verity => r1c6=7
r1c6=3 (r6c6<>3 r6c6=9 r9c6<>9) (r1c8<>3) r2c5<>3 (r2c5=9 r9c5<>9) (r2c5=9 r2c7<>9) r9c5=3 r9c8<>3 r6c8=3 r5c9<>3 r5c9=9 r3c9<>9 r1c8=9 (r9c8<>9) r9c8<>9 r9c7=9 r9c5<>9 r9c5=3 r9c8<>3 r9c8=7 (r9c6<>7) (r7c9<>7) r8c9<>7 r3c9=7 r3c4<>7 r7c4=7 (r7c6<>7) r8c6<>7 r1c6=7
r1c6=7 r1c6=7
r1c6=9 (r6c6<>9 r6c6=3 r9c6<>3) (r1c6<>3) (r1c8<>9) r2c5<>9 (r2c5=3 r9c5<>3) (r2c5=3 r3c4<>3) r9c5=9 r9c8<>9 r6c8=9 r5c9<>9 r5c9=3 r3c9<>3 r3c2=3 (r1c1<>3) r1c2<>3 r1c8=3 (r9c8<>3) r9c8<>3 r9c7=3 r9c5<>3 r9c5=9 r9c8<>9 r9c8=7 (r9c6<>7) (r7c9<>7) r8c9<>7 r3c9=7 r3c4<>7 r7c4=7 (r7c6<>7) r8c6<>7 r1c6=7
Naked Single: r8c6=5
Hidden Single: r7c4=7
Hidden Pair: 5,8 in r9c12 => r9c12<>1, r9c12<>7
Skyscraper: 9 in r1c8,r5c9 (connected by r15c2) => r3c9,r6c8<>9
Skyscraper: 9 in r1c8,r2c5 (connected by r9c58) => r2c7<>9
Hidden Single: r1c8=9
Locked Candidates Type 2 (Claiming): 3 in r1 => r2c12,r3c2<>3
2-String Kite: 3 in r2c7,r4c4 (connected by r2c5,r3c4) => r4c7<>3
Jellyfish: 3 r1345 c1249 => r6c1,r7c9<>3
Skyscraper: 3 in r2c5,r7c6 (connected by r27c7) => r9c5<>3
Naked Single: r9c5=9
Full House: r2c5=3
Naked Single: r2c7=7
Naked Single: r3c4=9
Full House: r4c4=3
Full House: r6c6=9
Naked Single: r3c9=3
Naked Single: r5c9=9
Naked Single: r4c7=1
Naked Single: r7c9=4
Full House: r8c9=7
Full House: r8c2=4
Naked Single: r6c7=3
Full House: r6c8=7
Naked Single: r9c8=3
Naked Single: r9c7=2
Full House: r7c7=9
Naked Single: r9c6=1
Full House: r7c6=3
Naked Single: r9c3=7
Hidden Single: r4c1=7
Naked Single: r4c2=9
Full House: r4c3=4
Naked Single: r3c3=6
Naked Single: r2c2=5
Naked Single: r2c3=9
Naked Single: r3c2=7
Naked Single: r3c8=8
Full House: r2c8=6
Full House: r3c6=4
Full House: r2c6=8
Full House: r2c1=4
Naked Single: r6c3=1
Full House: r6c1=6
Full House: r7c3=2
Naked Single: r9c2=8
Full House: r9c1=5
Naked Single: r7c1=1
Full House: r7c2=6
Naked Single: r5c2=3
Full House: r1c2=1
Full House: r1c1=3
Full House: r5c1=8
|
normal_sudoku_218
|
.46..3.9...9.286....8.64...4.1..69...67.5.4..8.3....76185432769..46.7.52672..53..
|
546173298319528647728964135451786923267359481893241576185432769934617852672895314
|
Basic 9x9 Sudoku 218
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 4 6 . . 3 . 9 .
. . 9 . 2 8 6 . .
. . 8 . 6 4 . . .
4 . 1 . . 6 9 . .
. 6 7 . 5 . 4 . .
8 . 3 . . . . 7 6
1 8 5 4 3 2 7 6 9
. . 4 6 . 7 . 5 2
6 7 2 . . 5 3 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
546173298319528647728964135451786923267359481893241576185432769934617852672895314 #1 Unfair (1196)
Naked Single: r7c3=5
Naked Single: r6c3=3
Naked Single: r7c1=1
Naked Single: r5c3=7
Full House: r1c3=6
Naked Single: r7c2=8
Naked Single: r7c7=7
Naked Single: r7c6=2
Naked Single: r7c4=4
Full House: r7c8=6
Hidden Single: r6c9=6
Hidden Single: r4c1=4
Hidden Single: r3c5=6
Hidden Single: r9c6=5
Hidden Single: r8c6=7
Hidden Single: r6c5=4
Hidden Single: r3c4=9
Hidden Single: r9c5=9
Locked Candidates Type 1 (Pointing): 5 in b4 => r23c2<>5
Locked Candidates Type 2 (Claiming): 1 in c6 => r56c4<>1
Naked Single: r6c4=2
Locked Candidates Type 1 (Pointing): 2 in b6 => r3c8<>2
AIC: 5/8 8- r1c9 =8= r1c7 =2= r1c1 -2- r5c1 =2= r4c2 =5= r4c9 -5 => r1c9<>5, r4c9<>8
XY-Chain: 3 3- r4c9 -5- r6c7 -1- r8c7 -8- r8c5 -1- r9c4 -8- r5c4 -3 => r4c4,r5c89<>3
Hidden Single: r5c4=3
Locked Candidates Type 1 (Pointing): 8 in b5 => r4c8<>8
W-Wing: 1/8 in r5c9,r8c7 connected by 8 in r1c79 => r6c7,r9c9<>1
Naked Single: r6c7=5
Naked Single: r4c9=3
Naked Single: r6c2=9
Full House: r6c6=1
Full House: r5c6=9
Naked Single: r4c8=2
Naked Single: r5c1=2
Full House: r4c2=5
Naked Single: r8c2=3
Full House: r8c1=9
Naked Single: r2c2=1
Full House: r3c2=2
Naked Single: r3c7=1
Naked Single: r3c8=3
Naked Single: r8c7=8
Full House: r1c7=2
Full House: r8c5=1
Full House: r9c4=8
Naked Single: r2c8=4
Naked Single: r9c9=4
Full House: r9c8=1
Full House: r5c8=8
Full House: r5c9=1
Naked Single: r1c5=7
Full House: r4c5=8
Full House: r4c4=7
Naked Single: r1c1=5
Naked Single: r1c9=8
Full House: r1c4=1
Full House: r2c4=5
Naked Single: r3c1=7
Full House: r2c1=3
Full House: r2c9=7
Full House: r3c9=5
|
normal_sudoku_3305
|
.3...9..55.....2...965.....9.8...4..4532189766..9.4........78......4..1.3..6....2
|
132479685547186293896523147928765431453218976671934528219357864765842319384691752
|
Basic 9x9 Sudoku 3305
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 3 . . . 9 . . 5
5 . . . . . 2 . .
. 9 6 5 . . . . .
9 . 8 . . . 4 . .
4 5 3 2 1 8 9 7 6
6 . . 9 . 4 . . .
. . . . . 7 8 . .
. . . . 4 . . 1 .
3 . . 6 . . . . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
132479685547186293896523147928765431453218976671934528219357864765842319384691752 #1 Extreme (37916) bf
Locked Candidates Type 1 (Pointing): 6 in b5 => r4c89<>6
Brute Force: r5c4=2
Hidden Single: r6c6=4
Discontinuous Nice Loop: 5 r9c2 -5- r9c6 -1- r7c4 -3- r8c4 -8- r9c5 =8= r9c2 => r9c2<>5
Brute Force: r5c3=3
Locked Candidates Type 1 (Pointing): 9 in b4 => r78c1<>9
Forcing Net Contradiction in r8c9 => r4c1<>7
r4c1=7 (r8c1<>7) r4c4<>7 r4c4=3 (r7c4<>3 r7c4=1 r9c6<>1 r9c6=5 r8c6<>5) r8c4<>3 r8c4=8 r8c1<>8 r8c1=2 r8c6<>2 r8c6=3 r8c9<>3
r4c1=7 r4c1<>9 r5c1=9 r5c9<>9 r5c9=6 r8c9<>6
r4c1=7 r4c4<>7 r4c4=3 (r8c4<>3 r8c4=8 r9c5<>8) r7c4<>3 r7c4=1 r9c6<>1 r9c6=5 (r9c7<>5) r9c5<>5 r9c5=9 r9c7<>9 r9c7=7 r8c9<>7
r4c1=7 r4c1<>9 r5c1=9 r5c7<>9 r89c7=9 r8c9<>9
Forcing Net Contradiction in r3c9 => r8c6<>3
r8c6=3 (r7c4<>3 r7c4=1 r9c6<>1 r9c6=5 r9c8<>5) r8c6<>2 r3c6=2 (r1c5<>2) r3c5<>2 r7c5=2 (r7c1<>2 r7c1=4 r3c1<>4) r7c5<>9 r9c5=9 r9c8<>9 r9c8=4 r3c8<>4 r3c9=4
r8c6=3 (r8c4<>3 r8c4=8 r9c5<>8 r9c2=8 r2c2<>8) (r7c4<>3 r7c4=1 r7c1<>1) r8c6<>2 r3c6=2 (r3c6<>1 r2c6=1 r2c2<>1) (r1c5<>2) r3c5<>2 r7c5=2 r7c1<>2 r7c1=4 r5c1<>4 r5c2=4 r2c2<>4 r2c2=7 (r2c9<>7) (r1c1<>7) r3c1<>7 r8c1=7 r8c9<>7 r3c9=7
Forcing Net Contradiction in r2c3 => r9c2<>7
r9c2=7 (r9c2<>1) r9c2<>8 r9c5=8 r8c4<>8 r8c4=3 r7c4<>3 r7c4=1 r9c6<>1 r9c3=1 r2c3<>1
r9c2=7 (r8c1<>7) r9c2<>8 (r2c2=8 r2c4<>8) r9c5=8 r9c5<>9 r7c5=9 r7c5<>2 r8c6=2 r8c1<>2 r8c1=8 r8c4<>8 r8c4=3 (r2c4<>3) (r4c4<>3 r4c4=7 r2c4<>7) r7c4<>3 r7c4=1 r2c4<>1 r2c4=4 r2c3<>4
r9c2=7 (r4c2<>7) r6c2<>7 r6c3=7 r2c3<>7
Brute Force: r5c7=9
Naked Single: r5c1=4
Naked Single: r5c9=6
Full House: r5c2=5
Hidden Single: r4c1=9
Locked Candidates Type 2 (Claiming): 4 in r3 => r12c8,r2c9<>4
Grouped Discontinuous Nice Loop: 7 r1c4 -7- r4c4 -3- r7c4 -1- r7c1 -2- r13c1 =2= r1c3 =4= r1c4 => r1c4<>7
Grouped Discontinuous Nice Loop: 8 r1c4 -8- r8c4 -3- r7c4 -1- r7c1 -2- r13c1 =2= r1c3 =4= r1c4 => r1c4<>8
2-String Kite: 8 in r2c4,r9c2 (connected by r8c4,r9c5) => r2c2<>8
Locked Candidates Type 1 (Pointing): 8 in b1 => r8c1<>8
Almost Locked Set XZ-Rule: A=r7c4,r9c6 {135}, B=r78c9,r9c78 {34579}, X=5, Z=3 => r7c8<>3
Grouped Discontinuous Nice Loop: 1 r6c9 -1- r4c9 -3- r78c9 =3= r8c7 =6= r1c7 -6- r1c8 -8- r6c8 =8= r6c9 => r6c9<>1
Grouped AIC: 8 8- r1c8 -6- r1c7 =6= r8c7 =3= r78c9 -3- r6c9 -8 => r23c9,r6c8<>8
Hidden Single: r6c9=8
Forcing Chain Contradiction in b1 => r4c4=7
r4c4<>7 r4c4=3 r7c4<>3 r7c4=1 r7c1<>1 r7c1=2 r8c1<>2 r8c1=7 r1c1<>7
r4c4<>7 r4c4=3 r7c4<>3 r7c4=1 r7c1<>1 r7c1=2 r13c1<>2 r1c3=2 r1c3<>7
r4c4<>7 r2c4=7 r2c2<>7
r4c4<>7 r2c4=7 r2c3<>7
r4c4<>7 r4c4=3 r7c4<>3 r7c4=1 r7c1<>1 r7c1=2 r8c1<>2 r8c1=7 r3c1<>7
XYZ-Wing: 1/3/5 in r4c9,r6c57 => r6c8<>3
Grouped Discontinuous Nice Loop: 2 r8c2 -2- r4c2 -1- r4c9 -3- r78c9 =3= r8c7 =6= r8c2 => r8c2<>2
Forcing Chain Contradiction in r8c2 => r1c5<>2
r1c5=2 r1c13<>2 r3c1=2 r3c1<>8 r1c1=8 r1c8<>8 r1c8=6 r1c7<>6 r8c7=6 r8c2<>6
r1c5=2 r1c3<>2 r13c1=2 r8c1<>2 r8c1=7 r8c2<>7
r1c5=2 r1c3<>2 r13c1=2 r7c1<>2 r7c1=1 r7c4<>1 r7c4=3 r8c4<>3 r8c4=8 r8c2<>8
Locked Candidates Type 1 (Pointing): 2 in b2 => r3c1<>2
Forcing Chain Contradiction in r3 => r8c4=8
r8c4<>8 r8c4=3 r7c4<>3 r7c4=1 r7c1<>1 r7c1=2 r8c1<>2 r8c1=7 r3c1<>7
r8c4<>8 r9c5=8 r9c5<>9 r7c5=9 r7c5<>2 r3c5=2 r3c5<>7
r8c4<>8 r8c4=3 r7c4<>3 r7c4=1 r9c6<>1 r9c6=5 r9c7<>5 r9c7=7 r3c7<>7
r8c4<>8 r8c4=3 r7c45<>3 r7c9=3 r7c9<>4 r3c9=4 r3c9<>7
Hidden Single: r9c2=8
Locked Candidates Type 1 (Pointing): 3 in b8 => r7c9<>3
Discontinuous Nice Loop: 7 r1c7 -7- r9c7 =7= r9c3 -7- r8c2 -6- r8c7 =6= r1c7 => r1c7<>7
Discontinuous Nice Loop: 1 r3c1 -1- r7c1 -2- r8c1 -7- r8c2 -6- r8c7 =6= r1c7 -6- r1c8 -8- r1c1 =8= r3c1 => r3c1<>1
Discontinuous Nice Loop: 9 r9c3 -9- r9c5 =9= r7c5 -9- r7c9 -4- r9c8 =4= r9c3 => r9c3<>9
Grouped AIC: 6 6- r7c8 =6= r7c2 -6- r8c2 -7- r8c1 -2- r8c6 =2= r3c6 =1= r3c79 -1- r1c7 -6 => r12c8,r8c7<>6
Naked Single: r1c8=8
Hidden Single: r7c8=6
Hidden Single: r1c7=6
Naked Single: r1c5=7
Hidden Single: r8c2=6
Hidden Single: r3c1=8
Hidden Single: r2c5=8
Hidden Single: r8c1=7
Hidden Single: r2c6=6
Hidden Single: r4c5=6
Hidden Single: r9c7=7
Hidden Single: r3c9=7
Hidden Single: r3c8=4
Hidden Single: r7c9=4
Hidden Single: r9c3=4
Hidden Single: r2c2=4
Hidden Single: r1c4=4
Hidden Single: r9c6=1
Naked Single: r7c4=3
Full House: r2c4=1
Naked Single: r2c3=7
Hidden Single: r6c2=7
Hidden Single: r3c7=1
Hidden Single: r4c9=1
Naked Single: r4c2=2
Full House: r6c3=1
Full House: r7c2=1
Naked Single: r1c3=2
Full House: r1c1=1
Full House: r7c1=2
Hidden Single: r6c8=2
Hidden Single: r8c6=2
Naked Single: r3c6=3
Full House: r3c5=2
Full House: r4c6=5
Full House: r4c8=3
Full House: r6c5=3
Full House: r6c7=5
Full House: r8c7=3
Naked Single: r2c8=9
Full House: r2c9=3
Full House: r8c9=9
Full House: r9c8=5
Full House: r8c3=5
Full House: r9c5=9
Full House: r7c3=9
Full House: r7c5=5
|
normal_sudoku_4685
|
.3.9...8676.3.......165.3....9..56..62...3.7.4....6..8..653.9......6...2.4..19.6.
|
532941786764382159891657324179825643628493571453176298286534917915768432347219865
|
Basic 9x9 Sudoku 4685
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 3 . 9 . . . 8 6
7 6 . 3 . . . . .
. . 1 6 5 . 3 . .
. . 9 . . 5 6 . .
6 2 . . . 3 . 7 .
4 . . . . 6 . . 8
. . 6 5 3 . 9 . .
. . . . 6 . . . 2
. 4 . . 1 9 . 6 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
532941786764382159891657324179825643628493571453176298286534917915768432347219865 #1 Extreme (17650) bf
Hidden Single: r9c8=6
Locked Candidates Type 1 (Pointing): 1 in b2 => r56c6<>1
2-String Kite: 6 in r2c6,r5c1 (connected by r2c2,r3c1) => r5c6<>6
Brute Force: r5c6=3
Hidden Single: r7c5=3
2-String Kite: 3 in r6c3,r9c9 (connected by r4c9,r6c8) => r9c3<>3
Forcing Chain Contradiction in r3 => r6c6<>2
r6c6=2 r7c6<>2 r7c1=2 r3c1<>2
r6c6=2 r7c6<>2 r9c4=2 r3c4<>2
r6c6=2 r3c6<>2
r6c6=2 r6c7<>2 r12c7=2 r3c8<>2
Grouped Discontinuous Nice Loop: 7 r3c4 -7- r1c5 =7= r46c5 -7- r6c6 -6- r56c4 =6= r3c4 => r3c4<>7
Sashimi Swordfish: 7 r347 c269 fr4c4 fr4c5 => r6c6<>7
Naked Single: r6c6=6
Hidden Single: r2c2=6
Hidden Single: r3c4=6
Hidden Single: r5c1=6
Locked Candidates Type 1 (Pointing): 9 in b1 => r3c89<>9
Hidden Rectangle: 8/9 in r3c12,r8c12 => r8c1<>8
Forcing Chain Contradiction in c8 => r6c3<>5
r6c3=5 r6c3<>3 r6c8=3 r6c8<>9 r2c8=9 r2c8<>5
r6c3=5 r6c8<>5
r6c3=5 r6c2<>5 r8c2=5 r8c8<>5
Forcing Chain Contradiction in r8 => r6c7<>5
r6c7=5 r6c2<>5 r8c2=5 r8c2<>9 r8c1=9 r8c1<>1
r6c7=5 r6c2<>5 r8c2=5 r8c2<>1
r6c7=5 r6c7<>2 r12c7=2 r3c8<>2 r3c8=4 r7c8<>4 r7c8=1 r8c7<>1
r6c7=5 r6c7<>2 r12c7=2 r3c8<>2 r3c8=4 r7c8<>4 r7c8=1 r8c8<>1
Forcing Chain Contradiction in r8 => r4c9<>1
r4c9=1 r4c12<>1 r6c2=1 r6c2<>5 r8c2=5 r8c2<>9 r8c1=9 r8c1<>3
r4c9=1 r4c12<>1 r6c2=1 r6c2<>5 r6c8=5 r6c8<>3 r6c3=3 r8c3<>3
r4c9=1 r4c9<>3 r9c9=3 r8c8<>3
Almost Locked Set XZ-Rule: A=r23467c8 {123459}, B=r347c9 {1347}, X=3, Z=1 => r8c8<>1
Almost Locked Set XY-Wing: A=r8c34678 {134578}, B=r4c12,r5c3,r6c2 {13578}, C=r347c9 {1347}, X,Y=1,3, Z=7 => r8c2<>7
Almost Locked Set XY-Wing: A=r8c34678 {134578}, B=r9c1347 {23578}, C=r3479c9 {13457}, X,Y=1,5, Z=3 => r8c1<>3
X-Wing: 3 r68 c38 => r4c8<>3
Naked Triple: 1,2,4 in r347c8 => r26c8<>1, r26c8<>2, r28c8<>4
Empty Rectangle: 1 in b4 (r47c8) => r7c2<>1
Grouped AIC: 8 8- r5c3 -5- r6c2 =5= r6c8 =3= r6c3 =7= r46c2 -7- r7c2 -8 => r4c2,r89c3<>8
Finned X-Wing: 8 c35 r25 fr4c5 => r5c4<>8
Grouped Discontinuous Nice Loop: 2 r6c5 -2- r6c7 -1- r12c7 =1= r2c9 =9= r2c8 -9- r6c8 =9= r6c5 => r6c5<>2
Sashimi X-Wing: 2 c58 r34 fr1c5 fr2c5 => r3c6<>2
Grouped Discontinuous Nice Loop: 5 r8c1 -5- r8c8 -3- r8c3 =3= r6c3 =7= r46c2 -7- r7c2 -8- r3c2 -9- r3c1 =9= r8c1 => r8c1<>5
Almost Locked Set XZ-Rule: A=r7c289 {1478}, B=r8c34678 {134578}, X=1, Z=8 => r8c2<>8
Almost Locked Set XZ-Rule: A=r13478c1 {123589}, B=r4c89,r56c7 {12345}, X=3, Z=5 => r1c7<>5
Locked Candidates Type 1 (Pointing): 5 in b3 => r2c3<>5
Almost Locked Set XZ-Rule: A=r6c7 {12}, B=r1c7,r3c89 {1247}, X=1, Z=2 => r2c7<>2
Forcing Chain Contradiction in r4c8 => r1c1=5
r1c1<>5 r1c3=5 r5c3<>5 r6c2=5 r6c2<>1 r4c12=1 r4c8<>1
r1c1<>5 r1c1=2 r1c7<>2 r6c7=2 r4c8<>2
r1c1<>5 r9c1=5 r9c1<>3 r9c9=3 r4c9<>3 r4c9=4 r4c8<>4
Almost Locked Set XY-Wing: A=r125c3 {2458}, B=r23678c8 {123459}, C=r7c12,r89c3,r9c1 {123578}, X,Y=1,5, Z=2 => r3c1<>2
Hidden Single: r3c8=2
Hidden Single: r6c7=2
Locked Pair: 8,9 in r3c12 => r2c3,r3c6<>8
Hidden Single: r5c3=8
Hidden Single: r6c2=5
Hidden Single: r6c4=1
Naked Single: r5c4=4
Naked Single: r5c5=9
Naked Single: r6c5=7
Naked Single: r6c3=3
Full House: r6c8=9
Naked Single: r4c1=1
Full House: r4c2=7
Naked Single: r2c8=5
Naked Single: r4c8=4
Naked Single: r8c1=9
Naked Single: r7c2=8
Naked Single: r8c8=3
Full House: r7c8=1
Naked Single: r4c9=3
Naked Single: r3c1=8
Naked Single: r8c2=1
Full House: r3c2=9
Naked Single: r7c1=2
Full House: r9c1=3
Hidden Single: r2c9=9
Hidden Single: r9c4=2
Naked Single: r4c4=8
Full House: r4c5=2
Full House: r8c4=7
Naked Single: r1c5=4
Full House: r2c5=8
Naked Single: r7c6=4
Full House: r7c9=7
Full House: r8c6=8
Naked Single: r8c3=5
Full House: r8c7=4
Full House: r9c3=7
Naked Single: r1c3=2
Full House: r2c3=4
Naked Single: r3c6=7
Full House: r3c9=4
Naked Single: r9c9=5
Full House: r5c9=1
Full House: r9c7=8
Full House: r5c7=5
Naked Single: r2c7=1
Full House: r1c7=7
Full House: r1c6=1
Full House: r2c6=2
|
normal_sudoku_5241
|
751..468.8..15.9..2.3...5..614537.9.5......3737.....654.76.5...1..4.8.59985.1..46
|
751924683846153972293786514614537298529861437378249165437695821162478359985312746
|
Basic 9x9 Sudoku 5241
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
7 5 1 . . 4 6 8 .
8 . . 1 5 . 9 . .
2 . 3 . . . 5 . .
6 1 4 5 3 7 . 9 .
5 . . . . . . 3 7
3 7 . . . . . 6 5
4 . 7 6 . 5 . . .
