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_2377
|
8725.6......2......193....6...4....1...93...52...5..9..5674..827.48..6........7..
|
872516439563294178419387526935472861687931245241658397156743982794825613328169754
|
Basic 9x9 Sudoku 2377
|
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 2 5 . 6 . . .
. . . 2 . . . . .
. 1 9 3 . . . . 6
. . . 4 . . . . 1
. . . 9 3 . . . 5
2 . . . 5 . . 9 .
. 5 6 7 4 . . 8 2
7 . 4 8 . . 6 . .
. . . . . . 7 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
872516439563294178419387526935472861687931245241658397156743982794825613328169754 #1 Extreme (4400)
Naked Single: r3c4=3
Hidden Single: r1c3=2
Hidden Single: r8c1=7
Locked Candidates Type 1 (Pointing): 3 in b1 => r2c789<>3
Locked Candidates Type 1 (Pointing): 5 in b9 => r23c8<>5
Locked Candidates Type 2 (Claiming): 4 in r1 => r2c789,r3c78<>4
Naked Triple: 3,4,9 in r189c9 => r2c9<>9, r6c9<>3, r6c9<>4
Grouped Discontinuous Nice Loop: 1 r2c6 -1- r1c5 -9- r1c79 =9= r2c7 =5= r3c7 -5- r3c1 -4- r3c6 =4= r2c6 => r2c6<>1
Locked Candidates Type 1 (Pointing): 1 in b2 => r89c5<>1
Naked Triple: 2,3,9 in r8c259 => r8c6<>2, r8c68<>3, r8c6<>9
Uniqueness Test 4: 1/5 in r8c68,r9c68 => r9c68<>1
Discontinuous Nice Loop: 2 r5c8 -2- r3c8 -7- r2c8 -1- r8c8 =1= r8c6 -1- r9c4 -6- r9c5 =6= r4c5 -6- r4c8 =6= r5c8 => r5c8<>2
Discontinuous Nice Loop: 7 r5c8 -7- r2c8 -1- r8c8 =1= r8c6 -1- r9c4 -6- r9c5 =6= r4c5 -6- r4c8 =6= r5c8 => r5c8<>7
Grouped Discontinuous Nice Loop: 7 r2c6 -7- r2c8 -1- r8c8 =1= r8c6 -1- r9c4 -6- r9c5 =6= r4c5 =7= r23c5 -7- r2c6 => r2c6<>7
Grouped Discontinuous Nice Loop: 8 r2c6 -8- r2c9 -7- r2c8 -1- r8c8 =1= r8c6 -1- r9c4 -6- r9c5 =6= r4c5 =8= r23c5 -8- r2c6 => r2c6<>8
Grouped Discontinuous Nice Loop: 8 r4c3 -8- r9c3 =8= r9c2 =2= r8c2 -2- r8c5 -9- r12c5 =9= r2c6 =4= r3c6 -4- r3c1 -5- r4c1 =5= r4c3 => r4c3<>8
Grouped Discontinuous Nice Loop: 3 r9c3 -3- r2c3 -5- r3c1 -4- r3c6 =4= r2c6 =9= r12c5 -9- r8c5 -2- r8c2 =2= r9c2 =8= r9c3 => r9c3<>3
Almost Locked Set XZ-Rule: A=r5c128 {1468}, B=r2456c3 {13578}, X=1,8 => r46c2<>8, r5c7<>4
Discontinuous Nice Loop: 6 r5c2 -6- r6c2 =6= r6c4 =1= r9c4 -1- r9c3 -8- r9c2 =8= r5c2 => r5c2<>6
Almost Locked Set XZ-Rule: A=r6c469 {1678}, B=r9c34 {168}, X=6, Z=8 => r6c3<>8
Locked Candidates Type 1 (Pointing): 8 in b4 => r5c67<>8
Naked Single: r5c7=2
Hidden Single: r3c8=2
Locked Candidates Type 1 (Pointing): 7 in b3 => r2c5<>7
XY-Chain: 7 7- r5c6 -1- r8c6 -5- r8c8 -1- r2c8 -7- r2c9 -8- r6c9 -7 => r6c6<>7
XY-Chain: 7 7- r2c8 -1- r8c8 -5- r8c6 -1- r6c6 -8- r6c9 -7 => r2c9,r4c8<>7
Naked Single: r2c9=8
Naked Single: r3c7=5
Naked Single: r6c9=7
Naked Single: r3c1=4
Hidden Single: r2c8=7
Hidden Single: r2c6=4
Locked Candidates Type 1 (Pointing): 9 in b2 => r89c5<>9
Naked Single: r8c5=2
Naked Single: r9c5=6
Naked Single: r9c4=1
Full House: r6c4=6
Naked Single: r8c6=5
Naked Single: r9c3=8
Naked Single: r8c8=1
Hidden Single: r4c6=2
Hidden Single: r9c2=2
Hidden Single: r7c1=1
Naked Single: r5c1=6
Naked Single: r5c8=4
Naked Single: r1c8=3
Naked Single: r5c2=8
Naked Single: r4c8=6
Full House: r9c8=5
Hidden Single: r2c2=6
Hidden Single: r6c2=4
Hidden Single: r1c7=4
Naked Single: r1c9=9
Full House: r1c5=1
Full House: r2c7=1
Naked Single: r8c9=3
Full House: r8c2=9
Full House: r9c9=4
Full House: r7c7=9
Full House: r4c2=3
Full House: r9c1=3
Full House: r7c6=3
Full House: r9c6=9
Naked Single: r2c5=9
Naked Single: r4c7=8
Full House: r6c7=3
Naked Single: r6c3=1
Full House: r6c6=8
Naked Single: r2c1=5
Full House: r2c3=3
Full House: r4c1=9
Naked Single: r4c5=7
Full House: r3c5=8
Full House: r3c6=7
Full House: r4c3=5
Full House: r5c3=7
Full House: r5c6=1
|
normal_sudoku_3466
|
3....79.6986..4...57..6..2.2.9.1.4734.739.281138.72569.257...1.....5..9.7....16..
|
312587946986124735574963128259618473467395281138472569625739814841256397793841652
|
Basic 9x9 Sudoku 3466
|
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 9 . 6
9 8 6 . . 4 . . .