1 . . 4 . 8 . 5 9
9 8 5 . 1 . . 4 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
751924683846153972293786514614537298529861437378249165437695821162478359985312746 #1 Easy (298)
Hidden Single: r4c5=3
Hidden Single: r6c2=7
Hidden Single: r2c5=5
Hidden Single: r1c3=1
Hidden Single: r6c9=5
Hidden Single: r9c3=5
Hidden Single: r6c8=6
Hidden Single: r9c9=6
Naked Single: r9c1=9
Naked Single: r1c1=7
Naked Single: r7c1=4
Hidden Single: r4c1=6
Full House: r2c1=8
Naked Single: r2c3=6
Naked Single: r2c2=4
Full House: r3c2=9
Naked Single: r8c3=2
Naked Single: r3c6=6
Naked Single: r5c2=2
Naked Single: r7c2=3
Full House: r8c2=6
Naked Single: r8c5=7
Full House: r8c7=3
Naked Single: r3c5=8
Naked Single: r3c4=7
Naked Single: r3c8=1
Full House: r3c9=4
Naked Single: r7c8=2
Full House: r2c8=7
Naked Single: r7c5=9
Naked Single: r9c7=7
Naked Single: r1c5=2
Naked Single: r1c9=3
Full House: r1c4=9
Full House: r2c6=3
Full House: r2c9=2
Naked Single: r6c5=4
Full House: r5c5=6
Naked Single: r5c4=8
Naked Single: r9c6=2
Full House: r9c4=3
Full House: r6c4=2
Naked Single: r4c9=8
Full House: r4c7=2
Full House: r7c9=1
Full House: r7c7=8
Naked Single: r5c3=9
Full House: r6c3=8
Naked Single: r6c7=1
Full House: r5c7=4
Full House: r5c6=1
Full House: r6c6=9
|
normal_sudoku_169
|
8.......66.....32.1.45...8.49.......7.349...5561278.3.91785264334..1.2..2..643.9.
|
872934516659187324134526987498365172723491865561278439917852643346719258285643791
|
Basic 9x9 Sudoku 169
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
8 . . . . . . . 6
6 . . . . . 3 2 .
1 . 4 5 . . . 8 .
4 9 . . . . . . .
7 . 3 4 9 . . . 5
5 6 1 2 7 8 . 3 .
9 1 7 8 5 2 6 4 3
3 4 . . 1 . 2 . .
2 . . 6 4 3 . 9 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
872934516659187324134526987498365172723491865561278439917852643346719258285643791 #1 Easy (252)
Naked Single: r7c1=9
Naked Single: r7c4=8
Naked Single: r7c2=1
Full House: r7c8=4
Naked Single: r9c5=4
Naked Single: r6c8=3
Naked Single: r6c4=2
Naked Single: r6c1=5
Naked Single: r6c6=8
Naked Single: r9c1=2
Naked Single: r5c1=7
Naked Single: r2c1=6
Full House: r8c1=3
Naked Single: r2c5=8
Hidden Single: r4c9=2
Naked Single: r4c3=8
Full House: r5c2=2
Naked Single: r9c3=5
Naked Single: r2c3=9
Naked Single: r8c3=6
Full House: r9c2=8
Full House: r1c3=2
Naked Single: r1c5=3
Naked Single: r4c5=6
Full House: r3c5=2
Naked Single: r5c6=1
Naked Single: r4c4=3
Full House: r4c6=5
Naked Single: r5c7=8
Full House: r5c8=6
Hidden Single: r8c9=8
Hidden Single: r2c2=5
Naked Single: r1c2=7
Full House: r3c2=3
Hidden Single: r8c8=5
Naked Single: r1c8=1
Full House: r4c8=7
Full House: r4c7=1
Naked Single: r1c4=9
Naked Single: r9c7=7
Full House: r9c9=1
Naked Single: r1c6=4
Full House: r1c7=5
Naked Single: r8c4=7
Full House: r2c4=1
Full House: r8c6=9
Naked Single: r3c7=9
Full House: r6c7=4
Full House: r6c9=9
Naked Single: r2c6=7
Full House: r2c9=4
Full House: r3c9=7
Full House: r3c6=6
|
normal_sudoku_2615
|
413895...78..62...56..7....658.1.3..324.8.1.997142..5..4....98529..5..1.83....7..
|
413895267789162534562374891658719342324586179971423658146237985297658413835941726
|
Basic 9x9 Sudoku 2615
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
4 1 3 8 9 5 . . .
7 8 . . 6 2 . . .
5 6 . . 7 . . . .
6 5 8 . 1 . 3 . .
3 2 4 . 8 . 1 . 9
9 7 1 4 2 . . 5 .
. 4 . . . . 9 8 5
2 9 . . 5 . . 1 .
8 3 . . . . 7 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
413895267789162534562374891658719342324586179971423658146237985297658413835941726 #1 Easy (222)
Naked Single: r6c2=7
Naked Single: r4c2=5
Naked Single: r1c2=1
Naked Single: r5c1=3
Full House: r6c1=9
Naked Single: r1c5=9
Naked Single: r2c2=8
Full House: r7c2=4
Naked Single: r5c5=8
Naked Single: r3c1=5
Naked Single: r1c6=5
Naked Single: r4c5=1
Naked Single: r2c1=7
Full House: r7c1=1
Naked Single: r7c5=3
Full House: r9c5=4
Naked Single: r2c3=9
Full House: r3c3=2
Hidden Single: r3c6=4
Naked Single: r3c7=8
Naked Single: r6c7=6
Naked Single: r1c7=2
Naked Single: r5c8=7
Naked Single: r6c6=3
Full House: r6c9=8
Naked Single: r8c7=4
Full House: r2c7=5
Naked Single: r1c8=6
Full House: r1c9=7
Naked Single: r5c6=6
Full House: r5c4=5
Naked Single: r9c8=2
Naked Single: r7c6=7
Naked Single: r4c8=4
Full House: r4c9=2
Naked Single: r9c9=6
Full House: r8c9=3
Naked Single: r4c6=9
Full House: r4c4=7
Naked Single: r7c3=6
Full House: r7c4=2
Naked Single: r8c4=6
Naked Single: r8c6=8
Full House: r9c6=1
Full House: r8c3=7
Full House: r9c3=5
Full House: r9c4=9
Naked Single: r2c8=3
Full House: r3c8=9
Naked Single: r3c9=1
Full House: r2c9=4
Full House: r2c4=1
Full House: r3c4=3
|
normal_sudoku_907
|
65....2.3..4..3..1132.8.7..3.18...7..6.39.12.4....1.36.1..38.9.5.3.7.....4...53.7
|
657149283984723651132586749321864975865397124479251836716438592593672418248915367
|
Basic 9x9 Sudoku 907
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
6 5 . . . . 2 . 3
. . 4 . . 3 . . 1
1 3 2 . 8 . 7 . .
3 . 1 8 . . . 7 .
. 6 . 3 9 . 1 2 .
4 . . . . 1 . 3 6
. 1 . . 3 8 . 9 .
5 . 3 . 7 . . . .
. 4 . . . 5 3 . 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
657149283984723651132586749321864975865397124479251836716438592593672418248915367 #1 Extreme (13166) bf
Brute Force: r5c4=3
Hidden Single: r7c5=3
Hidden Single: r8c3=3
Hidden Single: r4c1=3
Hidden Single: r6c8=3
Hidden Single: r1c9=3
Locked Candidates Type 2 (Claiming): 5 in c8 => r2c7,r3c9<>5
Continuous Nice Loop: 2/4/7/8 8= r8c9 =2= r7c9 -2- r7c1 -7- r5c1 -8- r5c9 =8= r8c9 =2 => r7c234<>2, r8c9<>4, r2c1<>7, r5c23<>8
2-String Kite: 7 in r2c2,r5c6 (connected by r1c6,r2c4) => r5c2<>7
Naked Single: r5c2=6
X-Chain: 7 r2c2 =7= r2c4 -7- r6c4 =7= r5c6 -7- r5c1 =7= r7c1 => r7c2<>7
Naked Single: r7c2=1
Hidden Single: r4c3=1
W-Wing: 2/9 in r3c3,r4c2 connected by 9 in r34c9 => r2c2,r6c3<>2
Locked Candidates Type 1 (Pointing): 2 in b4 => r8c2<>2
AIC: 2/9 2- r3c3 =2= r9c3 -2- r7c1 =2= r7c9 -2- r8c9 -8- r8c2 -9- r9c1 =9= r2c1 -9 => r2c1<>2, r3c3<>9
Naked Single: r3c3=2
AIC: 4 4- r1c5 =4= r4c5 -4- r5c6 -7- r5c1 =7= r7c1 -7- r7c3 -6- r7c4 -4 => r13c4<>4
Locked Candidates Type 2 (Claiming): 4 in c4 => r8c6<>4
AIC: 9 9- r4c2 -2- r4c6 =2= r8c6 -2- r8c9 -8- r8c2 -9 => r26c2<>9
Turbot Fish: 9 r2c1 =9= r1c3 -9- r6c3 =9= r6c7 => r2c7<>9
Hidden Single: r3c9=9
Locked Candidates Type 1 (Pointing): 4 in b3 => r8c8<>4
Sue de Coq: r45c6 - {2467} (r3c6 - {46}, r6c45 - {257}) => r4c5<>2, r4c5<>5, r1c6<>4, r8c6<>6
Locked Candidates Type 1 (Pointing): 5 in b5 => r6c37<>5
Hidden Single: r5c3=5
Naked Triple: 2,8,9 in r8c269 => r8c4<>2, r8c4<>9, r8c78<>8
Skyscraper: 8 in r5c1,r8c2 (connected by r58c9) => r6c2,r9c1<>8
Naked Triple: 2,5,7 in r6c245 => r6c3<>7
X-Wing: 7 r26 c24 => r1c4<>7
X-Wing: 8 r19 c38 => r2c8,r6c3<>8
Naked Single: r6c3=9
Naked Single: r4c2=2
Naked Single: r6c7=8
Naked Single: r6c2=7
Full House: r5c1=8
Naked Single: r2c7=6
Naked Single: r5c9=4
Full House: r5c6=7
Naked Single: r2c2=8
Full House: r8c2=9
Naked Single: r2c1=9
Full House: r1c3=7
Naked Single: r2c8=5
Naked Single: r8c7=4
Naked Single: r4c9=5
Full House: r4c7=9
Full House: r7c7=5
Naked Single: r1c6=9
Naked Single: r8c6=2
Naked Single: r9c1=2
Full House: r7c1=7
Naked Single: r7c3=6
Full House: r9c3=8
Naked Single: r2c5=2
Full House: r2c4=7
Naked Single: r3c8=4
Full House: r1c8=8
Naked Single: r7c9=2
Full House: r8c9=8
Full House: r7c4=4
Naked Single: r1c4=1
Full House: r1c5=4
Naked Single: r6c5=5
Full House: r6c4=2
Naked Single: r3c6=6
Full House: r3c4=5
Full House: r4c6=4
Full House: r4c5=6
Full House: r9c5=1
Naked Single: r8c4=6
Full House: r8c8=1
Full House: r9c8=6
Full House: r9c4=9
|
normal_sudoku_284
|
15.6.7..276...45.124.5197....1348.9...4..5....3..614....6.73..44..1.6....174.2.5.
|
158637942769824531243519768671348295824795316935261487586973124492156873317482659
|
Basic 9x9 Sudoku 284
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
1 5 . 6 . 7 . . 2
7 6 . . . 4 5 . 1
2 4 . 5 1 9 7 . .
. . 1 3 4 8 . 9 .
. . 4 . . 5 . . .
. 3 . . 6 1 4 . .
. . 6 . 7 3 . . 4
4 . . 1 . 6 . . .
. 1 7 4 . 2 . 5 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
158637942769824531243519768671348295824795316935261487586973124492156873317482659 #1 Easy (400)
Naked Single: r3c6=9
Hidden Single: r1c1=1
Hidden Single: r3c5=1
Hidden Single: r4c5=4
Hidden Single: r5c3=4
Hidden Single: r7c9=4
Hidden Single: r8c6=6
Hidden Single: r2c7=5
Hidden Single: r1c6=7
Naked Single: r2c6=4
Full House: r5c6=5
Hidden Single: r2c1=7
Hidden Single: r7c3=6
Hidden Single: r8c5=5
Hidden Single: r1c7=9
Hidden Single: r1c8=4
Hidden Single: r9c1=3
Hidden Single: r2c3=9
Hidden Single: r7c1=5
Naked Single: r4c1=6
Naked Single: r4c7=2
Naked Single: r4c2=7
Full House: r4c9=5
Hidden Single: r6c3=5
Hidden Single: r6c4=2
Naked Single: r2c4=8
Naked Single: r5c5=9
Full House: r5c4=7
Full House: r7c4=9
Full House: r9c5=8
Naked Single: r1c5=3
Full House: r1c3=8
Full House: r2c5=2
Full House: r2c8=3
Full House: r3c3=3
Full House: r8c3=2
Naked Single: r5c1=8
Full House: r6c1=9
Full House: r5c2=2
Naked Single: r9c7=6
Full House: r9c9=9
Naked Single: r7c2=8
Full House: r8c2=9
Naked Single: r7c7=1
Full House: r7c8=2
Naked Single: r5c7=3
Full House: r8c7=8
Naked Single: r5c9=6
Full House: r5c8=1
Naked Single: r8c8=7
Full House: r8c9=3
Naked Single: r3c9=8
Full House: r3c8=6
Full House: r6c8=8
Full House: r6c9=7
|
normal_sudoku_466
|
.6...5..3..83...1.3..7..4..2.7.5.....8.237..6....482..5..8..7....1.7..9..7...3..1
|
462185973798324615315796482237651849984237156156948237523819764641572398879463521
|
Basic 9x9 Sudoku 466
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 6 . . . 5 . . 3
. . 8 3 . . . 1 .
3 . . 7 . . 4 . .
2 . 7 . 5 . . . .
. 8 . 2 3 7 . . 6
. . . . 4 8 2 . .
5 . . 8 . . 7 . .
. . 1 . 7 . . 9 .
. 7 . . . 3 . . 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
462185973798324615315796482237651849984237156156948237523819764641572398879463521 #1 Extreme (31274) bf
Locked Candidates Type 1 (Pointing): 6 in b4 => r6c4<>6
Locked Candidates Type 1 (Pointing): 7 in b5 => r5c8<>7
Brute Force: r5c6=7
Hidden Single: r8c5=7
Brute Force: r5c5=3
Hidden Single: r2c4=3
Forcing Chain Contradiction in r6c8 => r4c2<>1
r4c2=1 r4c2<>3 r4c78=3 r6c8<>3
r4c2=1 r4c2<>4 r4c89=4 r5c8<>4 r5c8=5 r6c8<>5
r4c2=1 r3c2<>1 r1c1=1 r1c1<>7 r1c8=7 r6c8<>7
Forcing Chain Contradiction in r5c8 => r4c2<>9
r4c2=9 r4c46<>9 r6c4=9 r6c4<>1 r4c46=1 r4c7<>1 r5c7=1 r5c7<>9 r5c13=9 r4c2<>9
Forcing Net Contradiction in r8c7 => r8c7=3
r8c7<>3 (r8c2=3 r6c2<>3) r4c7=3 (r4c7<>1 r5c7=1 r5c1<>1) r6c8<>3 r6c3=3 r6c3<>6 r6c1=6 r6c1<>1 r1c1=1 (r1c1<>7 r1c8=7 r2c9<>7 r2c1=7 r2c1<>4) (r1c4<>1) r3c2<>1 r6c2=1 r6c4<>1 r6c4=9 r1c4<>9 r1c4=4 r2c6<>4 r2c2=4 r4c2<>4 r4c2=3 r8c2<>3 r8c7=3
Discontinuous Nice Loop: 2 r7c3 -2- r8c2 -4- r4c2 -3- r7c2 =3= r7c3 => r7c3<>2
Forcing Net Contradiction in b6 => r2c6<>6
r2c6=6 (r2c6<>4 r1c4=4 r1c4<>1 r6c4=1 r4c6<>1 r4c6=9 r4c9<>9) (r8c6<>6) r4c6<>6 r4c4=6 r8c4<>6 r8c1=6 r8c1<>8 r8c9=8 r4c9<>8 r4c9=4
r2c6=6 (r2c7<>6 r9c7=6 r9c7<>5) (r4c6<>6 r4c4=6 r8c4<>6) r2c6<>4 r1c4=4 r8c4<>4 r8c4=5 r9c4<>5 r9c8=5 r5c8<>5 r5c8=4
Forcing Net Contradiction in r4c2 => r2c7<>9
r2c7=9 (r1c7<>9 r1c7=8 r1c8<>8) (r1c7<>9 r1c7=8 r3c8<>8) (r2c7<>5) r2c7<>6 (r2c5=6 r3c6<>6 r3c8=6 r3c8<>5) r9c7=6 r9c7<>5 r5c7=5 (r5c8<>5) r6c8<>5 r9c8=5 r9c8<>8 r4c8=8 r4c8<>3 r4c2=3
r2c7=9 (r2c7<>5) r2c7<>6 r9c7=6 r9c7<>5 r5c7=5 r5c8<>5 r5c8=4 (r4c8<>4) r4c9<>4 r4c2=4
Forcing Net Verity => r3c2<>2
r3c2=1 r3c2<>2
r6c2=1 (r5c1<>1) r6c1<>1 r1c1=1 (r1c4<>1 r1c4=4 r2c6<>4) r1c1<>7 r1c8=7 r2c9<>7 r2c1=7 r2c1<>4 r2c2=4 r8c2<>4 r8c2=2 r3c2<>2
Forcing Net Verity => r3c2<>9
r3c2=1 r3c2<>9
r6c2=1 (r6c2<>5) (r5c1<>1) r6c1<>1 r1c1=1 (r1c4<>1 r1c4=4 r2c6<>4) r1c1<>7 r1c8=7 r2c9<>7 r2c1=7 r2c1<>4 r2c2=4 r2c2<>5 r3c2=5 r3c2<>9
Forcing Net Contradiction in c3 => r3c5<>1
r3c5=1 (r1c5<>1 r1c1=1 r6c1<>1) r3c2<>1 r6c2=1 r6c4<>1 r6c4=9 r6c1<>9 r6c1=6 r6c3<>6
r3c5=1 (r1c5<>1 r1c1=1 r1c1<>7 r1c8=7 r2c9<>7 r2c1=7 r2c1<>4) (r1c4<>1) r3c2<>1 r6c2=1 r6c4<>1 r6c4=9 r1c4<>9 r1c4=4 r2c6<>4 r2c2=4 r4c2<>4 r4c2=3 r7c2<>3 r7c3=3 r7c3<>6
r3c5=1 (r3c5<>6) (r7c5<>1 r7c6=1 r4c6<>1) r3c2<>1 r6c2=1 r6c4<>1 r6c4=9 r4c6<>9 r4c6=6 r3c6<>6 r3c8=6 r2c7<>6 r9c7=6 r9c3<>6
Forcing Net Contradiction in r3 => r5c7<>5
r5c7=5 (r2c7<>5 r2c7=6 r9c7<>6 r9c7=8 r1c7<>8) r5c7<>1 r5c1=1 (r1c1<>1) (r6c1<>1) r6c2<>1 r6c4=1 (r6c4<>9 r6c9=9 r4c9<>9 r4c9=8 r3c9<>8) r1c4<>1 r1c5=1 r1c5<>8 r1c8=8 r3c8<>8 r3c5=8 r3c5<>6
r5c7=5 (r5c7<>1 r5c1=1 r6c1<>1) (r5c3<>5) r5c8<>5 r5c8=4 r5c3<>4 r5c3=9 r6c1<>9 r6c1=6 r8c1<>6 r8c46=6 r79c5<>6 r23c5=6 r3c6<>6
r5c7=5 r2c7<>5 r2c7=6 r3c8<>6
Naked Triple: 1,8,9 in r145c7 => r9c7<>8
Sue de Coq: r4c789 - {13489} (r4c2 - {34}, r5c7 - {19}) => r6c9<>9
Forcing Chain Contradiction in c2 => r9c8<>5
r9c8=5 r9c7<>5 r2c7=5 r2c2<>5
r9c8=5 r56c8<>5 r6c9=5 r6c9<>7 r6c8=7 r1c8<>7 r1c1=7 r1c1<>1 r3c2=1 r3c2<>5
r9c8=5 r5c8<>5 r5c3=5 r6c2<>5
Forcing Net Contradiction in r7c3 => r3c2=1
r3c2<>1 (r3c6=1 r1c5<>1 r1c1=1 r1c1<>7 r1c8=7 r2c9<>7 r2c1=7 r2c1<>4) (r3c6=1 r1c4<>1) r6c2=1 r6c4<>1 r6c4=9 r1c4<>9 r1c4=4 r2c6<>4 r2c2=4 r4c2<>4 r4c2=3 r7c2<>3 r7c3=3
r3c2<>1 (r3c6=1 r7c6<>1 r7c5=1 r7c5<>6) r6c2=1 (r6c1<>1) r6c4<>1 r6c4=9 (r4c6<>9 r4c6=6 r7c6<>6) (r4c6<>9 r4c6=6 r8c6<>6) r6c1<>9 r6c1=6 r8c1<>6 r8c4=6 r8c4<>5 r8c9=5 r9c7<>5 r9c7=6 r7c8<>6 r7c3=6
Discontinuous Nice Loop: 4 r7c6 -4- r2c6 =4= r1c4 =1= r1c5 -1- r7c5 =1= r7c6 => r7c6<>4
Forcing Chain Contradiction in b7 => r2c7=6
r2c7<>6 r2c7=5 r2c2<>5 r6c2=5 r5c3<>5 r5c8=5 r5c8<>4 r4c89=4 r4c2<>4 r4c2=3 r7c2<>3 r7c3=3 r7c3<>6
r2c7<>6 r2c7=5 r9c7<>5 r8c9=5 r8c9<>8 r8c1=8 r8c1<>6
r2c7<>6 r9c7=6 r9c1<>6
r2c7<>6 r9c7=6 r9c3<>6
Naked Single: r9c7=5
Hidden Single: r8c4=5
AIC: 6 6- r6c3 =6= r6c1 =1= r6c4 -1- r1c4 =1= r1c5 =8= r3c5 =6= r3c6 -6- r8c6 =6= r8c1 -6 => r6c1,r79c3<>6
Hidden Single: r6c3=6
Hidden Single: r7c3=3
Naked Pair: 1,9 in r6c14 => r6c2<>9
Naked Triple: 2,4,9 in r78c2,r9c3 => r89c1<>4, r9c1<>9
Discontinuous Nice Loop: 1 r4c4 -1- r1c4 =1= r1c5 =8= r3c5 =6= r3c6 -6- r4c6 =6= r4c4 => r4c4<>1
Discontinuous Nice Loop: 6 r4c6 -6- r3c6 =6= r3c5 =8= r1c5 =1= r1c4 -1- r6c4 =1= r4c6 => r4c6<>6
Hidden Single: r4c4=6
Discontinuous Nice Loop: 9 r2c6 -9- r4c6 -1- r6c4 =1= r1c4 =4= r2c6 => r2c6<>9
Discontinuous Nice Loop: 8 r4c9 -8- r4c7 =8= r1c7 -8- r1c5 =8= r3c5 =6= r3c6 -6- r8c6 =6= r8c1 =8= r8c9 -8- r4c9 => r4c9<>8
Discontinuous Nice Loop: 4 r2c1 -4- r2c6 =4= r8c6 -4- r9c4 -9- r6c4 =9= r4c6 -9- r4c9 -4- r5c8 -5- r6c9 -7- r2c9 =7= r2c1 => r2c1<>4
Swordfish: 4 c134 r159 => r59c8<>4
Naked Single: r5c8=5
Naked Single: r6c9=7
Naked Single: r6c8=3
Naked Single: r6c2=5
Hidden Single: r3c3=5
Hidden Single: r2c1=7
Hidden Single: r1c8=7
Hidden Single: r4c2=3
Hidden Single: r2c9=5
Locked Candidates Type 1 (Pointing): 2 in b3 => r3c56<>2
Turbot Fish: 9 r2c5 =9= r2c2 -9- r7c2 =9= r9c3 => r9c5<>9
Naked Triple: 2,6,8 in r9c158 => r9c3<>2
Hidden Single: r1c3=2
Skyscraper: 9 in r6c1,r9c3 (connected by r69c4) => r5c3<>9
Naked Single: r5c3=4
Full House: r9c3=9
Naked Single: r9c4=4
Hidden Single: r1c1=4
Full House: r2c2=9
Naked Single: r2c5=2
Full House: r2c6=4
Naked Single: r9c5=6
Naked Single: r8c6=2
Naked Single: r9c1=8
Full House: r9c8=2
Naked Single: r8c2=4
Full House: r7c2=2
Full House: r8c1=6
Full House: r8c9=8
Naked Single: r3c8=8
Naked Single: r7c9=4
Full House: r7c8=6
Full House: r4c8=4
Naked Single: r1c7=9
Full House: r3c9=2
Full House: r4c9=9
Naked Single: r3c5=9
Full House: r3c6=6
Naked Single: r1c4=1
Full House: r1c5=8
Full House: r7c5=1
Full House: r6c4=9
Full House: r4c6=1
Full House: r7c6=9
Full House: r6c1=1
Full House: r4c7=8
Full House: r5c7=1
Full House: r5c1=9
|
normal_sudoku_436
|
...6.9..1.19.2367.....1.3..26.5.....958364712.7.29.5.6.9..3.257735..2.6.82.....43
|
387659421519423678642718395261587934958364712473291586194836257735142869826975143
|
Basic 9x9 Sudoku 436
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . 6 . 9 . . 1
. 1 9 . 2 3 6 7 .
. . . . 1 . 3 . .
2 6 . 5 . . . . .
9 5 8 3 6 4 7 1 2
. 7 . 2 9 . 5 . 6
. 9 . . 3 . 2 5 7
7 3 5 . . 2 . 6 .
8 2 . . . . . 4 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
387659421519423678642718395261587934958364712473291586194836257735142869826975143 #1 Medium (534)
Naked Single: r5c2=5
Naked Single: r9c2=2
Naked Single: r5c9=2
Hidden Single: r5c5=6
Hidden Single: r7c8=5
Hidden Single: r6c4=2
Hidden Single: r8c8=6
Hidden Single: r7c7=2
Hidden Single: r2c5=2
Hidden Single: r5c4=3
Naked Single: r5c8=1
Full House: r5c7=7
Locked Candidates Type 1 (Pointing): 1 in b5 => r79c6<>1
Locked Candidates Type 1 (Pointing): 4 in b6 => r4c3<>4
Locked Candidates Type 1 (Pointing): 4 in b7 => r7c4<>4
Locked Candidates Type 1 (Pointing): 8 in b9 => r8c45<>8
Naked Single: r8c5=4
Locked Candidates Type 2 (Claiming): 4 in c2 => r1c13,r23c1,r3c3<>4
Naked Single: r2c1=5
Naked Single: r1c1=3
Naked Single: r3c1=6
Hidden Single: r1c5=5
Naked Single: r9c5=7
Full House: r4c5=8
Naked Single: r6c6=1
Full House: r4c6=7
Naked Single: r6c1=4
Full House: r7c1=1
Naked Single: r3c6=8
Naked Single: r6c3=3
Full House: r4c3=1
Full House: r6c8=8
Naked Single: r7c4=8
Naked Single: r9c3=6
Full House: r7c3=4
Full House: r7c6=6
Full House: r9c6=5
Naked Single: r2c4=4
Full House: r2c9=8
Full House: r3c4=7
Naked Single: r3c2=4
Full House: r1c2=8
Naked Single: r1c8=2
Naked Single: r1c7=4
Full House: r1c3=7
Full House: r3c3=2
Naked Single: r8c9=9
Naked Single: r3c8=9
Full House: r3c9=5
Full House: r4c9=4
Full House: r4c8=3
Full House: r4c7=9
Naked Single: r8c4=1
Full House: r8c7=8
Full House: r9c7=1
Full House: r9c4=9
|
normal_sudoku_2243
|
8493..526.2.49.173.1....498...1..3656.1..9842...6.4917......6.4.....6..9..39....1
|
849371526526498173317265498984127365671539842235684917792813654158746239463952781
|
Basic 9x9 Sudoku 2243
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
8 4 9 3 . . 5 2 6
. 2 . 4 9 . 1 7 3
. 1 . . . . 4 9 8
. . . 1 . . 3 6 5
6 . 1 . . 9 8 4 2
. . . 6 . 4 9 1 7
. . . . . . 6 . 4
. . . . . 6 . . 9
. . 3 9 . . . . 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
849371526526498173317265498984127365671539842235684917792813654158746239463952781 #1 Hard (608)
Naked Single: r5c9=2
Naked Single: r9c9=1
Naked Single: r1c9=6
Naked Single: r2c9=3
Full House: r8c9=9
Hidden Single: r2c5=9
Hidden Single: r4c8=6
Hidden Single: r6c7=9
Hidden Single: r1c2=4
Hidden Single: r3c7=4
Naked Single: r5c7=8
Naked Single: r5c8=4
Full House: r6c8=1
Naked Single: r2c8=7
Full House: r2c7=1
Naked Single: r2c1=5
Naked Single: r2c3=6
Full House: r2c6=8
Naked Single: r3c3=7
Full House: r3c1=3
Naked Single: r6c1=2
Hidden Single: r7c6=3
Hidden Single: r9c2=6
Hidden Single: r3c5=6
Hidden Single: r8c8=3
Hidden Single: r1c6=1
Full House: r1c5=7
Locked Candidates Type 1 (Pointing): 8 in b5 => r789c5<>8
Hidden Single: r9c8=8
Full House: r7c8=5
Locked Candidates Type 1 (Pointing): 5 in b7 => r8c45<>5
XY-Wing: 5/7/2 in r35c4,r4c6 => r3c6<>2
Naked Single: r3c6=5
Full House: r3c4=2
Hidden Single: r5c4=5
Naked Single: r5c5=3
Full House: r5c2=7
Naked Single: r6c5=8
Naked Single: r4c5=2
Full House: r4c6=7
Full House: r9c6=2
Naked Single: r6c3=5
Full House: r6c2=3
Naked Single: r7c5=1
Naked Single: r9c7=7
Full House: r8c7=2
Naked Single: r8c5=4
Full House: r9c5=5
Full House: r9c1=4
Naked Single: r8c3=8
Naked Single: r4c1=9
Naked Single: r4c3=4
Full House: r7c3=2
Full House: r4c2=8
Naked Single: r7c2=9
Full House: r8c2=5
Naked Single: r8c4=7
Full House: r7c4=8
Full House: r7c1=7
Full House: r8c1=1
|
normal_sudoku_5100
|
45..36.8.8...52..6..684.5......95...6..217.5...5.83..12..5...385..3...6...4...7.5
|
451736982837952416926841573182695347643217859795483621279564138518379264364128795
|
Basic 9x9 Sudoku 5100
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
4 5 . . 3 6 . 8 .
8 . . . 5 2 . . 6
. . 6 8 4 . 5 . .
. . . . 9 5 . . .
6 . . 2 1 7 . 5 .
. . 5 . 8 3 . . 1
2 . . 5 . . . 3 8
5 . . 3 . . . 6 .
. . 4 . . . 7 . 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
451736982837952416926841573182695347643217859795483621279564138518379264364128795 #1 Extreme (24776) bf
Hidden Single: r2c5=5
Hidden Single: r4c6=5
Hidden Single: r8c1=5
Brute Force: r5c6=7
Hidden Single: r6c6=3
Locked Candidates Type 1 (Pointing): 8 in b5 => r89c5<>8
Locked Candidates Type 1 (Pointing): 7 in b8 => r3c5<>7
Hidden Rectangle: 4/6 in r4c47,r6c47 => r4c7<>4
Grouped Discontinuous Nice Loop: 8 r6c2 -8- r6c5 =8= r5c5 =1= r4c4 =6= r4c7 =8= r4c23 -8- r6c2 => r6c2<>8
Forcing Net Contradiction in r7c7 => r9c5<>1
r9c5=1 (r5c5<>1 r4c4=1 r4c4<>6 r4c7=6 r4c7<>2) (r9c5<>2 r9c8=2 r8c7<>2) (r5c5<>1) r3c5<>1 r3c5=4 r5c5<>4 r5c5=8 r6c5<>8 r6c7=8 r6c7<>2 r1c7=2 (r1c9<>2) (r3c9<>2) r1c3<>2 r4c3=2 r4c9<>2 r8c9=2 r9c8<>2 r9c5=2 r9c5<>1
Brute Force: r5c5=1
Naked Single: r3c5=4
Hidden Single: r6c5=8
Locked Candidates Type 1 (Pointing): 6 in b5 => r19c4<>6
Hidden Single: r1c6=6
Uniqueness Test 4: 4/6 in r4c47,r6c47 => r6c7<>4
Finned Swordfish: 4 c148 r146 fr2c8 => r1c79<>4
Hidden Single: r1c1=4
Almost Locked Set XY-Wing: A=r2c2348 {13479}, B=r6c4 {46}, C=r12678c7 {123469}, X,Y=3,6, Z=4 => r6c8<>4
Forcing Chain Contradiction in r1 => r3c2<>9
r3c2=9 r3c2<>2 r1c3=2 r1c3<>1
r3c2=9 r3c6<>9 r3c6=1 r1c4<>1
r3c2=9 r3c6<>9 r3c6=1 r12c4<>1 r9c4=1 r9c8<>1 r78c7=1 r1c7<>1
Forcing Chain Contradiction in c8 => r3c9<>9
r3c9=9 r3c9<>3 r2c7=3 r2c7<>4 r2c8=4 r2c8<>1
r3c9=9 r3c6<>9 r3c6=1 r3c8<>1
r3c9=9 r3c6<>9 r3c6=1 r12c4<>1 r9c4=1 r9c8<>1
Forcing Chain Contradiction in c8 => r7c6<>9
r7c6=9 r7c6<>4 r7c7=4 r2c7<>4 r2c8=4 r2c8<>1
r7c6=9 r3c6<>9 r3c6=1 r3c8<>1
r7c6=9 r9c4<>9 r9c4=1 r9c8<>1
Forcing Net Verity => r2c7=4
r3c6=1 (r3c8<>1) (r1c4<>1) r2c4<>1 r9c4=1 r9c8<>1 r2c8=1 r2c8<>4 r2c7=4
r3c6=9 (r3c8<>9) (r3c1<>9) (r1c4<>9) r2c4<>9 r9c4=9 (r9c8<>9) r9c1<>9 r6c1=9 r6c8<>9 r2c8=9 r2c8<>4 r2c7=4
Hidden Single: r4c8=4
Naked Single: r4c4=6
Full House: r6c4=4
Hidden Single: r7c6=4
Hidden Single: r8c9=4
Hidden Single: r3c9=3
Naked Single: r5c9=9
Hidden Single: r5c2=4
Hidden Single: r6c7=6
Naked Pair: 2,7 in r4c9,r6c8 => r4c7<>2
X-Wing: 2 r36 c28 => r4c2,r9c8<>2
Hidden Single: r9c5=2
Naked Single: r8c5=7
Full House: r7c5=6
Hidden Single: r8c7=2
Hidden Single: r9c2=6
Hidden Single: r9c1=3
Hidden Single: r9c6=8
Remote Pair: 1/9 r1c7 -9- r7c7 -1- r9c8 -9- r9c4 -1- r8c6 -9- r3c6 => r1c4,r3c8<>1, r1c4,r3c8<>9
Naked Single: r1c4=7
Naked Single: r1c9=2
Full House: r4c9=7
Naked Single: r3c8=7
Naked Single: r4c1=1
Naked Single: r6c8=2
Naked Single: r3c1=9
Full House: r6c1=7
Full House: r6c2=9
Naked Single: r1c3=1
Full House: r1c7=9
Full House: r2c8=1
Full House: r9c8=9
Full House: r7c7=1
Full House: r9c4=1
Full House: r2c4=9
Full House: r3c6=1
Full House: r3c2=2
Full House: r8c6=9
Naked Single: r7c2=7
Full House: r7c3=9
Naked Single: r8c3=8
Full House: r8c2=1
Naked Single: r2c2=3
Full House: r2c3=7
Full House: r4c2=8
Naked Single: r5c3=3
Full House: r4c3=2
Full House: r4c7=3
Full House: r5c7=8
|
normal_sudoku_1338
|
..69318.58.5.6..9339...5..7..3..9..665..1.7.99......3156927431823..9...4.8..5.9.2
|
476931825825467193391825467713549286658312749942786531569274318237198654184653972
|
Basic 9x9 Sudoku 1338
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 6 9 3 1 8 . 5
8 . 5 . 6 . . 9 3
3 9 . . . 5 . . 7
. . 3 . . 9 . . 6
6 5 . . 1 . 7 . 9
9 . . . . . . 3 1
5 6 9 2 7 4 3 1 8
2 3 . . 9 . . . 4
. 8 . . 5 . 9 . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
476931825825467193391825467713549286658312749942786531569274318237198654184653972 #1 Extreme (1944)
Naked Single: r1c9=5
Hidden Single: r8c2=3
Hidden Single: r4c9=6
Hidden Single: r7c1=5
Naked Single: r7c7=3
Naked Single: r7c9=8
Naked Single: r5c9=9
Full House: r2c9=3
Naked Single: r7c5=7
Full House: r7c3=9
Hidden Single: r2c3=5
Hidden Single: r6c1=9
Hidden Single: r2c8=9
Locked Candidates Type 1 (Pointing): 7 in b2 => r2c2<>7
Hidden Triple: 5,6,7 in r46c4,r6c6 => r46c4<>4, r46c4,r6c6<>8, r6c6<>2
AIC: 7 7- r8c3 -1- r3c3 =1= r3c7 =6= r3c8 -6- r9c8 -7 => r8c8,r9c13<>7
Hidden Single: r8c3=7
Hidden Single: r9c8=7
Hidden Single: r8c4=1
Hidden Single: r8c6=8
Discontinuous Nice Loop: 2 r3c8 -2- r3c5 =2= r2c6 =7= r2c4 -7- r4c4 -5- r4c8 =5= r8c8 =6= r3c8 => r3c8<>2
Finned Franken Swordfish: 2 r15b2 c368 fr1c2 fr3c5 => r3c3<>2
Locked Candidates Type 1 (Pointing): 2 in b1 => r46c2<>2
Naked Pair: 1,4 in r39c3 => r56c3<>4
Empty Rectangle: 4 in b2 (r5c48) => r3c8<>4
Naked Single: r3c8=6
Naked Single: r8c8=5
Full House: r8c7=6
W-Wing: 4/7 in r2c4,r6c2 connected by 7 in r26c6 => r2c2<>4
Skyscraper: 4 in r2c7,r5c8 (connected by r25c4) => r1c8,r46c7<>4
Naked Single: r1c8=2
Hidden Single: r2c2=2
Naked Single: r2c6=7
Naked Single: r2c4=4
Full House: r2c7=1
Full House: r3c7=4
Naked Single: r6c6=6
Naked Single: r3c4=8
Full House: r3c5=2
Full House: r3c3=1
Naked Single: r9c6=3
Full House: r5c6=2
Full House: r9c4=6
Naked Single: r5c4=3
Naked Single: r9c3=4
Full House: r9c1=1
Naked Single: r5c3=8
Full House: r5c8=4
Full House: r6c3=2
Full House: r4c8=8
Naked Single: r6c7=5
Full House: r4c7=2
Naked Single: r4c5=4
Full House: r6c5=8
Naked Single: r6c4=7
Full House: r4c4=5
Full House: r6c2=4
Naked Single: r4c1=7
Full House: r1c1=4
Full House: r1c2=7
Full House: r4c2=1
|
normal_sudoku_175
|
...87..5.78..9..3..4961.287..17..892..7..831.8..9.174..2.187.6..7.349.28..85..47.
|
612873954785294631349615287451736892297458316863921745924187563576349128138562479
|
Basic 9x9 Sudoku 175
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . 8 7 . . 5 .
7 8 . . 9 . . 3 .
. 4 9 6 1 . 2 8 7
. . 1 7 . . 8 9 2
. . 7 . . 8 3 1 .
8 . . 9 . 1 7 4 .
. 2 . 1 8 7 . 6 .
. 7 . 3 4 9 . 2 8
. . 8 5 . . 4 7 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
612873954785294631349615287451736892297458316863921745924187563576349128138562479 #1 Hard (1006)
Naked Single: r8c8=2
Naked Single: r7c6=7
Hidden Single: r2c5=9
Naked Single: r2c8=3
Naked Single: r3c8=8
Full House: r4c8=9
Hidden Single: r1c4=8
Naked Single: r7c4=1
Naked Single: r7c5=8
Hidden Single: r3c5=1
Naked Single: r3c9=7
Naked Single: r3c7=2
Hidden Single: r6c7=7
Hidden Single: r5c3=7
Hidden Single: r6c1=8
Hidden Single: r4c7=8
Hidden Single: r7c3=4
Locked Candidates Type 1 (Pointing): 1 in b1 => r1c79<>1
Locked Candidates Type 1 (Pointing): 3 in b2 => r4c6<>3
Locked Candidates Type 1 (Pointing): 5 in b2 => r4c6<>5
Locked Candidates Type 1 (Pointing): 5 in b6 => r7c9<>5
Locked Candidates Type 1 (Pointing): 6 in b6 => r12c9<>6
Locked Candidates Type 1 (Pointing): 6 in b8 => r9c12<>6
Locked Candidates Type 2 (Claiming): 5 in c2 => r45c1,r6c3<>5
Skyscraper: 2 in r1c1,r2c4 (connected by r5c14) => r1c6,r2c3<>2
Naked Pair: 5,6 in r28c3 => r16c3<>6
XY-Wing: 1/6/5 in r2c37,r8c7 => r8c3<>5
Naked Single: r8c3=6
Naked Single: r2c3=5
Naked Single: r3c1=3
Full House: r3c6=5
Naked Single: r1c3=2
Full House: r6c3=3
Hidden Single: r2c7=6
Naked Single: r1c7=9
Naked Single: r1c9=4
Full House: r2c9=1
Naked Single: r7c7=5
Full House: r8c7=1
Full House: r8c1=5
Naked Single: r1c6=3
Naked Single: r7c1=9
Full House: r7c9=3
Full House: r9c9=9
Naked Single: r9c1=1
Full House: r9c2=3
Naked Single: r1c1=6
Full House: r1c2=1
Naked Single: r4c1=4
Full House: r5c1=2
Naked Single: r4c6=6
Naked Single: r5c4=4
Full House: r2c4=2
Full House: r2c6=4
Full House: r9c6=2
Full House: r9c5=6
Naked Single: r4c2=5
Full House: r4c5=3
Naked Single: r5c5=5
Full House: r6c5=2
Naked Single: r6c2=6
Full House: r5c2=9
Full House: r5c9=6
Full House: r6c9=5
|
normal_sudoku_2223
|
....6....8..4.2..6...7.82...9.2...3.4...856....8....52.1.5.......3..9..12...4.7..
|
342961587857432916169758243695217834421385679738694152914576328573829461286143795
|
Basic 9x9 Sudoku 2223
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . 6 . . . .
8 . . 4 . 2 . . 6
. . . 7 . 8 2 . .
. 9 . 2 . . . 3 .
4 . . . 8 5 6 . .
. . 8 . . . . 5 2
. 1 . 5 . . . . .