5 7 . . 6 . . 2 .
2 . 9 . 1 . 4 7 3
4 . 7 3 9 . 2 8 1
1 3 8 . 7 2 5 6 9
. 2 5 7 . . . 1 .
. . . . 5 . . 9 .
7 . . . . 1 6 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
312587946986124735574963128259618473467395281138472569625739814841256397793841652 #1 Easy (274)
Naked Single: r1c1=3
Naked Single: r5c8=8
Naked Single: r2c1=9
Naked Single: r4c7=4
Naked Single: r5c5=9
Naked Single: r6c9=9
Full House: r5c9=1
Naked Single: r5c3=7
Naked Single: r6c2=3
Naked Single: r6c3=8
Naked Single: r4c3=9
Naked Single: r6c6=2
Full House: r6c4=4
Hidden Single: r1c3=2
Naked Single: r1c5=8
Hidden Single: r7c6=9
Naked Single: r3c6=3
Naked Single: r2c5=2
Hidden Single: r9c2=9
Hidden Single: r3c4=9
Hidden Single: r7c1=6
Full House: r8c1=8
Naked Single: r8c6=6
Naked Single: r5c6=5
Full House: r4c6=8
Full House: r5c2=6
Full House: r4c4=6
Full House: r4c2=5
Naked Single: r8c4=2
Naked Single: r9c4=8
Hidden Single: r9c9=2
Hidden Single: r9c8=5
Naked Single: r1c8=4
Full House: r2c8=3
Naked Single: r1c2=1
Full House: r1c4=5
Full House: r3c3=4
Full House: r8c2=4
Full House: r2c4=1
Naked Single: r3c9=8
Full House: r3c7=1
Naked Single: r9c3=3
Full House: r8c3=1
Full House: r9c5=4
Full House: r7c5=3
Naked Single: r8c9=7
Full House: r8c7=3
Naked Single: r2c7=7
Full House: r7c7=8
Full House: r7c9=4
Full House: r2c9=5
|
normal_sudoku_5036
|
.6.3.....2.1.7.3...37..2.8..5...9..31.37..94.....13..........348..23..5.3.5..72..
|
568394721241578369937162485756429813183756942429813576672985134894231657315647298
|
Basic 9x9 Sudoku 5036
|
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 . . . . .
2 . 1 . 7 . 3 . .
. 3 7 . . 2 . 8 .
. 5 . . . 9 . . 3
1 . 3 7 . . 9 4 .
. . . . 1 3 . . .
. . . . . . . 3 4
8 . . 2 3 . . 5 .
3 . 5 . . 7 2 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
568394721241578369937162485756429813183756942429813576672985134894231657315647298 #1 Extreme (18812) bf
Hidden Single: r9c1=3
Hidden Single: r4c9=3
Hidden Single: r6c6=3
Brute Force: r5c8=4
Grouped Discontinuous Nice Loop: 4 r1c5 -4- r2c46 =4= r2c2 -4- r9c2 =4= r8c23 -4- r8c6 =4= r12c6 -4- r1c5 => r1c5<>4
Grouped Discontinuous Nice Loop: 4 r3c4 -4- r2c46 =4= r2c2 -4- r9c2 =4= r8c23 -4- r8c6 =4= r12c6 -4- r3c4 => r3c4<>4
Grouped Discontinuous Nice Loop: 4 r3c5 -4- r2c46 =4= r2c2 -4- r9c2 =4= r8c23 -4- r8c6 =4= r12c6 -4- r3c5 => r3c5<>4
Forcing Net Contradiction in b5 => r5c9<>8
r5c9=8 (r9c9<>8) r5c2<>8 r5c2=2 r5c5<>2 r4c5=2 r4c5<>4 r9c5=4 r9c5<>8 r9c4=8 r4c4<>8
r5c9=8 r5c2<>8 r5c2=2 r5c5<>2 r4c5=2 r4c5<>8
r5c9=8 r5c5<>8
r5c9=8 r5c6<>8
r5c9=8 (r9c9<>8) r5c2<>8 r5c2=2 r5c5<>2 r4c5=2 r4c5<>4 r9c5=4 r9c5<>8 r9c4=8 r6c4<>8
Forcing Net Contradiction in r7c6 => r1c8<>9
r1c8=9 (r2c8<>9 r2c8=6 r9c8<>6 r9c8=1 r8c7<>1) (r1c8<>7) r1c8<>2 r1c9=2 r1c9<>7 r1c7=7 r8c7<>7 r8c7=6 r8c3<>6 r7c13=6 r7c6<>6
r1c8=9 (r2c8<>9 r2c8=6 r2c6<>6) (r2c8<>9 r2c8=6 r2c9<>6 r2c9=5 r5c9<>5 r5c9=6 r5c6<>6) (r2c8<>9 r2c8=6 r9c8<>6 r9c8=1 r8c7<>1) (r1c8<>7) r1c8<>2 r1c9=2 r1c9<>7 r1c7=7 r8c7<>7 r8c7=6 r8c6<>6 r7c6=6
Forcing Net Contradiction in r6c9 => r3c9<>6
r3c9=6 (r5c9<>6) (r2c9<>6) r2c8<>6 r2c8=9 r2c9<>9 r2c9=5 r5c9<>5 r5c9=2 r6c9<>2
r3c9=6 (r2c9<>6) r2c8<>6 r2c8=9 r2c9<>9 r2c9=5 r6c9<>5
r3c9=6 r6c9<>6