. . 3 . . 9 . . 1
2 . . . 4 . 7 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
342961587857432916169758243695217834421385679738694152914576328573829461286143795 #1 Extreme (28008) bf
Locked Candidates Type 2 (Claiming): 8 in r7 => r8c78,r9c89<>8
Hidden Rectangle: 6/8 in r8c24,r9c24 => r9c2<>6
Forcing Net Contradiction in c4 => r6c6<>3
r6c6=3 (r5c4<>3) (r6c6<>6) r6c6<>4 r6c7=4 (r6c7<>9) (r4c7<>4) r4c9<>4 r4c6=4 r4c6<>6 r6c4=6 r6c4<>9 r6c5=9 r5c4<>9 r5c4=1
r6c6=3 (r1c6<>3) (r5c4<>3) r5c6<>3 r5c2=3 (r5c2<>5) r5c2<>2 r5c3=2 r5c3<>5 r5c6=5 r1c6<>5 r1c6=1 r9c6<>1 r9c4=1
Brute Force: r5c6=5
Grouped Discontinuous Nice Loop: 1 r1c8 -1- r1c46 =1= r23c5 -1- r4c5 -7- r8c5 -2- r8c8 =2= r7c8 =8= r1c8 => r1c8<>1
Forcing Net Contradiction in r5c4 => r1c4<>3
r1c4=3 (r5c4<>3 r5c2=3 r6c2<>3 r6c5=3 r6c5<>1) r1c6<>3 r1c6=1 (r6c6<>1) r9c6<>1 r9c4=1 r6c4<>1 r6c7=1 r6c7<>9 r5c89=9 r5c4<>9
r1c4=3 (r5c4<>3) r1c6<>3 r1c6=1 r9c6<>1 r9c4=1 r5c4<>1 r5c4=9
Forcing Net Contradiction in r2c7 => r1c3<>9
r1c3=9 (r1c4<>9 r1c4=1 r1c7<>1) (r1c4<>9 r1c4=1 r5c4<>1) r1c3<>2 r1c2=2 r5c2<>2 r5c3=2 r5c3<>1 r5c8=1 (r4c7<>1) r6c7<>1 r2c7=1
r1c3=9 (r1c7<>9) (r3c1<>9 r7c1=9 r7c7<>9) r1c3<>2 r1c2=2 r5c2<>2 r5c3=2 r5c3<>1 r5c8=1 (r5c8<>9) (r4c7<>1) r6c7<>1 r2c7=1 r2c7<>9 r6c7=9 r5c9<>9 r5c4=9 (r5c4<>3 r5c2=3 r2c2<>3) r1c4<>9 r1c4=1 (r1c7<>1) (r5c4<>1) r1c6<>1 r1c6=3 r2c5<>3 r2c7=3
Forcing Net Contradiction in r7c7 => r1c7<>1
r1c7=1 (r1c4<>1 r1c4=9 r5c4<>9) (r2c8<>1) r3c8<>1 r5c8=1 (r5c8<>7) r5c8<>9 r5c9=9 r5c9<>7 r4c9=7 r4c5<>7 r4c5=1 r23c5<>1 r1c46=1 r1c7<>1
Forcing Chain Contradiction in r5 => r2c3<>1
r2c3=1 r5c3<>1
r2c3=1 r1c13<>1 r1c46=1 r23c5<>1 r46c5=1 r5c4<>1
r2c3=1 r2c7<>1 r46c7=1 r5c8<>1
Forcing Chain Contradiction in r1c7 => r6c6<>1
r6c6=1 r1c6<>1 r1c6=3 r1c7<>3
r6c6=1 r6c6<>4 r6c7=4 r1c7<>4
r6c6=1 r6c6<>4 r6c7=4 r8c7<>4 r8c7=5 r1c7<>5
r6c6=1 r4c5<>1 r4c5=7 r8c5<>7 r8c5=2 r8c8<>2 r7c8=2 r7c8<>8 r1c8=8 r1c7<>8
r6c6=1 r9c6<>1 r9c4=1 r1c4<>1 r1c4=9 r1c7<>9
Forcing Net Verity => r1c8<>9
r2c5=3 r1c6<>3 r1c6=1 r1c4<>1 r1c4=9 r1c8<>9
r3c5=3 r1c6<>3 r1c6=1 r1c4<>1 r1c4=9 r1c8<>9
r6c5=3 (r5c4<>3 r5c2=3 r2c2<>3 r2c7=3 r2c7<>1) (r6c5<>9) (r5c4<>3) r6c4<>3 r9c4=3 (r9c4<>6) r9c4<>8 r9c2=8 r8c2<>8 r8c4=8 r8c4<>6 r6c4=6 r6c4<>9 r6c7=9 r6c7<>1 r4c7=1 r4c5<>1 r4c5=7 r8c5<>7 r8c5=2 r7c5<>2 r7c8=2 r7c8<>8 r1c8=8 r1c8<>9
r7c5=3 r7c5<>2 r7c8=2 r7c8<>8 r1c8=8 r1c8<>9
Forcing Net Contradiction in r2c7 => r4c6<>1
r4c6=1 (r1c6<>1 r1c6=3 r1c7<>3) (r1c6<>1 r1c6=3 r9c6<>3) r9c6<>1 r9c4=1 r9c4<>3 r9c9=3 r7c7<>3 r2c7=3
r4c6=1 (r9c6<>1) r1c6<>1 r1c6=3 r9c6<>3 r9c6=6 (r9c8<>6 r9c8=9 r7c7<>9) r9c6<>1 r9c4=1 r1c4<>1 r1c4=9 (r1c7<>9) (r2c5<>9) r3c5<>9 r6c5=9 r6c7<>9 r2c7=9
Forcing Net Contradiction in c7 => r5c4<>1
r5c4=1 r1c4<>1 r1c4=9 r1c7<>9
r5c4=1 (r5c4<>3 r5c2=3 r2c2<>3) r9c4<>1 r9c6=1 r1c6<>1 r1c6=3 r2c5<>3 r2c7=3 r2c7<>9
r5c4=1 r1c4<>1 r1c4=9 (r2c5<>9) r3c5<>9 r6c5=9 r6c7<>9
r5c4=1 (r1c4<>1 r1c4=9 r1c1<>9) (r5c4<>3 r5c2=3 r6c1<>3) r9c4<>1 r9c6=1 r1c6<>1 r1c6=3 r1c1<>3 r3c1=3 r3c1<>9 r7c1=9 r7c7<>9
Forcing Chain Contradiction in r2 => r5c4=3
r5c4<>3 r5c2=3 r2c2<>3
r5c4<>3 r5c4=9 r1c4<>9 r1c4=1 r1c6<>1 r1c6=3 r2c5<>3
r5c4<>3 r5c2=3 r5c2<>2 r5c3=2 r5c3<>1 r5c8=1 r46c7<>1 r2c7=1 r2c7<>3
Locked Candidates Type 1 (Pointing): 9 in b5 => r6c7<>9
Hidden Rectangle: 2/7 in r1c23,r5c23 => r1c3<>7
Grouped Discontinuous Nice Loop: 1 r1c3 -1- r1c46 =1= r23c5 -1- r4c5 -7- r4c9 =7= r5c89 -7- r5c2 -2- r5c3 =2= r1c3 => r1c3<>1
Almost Locked Set XY-Wing: A=r4c5 {17}, B=r5c23,r6c12 {12367}, C=r6c4567 {14679}, X,Y=6,7, Z=1 => r4c13<>1
Forcing Chain Contradiction in r1c7 => r1c1<>1
r1c1=1 r1c6<>1 r1c6=3 r1c7<>3
r1c1=1 r1c46<>1 r23c5=1 r4c5<>1 r4c7=1 r6c7<>1 r6c7=4 r1c7<>4
r1c1=1 r1c6<>1 r1c6=3 r9c6<>3 r9c9=3 r9c9<>5 r8c7=5 r1c7<>5
r1c1=1 r1c6<>1 r1c6=3 r23c5<>3 r7c5=3 r7c5<>2 r7c8=2 r7c8<>8 r1c8=8 r1c7<>8
r1c1=1 r1c4<>1 r1c4=9 r1c7<>9
Locked Candidates Type 1 (Pointing): 1 in b1 => r3c58<>1
Locked Candidates Type 1 (Pointing): 1 in b3 => r2c5<>1
Locked Candidates Type 2 (Claiming): 1 in c5 => r6c4<>1
Almost Locked Set XY-Wing: A=r6c4 {69}, B=r1478c1 {35679}, C=r1c46 {139}, X,Y=3,9, Z=6 => r6c1<>6
Forcing Chain Contradiction in r2c2 => r1c3<>5
r1c3=5 r1c3<>2 r5c3=2 r5c3<>1 r6c1=1 r6c1<>3 r6c2=3 r2c2<>3
r1c3=5 r2c2<>5
r1c3=5 r1c3<>2 r1c2=2 r5c2<>2 r5c2=7 r2c2<>7
Forcing Chain Contradiction in c1 => r1c8<>4
r1c8=4 r1c8<>8 r7c8=8 r7c8<>2 r7c5=2 r7c5<>3 r23c5=3 r1c6<>3 r1c6=1 r1c4<>1 r1c4=9 r1c1<>9
r1c8=4 r3c8<>4 r3c8=9 r3c1<>9
r1c8=4 r3c8<>4 r3c8=9 r12c7<>9 r7c7=9 r7c1<>9
Forcing Chain Contradiction in c1 => r1c9<>9
r1c9=9 r1c1<>9
r1c9=9 r5c9<>9 r5c8=9 r5c8<>1 r5c3=1 r3c3<>1 r3c1=1 r3c1<>9
r1c9=9 r12c7<>9 r7c7=9 r7c1<>9
Forcing Chain Contradiction in r2 => r3c1<>5
r3c1=5 r3c1<>1 r6c1=1 r6c1<>3 r6c2=3 r2c2<>3
r3c1=5 r3c5<>5 r2c5=5 r2c5<>3
r3c1=5 r3c1<>1 r3c3=1 r5c3<>1 r5c8=1 r2c8<>1 r2c7=1 r2c7<>3
Forcing Chain Contradiction in r9 => r3c3<>4
r3c3=4 r7c3<>4 r8c2=4 r8c2<>8 r9c2=8 r9c2<>5
r3c3=4 r3c8<>4 r3c8=9 r12c7<>9 r7c7=9 r7c13<>9 r9c3=9 r9c3<>5
r3c3=4 r3c8<>4 r78c8=4 r8c7<>4 r8c7=5 r9c9<>5
Discontinuous Nice Loop: 4 r7c7 -4- r7c3 =4= r1c3 =2= r5c3 =1= r5c8 -1- r6c7 -4- r7c7 => r7c7<>4
Forcing Chain Contradiction in r8 => r1c7<>8
r1c7=8 r4c7<>8 r4c9=8 r4c9<>7 r5c89=7 r5c2<>7 r5c2=2 r5c3<>2 r1c3=2 r1c3<>4 r7c3=4 r8c2<>4
r1c7=8 r4c7<>8 r4c9=8 r4c9<>4 r46c7=4 r8c7<>4
r1c7=8 r1c8<>8 r7c8=8 r7c8<>2 r8c8=2 r8c8<>4
Forcing Chain Contradiction in r8 => r4c5=1
r4c5<>1 r4c7=1 r5c8<>1 r5c3=1 r5c3<>2 r1c3=2 r1c3<>4 r7c3=4 r8c2<>4
r4c5<>1 r4c7=1 r6c7<>1 r6c7=4 r8c7<>4
r4c5<>1 r4c7=1 r4c7<>8 r7c7=8 r7c7<>9 r12c7=9 r3c8<>9 r3c8=4 r8c8<>4
Forcing Chain Contradiction in r8 => r4c7=8
r4c7<>8 r4c7=4 r6c7<>4 r6c7=1 r6c1<>1 r5c3=1 r5c3<>2 r1c3=2 r1c3<>4 r7c3=4 r8c2<>4
r4c7<>8 r4c7=4 r8c7<>4
r4c7<>8 r7c7=8 r7c7<>9 r12c7=9 r3c8<>9 r3c8=4 r8c8<>4
Discontinuous Nice Loop: 9 r1c7 -9- r1c4 -1- r1c6 -3- r9c6 =3= r9c9 -3- r7c7 -9- r1c7 => r1c7<>9
Empty Rectangle: 9 in b7 (r27c7) => r2c3<>9
Discontinuous Nice Loop: 9 r7c3 -9- r7c7 =9= r2c7 =1= r2c8 -1- r5c8 =1= r5c3 =2= r1c3 =4= r7c3 => r7c3<>9
Discontinuous Nice Loop: 6 r9c4 -6- r9c8 -9- r9c3 =9= r3c3 -9- r1c1 =9= r1c4 =1= r9c4 => r9c4<>6
Discontinuous Nice Loop: 6 r9c6 -6- r9c8 -9- r7c7 -3- r9c9 =3= r9c6 => r9c6<>6
Naked Pair: 1,3 in r19c6 => r7c6<>3
Discontinuous Nice Loop: 6 r7c3 -6- r7c6 =6= r8c4 =8= r8c2 =4= r7c3 => r7c3<>6
Discontinuous Nice Loop: 6 r7c8 -6- r7c6 -7- r8c5 -2- r8c8 =2= r7c8 => r7c8<>6
Grouped Discontinuous Nice Loop: 4 r7c8 -4- r3c8 -9- r2c78 =9= r2c5 -9- r6c5 -7- r8c5 -2- r8c8 =2= r7c8 => r7c8<>4
Almost Locked Set XZ-Rule: A=r1c2346789 {12345789}, B=r2c235 {3579}, X=9, Z=7 => r1c1<>7
Grouped AIC: 2 2- r1c3 -4- r7c3 -7- r2c3 =7= r12c2 -7- r5c2 -2 => r1c2,r5c3<>2
Hidden Single: r1c3=2
Hidden Single: r5c2=2
Hidden Single: r7c3=4
AIC: 5/9 9- r9c3 =9= r3c3 -9- r3c8 -4- r8c8 =4= r8c7 =5= r9c9 -5 => r9c3<>5, r9c9<>9
Discontinuous Nice Loop: 3 r1c2 -3- r1c6 =3= r9c6 -3- r9c9 -5- r8c7 -4- r8c8 =4= r3c8 -4- r3c2 =4= r1c2 => r1c2<>3
Discontinuous Nice Loop: 5 r1c2 -5- r9c2 =5= r9c9 -5- r8c7 -4- r8c8 =4= r3c8 -4- r3c2 =4= r1c2 => r1c2<>5
Discontinuous Nice Loop: 6 r3c1 -6- r7c1 =6= r7c6 -6- r8c4 -8- r8c2 =8= r9c2 =5= r9c9 -5- r8c7 -4- r6c7 -1- r6c1 =1= r3c1 => r3c1<>6
Discontinuous Nice Loop: 4 r1c9 -4- r1c2 =4= r3c2 =6= r3c3 =1= r3c1 -1- r6c1 =1= r6c7 =4= r4c9 -4- r1c9 => r1c9<>4
Discontinuous Nice Loop: 9 r2c8 -9- r3c8 -4- r3c9 =4= r4c9 -4- r6c7 -1- r2c7 =1= r2c8 => r2c8<>9
Discontinuous Nice Loop: 3 r1c7 -3- r1c6 -1- r1c4 -9- r2c5 =9= r2c7 -9- r7c7 -3- r1c7 => r1c7<>3
Naked Pair: 4,5 in r18c7 => r2c7<>5, r6c7<>4
Naked Single: r6c7=1
Hidden Single: r6c6=4
Hidden Single: r4c9=4
Hidden Single: r2c8=1
Hidden Single: r5c3=1
Hidden Single: r3c1=1
Locked Candidates Type 1 (Pointing): 7 in b3 => r1c2<>7
Naked Single: r1c2=4
Naked Single: r1c7=5
Naked Single: r8c7=4
Hidden Single: r3c8=4
Hidden Single: r9c9=5
Naked Single: r9c2=8
Naked Single: r9c4=1
Naked Single: r1c4=9
Naked Single: r9c6=3
Naked Single: r1c1=3
Naked Single: r6c4=6
Full House: r8c4=8
Naked Single: r1c6=1
Naked Single: r6c1=7
Naked Single: r4c6=7
Full House: r6c5=9
Full House: r6c2=3
Full House: r7c6=6
Naked Single: r7c1=9
Naked Single: r7c7=3
Full House: r2c7=9
Naked Single: r9c3=6
Full House: r9c8=9
Naked Single: r7c9=8
Naked Single: r3c9=3
Naked Single: r4c3=5
Full House: r4c1=6
Full House: r8c1=5
Full House: r8c2=7
Naked Single: r5c8=7
Full House: r5c9=9
Full House: r1c9=7
Full House: r1c8=8
Naked Single: r7c8=2
Full House: r7c5=7
Full House: r8c5=2
Full House: r8c8=6
Naked Single: r3c5=5
Full House: r2c5=3
Naked Single: r2c3=7
Full House: r3c3=9
Full House: r2c2=5
Full House: r3c2=6
|
normal_sudoku_3412
|
14...65....34....17......426....1..9.1..62......58.1.62......7..9...56..4..6..2.3
|
142376598583429761769158342625741839318962457974583126236814975897235614451697283
|
Basic 9x9 Sudoku 3412
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
1 4 . . . 6 5 . .
. . 3 4 . . . . 1
7 . . . . . . 4 2
6 . . . . 1 . . 9
. 1 . . 6 2 . . .
. . . 5 8 . 1 . 6
2 . . . . . . 7 .
. 9 . . . 5 6 . .
4 . . 6 . . 2 . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
142376598583429761769158342625741839318962457974583126236814975897235614451697283 #1 Extreme (22764) bf
Locked Candidates Type 1 (Pointing): 1 in b3 => r2c5<>1
Locked Candidates Type 1 (Pointing): 6 in b3 => r2c12<>6
Locked Candidates Type 2 (Claiming): 6 in c1 => r4c23,r6c23<>6
Hidden Pair: 1,6 in r2c89 => r2c89<>8, r2c8<>9, r2c9<>7
Brute Force: r5c6=2
2-String Kite: 4 in r6c6,r8c9 (connected by r7c6,r8c5) => r6c9<>4
Forcing Net Contradiction in r7c7 => r2c8=6
r2c8<>6 r2c8=1 r2c9<>1 r2c9=6 r6c9<>6 r6c9=7 (r5c7<>7) (r5c9<>7) (r6c6<>7) (r4c7<>7) r5c7<>7 r2c7=7 r2c6<>7 r9c6=7 (r9c2<>7 r4c2=7 r4c4<>7 r4c4=3 r4c8<>3) (r8c4<>7) r8c5<>7 r8c3=7 r5c3<>7 r5c4=7 r5c4<>9 r6c6=9 r6c6<>4 (r6c3=4 r5c3<>4) r7c6=4 (r7c6<>3 r3c6=3 r3c7<>3) r8c5<>4 r8c9=4 (r8c9<>1) r5c9<>4 r5c7=4 r5c7<>3 r4c7=3 r6c8<>3 r1c8=3 (r5c8<>3) r1c8<>9 r9c8=9 r9c8<>5 r7c9=5 r7c9<>1 r2c9=1 r2c8<>1 r2c8=6
Naked Single: r2c9=1
Hidden Single: r6c9=6
Hidden Single: r4c1=6
Forcing Chain Contradiction in b1 => r7c3<>5
r7c3=5 r7c9<>5 r9c8=5 r9c8<>9 r1c8=9 r1c3<>9
r7c3=5 r7c9<>5 r5c9=5 r5c1<>5 r2c1=5 r2c1<>9
r7c3=5 r7c3<>6 r3c3=6 r3c3<>9
Forcing Chain Contradiction in b1 => r8c4<>1
r8c4=1 r8c8<>1 r9c8=1 r9c8<>9 r1c8=9 r1c3<>9
r8c4=1 r7c45<>1 r7c3=1 r7c3<>6 r7c2=6 r7c2<>3 r8c1=3 r6c1<>3 r6c1=9 r2c1<>9
r8c4=1 r7c45<>1 r7c3=1 r7c3<>6 r3c3=6 r3c3<>9
Forcing Chain Contradiction in b1 => r8c5<>1
r8c5=1 r8c8<>1 r9c8=1 r9c8<>9 r1c8=9 r1c3<>9
r8c5=1 r7c45<>1 r7c3=1 r7c3<>6 r7c2=6 r7c2<>3 r8c1=3 r6c1<>3 r6c1=9 r2c1<>9
r8c5=1 r7c45<>1 r7c3=1 r7c3<>6 r3c3=6 r3c3<>9
Forcing Net Contradiction in b7 => r6c8=2
r6c8<>2 r6c8=3 (r6c6<>3) (r4c7<>3) r5c7<>3 r3c7=3 r3c6<>3 r7c6=3 r7c2<>3
r6c8<>2 r6c8=3 (r5c7<>3) (r5c8<>3) r6c1<>3 r6c1=9 (r5c1<>9) r5c3<>9 r5c4=9 r5c4<>3 r5c1=3 r8c1<>3
Hidden Single: r9c7=2
Forcing Net Contradiction in r4c3 => r7c9=5
r7c9<>5 (r5c9=5 r5c9<>7 r1c9=7 r2c7<>7) r7c2=5 (r2c2<>5) (r9c2<>5) r9c3<>5 r9c8=5 r9c8<>9 r1c8=9 r2c7<>9 r2c7=8 r2c2<>8 r2c2=2 r4c2<>2 r4c3=2
r7c9<>5 (r7c2=5 r4c2<>5) r5c9=5 r4c8<>5 r4c3=5
Forcing Net Contradiction in r7c7 => r8c9=4
r8c9<>4 r8c9=8 (r8c1<>8 r8c1=3 r6c1<>3 r6c1=9 r6c3<>9) (r8c3<>8) r8c8<>8 r8c8=1 r8c3<>1 r8c3=7 r6c3<>7 r6c3=4 r6c6<>4 r7c6=4 r8c5<>4 r8c9=4
XYZ-Wing: 7/8/9 in r1c9,r27c7 => r3c7<>8
Almost Locked Set XZ-Rule: A=r239c6 {3789}, B=r37c7 {389}, X=3, Z=8 => r7c6<>8
Forcing Chain Contradiction in c6 => r3c4<>9
r3c4=9 r3c7<>9 r3c7=3 r3c6<>3
r3c4=9 r5c4<>9 r6c6=9 r6c6<>3
r3c4=9 r5c4<>9 r6c6=9 r6c6<>4 r7c6=4 r7c6<>3
Forcing Chain Contradiction in b1 => r7c3<>8
r7c3=8 r7c7<>8 r7c7=9 r9c8<>9 r1c8=9 r1c3<>9
r7c3=8 r8c1<>8 r8c1=3 r6c1<>3 r6c1=9 r2c1<>9
r7c3=8 r7c3<>6 r3c3=6 r3c3<>9
Forcing Chain Contradiction in c4 => r7c4<>9
r7c4=9 r7c7<>9 r7c7=8 r2c7<>8 r1c89=8 r1c4<>8
r7c4=9 r7c4<>1 r3c4=1 r3c4<>8
r7c4=9 r7c4<>8
r7c4=9 r5c4<>9 r6c6=9 r6c1<>9 r6c1=3 r8c1<>3 r8c1=8 r8c4<>8
Forcing Chain Contradiction in r7c4 => r5c1<>9
r5c1=9 r5c1<>5 r2c1=5 r2c5<>5 r3c5=5 r3c5<>1 r3c4=1 r7c4<>1
r5c1=9 r6c1<>9 r6c1=3 r8c1<>3 r7c2=3 r7c4<>3
r5c1=9 r5c4<>9 r1c4=9 r1c8<>9 r9c8=9 r7c7<>9 r7c7=8 r7c4<>8
Forcing Chain Contradiction in r2c7 => r5c4<>7
r5c4=7 r5c9<>7 r1c9=7 r2c7<>7
r5c4=7 r5c4<>9 r1c4=9 r1c8<>9 r9c8=9 r7c7<>9 r7c7=8 r2c7<>8
r5c4=7 r5c4<>9 r5c3=9 r6c1<>9 r2c1=9 r2c7<>9
Forcing Net Verity => r1c9=8
r3c6=3 (r1c5<>3 r1c8=3 r1c8<>8) r3c7<>3 r3c7=9 r7c7<>9 r7c7=8 r2c7<>8 r1c9=8
r6c6=3 (r6c2<>3 r6c2=7 r5c3<>7) r6c6<>4 r6c3=4 r5c3<>4 r5c7=4 r5c7<>7 r5c9=7 r1c9<>7 r1c9=8
r7c6=3 (r8c5<>3 r8c1=3 r6c1<>3 r6c1=9 r6c3<>9 r6c3=7 r5c3<>7) (r8c5<>3 r8c1=3 r6c1<>3 r6c1=9 r5c3<>9) (r8c5<>3 r8c1=3 r6c1<>3 r6c1=9 r6c3<>9) (r7c6<>9) r7c6<>4 r7c5=4 (r7c5<>9) r7c5<>9 r7c7=9 r9c8<>9 r1c8=9 r1c3<>9 r3c3=9 (r3c3<>6 r3c2=6 r7c2<>6 r7c3=6 r7c3<>1) (r3c6<>9) r3c7<>9 r3c7=3 (r3c4<>3) r3c6<>3 r3c6=8 r3c4<>8 r3c4=1 r7c4<>1 r7c5=1 r7c5<>4 r7c6=4 (r7c6<>3) r7c6<>9 r7c7=9 r3c7<>9 r3c7=3 (r3c4<>3) r3c6<>3 r6c6=3 r6c6<>4 r6c3=4 r5c3<>4 r5c7=4 r5c7<>7 r5c9=7 r1c9<>7 r1c9=8
Full House: r5c9=7
Hidden Single: r2c7=7
Empty Rectangle: 7 in b7 (r69c6) => r6c3<>7
XYZ-Wing: 3/8/9 in r23c6,r3c7 => r3c5<>9
Discontinuous Nice Loop: 3 r7c6 -3- r7c2 =3= r8c1 -3- r6c1 -9- r6c3 -4- r6c6 =4= r7c6 => r7c6<>3
Discontinuous Nice Loop: 3 r1c5 -3- r3c6 =3= r6c6 -3- r4c4 -7- r1c4 =7= r1c5 => r1c5<>3
Discontinuous Nice Loop: 8 r5c7 -8- r7c7 -9- r7c6 -4- r7c5 =4= r4c5 -4- r4c7 =4= r5c7 => r5c7<>8
Discontinuous Nice Loop: 9 r9c6 -9- r9c8 =9= r1c8 =3= r1c4 -3- r4c4 -7- r6c6 =7= r9c6 => r9c6<>9
Grouped Discontinuous Nice Loop: 9 r2c5 -9- r2c1 =9= r6c1 -9- r6c3 -4- r6c6 =4= r7c6 =9= r79c5 -9- r2c5 => r2c5<>9
Discontinuous Nice Loop: 9 r3c6 -9- r2c6 =9= r2c1 -9- r6c1 -3- r6c6 =3= r3c6 => r3c6<>9
Discontinuous Nice Loop: 5 r4c2 -5- r5c1 =5= r2c1 -5- r2c5 -2- r2c2 =2= r4c2 => r4c2<>5
Grouped Discontinuous Nice Loop: 7 r4c3 -7- r8c3 =7= r8c45 -7- r9c6 -8- r78c4 =8= r3c4 =1= r3c5 =5= r2c5 =2= r2c2 -2- r4c2 =2= r4c3 => r4c3<>7
Locked Candidates Type 1 (Pointing): 7 in b4 => r9c2<>7
Discontinuous Nice Loop: 1 r8c3 -1- r8c8 -8- r7c7 -9- r3c7 -3- r3c6 -8- r9c6 -7- r9c3 =7= r8c3 => r8c3<>1
Hidden Single: r8c8=1
Grouped AIC: 7 7- r8c3 =7= r9c3 =1= r9c5 -1- r3c5 =1= r3c4 =8= r78c4 -8- r9c6 -7 => r8c45,r9c3<>7
Hidden Single: r8c3=7
XY-Chain: 5 5- r2c5 -2- r8c5 -3- r8c1 -8- r9c2 -5 => r2c2<>5
XY-Wing: 2/8/9 in r1c3,r2c26 => r1c45,r2c1<>9
Hidden Single: r5c4=9
Hidden Single: r2c6=9
Naked Single: r7c6=4
Hidden Single: r6c1=9
Naked Single: r6c3=4
Hidden Single: r4c5=4
Hidden Single: r5c7=4
Locked Candidates Type 1 (Pointing): 8 in b2 => r3c23<>8
Skyscraper: 3 in r4c7,r6c6 (connected by r3c67) => r4c4<>3
Naked Single: r4c4=7
Full House: r6c6=3
Full House: r6c2=7
Naked Single: r3c6=8
Full House: r9c6=7
Hidden Single: r1c5=7
Hidden Rectangle: 5/8 in r4c38,r5c38 => r4c8<>8
W-Wing: 5/8 in r5c3,r9c2 connected by 8 in r59c8 => r9c3<>5
Hidden Single: r9c2=5
Naked Single: r3c2=6
Hidden Single: r7c3=6
Hidden Single: r9c3=1
Naked Single: r9c5=9
Full House: r9c8=8
Full House: r7c7=9
Naked Single: r3c7=3
Full House: r1c8=9
Full House: r4c7=8
Naked Single: r3c4=1
Naked Single: r1c3=2
Full House: r1c4=3
Naked Single: r3c5=5
Full House: r2c5=2
Full House: r3c3=9
Naked Single: r2c2=8
Full House: r2c1=5
Naked Single: r4c3=5
Full House: r5c3=8
Naked Single: r7c4=8
Full House: r8c4=2
Naked Single: r8c5=3
Full House: r7c5=1
Full House: r7c2=3
Full House: r8c1=8
Full House: r5c1=3
Full House: r4c2=2
Full House: r4c8=3
Full House: r5c8=5
|
normal_sudoku_941
|
3.5.24....2163.....6.5.1.3...61438.9..32.7....4...63..61.3.2..4.34.15...5.246.1.3
|
385724916421639785967581432276143859853297641149856327618372594734915268592468173
|
Basic 9x9 Sudoku 941
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
3 . 5 . 2 4 . . .
. 2 1 6 3 . . . .
. 6 . 5 . 1 . 3 .
. . 6 1 4 3 8 . 9
. . 3 2 . 7 . . .
. 4 . . . 6 3 . .
6 1 . 3 . 2 . . 4
. 3 4 . 1 5 . . .
5 . 2 4 6 . 1 . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
385724916421639785967581432276143859853297641149856327618372594734915268592468173 #1 Extreme (15984) bf
Hidden Single: r2c5=3
Hidden Single: r4c3=6
Hidden Single: r9c4=4
Hidden Single: r3c6=1
Hidden Single: r9c5=6
Hidden Single: r7c6=2
Hidden Single: r7c2=1
Hidden Single: r6c7=3
Hidden Single: r7c4=3
Hidden Single: r8c2=3
Brute Force: r5c6=7
Finned Swordfish: 7 r249 c128 fr2c7 fr2c9 => r1c8<>7
Almost Locked Set XZ-Rule: A=r4c12 {257}, B=r6c345 {5789}, X=7, Z=5 => r4c5<>5
Naked Single: r4c5=4
Finned Franken Swordfish: 7 c35b6 r367 fr4c8 => r7c8<>7
Forcing Net Verity => r1c2<>7
r1c4=7 r1c2<>7
r1c4=8 (r1c4<>7 r8c4=7 r7c5<>7 r3c5=7 r3c1<>7) (r1c4<>7 r8c4=7 r8c1<>7) (r6c4<>8 r6c4=9 r6c3<>9) (r1c2<>8) r2c6<>8 r9c6=8 r9c2<>8 r5c2=8 r6c3<>8 r6c3=7 (r4c1<>7) r6c1<>7 r2c1=7 r1c2<>7
r1c4=9 (r1c4<>7 r8c4=7 r7c5<>7 r3c5=7 r3c1<>7) (r1c4<>7 r8c4=7 r8c1<>7) (r6c4<>9 r6c4=8 r6c3<>8) (r1c2<>9) r2c6<>9 r9c6=9 r9c2<>9 r5c2=9 r6c3<>9 r6c3=7 (r4c1<>7) r6c1<>7 r2c1=7 r1c2<>7
Forcing Net Verity => r4c1=2
r3c5=7 (r3c1<>7) r3c3<>7 r2c1=7 r4c1<>7 r4c1=2
r3c5=8 (r3c5<>7 r7c5=7 r8c4<>7 r8c4=9 r8c1<>9) (r3c3<>8) (r1c4<>8) r2c6<>8 r9c6=8 r8c4<>8 r6c4=8 r6c3<>8 r7c3=8 r8c1<>8 r8c1=7 r4c1<>7 r4c1=2
r3c5=9 (r3c5<>7 r7c5=7 r8c4<>7 r8c4=8 r8c1<>8) (r3c3<>9) (r1c4<>9) r2c6<>9 r9c6=9 r8c4<>9 r6c4=9 r6c3<>9 r7c3=9 r8c1<>9 r8c1=7 r4c1<>7 r4c1=2
X-Wing: 7 r49 c28 => r268c8<>7
Forcing Net Contradiction in c3 => r1c4<>8
r1c4=8 r1c2<>8 r1c2=9 r3c3<>9
r1c4=8 r6c4<>8 r6c4=9 r6c3<>9
r1c4=8 (r2c6<>8 r9c6=8 r7c5<>8) r1c4<>7 r8c4=7 r7c5<>7 r7c5=9 r7c3<>9
Discontinuous Nice Loop: 9 r7c5 -9- r9c6 -8- r2c6 =8= r3c5 =7= r7c5 => r7c5<>9
Forcing Chain Contradiction in c3 => r1c4=7
r1c4<>7 r1c4=9 r1c2<>9 r1c2=8 r3c3<>8
r1c4<>7 r1c4=9 r6c4<>9 r6c4=8 r6c3<>8
r1c4<>7 r8c4=7 r7c5<>7 r7c5=8 r7c3<>8
Hidden Single: r7c5=7
Forcing Chain Contradiction in b7 => r1c8<>8
r1c8=8 r7c8<>8 r7c3=8 r7c3<>9
r1c8=8 r789c8<>8 r8c9=8 r8c4<>8 r8c4=9 r8c1<>9
r1c8=8 r1c2<>8 r1c2=9 r9c2<>9
Forcing Chain Contradiction in r8c1 => r3c3<>8
r3c3=8 r3c3<>7 r23c1=7 r8c1<>7
r3c3=8 r3c5<>8 r2c6=8 r9c6<>8 r8c4=8 r8c1<>8
r3c3=8 r7c3<>8 r7c3=9 r8c1<>9
Skyscraper: 8 in r7c3,r8c4 (connected by r6c34) => r8c1<>8
XY-Chain: 7 7- r3c3 -9- r3c5 -8- r2c6 -9- r9c6 -8- r8c4 -9- r8c1 -7 => r23c1<>7
Hidden Single: r3c3=7
Naked Pair: 8,9 in r6c34 => r6c15<>8, r6c15<>9
Naked Single: r6c5=5
Remote Pair: 9/8 r7c3 -8- r6c3 -9- r6c4 -8- r8c4 => r8c1<>9
Naked Single: r8c1=7
Naked Single: r6c1=1
Naked Single: r6c8=2
Naked Single: r6c9=7
Naked Single: r4c8=5
Full House: r4c2=7
Hidden Single: r2c7=7
Hidden Single: r9c8=7
Hidden Single: r5c2=5
Hidden Single: r2c9=5
Hidden Single: r7c7=5
Remote Pair: 9/8 r1c2 -8- r9c2 -9- r9c6 -8- r2c6 -9- r3c5 -8- r5c5 -9- r5c1 -8- r6c3 -9- r7c3 -8- r7c8 => r2c1<>8, r1c8,r2c1<>9
Naked Single: r2c1=4
Hidden Single: r5c8=4
Naked Single: r5c7=6
Full House: r5c9=1
Naked Single: r1c7=9
Naked Single: r1c2=8
Full House: r3c1=9
Full House: r9c2=9
Full House: r5c1=8
Full House: r7c3=8
Full House: r9c6=8
Full House: r5c5=9
Full House: r3c5=8
Full House: r6c3=9
Full House: r7c8=9
Full House: r2c6=9
Full House: r2c8=8
Full House: r8c4=9
Full House: r6c4=8
Naked Single: r8c7=2
Full House: r3c7=4
Full House: r3c9=2
Naked Single: r1c9=6
Full House: r1c8=1
Full House: r8c8=6
Full House: r8c9=8
|
normal_sudoku_3737
|
..6....29.3.62.48.2.49.83.6...4.68.26.289.134.4831269...72....8..1......4...8..6.
|
786143529935627481214958376193476852672895134548312697357264918861739245429581763
|
Basic 9x9 Sudoku 3737
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 6 . . . . 2 9
. 3 . 6 2 . 4 8 .
2 . 4 9 . 8 3 . 6
. . . 4 . 6 8 . 2
6 . 2 8 9 . 1 3 4
. 4 8 3 1 2 6 9 .
. . 7 2 . . . . 8
. . 1 . . . . . .
4 . . . 8 . . 6 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
786143529935627481214958376193476852672895134548312697357264918861739245429581763 #1 Extreme (21368) bf
Hidden Single: r5c9=4
Hidden Single: r5c4=8
Hidden Single: r2c5=2
Hidden Single: r4c9=2
Hidden Single: r2c8=8
Hidden Single: r1c3=6
Hidden Single: r6c7=6
Hidden Single: r3c9=6
Discontinuous Nice Loop: 1/3/5/7 r9c5 =8= r9c2 =2= r8c2 =6= r8c5 =8= r9c5 => r9c5<>1, r9c5<>3, r9c5<>5, r9c5<>7
Naked Single: r9c5=8
Brute Force: r6c4=3
Naked Triple: 1,5,7 in r1c4,r2c6,r3c5 => r1c56<>1, r1c56<>5, r1c56<>7
Naked Triple: 1,5,7 in r346c5 => r7c5<>1, r78c5<>5, r8c5<>7
Brute Force: r6c5=1
Skyscraper: 1 in r3c8,r5c7 (connected by r35c2) => r1c7,r4c8<>1
Hidden Single: r5c7=1
Naked Pair: 5,7 in r5c2,r6c1 => r4c123<>5, r4c12<>7
Remote Pair: 5/7 r3c5 -7- r4c5 -5- r5c6 -7- r5c2 => r3c2<>5, r3c2<>7
Naked Single: r3c2=1
Naked Single: r4c2=9
Naked Single: r4c3=3
Naked Single: r4c1=1
Hidden Single: r1c4=1
Hidden Single: r7c8=1
Hidden Single: r2c9=1
Hidden Single: r9c6=1
Hidden Single: r8c8=4
Hidden Single: r9c9=3
Locked Candidates Type 2 (Claiming): 5 in c4 => r78c6<>5
Locked Candidates Type 2 (Claiming): 7 in c4 => r8c6<>7
Naked Pair: 5,7 in r8c49 => r8c127<>5, r8c7<>7
Remote Pair: 5/7 r1c7 -7- r3c8 -5- r3c5 -7- r2c6 -5- r5c6 -7- r4c5 -5- r4c8 -7- r6c9 -5- r6c1 -7- r5c2 => r1c2,r2c1<>5, r1c2,r2c1<>7
Naked Single: r1c2=8
Naked Single: r2c1=9
Naked Single: r2c3=5
Full House: r1c1=7
Full House: r2c6=7
Full House: r9c3=9
Naked Single: r1c7=5
Full House: r3c8=7
Full House: r3c5=5
Full House: r4c8=5
Full House: r4c5=7
Full House: r5c6=5
Full House: r6c9=7
Full House: r6c1=5
Full House: r5c2=7
Full House: r8c9=5
Naked Single: r7c7=9
Naked Single: r7c1=3
Full House: r8c1=8
Naked Single: r8c4=7
Full House: r9c4=5
Naked Single: r8c7=2
Full House: r9c7=7
Full House: r9c2=2
Naked Single: r7c6=4
Naked Single: r8c2=6
Full House: r7c2=5
Full House: r7c5=6
Naked Single: r1c6=3
Full House: r1c5=4
Full House: r8c5=3
Full House: r8c6=9
|
normal_sudoku_2011
|
3.2..918...917.62...12....5.95.3..1...4.......23.1..69546..1392937...851..8.9.746
|
372569184459178623681243975895632417164957238723814569546781392937426851218395746
|
Basic 9x9 Sudoku 2011
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
3 . 2 . . 9 1 8 .
. . 9 1 7 . 6 2 .
. . 1 2 . . . . 5
. 9 5 . 3 . . 1 .
. . 4 . . . . . .
. 2 3 . 1 . . 6 9
5 4 6 . . 1 3 9 2
9 3 7 . . . 8 5 1
. . 8 . 9 . 7 4 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
372569184459178623681243975895632417164957238723814569546781392937426851218395746 #1 Hard (870)
Naked Single: r8c8=5
Naked Single: r8c7=8
Naked Single: r9c7=7
Naked Single: r7c8=9
Hidden Single: r2c4=1
Hidden Single: r6c3=3
Hidden Single: r1c3=2
Hidden Single: r2c8=2
Hidden Single: r2c3=9
Hidden Single: r8c9=1
Full House: r9c9=6
Naked Single: r9c3=8
Naked Single: r7c3=6
Full House: r5c3=4
Naked Single: r7c1=5
Naked Single: r7c5=8
Full House: r7c4=7
Naked Single: r9c2=1
Full House: r9c1=2
Hidden Single: r5c4=9
Hidden Single: r3c7=9
Hidden Single: r9c4=3
Full House: r9c6=5
Hidden Single: r5c1=1
Hidden Single: r2c2=5
Locked Candidates Type 1 (Pointing): 8 in b2 => r456c6<>8
Locked Candidates Type 1 (Pointing): 4 in b3 => r4c9<>4
Naked Triple: 4,5,6 in r1c45,r3c5 => r23c6<>4, r3c6<>6
2-String Kite: 7 in r1c2,r5c8 (connected by r1c9,r3c8) => r5c2<>7
Locked Candidates Type 1 (Pointing): 7 in b4 => r3c1<>7
W-Wing: 7/8 in r4c9,r6c1 connected by 8 in r5c29 => r4c1<>7
Hidden Single: r6c1=7
Naked Single: r6c6=4
Naked Single: r6c7=5
Full House: r6c4=8
Naked Single: r5c7=2
Full House: r4c7=4
Naked Single: r4c4=6
Naked Single: r4c1=8
Full House: r5c2=6
Naked Single: r5c5=5
Naked Single: r5c6=7
Full House: r4c6=2
Full House: r4c9=7
Naked Single: r8c4=4
Full House: r1c4=5
Naked Single: r2c1=4
Full House: r3c1=6
Naked Single: r1c2=7
Full House: r3c2=8
Naked Single: r5c8=3
Full House: r3c8=7
Full House: r5c9=8
Naked Single: r8c6=6
Full House: r8c5=2
Naked Single: r1c9=4
Full House: r2c9=3
Full House: r1c5=6
Full House: r3c5=4
Full House: r3c6=3
Full House: r2c6=8
|
normal_sudoku_2971
|
....3.8.131..8.4..82..9.3.517.6.35.85.3..891...8.51637...3..1...514..783.348..2.9
|
497536821315287496826194375179623548563748912248951637682379154951462783734815269
|
Basic 9x9 Sudoku 2971
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . 3 . 8 . 1
3 1 . . 8 . 4 . .
8 2 . . 9 . 3 . 5
1 7 . 6 . 3 5 . 8
5 . 3 . . 8 9 1 .
. . 8 . 5 1 6 3 7
. . . 3 . . 1 . .
. 5 1 4 . . 7 8 3
. 3 4 8 . . 2 . 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
497536821315287496826194375179623548563748912248951637682379154951462783734815269 #1 Hard (628)
Naked Single: r5c7=9
Naked Single: r1c7=8
Full House: r4c7=5
Hidden Single: r1c5=3
Hidden Single: r5c8=1
Hidden Single: r9c4=8
Hidden Single: r3c1=8
Hidden Single: r4c9=8
Hidden Single: r6c8=3
Hidden Single: r5c3=3
Hidden Single: r8c9=3
Hidden Single: r2c2=1
Hidden Single: r8c3=1
Hidden Single: r4c3=9
Naked Single: r6c2=4
Naked Single: r5c2=6
Full House: r6c1=2
Full House: r6c4=9
Naked Single: r1c2=9
Full House: r7c2=8
Hidden Single: r9c5=1
Hidden Single: r3c6=4
Hidden Single: r3c4=1
Hidden Single: r2c8=9
Hidden Single: r7c3=2
Hidden Single: r1c1=4
Locked Candidates Type 1 (Pointing): 6 in b2 => r789c6<>6
Locked Candidates Type 1 (Pointing): 5 in b8 => r12c6<>5
W-Wing: 7/6 in r7c5,r9c1 connected by 6 in r8c15 => r7c1,r9c6<>7
Naked Single: r9c6=5
Naked Single: r9c8=6
Full House: r9c1=7
Naked Single: r3c8=7
Full House: r3c3=6
Naked Single: r7c9=4
Full House: r7c8=5
Naked Single: r1c8=2
Full House: r2c9=6
Full House: r5c9=2
Full House: r4c8=4
Full House: r4c5=2
Naked Single: r5c4=7
Full House: r5c5=4
Naked Single: r8c5=6
Full House: r7c5=7
Naked Single: r1c4=5
Full House: r2c4=2
Naked Single: r8c1=9
Full House: r7c1=6
Full House: r7c6=9
Full House: r8c6=2
Naked Single: r1c3=7
Full House: r1c6=6
Full House: r2c6=7
Full House: r2c3=5
|
normal_sudoku_3575
|
..9..1..6.6....1..1.4....7.721...369983..2451..69138276..13.78....8.6.15.1..576.3
|
879321546265794138134568972721485369983672451546913827652139784397846215418257693
|
Basic 9x9 Sudoku 3575
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 9 . . 1 . . 6
. 6 . . . . 1 . .
1 . 4 . . . . 7 .
7 2 1 . . . 3 6 9
9 8 3 . . 2 4 5 1
. . 6 9 1 3 8 2 7
6 . . 1 3 . 7 8 .
. . . 8 . 6 . 1 5
. 1 . . 5 7 6 . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
879321546265794138134568972721485369983672451546913827652139784397846215418257693 #1 Easy (318)
Hidden Single: r5c1=9
Hidden Single: r4c3=1
Hidden Single: r6c9=7
Hidden Single: r6c3=6
Hidden Single: r9c7=6
Hidden Single: r3c1=1
Hidden Single: r7c4=1
Hidden Single: r8c8=1
Hidden Single: r4c7=3
Hidden Single: r6c8=2
Naked Single: r5c7=4
Full House: r4c9=9
Naked Single: r5c6=2
Hidden Single: r9c8=9
Naked Single: r8c7=2
Full House: r7c9=4
Naked Single: r1c7=5
Full House: r3c7=9
Naked Single: r8c3=7
Naked Single: r7c6=9
Naked Single: r7c2=5
Full House: r7c3=2
Naked Single: r8c5=4
Full House: r9c4=2
Naked Single: r3c2=3
Naked Single: r6c2=4
Full House: r6c1=5
Naked Single: r9c3=8
Full House: r2c3=5
Full House: r9c1=4
Naked Single: r4c5=8
Naked Single: r8c1=3
Full House: r8c2=9
Full House: r1c2=7
Naked Single: r1c5=2
Naked Single: r1c1=8
Full House: r2c1=2
Naked Single: r3c5=6
Naked Single: r2c9=8
Full House: r3c9=2
Naked Single: r3c4=5
Full House: r3c6=8
Naked Single: r5c5=7
Full House: r2c5=9
Full House: r5c4=6
Naked Single: r2c6=4
Full House: r4c6=5
Full House: r4c4=4
Naked Single: r1c4=3
Full House: r1c8=4
Full House: r2c8=3
Full House: r2c4=7
|
normal_sudoku_2575
|
.79..841558...12...1..5..8..256.41.8..8.157421..82.65.851..6.2....5..8.1...1825..
|
679238415584961237213457986325674198968315742147829653851796324792543861436182579
|
Basic 9x9 Sudoku 2575
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 7 9 . . 8 4 1 5
5 8 . . . 1 2 . .
. 1 . . 5 . . 8 .
. 2 5 6 . 4 1 . 8
. . 8 . 1 5 7 4 2
1 . . 8 2 . 6 5 .
8 5 1 . . 6 . 2 .
. . . 5 . . 8 . 1
. . . 1 8 2 5 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
679238415584961237213457986325674198968315742147829653851796324792543861436182579 #1 Extreme (15986) bf
Hidden Single: r4c9=8
Hidden Single: r2c2=8
Hidden Single: r9c7=5
Hidden Single: r6c5=2
Hidden Single: r7c8=2
Hidden Single: r9c5=8
Hidden Single: r1c6=8
Hidden Single: r3c2=1
Hidden Single: r8c4=5
Hidden Single: r9c4=1
Hidden Single: r2c6=1
Hidden Single: r5c5=1
Hidden Single: r1c8=1
Hidden Single: r1c9=5
Hidden Single: r6c8=5
Brute Force: r5c7=7
Finned Franken Swordfish: 3 c67b6 r368 fr4c8 fr7c7 => r8c8<>3
Finned Franken Swordfish: 9 c67b6 r368 fr4c8 fr7c7 => r8c8<>9
Forcing Chain Contradiction in c6 => r9c8<>3
r9c8=3 r7c7<>3 r3c7=3 r3c6<>3
r9c8=3 r4c8<>3 r6c9=3 r6c6<>3
r9c8=3 r7c79<>3 r7c45=3 r8c6<>3
W-Wing: 9/3 in r3c7,r6c9 connected by 3 in r24c8 => r23c9<>9
Forcing Chain Contradiction in c5 => r7c4<>3
r7c4=3 r7c7<>3 r7c7=9 r3c7<>9 r2c8=9 r2c5<>9
r7c4=3 r5c4<>3 r5c4=9 r4c5<>9
r7c4=3 r7c7<>3 r7c7=9 r7c5<>9
r7c4=3 r7c79<>3 r9c9=3 r9c9<>4 r7c9=4 r7c45<>4 r8c5=4 r8c5<>9
Forcing Chain Contradiction in r3c6 => r4c5<>3
r4c5=3 r5c4<>3 r123c4=3 r3c6<>3
r4c5=3 r4c5<>7 r6c6=7 r3c6<>7
r4c5=3 r4c8<>3 r4c8=9 r2c8<>9 r3c7=9 r3c6<>9
Discontinuous Nice Loop: 9 r6c2 -9- r6c9 -3- r4c8 =3= r4c1 =7= r6c3 =4= r6c2 => r6c2<>9
Forcing Chain Contradiction in c6 => r8c6<>7
r8c6=7 r7c45<>7 r7c9=7 r89c8<>7 r2c8=7 r2c8<>9 r3c7=9 r3c6<>9
r8c6=7 r7c45<>7 r7c9=7 r89c8<>7 r2c8=7 r2c8<>3 r4c8=3 r4c8<>9 r6c9=9 r6c6<>9
r8c6=7 r8c6<>9
Forcing Chain Verity => r3c4<>3
r2c8=9 r3c7<>9 r3c7=3 r3c4<>3
r4c8=9 r4c8<>3 r4c1=3 r1c1<>3 r1c45=3 r3c4<>3
r9c8=9 r7c79<>9 r7c45=9 r8c6<>9 r8c6=3 r6c6<>3 r5c4=3 r3c4<>3
Forcing Chain Verity => r3c6<>3
r2c8=9 r3c7<>9 r3c7=3 r3c6<>3
r4c8=9 r4c8<>3 r4c1=3 r1c1<>3 r1c45=3 r3c6<>3
r9c8=9 r7c79<>9 r7c45=9 r8c6<>9 r8c6=3 r3c6<>3
Grouped Discontinuous Nice Loop: 9 r7c4 -9- r7c7 =9= r3c7 -9- r3c6 -7- r23c4 =7= r7c4 => r7c4<>9
Grouped AIC: 7 7- r7c4 =7= r78c5 -7- r4c5 -9- r5c4 =9= r23c4 -9- r3c6 -7 => r23c4<>7
Hidden Single: r7c4=7
Locked Candidates Type 1 (Pointing): 4 in b8 => r2c5<>4
Grouped AIC: 7/9 9- r4c1 =9= r5c12 -9- r5c4 =9= r23c4 -9- r3c6 -7- r6c6 =7= r4c5 -7 => r4c1<>7, r4c5<>9
Naked Single: r4c5=7
Hidden Single: r6c3=7
Hidden Single: r3c6=7
Hidden Single: r6c2=4
Multi Colors 2: 9 (r2c8,r3c4,r7c7) / (r3c7), (r4c1,r5c4,r6c9,r8c6) / (r4c8,r6c6) => r2c8,r3c4,r7c7<>9
Naked Single: r7c7=3
Full House: r3c7=9
Locked Candidates Type 1 (Pointing): 3 in b8 => r8c123<>3
Skyscraper: 9 in r6c6,r7c5 (connected by r67c9) => r8c6<>9
Naked Single: r8c6=3
Full House: r6c6=9
Full House: r5c4=3
Full House: r6c9=3
Full House: r4c8=9
Full House: r4c1=3
Naked Single: r1c4=2
Naked Single: r3c9=6
Naked Single: r1c1=6
Full House: r1c5=3
Naked Single: r3c4=4
Full House: r2c4=9
Full House: r2c5=6
Naked Single: r2c9=7
Full House: r2c8=3
Full House: r2c3=4
Naked Single: r5c1=9
Full House: r5c2=6
Naked Single: r3c1=2
Full House: r3c3=3
Naked Single: r8c2=9
Full House: r9c2=3
Naked Single: r9c3=6
Full House: r8c3=2
Naked Single: r8c5=4
Full House: r7c5=9
Full House: r7c9=4
Full House: r9c9=9
Naked Single: r9c8=7
Full House: r8c8=6
Full House: r8c1=7
Full House: r9c1=4
|
normal_sudoku_2942
|
...836279367912...8..745361.13..4.9.....5.7......8........98.272.....9.59.4....36
|
145836279367912854892745361613274598428659713759381642536198427271463985984527136
|
Basic 9x9 Sudoku 2942
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . 8 3 6 2 7 9
3 6 7 9 1 2 . . .
8 . . 7 4 5 3 6 1
. 1 3 . . 4 . 9 .
. . . . 5 . 7 . .
. . . . 8 . . . .
. . . . 9 8 . 2 7
2 . . . . . 9 . 5
9 . 4 . . . . 3 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
145836279367912854892745361613274598428659713759381642536198427271463985984527136 #1 Extreme (1818)
Hidden Single: r2c3=7
Hidden Single: r3c7=3
Naked Single: r3c5=4
Naked Single: r2c5=1
Naked Single: r1c5=3
Hidden Single: r7c9=7
Hidden Single: r2c4=9
Naked Single: r3c6=5
Full House: r1c4=8
Naked Single: r3c1=8
Naked Single: r3c8=6
Hidden Single: r7c8=2
Hidden Single: r4c8=9
Locked Candidates Type 1 (Pointing): 8 in b4 => r5c89<>8
Locked Candidates Type 1 (Pointing): 7 in b7 => r6c2<>7
Uniqueness Test 3: 2/9 in r3c23,r6c23 => r5c2<>4, r5c3<>6
Discontinuous Nice Loop: 4/5/6 r6c1 =7= r6c6 -7- r9c6 -1- r9c7 -8- r8c8 =8= r2c8 =5= r2c7 -5- r4c7 =5= r4c1 =7= r6c1 => r6c1<>4, r6c1<>5, r6c1<>6
Naked Single: r6c1=7
Hidden Single: r4c5=7
Naked Single: r8c5=6
Full House: r9c5=2
AIC: 4/8 8- r2c8 =8= r8c8 -8- r8c3 -1- r1c3 =1= r1c1 =4= r5c1 =6= r5c4 -6- r4c4 -2- r4c9 -8- r2c9 -4 => r2c8<>4, r2c9<>8
Naked Single: r2c9=4
Hidden Single: r4c9=8
Hidden Single: r4c4=2
AIC: 5 5- r1c3 -1- r8c3 -8- r8c8 =8= r2c8 =5= r2c7 -5- r4c7 =5= r4c1 -5 => r1c1,r6c3<>5
AIC: 4 4- r1c2 -5- r1c3 =5= r7c3 =6= r7c1 -6- r5c1 -4 => r1c1,r6c2<>4
Naked Single: r1c1=1
Naked Single: r1c3=5
Full House: r1c2=4
Hidden Single: r5c1=4
Naked Single: r5c8=1
Hidden Single: r5c4=6
XY-Wing: 4/8/1 in r7c7,r8c38 => r7c3<>1
Naked Single: r7c3=6
Naked Single: r7c1=5
Full House: r4c1=6
Full House: r4c7=5
Naked Single: r7c2=3
Naked Single: r2c7=8
Full House: r2c8=5
Naked Single: r6c8=4
Full House: r8c8=8
Naked Single: r9c7=1
Full House: r7c7=4
Full House: r6c7=6
Full House: r7c4=1
Naked Single: r8c2=7
Naked Single: r8c3=1
Full House: r9c2=8
Naked Single: r9c4=5
Full House: r9c6=7
Naked Single: r6c4=3
Full House: r8c4=4
Full House: r8c6=3
Naked Single: r5c6=9
Full House: r6c6=1
Naked Single: r6c9=2
Full House: r5c9=3
Naked Single: r5c2=2
Full House: r5c3=8
Naked Single: r6c3=9
Full House: r3c3=2
Full House: r3c2=9
Full House: r6c2=5
|
normal_sudoku_3684
|
8...56..7..23..86.67...2513..9.23......6......6..49.3...62...4..2..61..81...3....
|
893156427512374869674982513489523176235617984761849235356298741927461358148735692
|
Basic 9x9 Sudoku 3684
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
8 . . . 5 6 . . 7
. . 2 3 . . 8 6 .