r3c9=6 (r5c9<>6) (r2c9<>6) r2c8<>6 r2c8=9 r2c9<>9 r2c9=5 r5c9<>5 r5c9=2 r1c9<>2 r1c8=2 r1c8<>7 r46c8=7 r6c9<>7
r3c9=6 (r5c9<>6) (r2c9<>6) r2c8<>6 r2c8=9 r2c9<>9 r2c9=5 r5c9<>5 r5c9=2 (r5c2<>2 r5c2=8 r5c5<>8) (r5c2<>2 r5c2=8 r6c3<>8 r1c3=8 r1c5<>8) r5c5<>2 r4c5=2 (r4c5<>8) r4c5<>4 r9c5=4 (r9c5<>8) r9c5<>8 r7c5=8 r9c4<>8 r9c9=8 r6c9<>8
Forcing Net Contradiction in b5 => r2c4<>6
r2c4=6 r4c4<>6
r2c4=6 (r2c8<>6 r2c8=9 r2c2<>9) (r3c4<>6) r3c5<>6 r3c7=6 r3c7<>4 r3c1=4 r2c2<>4 r2c2=8 r5c2<>8 r5c2=2 r5c5<>2 r4c5=2 r4c5<>6
r2c4=6 (r2c8<>6 r2c8=9 r2c9<>9 r2c9=5 r5c9<>5) (r2c8<>6 r2c8=9 r2c2<>9) (r3c4<>6) r3c5<>6 r3c7=6 r3c7<>4 r3c1=4 r2c2<>4 r2c2=8 r5c2<>8 r5c2=2 r5c9<>2 r5c9=6 r5c5<>6
r2c4=6 (r2c8<>6 r2c8=9 r2c9<>9 r2c9=5 r5c9<>5) (r2c8<>6 r2c8=9 r2c2<>9) (r3c4<>6) r3c5<>6 r3c7=6 r3c7<>4 r3c1=4 r2c2<>4 r2c2=8 r5c2<>8 r5c2=2 r5c9<>2 r5c9=6 r5c6<>6
r2c4=6 r6c4<>6
Forcing Net Contradiction in r2c6 => r2c6<>6
r2c6=6 r2c6=6
r2c6=6 (r2c6<>4) (r3c4<>6) r3c5<>6 r3c7=6 r3c7<>4 (r3c1=4 r2c2<>4 r2c2=8 r2c4<>8) r1c7=4 r1c6<>4 r8c6=4 r9c5<>4 r4c5=4 r4c5<>2 r5c5=2 r5c2<>2 r5c2=8 r2c2<>8 r2c6=8
Locked Candidates Type 1 (Pointing): 6 in b2 => r3c7<>6
Finned Jellyfish: 6 r2359 c4589 fr5c6 => r4c45,r6c4<>6
Locked Candidates Type 1 (Pointing): 6 in b5 => r5c9<>6
Almost Locked Set XY-Wing: A=r1c135679 {1245789}, B=r2c89,r3c9 {1569}, C=r5c9 {25}, X,Y=2,5, Z=1 => r1c8<>1
Forcing Chain Contradiction in r8c6 => r3c4<>5
r3c4=5 r3c4<>1 r1c6=1 r8c6<>1
r3c4=5 r6c4<>5 r5c56=5 r5c9<>5 r5c9=2 r5c5<>2 r4c5=2 r4c5<>4 r9c5=4 r8c6<>4
r3c4=5 r3c4<>6 r79c4=6 r8c6<>6
Forcing Chain Contradiction in r8c6 => r7c6<>6
r7c6=6 r79c4<>6 r3c4=6 r3c4<>1 r1c6=1 r8c6<>1
r7c6=6 r5c6<>6 r5c5=6 r5c5<>2 r4c5=2 r4c5<>4 r9c5=4 r8c6<>4
r7c6=6 r8c6<>6
Forcing Chain Contradiction in r1c5 => r9c5<>9
r9c5=9 r9c8<>9 r2c8=9 r2c8<>6 r2c9=6 r2c9<>5 r2c46=5 r1c5<>5
r9c5=9 r9c5<>4 r4c5=4 r4c5<>2 r5c5=2 r5c2<>2 r5c2=8 r2c2<>8 r1c3=8 r1c5<>8
r9c5=9 r1c5<>9
Forcing Net Contradiction in r8c9 => r1c3=8
r1c3<>8 r2c2=8 r5c2<>8 r5c2=2 (r5c5<>2 r4c5=2 r4c5<>4) r5c9<>2 r5c9=5 (r6c7<>5) r6c9<>5 r6c4=5 (r2c4<>5 r2c6=5 r2c6<>4) r6c4<>4 r4c4=4 r2c4<>4 r2c2=4 r2c2<>8 r1c3=8
Grouped Discontinuous Nice Loop: 9 r7c1 -9- r7c45 =9= r9c4 -9- r9c8 =9= r2c8 -9- r2c2 =9= r13c1 -9- r7c1 => r7c1<>9
Almost Locked Set XZ-Rule: A=r1c15 {459}, B=r2c289 {4569}, X=4, Z=5 => r1c79<>5
Discontinuous Nice Loop: 2 r4c8 -2- r5c9 -5- r6c7 =5= r3c7 =4= r3c1 -4- r2c2 -9- r2c8 =9= r9c8 =1= r4c8 => r4c8<>2
Almost Locked Set XZ-Rule: A=r2c289 {4569}, B=r3c1459 {14569}, X=4, Z=5 => r3c7<>5
Hidden Single: r6c7=5
Naked Single: r5c9=2
Naked Single: r5c2=8
Hidden Single: r1c8=2
Hidden Single: r4c5=2
Hidden Single: r9c5=4
Hidden Single: r7c5=8
Hidden Single: r2c6=8
Hidden Single: r4c7=8
Naked Single: r4c4=4
Naked Single: r4c3=6
Naked Single: r6c4=8
Naked Single: r4c1=7
Full House: r4c8=1
Naked Single: r7c1=6
Hidden Single: r9c9=8
Hidden Single: r1c6=4
Hidden Single: r2c2=4
Hidden Single: r6c8=7
Full House: r6c9=6
Hidden Single: r8c7=6
Naked Single: r8c6=1
Naked Single: r9c8=9
Full House: r2c8=6
Naked Single: r7c6=5
Full House: r5c6=6
Full House: r5c5=5
Naked Single: r8c9=7
Full House: r7c7=1
Naked Single: r9c2=1
Full House: r9c4=6
Full House: r7c4=9
Naked Single: r1c5=9