6 7 . . . 2 5 1 3
. . 9 . 2 3 . . .
. . . 6 . . . . .
. 6 . . 4 9 . 3 .
. . 6 2 . . . 4 .
. 2 . . 6 1 . . 8
1 . . . 3 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
893156427512374869674982513489523176235617984761849235356298741927461358148735692 #1 Extreme (14446)
Hidden Single: r1c6=6
Hidden Single: r3c1=6
Hidden Single: r2c7=8
Hidden Single: r3c6=2
Almost Locked Set XY-Wing: A=r13c3 {134}, B=r579c6 {4578}, C=r2c1269 {14579}, X,Y=1,7, Z=4 => r9c3<>4
Forcing Net Contradiction in c3 => r1c2<>4
r1c2=4 (r1c4<>4) (r1c3<>4) r3c3<>4 r3c3=3 r1c3<>3 r1c3=1 r1c4<>1 r1c4=9 (r3c5<>9 r3c5=8 r5c5<>8) r1c4<>1 r2c5=1 r5c5<>1 r5c5=7 r5c3<>7
r1c2=4 (r1c2<>1) (r1c2<>3) r3c3<>4 r3c3=3 (r5c3<>3) (r8c3<>3) r1c3<>3 (r1c3=1 r2c2<>1) r1c7=3 r8c7<>3 r8c1=3 r5c1<>3 r5c2=3 r5c2<>1 r4c2=1 (r4c4<>1) r2c2<>1 r2c5=1 r1c4<>1 r6c4=1 r6c4<>8 r6c3=8 r6c3<>7
r1c2=4 (r9c2<>4) (r1c2<>3) r3c3<>4 r3c3=3 (r8c3<>3) r1c3<>3 r1c7=3 r8c7<>3 r8c1=3 r8c1<>4 r8c3=4 r8c3<>7
r1c2=4 (r1c4<>4) (r1c3<>4) r3c3<>4 r3c3=3 r1c3<>3 r1c3=1 (r2c2<>1 r2c5=1 r2c5<>7 r2c6=7 r7c6<>7) r1c4<>1 r1c4=9 (r3c4<>9) r3c5<>9 (r7c5=9 r7c5<>7) r3c9=9 r3c9<>3 r7c9=3 r7c9<>1 r7c7=1 r7c7<>7 r7c1=7 r9c3<>7
Forcing Net Contradiction in c1 => r1c3<>4
r1c3=4 (r8c3<>4) (r1c3<>3) r3c3<>4 r3c3=3 (r8c3<>3) r1c2<>3 r1c7=3 r8c7<>3 r8c1=3 r8c1<>4 r8c4=4 r9c6<>4 r2c6=4 r2c9<>4 r2c9=9 r2c1<>9
r1c3=4 (r1c3<>1) (r8c3<>4) (r1c3<>3) r3c3<>4 r3c3=3 (r8c3<>3) r1c2<>3 r1c7=3 r8c7<>3 r8c1=3 r8c1<>4 r8c4=4 (r3c4<>4) r9c6<>4 r2c6=4 (r2c9<>4 r2c9=9 r2c5<>9) r2c6<>7 r2c5=7 r2c5<>1 r5c5=1 r5c3<>1 r6c3=1 r6c3<>8 r6c4=8 r3c4<>8 r3c4=9 r3c5<>9 r7c5=9 r7c1<>9
r1c3=4 (r1c3<>3) r3c3<>4 r3c3=3 (r8c3<>3) r1c2<>3 r1c7=3 r8c7<>3 r8c1=3 r8c1<>9
Discontinuous Nice Loop: 9 r2c5 -9- r2c9 -4- r1c7 =4= r1c4 =1= r2c5 => r2c5<>9
Discontinuous Nice Loop: 4 r3c4 -4- r3c3 -3- r3c9 =3= r1c7 =4= r1c4 -4- r3c4 => r3c4<>4
Locked Pair: 8,9 in r3c45 => r1c4,r3c9<>9
Forcing Chain Contradiction in r4 => r4c9<>4
r4c9=4 r45c7<>4 r1c7=4 r1c4<>4 r1c4=1 r1c3<>1 r12c2=1 r4c2<>1
r4c9=4 r45c7<>4 r1c7=4 r1c4<>4 r1c4=1 r4c4<>1
r4c9=4 r4c9<>6 r4c7=6 r4c7<>1
r4c9=4 r4c9<>1
Forcing Net Contradiction in c3 => r3c3=4
r3c3<>4 r3c3=3 (r3c9<>3 r7c9=3 r7c9<>1 r7c7=1 r7c7<>7) (r8c3<>3) (r1c2<>3) r1c3<>3 (r1c3=1 r1c4<>1 r1c4=4 r2c6<>4 r2c6=7 r5c6<>7) (r1c3=1 r1c4<>1 r1c4=4 r2c6<>4 r2c6=7 r7c6<>7) (r1c3=1 r1c2<>1 r1c2=9 r2c1<>9) r1c7=3 r8c7<>3 r8c1=3 r8c1<>9 r7c1=9 r7c1<>7 r7c5=7 (r5c5<>7) r2c5<>7 r2c5=1 r5c5<>1 r5c5=8 r5c6<>8 r5c6=5 r5c3<>5
r3c3<>4 r3c3=3 (r1c3<>3 r1c3=1 r6c3<>1) (r1c3<>3 r1c3=1 r5c3<>1) (r1c3<>3 r1c3=1 r2c2<>1 r2c5=1 r5c5<>1) (r1c3<>3 r1c7=3 r8c7<>3 r8c1=3 r5c1<>3 r5c2=3 r5c2<>1) r3c9<>3 r7c9=3 r7c9<>1 r7c7=1 (r6c7<>1) r5c7<>1 r5c9=1 r6c9<>1 r6c4=1 r6c4<>8 r6c3=8 r6c3<>5
r3c3<>4 r3c3=3 (r8c3<>3) (r1c2<>3) r1c3<>3 (r1c3=1 r1c4<>1 r1c4=4 r8c4<>4) r1c7=3 r8c7<>3 r8c1=3 r8c1<>4 r8c3=4 r8c3<>5
r3c3<>4 r3c3=3 (r8c3<>3) (r1c2<>3) r1c3<>3 (r1c3=1 r1c2<>1 r1c2=9 r2c1<>9) r1c7=3 r8c7<>3 r8c1=3 (r8c1<>7) (r8c1<>4 r8c3=4 r8c3<>7) r8c1<>9 r7c1=9 r7c1<>7 r9c3=7 r9c3<>5
Naked Single: r3c9=3
Finned Swordfish: 4 r148 c147 fr4c2 => r5c1<>4
Discontinuous Nice Loop: 5 r8c1 -5- r2c1 -9- r2c9 -4- r2c6 =4= r9c6 -4- r9c2 =4= r8c1 => r8c1<>5
Forcing Net Contradiction in b7 => r7c9<>9
r7c9=9 r7c1<>9
r7c9=9 r7c2<>9
r7c9=9 r2c9<>9 r2c9=4 r1c7<>4 r1c4=4 r8c4<>4 r8c1=4 r8c1<>9
r7c9=9 (r2c9<>9 r2c9=4 r2c6<>4 r9c6=4 r9c6<>8) r7c5<>9 r3c5=9 r3c4<>9 r3c4=8 (r9c4<>8) r6c4<>8 r6c3=8 r9c3<>8 r9c2=8 r9c2<>9
Forcing Net Contradiction in c8 => r5c9<>1
r5c9=1 (r7c9<>1 r7c7=1 r7c7<>3 r8c7=3 r8c7<>9) (r5c9<>4 r2c9=4 r2c9<>9 r9c9=9 r8c8<>9) r5c5<>1 r2c5=1 r1c4<>1 r1c4=4 r8c4<>4 r8c1=4 r8c1<>9 r8c4=9 r3c4<>9 r3c4=8 (r4c4<>8) r6c4<>8 r6c3=8 r4c2<>8 r4c8=8 r4c8<>5
r5c9=1 (r7c9<>1 r7c9=5 r7c6<>5) r5c9<>4 r2c9=4 r2c6<>4 r9c6=4 r9c6<>5 r5c6=5 r5c8<>5
r5c9=1 r7c9<>1 r7c9=5 r8c8<>5
r5c9=1 r7c9<>1 r7c9=5 r9c8<>5
Forcing Net Contradiction in r5c8 => r5c9<>5
r5c9=5 (r6c9<>5) r7c9<>5 r7c9=1 r6c9<>1 r6c9=2 r5c8<>2
r5c9=5 r5c8<>5
r5c9=5 (r5c6<>5) r5c9<>4 r2c9=4 r2c6<>4 r2c6=7 (r2c5<>7 r2c5=1 r5c5<>1) r5c6<>7 r5c6=8 r5c5<>8 r5c5=7 r5c8<>7
r5c9=5 (r5c6<>5) r5c9<>4 r2c9=4 r2c6<>4 r2c6=7 r5c6<>7 r5c6=8 r5c8<>8
r5c9=5 (r7c9<>5 r7c9=1 r6c9<>1 r6c9=2 r9c9<>2) (r5c9<>9) r5c9<>4 r2c9=4 r2c9<>9 r9c9=9 r9c9<>6 r9c7=6 r9c7<>2 r9c8=2 r1c8<>2 r1c8=9 r5c8<>9
Forcing Net Contradiction in r3 => r8c1<>3
r8c1=3 r8c1<>4 r8c4=4 r1c4<>4 r1c4=1 (r1c3<>1) r2c5<>1 r5c5=1 r5c3<>1 r6c3=1 r6c3<>8 r6c4=8 r3c4<>8 r3c4=9
r8c1=3 (r8c1<>9) r8c1<>4 r8c4=4 r1c4<>4 r1c7=4 r2c9<>4 r2c9=9 r2c1<>9 r7c1=9 r7c5<>9 r3c5=9
Forcing Net Contradiction in c6 => r7c1<>5
r7c1=5 (r4c1<>5) (r2c1<>5 r2c2=5 r4c2<>5) (r7c9<>5 r7c9=1 r6c9<>1) r7c1<>3 r5c1=3 r5c1<>2 r6c1=2 r6c9<>2 r6c9=5 (r4c8<>5) r4c9<>5 r4c4=5 r5c6<>5
r7c1=5 r7c6<>5
r7c1=5 r2c1<>5 r2c1=9 r2c9<>9 r2c9=4 r2c6<>4 r9c6=4 r9c6<>5
Forcing Net Contradiction in r7c7 => r6c3<>5
r6c3=5 (r6c1<>5 r2c1=5 r2c1<>9) r6c3<>8 r6c4=8 r3c4<>8 r3c4=9 r3c5<>9 r7c5=9 r7c1<>9 r8c1=9 r8c1<>4 r8c4=4 r1c4<>4 r1c4=1 (r1c3<>1) r2c5<>1 r5c5=1 r5c3<>1 r6c3=1 r6c3<>5
Forcing Net Contradiction in r7c7 => r7c6<>7
r7c6=7 r2c6<>7 (r2c6=4 r2c9<>4 r2c9=9 r2c1<>9 r2c1=5 r6c1<>5) (r2c6=4 r1c4<>4 r1c4=1 r1c3<>1) r2c5=7 r2c5<>1 r5c5=1 r5c3<>1 r6c3=1 r6c3<>8 r6c4=8 r6c4<>5 r6c9=5 r7c9<>5 r7c9=1 r7c7<>1
r7c6=7 r2c6<>7 r2c6=4 r1c4<>4 r1c4=1 r1c3<>1 r1c3=3 r8c3<>3 r8c7=3 r7c7<>3
r7c6=7 r7c7<>7
r7c6=7 r2c6<>7 (r2c6=4 r1c4<>4 r1c4=1 r1c3<>1) r2c5=7 r2c5<>1 r5c5=1 r5c3<>1 r6c3=1 r6c3<>8 r6c4=8 r3c4<>8 r3c4=9 r3c5<>9 r7c5=9 r7c7<>9
Forcing Net Contradiction in r6c3 => r8c1<>7
r8c1=7 r8c1<>4 r8c4=4 r1c4<>4 r1c4=1 (r1c3<>1) r2c5<>1 r5c5=1 r5c3<>1 r6c3=1
r8c1=7 (r8c1<>9) r8c1<>4 r8c4=4 r1c4<>4 r1c7=4 r2c9<>4 r2c9=9 r2c1<>9 r7c1=9 r7c5<>9 r3c5=9 r3c4<>9 r3c4=8 r6c4<>8 r6c3=8
Forcing Net Contradiction in r7c7 => r5c3<>7
r5c3=7 (r5c5<>7) (r4c1<>7) (r5c1<>7) r6c1<>7 r7c1=7 (r7c1<>3 r5c1=3 r5c1<>2 r6c1=2 r6c1<>5) r7c5<>7 r2c5=7 r2c5<>1 (r2c2=1 r1c3<>1) r5c5=1 r5c3<>1 r6c3=1 r6c3<>8 r6c4=8 r6c4<>5 r6c9=5 r7c9<>5 r7c9=1 r7c7<>1
r5c3=7 (r5c5<>7) (r4c1<>7) (r5c1<>7) r6c1<>7 r7c1=7 r7c5<>7 r2c5=7 r2c5<>1 r2c2=1 r1c3<>1 r1c3=3 r8c3<>3 r8c7=3 r7c7<>3
r5c3=7 (r4c1<>7) (r5c1<>7) r6c1<>7 r7c1=7 r7c7<>7
r5c3=7 (r5c3<>1) (r5c5<>7) (r4c1<>7) (r5c1<>7) r6c1<>7 r7c1=7 r7c5<>7 r2c5=7 r2c5<>1 r2c2=1 r1c3<>1 r6c3=1 r6c3<>8 r6c4=8 r3c4<>8 r3c4=9 r3c5<>9 r7c5=9 r7c7<>9
Forcing Net Contradiction in r7c2 => r8c4<>5
r8c4=5 (r6c4<>5) (r7c6<>5) (r8c3<>5) (r7c6<>5) r9c6<>5 r5c6=5 r5c3<>5 r9c3=5 r7c2<>5 r7c9=5 r6c9<>5 r6c1=5 r6c1<>2 r5c1=2 r5c1<>3 r7c1=3 r7c2<>3
r8c4=5 (r8c3<>5) (r7c6<>5) r9c6<>5 r5c6=5 r5c3<>5 r9c3=5 r7c2<>5
r8c4=5 r7c6<>5 r7c6=8 r7c2<>8
r8c4=5 (r7c6<>5 r7c6=8 r9c4<>8) (r7c6<>5 r7c6=8 r9c6<>8) (r8c3<>5) (r7c6<>5) r9c6<>5 r5c6=5 r5c3<>5 r9c3=5 (r9c8<>5 r4c8=5 r4c8<>8) r9c3<>8 r9c2=8 r4c2<>8 r4c4=8 r3c4<>8 r3c4=9 r3c5<>9 r7c5=9 r7c2<>9
Forcing Net Contradiction in r7c7 => r5c5<>8
r5c5=8 (r5c6<>8) r5c5<>1 r2c5=1 r2c5<>7 r2c6=7 r5c6<>7 r5c6=5 (r5c8<>5) (r5c3<>5) (r4c4<>5) r6c4<>5 r9c4=5 (r9c8<>5) r9c3<>5 r8c3=5 r8c8<>5 r4c8=5 r4c8<>8 r5c8=8 r5c5<>8
Naked Pair: 1,7 in r25c5 => r7c5<>7
Empty Rectangle: 7 in b4 (r7c17) => r6c7<>7
XYZ-Wing: 1/2/5 in r6c79,r7c9 => r4c9<>1
AIC: 1 1- r6c7 -2- r6c1 =2= r5c1 =3= r7c1 =7= r7c7 =1= r7c9 -1 => r6c9,r7c7<>1
Hidden Single: r7c9=1
Discontinuous Nice Loop: 7 r9c7 -7- r7c7 =7= r7c1 =3= r5c1 =2= r6c1 -2- r6c9 -5- r4c9 -6- r4c7 =6= r9c7 => r9c7<>7
Grouped Discontinuous Nice Loop: 5 r5c6 -5- r5c3 =5= r89c3 -5- r7c2 =5= r7c6 -5- r5c6 => r5c6<>5
Locked Candidates Type 1 (Pointing): 5 in b5 => r9c4<>5
Grouped AIC: 3/7 7- r7c7 =7= r7c1 -7- r456c1 =7= r6c3 =8= r6c4 -8- r5c6 -7- r5c5 -1- r2c5 =1= r2c2 -1- r1c3 -3- r8c3 =3= r8c7 -3 => r7c7<>3, r8c7<>7
Hidden Single: r8c7=3
Grouped Discontinuous Nice Loop: 7 r5c7 -7- r5c6 -8- r6c4 =8= r6c3 =7= r456c1 -7- r7c1 =7= r7c7 -7- r5c7 => r5c7<>7
Grouped Discontinuous Nice Loop: 7 r6c3 -7- r456c1 =7= r7c1 -7- r7c7 -9- r7c5 -8- r3c5 =8= r3c4 -8- r6c4 =8= r6c3 => r6c3<>7
Locked Candidates Type 1 (Pointing): 7 in b4 => r7c1<>7
Hidden Single: r7c7=7
Naked Triple: 2,5,9 in r189c8 => r45c8<>5, r5c8<>2, r5c8<>9
Locked Candidates Type 1 (Pointing): 5 in b6 => r9c9<>5
Locked Candidates Type 2 (Claiming): 5 in r5 => r4c12,r6c1<>5
Naked Pair: 7,8 in r5c68 => r5c15<>7, r5c23<>8
Naked Single: r5c5=1
Naked Single: r2c5=7
Naked Single: r2c6=4
Naked Single: r1c4=1
Naked Single: r2c9=9
Naked Single: r1c3=3
Naked Single: r1c8=2
Full House: r1c7=4
Full House: r1c2=9
Naked Single: r2c1=5
Full House: r2c2=1
Naked Single: r5c3=5
Naked Single: r8c3=7
Naked Single: r9c3=8
Full House: r6c3=1
Naked Single: r6c7=2
Naked Single: r5c7=9
Naked Single: r5c9=4
Naked Single: r6c1=7
Naked Single: r6c9=5
Full House: r6c4=8
Naked Single: r9c7=6
Full House: r4c7=1
Naked Single: r5c2=3
Naked Single: r4c1=4
Naked Single: r4c9=6
Full House: r9c9=2
Naked Single: r3c4=9
Full House: r3c5=8
Full House: r7c5=9
Naked Single: r5c6=7
Full House: r4c4=5
Naked Single: r5c1=2
Full House: r4c2=8
Full House: r5c8=8
Full House: r4c8=7
Naked Single: r7c2=5
Full House: r9c2=4
Naked Single: r8c1=9
Full House: r7c1=3
Full House: r7c6=8
Full House: r9c6=5
Naked Single: r8c4=4
Full House: r9c4=7
Full House: r8c8=5
Full House: r9c8=9
|
normal_sudoku_3464
|
9.3.74...48.9.63...7638...9..746.....9...3.4..34.982.5.4.6.95....9.476.8.6.8...94
|
953274861481956372276381459127465983598123746634798215842619537319547628765832194
|
Basic 9x9 Sudoku 3464
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
9 . 3 . 7 4 . . .
4 8 . 9 . 6 3 . .
. 7 6 3 8 . . . 9
. . 7 4 6 . . . .
. 9 . . . 3 . 4 .
. 3 4 . 9 8 2 . 5
. 4 . 6 . 9 5 . .