Full House: r3c5=6
Naked Single: r8c2=9
Full House: r8c3=4
Naked Single: r1c7=7
Full House: r3c7=4
Naked Single: r2c4=5
Full House: r3c4=1
Full House: r2c9=9
Naked Single: r7c3=2
Full House: r6c3=9
Full House: r7c2=7
Full House: r6c2=2
Full House: r6c1=4
Naked Single: r1c1=5
Full House: r1c9=1
Full House: r3c9=5
Full House: r3c1=9
|
normal_sudoku_1280
|
.4.217.....5.9..422.64.839..64......5..864.13.3.975.26.....92.46...4..7.4......38
|
943217685875396142216458397764132859529864713138975426351789264682543971497621538
|
Basic 9x9 Sudoku 1280
|
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 7 . . .
. . 5 . 9 . . 4 2
2 . 6 4 . 8 3 9 .
. 6 4 . . . . . .
5 . . 8 6 4 . 1 3
. 3 . 9 7 5 . 2 6
. . . . . 9 2 . 4
6 . . . 4 . . 7 .
4 . . . . . . 3 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
943217685875396142216458397764132859529864713138975426351789264682543971497621538 #1 Hard (1194)
Hidden Single: r2c5=9
Hidden Single: r2c9=2
Hidden Single: r3c4=4
Hidden Single: r1c2=4
Hidden Single: r7c9=4
Locked Pair: 1,8 in r6c13 => r4c1,r5c23,r6c679<>1, r4c1,r6c7<>8
Locked Triple: 5,6,8 in r1c789 => r1c13,r2c7<>8, r1c3,r2c7,r3c9<>6, r3c9<>5
Hidden Single: r3c3=6
Locked Pair: 5,8 in r3c56 => r2c6,r3c2<>8
Locked Candidates Type 1 (Pointing): 3 in b2 => r2c1<>3
Locked Candidates Type 1 (Pointing): 2 in b4 => r5c56<>2
Naked Single: r5c5=6
Naked Single: r5c8=1
Naked Single: r5c6=4
Naked Single: r6c6=5
Naked Single: r3c6=8
Naked Single: r6c9=6
Naked Single: r3c5=5
Naked Single: r1c9=5
Naked Single: r6c7=4
Naked Single: r9c5=2
Naked Single: r4c5=3
Full House: r7c5=8
Naked Single: r4c4=1
Full House: r4c6=2
Locked Candidates Type 2 (Claiming): 1 in r7 => r8c23,r9c23<>1
Naked Pair: 7,9 in r4c9,r5c7 => r4c7<>7, r4c7<>9
Hidden Pair: 2,8 in r8c23 => r8c2<>5, r8c23<>9, r8c3<>3
Locked Candidates Type 1 (Pointing): 3 in b7 => r7c4<>3
Locked Candidates Type 1 (Pointing): 9 in b7 => r9c7<>9
Skyscraper: 7 in r3c2,r4c1 (connected by r34c9) => r2c1,r5c2<>7
Locked Candidates Type 1 (Pointing): 7 in b1 => r79c2<>7
Naked Pair: 1,8 in r26c1 => r7c1<>1
W-Wing: 7/9 in r4c1,r9c3 connected by 9 in r1c13 => r5c3,r7c1<>7
Naked Single: r7c1=3
Naked Single: r1c1=9
Naked Single: r1c3=3
Naked Single: r4c1=7
Naked Single: r4c9=9
Naked Single: r5c7=7
Naked Single: r8c9=1
Full House: r3c9=7
Full House: r3c2=1
Naked Single: r2c7=1
Naked Single: r8c6=3
Naked Single: r2c1=8
Full House: r2c2=7
Full House: r6c1=1
Full House: r6c3=8
Naked Single: r7c2=5
Naked Single: r2c6=6
Full House: r2c4=3
Full House: r9c6=1
Naked Single: r8c4=5
Naked Single: r8c3=2
Naked Single: r7c8=6
Naked Single: r9c2=9
Naked Single: r8c7=9
Full House: r8c2=8
Full House: r9c7=5
Full House: r5c2=2
Full House: r5c3=9
Naked Single: r1c8=8
Full House: r1c7=6
Full House: r4c7=8
Full House: r4c8=5
Naked Single: r7c4=7
Full House: r7c3=1
Full House: r9c3=7
Full House: r9c4=6
|
normal_sudoku_331
|
..15.49.245..2..1....3.15.419..5.4....8149.5.5.4..7.9124..1...5.164.5...8.5...14.
|
631584972457926813982371564193652487728149356564837291249718635316495728875263149
|
Basic 9x9 Sudoku 331
|
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 5 . 4 9 . 2
4 5 . . 2 . . 1 .
. . . 3 . 1 5 . 4
1 9 . . 5 . 4 . .