. . 9 . 4 7 6 . 8
. 6 . 8 . . . 9 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
953274861481956372276381459127465983598123746634798215842619537319547628765832194 #1 Extreme (8470)
Hidden Single: r4c4=4
Hidden Single: r9c2=6
Hidden Single: r3c5=8
Hidden Single: r8c3=9
Hidden Single: r8c5=4
Hidden Single: r7c4=6
Hidden Single: r2c6=6
Hidden Single: r3c2=7
Hidden Single: r3c4=3
Hidden Single: r2c4=9
Naked Triple: 1,2,5 in r3c168 => r3c79<>1, r3c9<>2
Discontinuous Nice Loop: 1 r4c7 -1- r1c7 -8- r1c8 =8= r4c8 =3= r4c9 =9= r4c7 => r4c7<>1
Forcing Chain Contradiction in r5c9 => r9c9<>1
r9c9=1 r5c9<>1
r9c9=1 r9c9<>4 r9c7=4 r3c7<>4 r3c7=9 r4c7<>9 r4c7=8 r4c8<>8 r1c8=8 r1c8<>6 r1c9=6 r5c9<>6
r9c9=1 r9c9<>4 r9c7=4 r9c7<>7 r5c7=7 r5c9<>7
Forcing Chain Contradiction in r5 => r9c9<>7
r9c9=7 r9c9<>4 r9c7=4 r3c7<>4 r3c7=9 r4c7<>9 r4c7=8 r4c8<>8 r1c8=8 r1c8<>6 r1c9=6 r5c9<>6 r5c1=6 r5c1<>8
r9c9=7 r9c1<>7 r7c1=7 r7c1<>8 r7c3=8 r5c3<>8
r9c9=7 r9c7<>7 r5c7=7 r5c7<>8
Forcing Net Contradiction in c6 => r3c7=4
r3c7<>4 r3c7=9 r4c7<>9 r4c7=8 r1c7<>8 (r1c7=1 r3c8<>1) r1c8=8 r1c8<>6 r6c8=6 r6c1<>6 r6c1=1 r3c1<>1 r3c6=1
r3c7<>4 r3c7=9 r4c7<>9 (r4c9=9 r4c9<>3 r4c8=3 r4c8<>1) (r4c9=9 r4c9<>1) r4c7=8 r1c7<>8 r1c8=8 r1c8<>6 r6c8=6 r6c1<>6 r6c1=1 (r4c1<>1) r4c2<>1 r4c6=1
Naked Single: r3c9=9
Hidden Single: r9c9=4
Hidden Single: r4c7=9
Forcing Net Contradiction in r8 => r1c7=8
r1c7<>8 (r1c7=1 r3c8<>1) r1c8=8 r1c8<>6 r6c8=6 (r6c8<>7 r2c8=7 r2c9<>7 r2c9=2 r3c8<>2) r6c1<>6 r6c1=1 r3c1<>1 r3c6=1 r3c6<>2 r3c1=2 r8c1<>2
r1c7<>8 (r1c7=1 r1c2<>1) r1c8=8 r1c8<>6 r6c8=6 r6c1<>6 r6c1=1 r4c2<>1 r8c2=1 r8c2<>2
r1c7<>8 (r1c7=1 r3c8<>1) r1c8=8 (r1c8<>2) r1c8<>6 (r1c9=6 r1c9<>2) r6c8=6 (r6c8<>7 r2c8=7 r2c9<>7 r2c9=2 r3c8<>2) r6c1<>6 r6c1=1 r3c1<>1 r3c6=1 r3c6<>2 r3c1=2 r1c2<>2 r1c4=2 r8c4<>2
r1c7<>8 (r1c7=1 r9c7<>1) (r1c7=1 r2c8<>1) (r1c7=1 r2c9<>1) (r1c7=1 r3c8<>1) r1c8=8 r1c8<>6 r6c8=6 r6c1<>6 r6c1=1 (r9c1<>1) r3c1<>1 r3c6=1 (r9c6<>1) r2c5<>1 r2c3=1 r9c3<>1 r9c5=1 r9c5<>3 r9c1=3 r8c1<>3 r8c8=3 r8c8<>2
Hidden Single: r4c8=8
Hidden Single: r4c9=3
Finned Jellyfish: 1 c3579 r2579 fr1c9 => r2c8<>1
Discontinuous Nice Loop: 7 r5c9 -7- r5c7 =7= r9c7 -7- r9c1 =7= r7c1 =8= r5c1 =6= r5c9 => r5c9<>7
Finned Franken Swordfish: 1 r34b6 c168 fr4c2 fr5c7 fr5c9 => r5c1<>1
Forcing Chain Contradiction in r3 => r1c8<>1
r1c8=1 r1c8<>6 r6c8=6 r6c1<>6 r6c1=1 r3c1<>1
r1c8=1 r1c8<>6 r6c8=6 r6c1<>6 r6c1=1 r4c12<>1 r4c6=1 r3c6<>1
r1c8=1 r3c8<>1
Forcing Net Contradiction in r8 => r1c8<>2
r1c8=2 r8c1=3
r1c8=2 (r8c8<>2) r1c8<>6 r6c8=6 r6c8<>7 r6c4=7 r5c4<>7 r5c7=7 r9c7<>7 r9c7=1 r8c8<>1 r8c8=3
Forcing Net Contradiction in c8 => r5c1<>2
r5c1=2 (r3c1<>2) (r4c1<>2) r4c2<>2 r4c6=2 r3c6<>2 r3c8=2
r5c1=2 r5c1<>8 r5c3=8 r7c3<>8 r7c1=8 (r7c1<>3) r7c1<>7 r9c1=7 (r9c7<>7 r9c7=1 r8c8<>1) r9c1<>3 r8c1=3 r8c8<>3 r8c8=2
Forcing Net Contradiction in c3 => r5c4<>5
r5c4=5 (r5c5<>5) r5c4<>7 r5c7=7 r9c7<>7 r9c1=7 r9c1<>3 r9c5=3 r9c5<>5 r2c5=5 r2c3<>5
r5c4=5 r5c3<>5
r5c4=5 (r4c6<>5) (r5c5<>5) r5c4<>7 r5c7=7 r9c7<>7 r9c1=7 r9c1<>3 r9c5=3 r9c5<>5 r2c5=5 r3c6<>5 r9c6=5 r9c3<>5
Forcing Net Contradiction in r4 => r1c8=6
r1c8<>6 r6c8=6 r6c1<>6 r6c1=1 (r4c1<>1) r4c2<>1 r4c6=1 r4c6<>5 r4c1=5
r1c8<>6 r1c8=5 (r1c2<>5) r1c4<>5 r8c4=5 r8c2<>5 r4c2=5
Hidden Single: r5c9=6
Hidden Single: r6c1=6
Forcing Net Verity => r2c3=1
r2c3=1 r2c3=1
r5c3=1 (r5c7<>1 r5c7=7 r5c4<>7 r5c4=2 r5c5<>2) (r5c7<>1 r5c7=7 r5c4<>7 r5c4=2 r5c5<>2) (r5c4<>1) (r4c2<>1) (r4c1<>1) r4c2<>1 r4c6=1 (r9c6<>1) (r6c4<>1) (r3c6<>1) r6c4<>1 r6c8=1 r3c8<>1 r3c1=1 (r7c1<>1 r7c5=1 r7c5<>2) r1c2<>1 r8c2=1 r8c4<>1 r1c4=1 (r1c4<>5 r1c2=5 r2c3<>5) (r1c4<>5 r1c2=5 r2c3<>5) (r1c9<>1 r1c9=2 r3c8<>2) r6c4<>1 r6c8=1 r3c8<>1 r3c8=5 r2c8<>5 r2c5=5 r5c5<>5 r5c5=1 r5c5<>5 r4c6=5 r9c6<>5 r9c6=2 r9c5<>2 r2c5=2 r2c3<>2 r2c3=1
r7c3=1 (r5c3<>1) (r9c3<>1) (r5c3<>1) r7c3<>8 r7c1=8 (r7c1<>7 r9c1=7 r9c1<>3 r9c5=3 r7c5<>3) r5c1<>8 r5c1=5 (r4c1<>5) r4c2<>5 r4c6=5 (r4c6<>1) r9c6<>5 r9c6=2 r7c5<>2 r7c5=1 (r5c5<>1) r5c5<>1 r5c4=1 r5c7<>1 r9c7=1 (r9c5<>1) (r5c7<>1) (r9c6<>1) r9c6<>1 r3c6=1 r2c5<>1 r7c5=1 (r5c5<>1) r7c3<>1 r2c3=1
r9c3=1 (r8c1<>1) (r8c2<>1) r9c7<>1 r5c7=1 r6c8<>1 (r6c8=7 r2c8<>7 r2c9=7 r2c9<>1) r6c4=1 r8c4<>1 r8c8=1 (r7c9<>1) r9c7<>1 r9c7=7 r7c9<>7 r7c9=2 r7c5<>2 r7c5=1 (r7c5<>3) r2c5<>1 r2c3=1
Locked Candidates Type 1 (Pointing): 1 in b4 => r4c6<>1
Skyscraper: 1 in r1c9,r6c8 (connected by r16c4) => r3c8<>1
Hidden Single: r3c6=1
Hidden Single: r1c9=1
Naked Pair: 2,5 in r9c36 => r9c15<>2, r9c15<>5
Skyscraper: 5 in r4c6,r5c3 (connected by r9c36) => r4c12,r5c5<>5
Hidden Single: r4c6=5
Full House: r9c6=2
Naked Single: r9c3=5
Hidden Single: r2c5=5
Full House: r1c4=2
Full House: r1c2=5
Full House: r3c1=2
Full House: r3c8=5
Naked Single: r4c1=1
Full House: r4c2=2
Full House: r8c2=1
Naked Single: r8c1=3
Naked Single: r5c3=8
Full House: r5c1=5
Full House: r7c3=2
Naked Single: r8c4=5
Full House: r8c8=2
Naked Single: r9c1=7
Full House: r7c1=8
Naked Single: r7c9=7
Full House: r2c9=2
Full House: r2c8=7
Naked Single: r9c7=1
Full House: r5c7=7
Full House: r6c8=1
Full House: r7c8=3
Full House: r9c5=3
Full House: r6c4=7
Full House: r5c4=1
Full House: r7c5=1
Full House: r5c5=2
|
normal_sudoku_5583
|
86.1....52...8..61.....6.48.5.8....43...49...4.2.7....94..12...127938456...4.7.1.
|
863124795294785361571396248759863124316249587482571639945612873127938456638457912
|
Basic 9x9 Sudoku 5583
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
8 6 . 1 . . . . 5
2 . . . 8 . . 6 1
. . . . . 6 . 4 8
. 5 . 8 . . . . 4
3 . . . 4 9 . . .
4 . 2 . 7 . . . .
9 4 . . 1 2 . . .
1 2 7 9 3 8 4 5 6
. . . 4 . 7 . 1 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
863124795294785361571396248759863124316249587482571639945612873127938456638457912 #1 Hard (900)
Hidden Single: r8c7=4
Hidden Single: r8c6=8
Naked Single: r8c2=2
Hidden Single: r7c5=1
Skyscraper: 4 in r2c6,r5c5 (connected by r25c3) => r1c5,r6c6<>4
Hidden Single: r5c5=4
Hidden Single: r6c1=4
X-Wing: 5 c15 r39 => r3c34,r9c37<>5
X-Wing: 6 c15 r49 => r4c37,r9c379<>6
Locked Pair: 3,8 in r9c23 => r7c3,r9c17<>8, r7c3,r9c79<>3
Hidden Single: r1c1=8
Locked Pair: 2,9 in r9c79 => r8c89,r9c5<>9
Naked Single: r8c8=5
Naked Single: r8c9=6
Full House: r8c4=9
Locked Candidates Type 2 (Claiming): 7 in r1 => r23c7<>7
Naked Triple: 2,3,9 in r239c7 => r145c7<>2, r1467c7<>3, r146c7<>9
Naked Single: r1c7=7
Naked Single: r4c7=1
Naked Single: r7c7=8
Naked Single: r4c3=9
Naked Single: r4c6=3
Naked Single: r1c6=4
Naked Single: r1c3=3
Naked Single: r2c6=5
Full House: r6c6=1
Naked Single: r3c3=1
Naked Single: r9c3=8
Naked Single: r2c3=4
Naked Single: r6c2=8
Naked Single: r5c3=6
Full House: r7c3=5
Naked Single: r9c2=3
Full House: r9c1=6
Naked Single: r4c1=7
Full House: r3c1=5
Full House: r5c2=1
Naked Single: r5c7=5
Naked Single: r7c4=6
Full House: r9c5=5
Naked Single: r4c8=2
Full House: r4c5=6
Naked Single: r5c4=2
Full House: r6c4=5
Naked Single: r6c7=6
Naked Single: r1c8=9
Full House: r1c5=2
Full House: r3c5=9
Naked Single: r5c9=7
Full House: r5c8=8
Naked Single: r2c7=3
Full House: r3c7=2
Full House: r9c7=9
Full House: r9c9=2
Naked Single: r6c8=3
Full House: r6c9=9
Full House: r7c9=3
Full House: r7c8=7
Naked Single: r3c2=7
Full House: r2c2=9
Full House: r2c4=7
Full House: r3c4=3
|
normal_sudoku_164
|
.8...2..69..4...3.....8.5.....6.41...4.52...3..6..3.457.9........1..7.59.3.2....7
|
584732916912456738673981524358694172147528693296173845769345281421867359835219467
|
Basic 9x9 Sudoku 164
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 8 . . . 2 . . 6
9 . . 4 . . . 3 .
. . . . 8 . 5 . .
. . . 6 . 4 1 . .
. 4 . 5 2 . . . 3
. . 6 . . 3 . 4 5
7 . 9 . . . . . .
. . 1 . . 7 . 5 9
. 3 . 2 . . . . 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
584732916912456738673981524358694172147528693296173845769345281421867359835219467 #1 Extreme (22022) bf
Brute Force: r5c4=5
Almost Locked Set XZ-Rule: A=r4c5 {79}, B=r5c136 {1789}, X=9, Z=7 => r4c23<>7
Forcing Net Contradiction in c2 => r2c2<>2
r2c2=2 (r2c3<>2) r3c3<>2 r4c3=2 (r4c3<>5) r4c3<>3 r4c1=3 r4c1<>5 r4c2=5
r2c2=2 (r7c2<>2) r8c2<>2 r8c2=6 r7c2<>6 r7c2=5
Forcing Net Contradiction in r8c7 => r3c1<>2
r3c1=2 (r2c3<>2) r3c3<>2 r4c3=2 (r4c8<>2 r7c8=2 r7c2<>2) (r4c3<>5) r4c3<>3 r4c1=3 r4c1<>5 r4c2=5 r7c2<>5 r7c2=6 (r8c1<>6) r9c1<>6 r3c1=6 r3c1<>2
Forcing Net Contradiction in c2 => r3c2<>2
r3c2=2 (r2c3<>2) r3c3<>2 r4c3=2 (r4c3<>5) r4c3<>3 r4c1=3 r4c1<>5 r4c2=5
r3c2=2 (r7c2<>2) r8c2<>2 r8c2=6 r7c2<>6 r7c2=5
Locked Candidates Type 1 (Pointing): 2 in b1 => r4c3<>2
Forcing Net Verity => r4c8<>9
r3c6=1 (r9c6<>1) (r1c4<>1) (r1c5<>1) r5c6<>1 r5c1=1 (r6c1<>1) (r6c2<>1) r1c1<>1 r1c8=1 r9c8<>1 r9c5=1 r6c5<>1 r6c4=1 r6c4<>8 r5c6=8 r5c6<>9 r5c78=9 r4c8<>9
r3c6=6 (r2c5<>6) r2c6<>6 r2c2=6 (r7c2<>6) r8c2<>6 r8c2=2 (r4c2<>2) r7c2<>2 r7c2=5 r4c2<>5 r4c2=9 r4c8<>9
r3c6=9 r5c6<>9 r5c78=9 r4c8<>9
Forcing Net Verity => r4c9<>9
r3c6=1 (r9c6<>1) (r1c4<>1) (r1c5<>1) r5c6<>1 r5c1=1 (r6c1<>1) (r6c2<>1) r1c1<>1 r1c8=1 r9c8<>1 r9c5=1 r6c5<>1 r6c4=1 r6c4<>8 r5c6=8 r5c6<>9 r5c78=9 r4c9<>9
r3c6=6 (r2c5<>6) r2c6<>6 r2c2=6 (r7c2<>6) r8c2<>6 r8c2=2 (r4c2<>2) r7c2<>2 r7c2=5 r4c2<>5 r4c2=9 r4c9<>9
r3c6=9 r5c6<>9 r5c78=9 r4c9<>9
Almost Locked Set XZ-Rule: A=r4c589 {2789}, B=r5c136 {1789}, X=9, Z=8 => r5c78<>8
Finned Franken Swordfish: 9 c69b6 r359 fr6c7 fr8c9 => r9c7<>9
Forcing Net Verity => r1c5<>7
r3c6=1 (r9c6<>1) (r1c4<>1) (r1c5<>1) r5c6<>1 r5c1=1 (r6c1<>1) (r6c2<>1) r1c1<>1 r1c8=1 r9c8<>1 r9c5=1 r6c5<>1 r6c4=1 r6c4<>7 r13c4=7 r1c5<>7
r3c6=6 (r2c5<>6) r2c6<>6 r2c2=6 (r7c2<>6) r8c2<>6 r8c2=2 (r4c2<>2) r7c2<>2 r7c2=5 r4c2<>5 r4c2=9 r4c5<>9 r4c5=7 r1c5<>7
r3c6=9 (r1c4<>9) (r3c4<>9) r3c9<>9 r8c9=9 r8c4<>9 r6c4=9 r4c5<>9 r4c5=7 r1c5<>7
Forcing Net Verity => r2c2<>5
r3c6=1 (r2c5<>1) (r2c6<>1) (r1c4<>1) (r1c5<>1) r5c6<>1 r5c1=1 r1c1<>1 r1c8=1 r2c9<>1 r2c2=1 r2c2<>5
r3c6=6 (r2c5<>6) r2c6<>6 r2c2=6 r2c2<>5
r3c6=9 (r1c4<>9) (r3c4<>9) r3c9<>9 r8c9=9 r8c4<>9 r6c4=9 (r4c5<>9 r4c5=7 r2c5<>7) (r6c4<>7) (r4c5<>9 r4c5=7 r6c5<>7) r6c4<>8 r5c6=8 r5c3<>8 r5c3=7 (r2c3<>7) r6c2<>7 r6c7=7 r2c7<>7 r2c2=7 r2c2<>5
Forcing Chain Contradiction in c7 => r8c9<>2
r8c9=2 r8c9<>9 r3c9=9 r3c9<>4 r1c7=4 r1c7<>7
r8c9=2 r4c9<>2 r4c9=8 r2c9<>8 r2c7=8 r2c7<>7
r8c9=2 r7c789<>2 r7c2=2 r7c2<>5 r4c2=5 r4c2<>9 r4c5=9 r4c5<>7 r4c8=7 r5c7<>7
r8c9=2 r7c789<>2 r7c2=2 r7c2<>5 r4c2=5 r4c2<>9 r4c5=9 r4c5<>7 r4c8=7 r6c7<>7
Forcing Net Verity => r2c5<>7
r3c6=1 (r9c6<>1) (r1c4<>1) (r1c5<>1) r5c6<>1 r5c1=1 (r6c1<>1) (r6c2<>1) r1c1<>1 r1c8=1 r9c8<>1 r9c5=1 r6c5<>1 r6c4=1 r6c4<>7 r13c4=7 r2c5<>7
r3c6=6 (r2c5<>6) r2c6<>6 r2c2=6 (r7c2<>6) r8c2<>6 r8c2=2 (r4c2<>2) r7c2<>2 r7c2=5 r4c2<>5 r4c2=9 r4c5<>9 r4c5=7 r2c5<>7
r3c6=9 (r1c4<>9) (r3c4<>9) r3c9<>9 r8c9=9 r8c4<>9 r6c4=9 r4c5<>9 r4c5=7 r2c5<>7
Locked Candidates Type 1 (Pointing): 7 in b2 => r6c4<>7
Forcing Net Verity => r1c5<>1
r1c4=9 (r1c4<>3) r1c4<>7 r3c4=7 r3c4<>3 r1c5=3 r1c5<>1
r3c4=9 (r3c4<>3) r3c4<>7 r1c4=7 r1c4<>3 r1c5=3 r1c5<>1
r6c4=9 (r6c5<>9) r4c5<>9 r4c5=7 r6c5<>7 r6c5=1 r1c5<>1
r8c4=9 (r1c4<>9) r8c9<>9 r3c9=9 (r1c7<>9) r1c8<>9 r1c5=9 r1c5<>1
Forcing Net Verity => r5c3=7
r1c4=1 (r1c4<>9) (r1c4<>9) (r1c4<>3) r1c4<>7 r3c4=7 (r3c4<>9) (r3c4<>9) r3c4<>3 r1c5=3 r1c5<>9 r3c6=9 r3c9<>9 r8c9=9 r8c4<>9 r6c4=9 r6c4<>8 r5c6=8 r5c3<>8 r5c3=7
r3c4=1 (r3c4<>9) (r3c4<>9) (r3c4<>3) r3c4<>7 r1c4=7 (r1c4<>9) (r1c4<>9) r1c4<>3 r1c5=3 r1c5<>9 r3c6=9 r3c9<>9 r8c9=9 r8c4<>9 r6c4=9 r6c4<>8 r5c6=8 r5c3<>8 r5c3=7
r6c4=1 r6c4<>8 r5c6=8 r5c3<>8 r5c3=7
r7c4=1 (r1c4<>1) (r9c5<>1) r9c6<>1 r9c8=1 r1c8<>1 r1c1=1 r5c1<>1 r5c1=8 r5c3<>8 r5c3=7
Locked Pair: 6,9 in r5c78 => r5c6,r6c7<>9
Skyscraper: 9 in r8c9,r9c6 (connected by r3c69) => r8c45,r9c8<>9
2-String Kite: 8 in r5c6,r9c3 (connected by r4c3,r5c1) => r9c6<>8
Empty Rectangle: 8 in b6 (r49c3) => r9c7<>8
AIC: 4/9 4- r3c9 =4= r1c7 -4- r9c7 -6- r5c7 -9- r8c7 =9= r8c9 -9 => r8c9<>4, r3c9<>9
Hidden Single: r8c9=9
Almost Locked Set XY-Wing: A=r1c13,r23c3 {12345}, B=r78c2,r89c1 {24568}, C=r5c1 {18}, X,Y=1,8, Z=4 => r3c1<>4
Forcing Chain Contradiction in r3c6 => r1c1<>1
r1c1=1 r5c1<>1 r5c6=1 r3c6<>1
r1c1=1 r56c1<>1 r6c2=1 r6c2<>9 r4c2=9 r4c5<>9 r4c5=7 r4c8<>7 r6c7=7 r2c7<>7 r2c2=7 r2c2<>6 r2c56=6 r3c6<>6
r1c1=1 r5c1<>1 r5c1=8 r5c6<>8 r6c4=8 r6c4<>9 r13c4=9 r3c6<>9
Hidden Triple: 1,6,7 in r23c2,r3c1 => r3c1<>3
Empty Rectangle: 1 in b9 (r1c48) => r7c4<>1
Locked Pair: 3,8 in r78c4 => r13c4,r78c5<>3, r6c4,r7c6<>8
Hidden Single: r3c3=3
Hidden Single: r1c5=3
Hidden Single: r5c6=8
Naked Single: r5c1=1
Naked Single: r3c1=6
Hidden Single: r4c1=3
Hidden Single: r2c3=2
Hidden Single: r3c9=4
Hidden Single: r3c8=2
Locked Candidates Type 1 (Pointing): 9 in b3 => r1c4<>9
Naked Triple: 1,7,9 in r13c4,r3c6 => r2c56<>1
W-Wing: 6/4 in r8c5,r9c7 connected by 4 in r7c57 => r8c7,r9c56<>6
Locked Candidates Type 2 (Claiming): 6 in r9 => r7c78<>6
Uniqueness Test 2: 4/5 in r1c13,r9c13 => r8c1,r9c8<>8
Naked Triple: 2,4,6 in r8c125 => r8c7<>2, r8c7<>4
Locked Candidates Type 1 (Pointing): 2 in b9 => r7c2<>2
W-Wing: 5/6 in r2c5,r7c2 connected by 6 in r8c25 => r7c5<>5
Uniqueness Test 1: 3/8 in r7c47,r8c47 => r7c7<>3, r7c7<>8
Hidden Single: r7c4=3
Naked Single: r8c4=8
Naked Single: r8c7=3
Finned Swordfish: 1 r169 c458 fr9c6 => r7c5<>1
Locked Pair: 4,6 in r78c5 => r2c5,r7c6<>6, r9c5<>4
Naked Single: r2c5=5
Naked Single: r2c6=6
XY-Chain: 9 9- r4c5 -7- r4c8 -8- r7c8 -1- r7c6 -5- r7c2 -6- r8c2 -2- r6c2 -9 => r4c2,r6c45<>9
Naked Single: r6c4=1
Naked Single: r1c4=7
Full House: r3c4=9
Full House: r3c6=1
Full House: r3c2=7
Naked Single: r6c5=7
Full House: r4c5=9
Naked Single: r1c7=9
Naked Single: r7c6=5
Full House: r9c6=9
Naked Single: r2c2=1
Naked Single: r9c5=1
Naked Single: r1c8=1
Naked Single: r5c7=6
Full House: r5c8=9
Naked Single: r7c2=6
Naked Single: r2c9=8
Full House: r2c7=7
Naked Single: r9c8=6
Naked Single: r7c8=8
Full House: r4c8=7
Naked Single: r9c7=4
Naked Single: r7c5=4
Full House: r8c5=6
Naked Single: r8c2=2
Full House: r8c1=4
Naked Single: r4c9=2
Full House: r6c7=8
Full House: r7c7=2
Full House: r7c9=1
Naked Single: r4c2=5
Full House: r6c2=9
Full House: r6c1=2
Full House: r4c3=8
Naked Single: r1c1=5
Full House: r1c3=4
Full House: r9c3=5
Full House: r9c1=8
|
normal_sudoku_593
|
67.8.4...2.4.16....8.27.46.4..1.2...817469532..2..7.4.12.64...8.487.1...7.6.28..4
|
671834925254916873983275461439152687817469532562387149125643798348791256796528314
|
Basic 9x9 Sudoku 593
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
6 7 . 8 . 4 . . .
2 . 4 . 1 6 . . .
. 8 . 2 7 . 4 6 .
4 . . 1 . 2 . . .
8 1 7 4 6 9 5 3 2
. . 2 . . 7 . 4 .
1 2 . 6 4 . . . 8
. 4 8 7 . 1 . . .
7 . 6 . 2 8 . . 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
671834925254916873983275461439152687817469532562387149125643798348791256796528314 #1 Extreme (35218) bf
Hidden Single: r3c5=7
Hidden Single: r9c1=7
Hidden Single: r1c1=6
Hidden Single: r9c6=8
Hidden Single: r3c7=4
Hidden Single: r7c5=4
Hidden Single: r8c2=4
Hidden Single: r6c8=4
Hidden Single: r2c1=2
Hidden Single: r8c6=1
Hidden Single: r5c4=4
Brute Force: r5c2=1
Brute Force: r5c5=6
Hidden Single: r5c1=8
Brute Force: r5c6=9
Full House: r5c9=2
Hidden Single: r4c6=2
Grouped Discontinuous Nice Loop: 3 r1c7 =2= r8c7 =6= r8c9 =3= r789c7 -3- r1c7 => r1c7<>3
Finned Franken Swordfish: 3 c16b5 r368 fr4c5 fr7c6 => r8c5<>3
W-Wing: 5/3 in r3c6,r6c4 connected by 3 in r7c6,r9c4 => r2c4<>5
Sashimi Swordfish: 5 c146 r368 fr7c6 fr9c4 => r8c5<>5
Naked Single: r8c5=9
Hidden Single: r2c4=9
Forcing Chain Contradiction in r7c3 => r3c1<>3
r3c1=3 r3c6<>3 r7c6=3 r7c3<>3
r3c1=3 r8c1<>3 r8c1=5 r7c3<>5
r3c1=3 r3c1<>9 r13c3=9 r7c3<>9
Skyscraper: 3 in r8c1,r9c4 (connected by r6c14) => r9c2<>3
Grouped Discontinuous Nice Loop: 3 r2c7 -3- r2c2 =3= r46c2 -3- r6c1 =3= r8c1 -3- r8c9 =3= r789c7 -3- r2c7 => r2c7<>3
Locked Candidates Type 1 (Pointing): 3 in b3 => r8c9<>3
Discontinuous Nice Loop: 7 r4c8 -7- r4c9 =7= r2c9 -7- r2c7 -8- r2c8 =8= r4c8 => r4c8<>7
Grouped Discontinuous Nice Loop: 5 r7c8 -5- r7c6 -3- r7c3 =3= r8c1 =5= r8c89 -5- r7c8 => r7c8<>5
Turbot Fish: 5 r1c5 =5= r3c6 -5- r7c6 =5= r7c3 => r1c3<>5
Grouped Discontinuous Nice Loop: 3 r3c9 -3- r3c6 -5- r3c13 =5= r2c2 =3= r2c9 -3- r3c9 => r3c9<>3
Discontinuous Nice Loop: 5 r6c2 -5- r6c4 -3- r9c4 =3= r7c6 -3- r3c6 =3= r3c3 -3- r2c2 -5- r6c2 => r6c2<>5
Discontinuous Nice Loop: 5 r6c5 -5- r1c5 -3- r3c6 =3= r3c3 =1= r3c9 -1- r6c9 =1= r6c7 =8= r6c5 => r6c5<>5
Almost Locked Set XZ-Rule: A=r6c14 {359}, B=r2c2,r3c1 {359}, X=9, Z=3 => r6c2<>3
Forcing Chain Contradiction in r7c3 => r3c1=9
r3c1<>9 r3c1=5 r8c1<>5 r8c1=3 r7c3<>3
r3c1<>9 r3c1=5 r3c6<>5 r7c6=5 r7c3<>5
r3c1<>9 r13c3=9 r7c3<>9
Naked Pair: 3,5 in r6c14 => r6c5<>3
Naked Single: r6c5=8
Swordfish: 3 r689 c147 => r7c7<>3
Locked Pair: 7,9 in r7c78 => r7c3,r9c78<>9
Hidden Single: r4c3=9
Naked Single: r4c8=8
Naked Single: r6c2=6
Hidden Single: r9c2=9
Hidden Single: r2c7=8
X-Wing: 3 r37 c36 => r1c3<>3
Naked Single: r1c3=1
Hidden Single: r9c8=1
Naked Single: r9c7=3
Full House: r9c4=5
Full House: r6c4=3
Full House: r7c6=3
Full House: r4c5=5
Full House: r3c6=5
Full House: r1c5=3
Naked Single: r6c1=5
Full House: r4c2=3
Full House: r8c1=3
Full House: r7c3=5
Full House: r3c3=3
Full House: r3c9=1
Full House: r2c2=5
Naked Single: r6c9=9
Full House: r6c7=1
Naked Single: r2c8=7
Full House: r2c9=3
Naked Single: r1c9=5
Naked Single: r7c8=9
Full House: r7c7=7
Naked Single: r8c9=6
Full House: r4c9=7
Full House: r4c7=6
Naked Single: r1c8=2
Full House: r1c7=9
Full House: r8c7=2
Full House: r8c8=5
|
normal_sudoku_4284
|
.9.3..26.5...921..........9.6.4...9...7.618..4...7.5.66..8....2.8...9.....3.4..8.
|
791354268548692173326187459865423791937561824412978536679815342284739615153246987
|
Basic 9x9 Sudoku 4284
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 9 . 3 . . 2 6 .
5 . . . 9 2 1 . .
. . . . . . . . 9
. 6 . 4 . . . 9 .
. . 7 . 6 1 8 . .
4 . . . 7 . 5 . 6
6 . . 8 . . . . 2
. 8 . . . 9 . . .
. . 3 . 4 . . 8 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
791354268548692173326187459865423791937561824412978536679815342284739615153246987 #1 Extreme (36298) bf
Brute Force: r5c5=6
Hidden Single: r6c9=6
Hidden Single: r2c5=9
Discontinuous Nice Loop: 2 r5c1 -2- r5c8 =2= r6c8 -2- r6c4 -9- r6c3 =9= r5c1 => r5c1<>2
Forcing Chain Contradiction in r9c7 => r4c9<>8
r4c9=8 r2c9<>8 r2c3=8 r2c3<>6 r2c4=6 r8c4<>6 r8c7=6 r9c7<>6
r4c9=8 r4c9<>7 r4c7=7 r9c7<>7
r4c9=8 r5c79<>8 r5c1=8 r5c1<>9 r9c1=9 r9c7<>9
Forcing Net Contradiction in r4 => r1c6<>8
r1c6=8 (r6c6<>8 r6c6=3 r4c6<>3 r4c6=5 r7c6<>5 r7c6=7 r7c7<>7) (r6c6<>8 r6c6=3 r4c5<>3) (r1c5<>8) r3c5<>8 r4c5=8 r4c5<>2 r8c5=2 r8c5<>3 r7c5=3 r7c7<>3 r7c7=4 (r8c9<>4 r8c3=4 r8c3<>5) r7c7<>9 r7c3=9 (r7c7<>9) r7c3<>5 r4c3=5
r1c6=8 (r4c6<>8) r6c6<>8 r6c6=3 r4c6<>3 r4c6=5
Forcing Net Contradiction in r5c4 => r3c6<>5
r3c6=5 (r1c6<>5 r1c9=5 r9c9<>5) (r3c6<>4 r1c6=4 r1c6<>7 r1c1=7 r2c2<>7) (r3c6<>4 r1c6=4 r1c6<>7 r1c1=7 r3c2<>7) (r3c6<>7) (r3c6<>4 r1c6=4 r1c6<>7) r3c6<>6 r9c6=6 r9c6<>7 r7c6=7 r7c2<>7 r9c2=7 r9c9<>7 r9c9=1 (r7c8<>1) r8c8<>1 r6c8=1 r6c8<>2 r5c8=2 r5c4<>2
r3c6=5 (r9c6<>5) (r1c6<>5 r1c9=5 r9c9<>5) (r3c6<>4 r1c6=4 r1c6<>7 r1c1=7 r2c2<>7) (r3c6<>4 r1c6=4 r1c6<>7 r1c1=7 r3c2<>7) (r3c6<>7) (r3c6<>4 r1c6=4 r1c6<>7) r3c6<>6 r9c6=6 r9c6<>7 r7c6=7 r7c2<>7 r9c2=7 r9c2<>5 r9c4=5 r5c4<>5
r3c6=5 (r3c6<>4 r1c6=4 r1c6<>7 r1c1=7 r2c2<>7) (r3c6<>4 r1c6=4 r1c6<>7 r1c1=7 r3c2<>7) (r3c6<>7) (r3c6<>4 r1c6=4 r1c6<>7) r3c6<>6 r9c6=6 (r9c7<>6) r9c6<>7 r7c6=7 r7c2<>7 r9c2=7 r9c7<>7 r9c7=9 r9c1<>9 r5c1=9 r5c4<>9
Forcing Net Contradiction in r4 => r3c6<>8
r3c6=8 (r3c6<>6 r9c6=6 r9c6<>7 r7c6=7 r7c7<>7) (r6c6<>8 r6c6=3 r4c5<>3) (r1c5<>8) r3c5<>8 r4c5=8 r4c5<>2 r8c5=2 r8c5<>3 r7c5=3 r7c7<>3 r7c7=4 (r8c9<>4 r8c3=4 r8c3<>5) r7c7<>9 r7c3=9 (r7c7<>9) r7c3<>5 r4c3=5
r3c6=8 (r4c6<>8) r6c6<>8 r6c6=3 r4c6<>3 r4c6=5
Locked Candidates Type 1 (Pointing): 8 in b2 => r4c5<>8
Forcing Net Contradiction in r7c7 => r5c4<>2
r5c4=2 r4c5<>2 r8c5=2 r8c5<>3 r7c56=3 r7c7<>3
r5c4=2 (r5c4<>5 r5c2=5 r4c3<>5) r6c4<>2 r6c4=9 r6c3<>9 r7c3=9 (r7c3<>4) r7c3<>5 r8c3=5 r8c3<>4 r7c2=4 r7c7<>4
r5c4=2 r5c8<>2 r6c8=2 r6c8<>1 r4c9=1 r4c9<>7 r4c7=7 r7c7<>7
r5c4=2 r6c4<>2 r6c4=9 r6c3<>9 r7c3=9 r7c7<>9
Forcing Net Contradiction in r1 => r8c4<>5
r8c4=5 (r8c4<>7) (r8c4<>6 r8c7=6 r8c7<>7) (r8c4<>6 r8c7=6 r9c7<>6) r5c4<>5 r5c4=9 r5c1<>9 r9c1=9 r9c7<>9 r9c7=7 (r8c8<>7) r8c9<>7 r8c1=7 r1c1<>7
r8c4=5 (r8c4<>7) (r8c4<>6 r8c7=6 r8c7<>7) (r8c4<>6 r8c7=6 r9c7<>6) r5c4<>5 r5c4=9 r5c1<>9 r9c1=9 r9c7<>9 r9c7=7 (r7c7<>7) (r7c8<>7) (r8c8<>7) r8c9<>7 r8c1=7 r7c2<>7 r7c6=7 r1c6<>7
r8c4=5 (r8c4<>6 r8c7=6 r9c7<>6) r5c4<>5 r5c4=9 r5c1<>9 r9c1=9 r9c7<>9 r9c7=7 r4c7<>7 r4c9=7 r1c9<>7
Brute Force: r5c7=8
Grouped Discontinuous Nice Loop: 7 r8c7 -7- r4c7 -3- r4c56 =3= r6c6 =8= r6c3 =9= r7c3 -9- r7c7 =9= r9c7 =6= r8c7 => r8c7<>7
Grouped Discontinuous Nice Loop: 7 r9c7 -7- r4c7 -3- r4c56 =3= r6c6 =8= r6c3 =9= r7c3 -9- r7c7 =9= r9c7 => r9c7<>7
Forcing Chain Contradiction in c7 => r1c3<>4
r1c3=4 r1c6<>4 r3c6=4 r3c7<>4
r1c3=4 r8c3<>4 r7c23=4 r7c7<>4
r1c3=4 r1c6<>4 r3c6=4 r3c6<>6 r9c6=6 r9c7<>6 r8c7=6 r8c7<>4
Forcing Chain Contradiction in r6c3 => r2c9<>4
r2c9=4 r2c9<>8 r2c3=8 r1c3<>8 r1c3=1 r6c3<>1
r2c9=4 r5c9<>4 r5c8=4 r5c8<>2 r5c2=2 r6c3<>2
r2c9=4 r2c9<>8 r2c3=8 r6c3<>8
r2c9=4 r5c9<>4 r5c9=3 r5c1<>3 r5c1=9 r6c3<>9
Forcing Chain Contradiction in r4 => r4c3<>1
r4c3=1 r1c3<>1 r1c3=8 r13c1<>8 r4c1=8 r4c1<>2
r4c3=1 r4c3<>2
r4c3=1 r4c3<>5 r5c2=5 r5c4<>5 r5c4=9 r6c4<>9 r6c4=2 r4c5<>2
Forcing Chain Contradiction in c9 => r8c7<>3
r8c7=3 r8c7<>6 r8c4=6 r2c4<>6 r2c3=6 r2c3<>8 r2c9=8 r2c9<>3
r8c7=3 r8c7<>6 r9c7=6 r9c7<>9 r9c1=9 r5c1<>9 r6c3=9 r6c3<>8 r6c6=8 r6c6<>3 r4c56=3 r4c9<>3
r8c7=3 r8c7<>6 r9c7=6 r9c7<>9 r9c1=9 r5c1<>9 r5c1=3 r5c9<>3
r8c7=3 r8c9<>3
Forcing Net Contradiction in r2c2 => r1c6=4
r1c6<>4 r1c9=4 (r3c7<>4) r5c9<>4 r5c9=3 (r2c9<>3) r4c7<>3 r4c7=7 r3c7<>7 r3c7=3 r2c8<>3 r2c2=3
r1c6<>4 (r1c9=4 r2c8<>4) (r1c9=4 r5c9<>4 r5c8=4 r8c8<>4) (r1c9=4 r8c9<>4) r3c6=4 r3c6<>6 r9c6=6 r8c4<>6 r8c7=6 r8c7<>4 r8c3=4 r2c3<>4 r2c2=4
Naked Pair: 6,7 in r2c4,r3c6 => r3c4<>6, r3c4<>7
Discontinuous Nice Loop: 1 r8c4 -1- r3c4 -5- r5c4 -9- r5c1 =9= r9c1 -9- r9c7 -6- r8c7 =6= r8c4 => r8c4<>1
Grouped Discontinuous Nice Loop: 5 r8c5 -5- r13c5 =5= r3c4 -5- r5c4 -9- r6c4 -2- r4c5 =2= r8c5 => r8c5<>5
Forcing Chain Contradiction in r9c9 => r2c9<>7
r2c9=7 r2c9<>8 r2c3=8 r13c1<>8 r4c1=8 r4c1<>1 r4c9=1 r9c9<>1
r2c9=7 r2c4<>7 r2c4=6 r8c4<>6 r8c7=6 r9c7<>6 r9c7=9 r9c1<>9 r5c1=9 r5c4<>9 r5c4=5 r5c2<>5 r4c3=5 r8c3<>5 r8c89=5 r9c9<>5
r2c9=7 r9c9<>7
Forcing Chain Contradiction in r8c1 => r3c1<>1
r3c1=1 r8c1<>1
r3c1=1 r3c4<>1 r9c4=1 r9c4<>2 r8c45=2 r8c1<>2
r3c1=1 r3c4<>1 r3c4=5 r3c8<>5 r1c9=5 r1c9<>7 r1c1=7 r8c1<>7
Forcing Chain Verity => r3c2<>1
r4c1=1 r4c1<>8 r13c1=8 r1c3<>8 r1c3=1 r3c2<>1
r6c2=1 r3c2<>1
r6c3=1 r6c3<>9 r6c4=9 r5c4<>9 r5c4=5 r3c4<>5 r3c4=1 r3c2<>1
Forcing Chain Contradiction in r9c9 => r6c3<>1
r6c3=1 r6c8<>1 r4c9=1 r9c9<>1
r6c3=1 r6c3<>9 r6c4=9 r5c4<>9 r5c4=5 r5c2<>5 r4c3=5 r8c3<>5 r8c89=5 r9c9<>5
r6c3=1 r13c3<>1 r1c1=1 r1c1<>7 r1c9=7 r9c9<>7
Almost Locked Set XY-Wing: A=r5c124 {2359}, B=r6c3468 {12389}, C=r23578c8 {123457}, X,Y=1,2, Z=3 => r6c2<>3
Forcing Chain Contradiction in r9 => r1c1<>1
r1c1=1 r9c1<>1
r1c1=1 r4c1<>1 r6c2=1 r9c2<>1
r1c1=1 r1c1<>7 r1c9=7 r1c9<>5 r1c5=5 r3c4<>5 r3c4=1 r9c4<>1
r1c1=1 r4c1<>1 r4c9=1 r9c9<>1
Locked Candidates Type 1 (Pointing): 1 in b1 => r78c3<>1
Forcing Chain Contradiction in r8c3 => r7c3<>5
r7c3=5 r7c3<>9 r6c3=9 r6c4<>9 r6c4=2 r9c4<>2 r8c45=2 r8c3<>2
r7c3=5 r7c3<>9 r7c7=9 r9c7<>9 r9c7=6 r8c7<>6 r8c7=4 r8c3<>4
r7c3=5 r8c3<>5
Forcing Chain Contradiction in c7 => r3c3<>4
r3c3=4 r3c7<>4
r3c3=4 r8c3<>4 r7c23=4 r7c7<>4
r3c3=4 r7c3<>4 r7c3=9 r7c7<>9 r9c7=9 r9c7<>6 r8c7=6 r8c7<>4
Forcing Chain Contradiction in c8 => r7c5<>5
r7c5=5 r1c5<>5 r1c9=5 r3c8<>5
r7c5=5 r7c8<>5
r7c5=5 r79c6<>5 r4c6=5 r4c3<>5 r8c3=5 r8c8<>5
Forcing Chain Contradiction in r9 => r4c5<>3
r4c5=3 r4c5<>2 r6c4=2 r6c4<>9 r6c3=9 r7c3<>9 r9c1=9 r9c1<>1
r4c5=3 r4c5<>2 r6c4=2 r6c2<>2 r6c2=1 r9c2<>1
r4c5=3 r7c5<>3 r7c5=1 r9c4<>1
r4c5=3 r6c6<>3 r6c8=3 r6c8<>1 r4c9=1 r9c9<>1
Locked Candidates Type 1 (Pointing): 3 in b5 => r7c6<>3
Naked Triple: 2,5,9 in r4c5,r56c4 => r4c6<>5
Locked Candidates Type 2 (Claiming): 5 in c6 => r9c4<>5
Finned Swordfish: 5 r148 c359 fr8c8 => r9c9<>5
Forcing Chain Contradiction in c2 => r1c3=1
r1c3<>1 r1c3=8 r1c1<>8 r1c1=7 r2c2<>7
r1c3<>1 r1c3=8 r1c1<>8 r1c1=7 r3c2<>7
r1c3<>1 r1c5=1 r3c4<>1 r3c4=5 r5c4<>5 r5c2=5 r9c2<>5 r9c6=5 r7c6<>5 r7c6=7 r7c2<>7
r1c3<>1 r1c5=1 r3c4<>1 r9c4=1 r9c9<>1 r9c9=7 r9c2<>7
Forcing Chain Contradiction in r7 => r3c4=1
r3c4<>1 r3c4=5 r5c4<>5 r5c4=9 r6c4<>9 r6c4=2 r6c2<>2 r6c2=1 r7c2<>1
r3c4<>1 r3c5=1 r7c5<>1
r3c4<>1 r3c4=5 r5c4<>5 r5c2=5 r4c3<>5 r8c3=5 r8c89<>5 r7c8=5 r7c8<>1
Hidden Single: r5c4=5
Naked Single: r4c5=2
Naked Single: r6c4=9
Hidden Single: r4c3=5
Hidden Single: r5c1=9
Hidden Single: r7c3=9
Hidden Single: r9c7=9
Hidden Single: r8c7=6
Locked Candidates Type 2 (Claiming): 5 in r8 => r7c8<>5
Hidden Rectangle: 5/7 in r7c26,r9c26 => r9c2<>7
Finned X-Wing: 1 r49 c19 fr9c2 => r8c1<>1
Naked Pair: 2,7 in r8c14 => r8c3<>2, r8c89<>7
Naked Single: r8c3=4
Hidden Single: r5c9=4
2-String Kite: 3 in r3c1,r5c8 (connected by r4c1,r5c2) => r3c8<>3
Turbot Fish: 7 r3c6 =7= r2c4 -7- r8c4 =7= r8c1 => r3c1<>7
XY-Wing: 6/8/7 in r1c1,r2c34 => r2c2<>7
Finned X-Wing: 7 c28 r37 fr2c8 => r3c7<>7
Sashimi Swordfish: 7 r128 c148 fr1c9 => r3c8<>7
Turbot Fish: 7 r3c6 =7= r2c4 -7- r2c8 =7= r7c8 => r7c6<>7
Naked Single: r7c6=5
Hidden Single: r9c2=5
Locked Candidates Type 1 (Pointing): 2 in b7 => r3c1<>2
Hidden Triple: 2,6,7 in r3c236 => r3c2<>3, r3c2<>4, r3c3<>8
Hidden Single: r2c2=4
Hidden Single: r5c2=3
Full House: r5c8=2
Hidden Single: r3c1=3
Naked Single: r3c7=4
Naked Single: r3c8=5
Naked Single: r3c5=8
Naked Single: r1c5=5
Hidden Single: r7c8=4
Hidden Single: r8c9=5
Hidden Single: r2c8=7
Naked Single: r1c9=8
Full House: r1c1=7
Full House: r2c9=3
Naked Single: r2c4=6
Full House: r2c3=8
Full House: r3c6=7
Naked Single: r3c2=2
Full House: r3c3=6
Full House: r6c3=2
Naked Single: r8c1=2
Naked Single: r9c6=6
Naked Single: r6c2=1
Full House: r4c1=8
Full House: r9c1=1
Full House: r7c2=7
Naked Single: r8c4=7
Full House: r9c4=2
Full House: r9c9=7
Full House: r4c9=1
Naked Single: r6c8=3
Full House: r4c7=7
Full House: r4c6=3
Full House: r7c7=3
Full House: r6c6=8
Full House: r8c8=1
Full House: r7c5=1
Full House: r8c5=3
|
normal_sudoku_1941
|
49.8.1....83.59.1452134....95.4...813.81.5...214..8...8....31..13..84.76..5.1....
|
496871253783259614521346798957462381368195427214738569879623145132584976645917832
|
Basic 9x9 Sudoku 1941
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
4 9 . 8 . 1 . . .
. 8 3 . 5 9 . 1 4
5 2 1 3 4 . . . .
9 5 . 4 . . . 8 1
3 . 8 1 . 5 . . .
2 1 4 . . 8 . . .
8 . . . . 3 1 . .
1 3 . . 8 4 . 7 6
. . 5 . 1 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
496871253783259614521346798957462381368195427214738569879623145132584976645917832 #1 Extreme (14508) bf
Hidden Single: r5c3=8
Hidden Single: r2c8=1
Hidden Single: r6c2=1
Hidden Single: r9c5=1
Hidden Single: r3c3=1
Hidden Single: r6c6=8
Hidden Single: r4c4=4
Hidden Single: r3c1=5
Hidden Single: r5c6=5
Brute Force: r6c1=2
Finned Franken Swordfish: 6 c16b4 r349 fr2c1 fr5c2 => r3c2<>6
W-Wing: 7/6 in r4c3,r9c1 connected by 6 in r1c3,r2c1 => r7c3<>7
Sashimi Swordfish: 7 c136 r349 fr1c3 fr2c1 => r3c2<>7
Naked Single: r3c2=2
Naked Single: r8c2=3
Naked Pair: 6,7 in r14c3 => r7c3<>6
Forcing Chain Contradiction in r9c6 => r2c4<>6
r2c4=6 r2c4<>2 r789c4=2 r9c6<>2
r2c4=6 r2c1<>6 r9c1=6 r9c6<>6
r2c4=6 r3c6<>6 r3c6=7 r9c6<>7
2-String Kite: 6 in r2c7,r4c3 (connected by r1c3,r2c1) => r4c7<>6
Turbot Fish: 6 r3c6 =6= r1c5 -6- r1c3 =6= r4c3 => r4c6<>6
Grouped Discontinuous Nice Loop: 7 r1c7 -7- r1c3 -6- r1c5 =6= r3c6 =7= r3c79 -7- r1c7 => r1c7<>7
Grouped Discontinuous Nice Loop: 7 r1c9 -7- r1c3 -6- r1c5 =6= r3c6 =7= r3c79 -7- r1c9 => r1c9<>7
Turbot Fish: 7 r1c5 =7= r1c3 -7- r4c3 =7= r5c2 => r5c5<>7
Grouped Discontinuous Nice Loop: 9 r7c8 -9- r3c8 -6- r3c6 =6= r9c6 -6- r7c45 =6= r7c2 =4= r7c8 => r7c8<>9
Almost Locked Set XY-Wing: A=r5c2 {67}, B=r9c16 {267}, C=r4c36 {267}, X,Y=2,6, Z=7 => r9c2<>7
Discontinuous Nice Loop: 7 r5c7 -7- r5c2 -6- r9c2 -4- r9c7 =4= r5c7 => r5c7<>7
Forcing Chain Contradiction in r9c6 => r2c4=2
r2c4<>2 r789c4=2 r9c6<>2
r2c4<>2 r2c4=7 r3c6<>7 r3c6=6 r9c6<>6
r2c4<>2 r2c4=7 r2c1<>7 r9c1=7 r9c6<>7
Naked Pair: 6,7 in r1c35 => r1c78<>6
X-Wing: 6 r14 c35 => r567c5<>6
Remote Pair: 7/6 r3c6 -6- r1c5 -7- r1c3 -6- r4c3 => r4c6<>7
Naked Single: r4c6=2
Naked Single: r5c5=9
Hidden Single: r7c5=2
Naked Single: r7c3=9
Naked Single: r7c9=5
Naked Single: r8c3=2
Naked Single: r7c8=4
Naked Single: r8c7=9
Full House: r8c4=5
Hidden Single: r5c7=4
Hidden Single: r9c2=4
Hidden Single: r9c4=9
Remote Pair: 6/7 r2c7 -7- r2c1 -6- r1c3 -7- r4c3 -6- r5c2 -7- r7c2 -6- r7c4 -7- r6c4 => r6c7<>6, r46c7<>7
Naked Single: r4c7=3
Naked Single: r6c7=5
Naked Single: r1c7=2
Naked Single: r1c9=3
Naked Single: r9c7=8
Naked Single: r1c8=5
Naked Single: r9c9=2
Full House: r9c8=3
Naked Single: r5c9=7
Naked Single: r5c2=6
Full House: r4c3=7
Full House: r5c8=2
Full House: r7c2=7
Full House: r1c3=6
Full House: r4c5=6
Full House: r7c4=6
Full House: r9c1=6
Full House: r1c5=7
Full House: r2c1=7
Full House: r6c4=7
Full House: r9c6=7
Full House: r3c6=6
Full House: r6c5=3
Full House: r2c7=6
Full House: r3c7=7
Naked Single: r6c9=9
Full House: r3c9=8
Full House: r3c8=9
Full House: r6c8=6
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