. . 8 1 4 9 . 5 .
5 . 4 . . 7 . 9 1
2 4 . . 1 . . . 5
. 1 6 4 . 5 . . .
8 . 5 . . . 1 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
631584972457926813982371564193652487728149356564837291249718635316495728875263149 #1 Extreme (22754) bf
Hidden Single: r4c1=1
Hidden Single: r6c3=4
Hidden Single: r9c8=4
Hidden Single: r2c2=5
Hidden Single: r7c9=5
Hidden Single: r4c5=5
Hidden Single: r6c1=5
Hidden Single: r9c7=1
Hidden Single: r2c8=1
Brute Force: r5c6=9
Hidden Single: r6c8=9
Hidden Single: r5c5=4
Hidden Single: r1c6=4
X-Wing: 9 r27 c34 => r3c3,r9c4<>9
Finned Swordfish: 8 r138 c258 fr8c7 fr8c9 => r7c8<>8
Forcing Net Contradiction in r8c9 => r2c4<>6
r2c4=6 (r2c6<>6 r2c6=8 r7c6<>8) r2c4<>9 r2c3=9 r7c3<>9 r7c4=9 (r9c5<>9 r9c9=9 r9c9<>6) r7c4<>8 r7c7=8 r7c7<>6 r7c8=6 r13c8<>6 r2c79=6 r2c4<>6
Forcing Net Contradiction in r8c9 => r2c4<>8
r2c4=8 (r2c79<>8 r13c8=8 r8c8<>8) (r7c4<>8) (r2c4<>7) r2c4<>9 r2c3=9 (r3c1<>9 r8c1=9 r8c1<>7) r7c3<>9 r7c4=9 r7c4<>7 r9c4=7 r9c2<>7 (r9c2=3 r9c6<>3) r7c3=7 (r4c3<>7) r3c3<>7 r3c3=2 r4c3<>2 r4c3=3 r4c6<>3 r7c6=3 r7c6<>8 r7c7=8 (r6c7<>8) (r8c7<>8) r8c9<>8 r8c5=8 r6c5<>8 r6c4=8 r2c4<>8
Forcing Net Verity => r3c3=2
r4c4=8 (r7c4<>8) (r6c4<>8) r6c5<>8 r6c7=8 (r8c7<>8) (r2c7<>8) r7c7<>8 r7c6=8 (r8c5<>8) r2c6<>8 r2c9=8 r8c9<>8 r8c8=8 r8c8<>2 r4c8=2 r4c3<>2 r3c3=2
r4c6=8 (r2c6<>8) (r6c4<>8) r6c5<>8 r6c7=8 (r8c7<>8) (r7c7<>8 r7c4=8 r8c5<>8) r2c7<>8 r2c9=8 r8c9<>8 r8c8=8 r8c8<>2 r4c8=2 r4c3<>2 r3c3=2
r6c4=8 r6c4<>2 r4c46=2 r4c3<>2 r3c3=2
r6c5=8 (r3c5<>8 r2c6=8 r2c9<>8) (r3c5<>8 r2c6=8 r7c6<>8) r6c5<>3 r4c6=3 r7c6<>3 r7c6=6 (r9c4<>6) (r9c5<>6) r9c6<>6 r9c9=6 (r2c9<>6 r2c7=6 r3c8<>6 r4c8=6 r4c4<>6) r9c9<>9 r8c9=9 r8c9<>8 r4c9=8 r4c4<>8 r4c4=2 r4c3<>2 r3c3=2
Forcing Chain Contradiction in r2c3 => r4c8<>7
r4c8=7 r4c3<>7 r4c3=3 r2c3<>3
r4c8=7 r13c8<>7 r2c79=7 r2c3<>7
r4c8=7 r13c8<>7 r2c79=7 r2c4<>7 r2c4=9 r2c3<>9
Forcing Chain Contradiction in r2 => r9c9<>7
r9c9=7 r4c9<>7 r4c3=7 r2c3<>7
r9c9=7 r9c9<>9 r9c5=9 r3c5<>9 r2c4=9 r2c4<>7
r9c9=7 r78c8<>7 r13c8=7 r2c7<>7
r9c9=7 r2c9<>7
Forcing Net Contradiction in c8 => r5c2<>7
r5c2=7 (r4c3<>7 r4c3=3 r5c1<>3) r9c2<>7 r9c2=3 r8c1<>3 r1c1=3 r1c8<>3
r5c2=7 r4c3<>7 r4c3=3 r4c8<>3
r5c2=7 (r4c3<>7 r4c3=3 r4c6<>3) r9c2<>7 r9c2=3 r9c6<>3 r7c6=3 r7c8<>3
r5c2=7 r5c2<>2 r5c7=2 r8c7<>2 r8c8=2 r8c8<>3
Forcing Net Contradiction in b8 => r3c1<>7
r3c1=7 r3c1<>9 r8c1=9 r7c3<>9 r7c4=9 r7c4<>8
r3c1=7 (r1c1<>7) (r1c2<>7) r3c1<>9 (r8c1=9 r7c3<>9 r7c3=3 r7c8<>3) r3c5=9 r2c4<>9 r2c4=7 r1c5<>7 r1c8=7 r7c8<>7 r7c8=6 r13c8<>6 r2c79=6 r2c6<>6 r2c6=8 r7c6<>8
r3c1=7 (r3c5<>7) (r3c2<>7 r9c2=7 r9c5<>7) r3c1<>9 r3c5=9 r2c4<>9 r2c4=7 r1c5<>7 r8c5=7 r8c5<>8
Forcing Net Contradiction in r7c8 => r1c2<>6
r1c2=6 (r1c2<>3) (r1c1<>6) r3c1<>6 (r3c1=9 r2c3<>9) r5c1=6 r5c1<>7 r4c3=7 r2c3<>7 r2c3=3 r1c1<>3 r1c8=3 r7c8<>3
r1c2=6 (r1c5<>6) (r3c1<>6 r5c1=6 r5c1<>7) (r1c2<>7) r1c2<>8 r3c2=8 r3c2<>7 r9c2=7 r8c1<>7 r1c1=7 r1c5<>7 r1c5=8 r2c6<>8 r2c6=6 r2c79<>6 r13c8=6 r7c8<>6
r1c2=6 (r3c1<>6 r3c1=9 r2c3<>9 r2c4=9 r2c4<>7) (r1c2<>7) r1c2<>8 r3c2=8 r3c2<>7 r9c2=7 r9c4<>7 r7c4=7 r7c8<>7
Forcing Net Contradiction in c7 => r4c6<>8
r4c6=8 (r6c5<>8 r6c7=8 r7c7<>8 r7c4=8 r7c4<>9 r7c3=9 r7c3<>7) (r4c6<>2 r9c6=2 r9c4<>2) (r2c6<>8 r2c6=6 r1c5<>6) (r2c6<>8 r2c6=6 r3c5<>6) r4c6<>3 r6c5=3 r6c5<>6 r9c5=6 r9c4<>6 r9c4=7 r9c2<>7 (r13c2=7 r2c3<>7) r8c1=7 r8c1<>9 r3c1=9 r2c3<>9 r2c3=3 r2c7<>3
r4c6=8 (r6c5<>8 r6c7=8 r7c7<>8 r7c4=8 r7c4<>9 r7c3=9 r7c3<>7) (r4c6<>2 r9c6=2 r9c4<>2) (r2c6<>8 r2c6=6 r1c5<>6) (r2c6<>8 r2c6=6 r3c5<>6) r4c6<>3 r6c5=3 r6c5<>6 r9c5=6 r9c4<>6 r9c4=7 r9c2<>7 (r9c2=3 r8c1<>3) (r13c2=7 r2c3<>7) r8c1=7 r8c1<>9 r3c1=9 r2c3<>9 r2c3=3 r1c1<>3 r5c1=3 r5c7<>3
r4c6=8 (r6c4<>8) r6c5<>8 r6c7=8 r6c7<>3
r4c6=8 (r7c6<>8) r2c6<>8 r2c6=6 r7c6<>6 r7c6=3 r7c7<>3
r4c6=8 (r2c6<>8) (r6c4<>8) r6c5<>8 r6c7=8 (r8c7<>8) (r7c7<>8 r7c4=8 r8c5<>8) r2c7<>8 r2c9=8 r8c9<>8 r8c8=8 r8c8<>2 r8c7=2 r8c7<>3
Forcing Net Contradiction in r8c9 => r6c2<>3
r6c2=3 (r6c5<>3) (r4c3<>3 r4c3=7 r5c1<>7) r9c2<>3 r9c2=7 (r1c2<>7 r1c2=8 r1c5<>8) r8c1<>7 r1c1=7 r1c5<>7 r1c5=6 r6c5<>6 r6c5=8 r6c5<>3 r4c6=3 (r7c6<>3 r7c6=6 r9c4<>6) r4c6<>2 r9c6=2 r9c4<>2 r9c4=7 r9c2<>7 r9c2=3 r6c2<>3
Forcing Net Verity => r8c8=2
r4c4=8 (r7c4<>8) (r6c4<>8) r6c5<>8 r6c7=8 (r6c7<>3 r6c5=3 r4c6<>3) r7c7<>8 r7c6=8 r2c6<>8 r2c6=6 r4c6<>6 r4c6=2 r4c8<>2 r8c8=2
r6c4=8 r6c4<>2 r4c46=2 r4c8<>2 r8c8=2
r7c4=8 (r6c4<>8 r6c5=8 r6c7<>8) (r7c7<>8) r7c6<>8 r2c6=8 r2c7<>8 r8c7=8 r8c7<>2 r8c8=2
Locked Candidates Type 2 (Claiming): 2 in r4 => r6c4<>2
Hidden Rectangle: 2/6 in r5c27,r6c27 => r5c7<>6
Forcing Chain Contradiction in r7c4 => r2c9<>7
r2c9=7 r45c9<>7 r5c7=7 r5c7<>2 r5c2=2 r6c2<>2 r6c2=6 r5c12<>6 r5c9=6 r9c9<>6 r7c78=6 r7c4<>6
r2c9=7 r13c8<>7 r7c8=7 r7c4<>7
r2c9=7 r45c9<>7 r5c7=7 r5c7<>2 r5c2=2 r6c2<>2 r6c2=6 r6c4<>6 r6c4=8 r7c4<>8
r2c9=7 r2c4<>7 r2c4=9 r7c4<>9
Forcing Chain Verity => r4c4<>8
r7c4=8 r4c4<>8
r7c6=8 r2c6<>8 r2c79=8 r13c8<>8 r4c8=8 r4c4<>8
r7c7=8 r6c7<>8 r4c89=8 r4c4<>8
Locked Candidates Type 1 (Pointing): 8 in b5 => r6c7<>8
Hidden Rectangle: 2/6 in r4c46,r9c46 => r9c6<>6
Forcing Chain Contradiction in c6 => r7c3<>7
r7c3=7 r4c3<>7 r4c3=3 r4c6<>3
r7c3=7 r4c3<>7 r4c9=7 r4c9<>8 r4c8=8 r13c8<>8 r2c79=8 r2c6<>8 r7c6=8 r7c6<>3
r7c3=7 r9c2<>7 r9c2=3 r9c6<>3
Almost Locked Set XZ-Rule: A=r4679c4 {26789}, B=r7c3,r9c2 {379}, X=9, Z=7 => r9c5<>7
Forcing Chain Verity => r5c7<>7
r2c3=7 r4c3<>7 r4c9=7 r5c7<>7
r2c4=7 r7c4<>7 r7c78=7 r8c9<>7 r45c9=7 r5c7<>7
r2c7=7 r5c7<>7
Locked Candidates Type 1 (Pointing): 7 in b6 => r8c9<>7
Forcing Net Verity => r1c1=6
r8c1=7 (r1c1<>7) (r5c1<>7 r5c9=7 r4c9<>7 r4c3=7 r2c3<>7) r8c1<>9 r3c1=9 r2c3<>9 r2c3=3 r1c1<>3 r1c1=6
r8c5=7 (r8c7<>7) (r8c5<>8) (r7c4<>7) r9c4<>7 (r9c2=7 r3c2<>7 r3c8=7 r1c8<>7 r1c1=7 r1c1<>3) (r9c2=7 r3c2<>7 r3c8=7 r1c8<>7) (r9c2=7 r3c2<>7 r3c8=7 r1c8<>7) r2c4=7 (r2c3<>7) r2c4<>9 r2c3=9 (r3c1<>9 r3c5=9 r3c5<>8) r7c3<>9 (r7c3=3 r7c8<>3 r7c8=6 r1c8<>6) r7c4=9 r7c4<>8 r6c4=8 r6c5<>8 r1c5=8 r1c8<>8 r1c8=3 (r2c7<>3) r2c9<>3 r2c3=3 r2c3<>9 r2c4=9 (r2c4<>7) r2c4<>7 r2c7=7 r3c8<>7 r7c8=7 r7c4<>7 r9c4=7 r8c5<>7 r8c1=7 r1c1<>7 r1c1=6
r8c7=7 (r8c1<>7) (r7c7<>7) r7c8<>7 r7c4=7 (r2c4<>7 r2c3=7 r1c1<>7) r7c4<>9 r7c3=9 r8c1<>9 r8c1=3 r1c1<>3 r1c1=6
Naked Single: r3c1=9
Hidden Single: r2c4=9
Hidden Single: r7c3=9
Locked Candidates Type 1 (Pointing): 7 in b2 => r8c5<>7
Naked Pair: 3,7 in r4c3,r5c1 => r5c2<>3
Jellyfish: 7 r2458 c1379 => r7c7<>7
2-String Kite: 3 in r1c8,r4c3 (connected by r1c2,r2c3) => r4c8<>3
Skyscraper: 3 in r7c8,r9c2 (connected by r1c28) => r9c9<>3
Uniqueness Test 2: 2/6 in r5c27,r6c27 => r278c7,r45c9<>3
Naked Triple: 6,7,8 in r4c89,r5c9 => r6c7<>6
Finned Swordfish: 6 c678 r247 fr3c8 => r2c9<>6
XY-Wing: 3/7/8 in r2c39,r3c2 => r3c8<>8
Hidden Rectangle: 7/8 in r1c25,r3c25 => r3c2<>7
Naked Single: r3c2=8
W-Wing: 6/8 in r2c6,r4c8 connected by 8 in r1c58 => r4c6<>6
Naked Pair: 2,3 in r49c6 => r7c6<>3
Hidden Single: r7c8=3
Hidden Single: r1c2=3
Full House: r2c3=7
Full House: r4c3=3
Naked Single: r9c2=7
Full House: r8c1=3
Full House: r5c1=7
Naked Single: r4c6=2
Naked Single: r5c9=6
Naked Single: r4c4=6
Naked Single: r9c6=3
Naked Single: r4c8=8
Full House: r4c9=7
Naked Single: r5c2=2
Full House: r5c7=3
Full House: r6c2=6
Full House: r6c7=2
Naked Single: r9c9=9
Naked Single: r6c4=8
Full House: r6c5=3
Naked Single: r9c4=2
Full House: r9c5=6
Full House: r7c4=7
Naked Single: r1c8=7
Full House: r1c5=8
Full House: r3c8=6
Full House: r3c5=7
Full House: r2c6=6
Full House: r7c6=8
Full House: r8c5=9
Full House: r7c7=6
Naked Single: r8c9=8
Full House: r2c9=3
Full House: r2c7=8
Full House: r8c7=7
|
normal_sudoku_1479
|
.....1.....3.4...712.....9....8...7.817.6..539.....28..4.3.7..57.54.6.3.....5..4.
|
479521368583649127126783594652834971817962453934175286248397615795416832361258749
|
Basic 9x9 Sudoku 1479
|
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 . . . 7
1 2 . . . . . 9 .
. . . 8 . . . 7 .
8 1 7 . 6 . . 5 3
9 . . . . . 2 8 .
. 4 . 3 . 7 . . 5
7 . 5 4 . 6 . 3 .
. . . . 5 . . 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
479521368583649127126783594652834971817962453934175286248397615795416832361258749 #1 Extreme (17538) bf
Hidden Single: r8c4=4
Hidden Single: r4c8=7
Locked Candidates Type 1 (Pointing): 7 in b1 => r1c45<>7
Brute Force: r5c2=1
Naked Single: r5c8=5
Hidden Single: r5c1=8
Locked Candidates Type 1 (Pointing): 2 in b4 => r4c56<>2
Discontinuous Nice Loop: 5 r1c2 -5- r2c1 -6- r7c1 -2- r8c1 -7- r1c1 =7= r1c2 => r1c2<>5
Forcing Chain Contradiction in r9c4 => r1c4<>2
r1c4=2 r1c89<>2 r2c8=2 r2c8<>1 r7c8=1 r7c3<>1 r9c3=1 r9c4<>1
r1c4=2 r9c4<>2
r1c4=2 r5c4<>2 r5c4=9 r9c4<>9
Forcing Chain Contradiction in b9 => r4c3<>6
r4c3=6 r4c3<>2 r4c1=2 r7c1<>2 r7c1=6 r7c7<>6
r4c3=6 r4c3<>2 r4c1=2 r7c1<>2 r7c1=6 r7c8<>6
r4c3=6 r4c3<>2 r4c1=2 r8c1<>2 r8c1=7 r8c7<>7 r9c7=7 r9c7<>6
r4c3=6 r4c7<>6 r46c9=6 r9c9<>6
Forcing Chain Contradiction in r3 => r7c3<>2
r7c3=2 r4c3<>2 r4c3=4 r6c3<>4 r6c3=6 r3c3<>6
r7c3=2 r7c3<>1 r9c3=1 r9c4<>1 r6c4=1 r6c4<>7 r3c4=7 r3c4<>6
r7c3=2 r7c1<>2 r7c1=6 r7c8<>6 r12c8=6 r3c7<>6
r7c3=2 r7c1<>2 r7c1=6 r7c8<>6 r12c8=6 r3c9<>6
Forcing Chain Contradiction in r3 => r7c3<>6
r7c3=6 r3c3<>6
r7c3=6 r7c3<>1 r9c3=1 r9c4<>1 r6c4=1 r6c4<>7 r3c4=7 r3c4<>6
r7c3=6 r7c8<>6 r12c8=6 r3c7<>6
r7c3=6 r7c8<>6 r12c8=6 r3c9<>6
Forcing Net Contradiction in c4 => r1c2<>6
r1c2=6 r1c4<>6
r1c2=6 (r1c8<>6) r1c2<>7 r1c1=7 r8c1<>7 r8c1=2 r7c1<>2 r7c1=6 r7c8<>6 r2c8=6 r2c4<>6
r1c2=6 (r1c8<>6 r1c8=2 r7c8<>2) r1c2<>7 r1c1=7 r8c1<>7 r8c1=2 r7c1<>2 r7c1=6 r7c8<>6 r7c8=1 r7c3<>1 r9c3=1 r9c4<>1 r6c4=1 r6c4<>7 r6c5=7 r3c5<>7 r3c4=7 r3c4<>6
Forcing Net Contradiction in r3 => r1c7<>6
r1c7=6 (r3c7<>6) (r3c9<>6) (r1c7<>5) r1c7<>3 r1c5=3 (r3c5<>3) r3c6<>3 r3c7=3 r3c7<>5 r2c7=5 r2c1<>5 r2c1=6 r3c3<>6 r3c4=6 r3c4<>5
r1c7=6 (r3c7<>6) (r3c9<>6) (r1c7<>5) r1c7<>3 r1c5=3 (r3c5<>3) r3c6<>3 r3c7=3 r3c7<>5 r2c7=5 r2c1<>5 r2c1=6 r3c3<>6 r3c4=6 r3c4<>7 r3c5=7 r6c5<>7 r6c4=7 r6c4<>5 r123c4=5 r3c6<>5
r1c7=6 r1c7<>3 r1c5=3 (r3c5<>3) r3c6<>3 r3c7=3 r3c7<>5
Forcing Net Verity => r2c8<>6
r2c4=2 (r9c4<>2) r5c4<>2 r5c4=9 r9c4<>9 r9c4=1 r9c3<>1 r7c3=1 r7c8<>1 r2c8=1 r2c8<>6
r2c4=5 r2c1<>5 r2c1=6 r2c8<>6
r2c4=6 r2c8<>6
r2c4=9 (r9c4<>9) r5c4<>9 r5c4=2 r9c4<>2 r9c4=1 r9c3<>1 r7c3=1 r7c8<>1 r2c8=1 r2c8<>6
Forcing Chain Contradiction in r7c8 => r7c5<>2
r7c5=2 r1c5<>2 r1c89=2 r2c8<>2 r2c8=1 r7c8<>1
r7c5=2 r7c8<>2
r7c5=2 r7c1<>2 r7c1=6 r7c8<>6
Grouped Continuous Nice Loop: 1/8/9 2= r8c5 =1= r8c79 -1- r7c8 =1= r2c8 =2= r1c89 -2- r1c5 =2= r8c5 =1 => r79c7,r9c9<>1, r8c5<>8, r8c5<>9
Grouped Discontinuous Nice Loop: 2 r8c1 -2- r8c5 -1- r8c79 =1= r7c8 =2= r7c1 -2- r8c1 => r8c1<>2
Naked Single: r8c1=7
Hidden Single: r1c2=7
Hidden Single: r9c7=7
Finned Franken Swordfish: 8 r28b8 c267 fr7c5 fr8c9 => r7c7<>8
Grouped Discontinuous Nice Loop: 6 r1c3 -6- r1c8 =6= r7c8 -6- r7c7 -9- r8c79 =9= r8c2 -9- r2c2 =9= r1c3 => r1c3<>6
Grouped Discontinuous Nice Loop: 9 r9c2 -9- r8c2 -8- r7c3 =8= r7c5 =9= r9c46 -9- r9c2 => r9c2<>9
Grouped Discontinuous Nice Loop: 9 r9c3 -9- r9c46 =9= r7c5 =8= r7c3 =1= r9c3 => r9c3<>9
Sashimi Swordfish: 9 c359 r147 fr8c9 fr9c9 => r7c7<>9
Naked Single: r7c7=6
Naked Single: r7c1=2
Naked Single: r7c8=1
Naked Single: r2c8=2
Full House: r1c8=6
Hidden Single: r4c3=2
Hidden Single: r2c7=1
Hidden Single: r9c3=1
Hidden Single: r8c5=1
Hidden Single: r1c5=2
Hidden Single: r6c4=1
Hidden Single: r4c9=1
Hidden Single: r8c9=2
Hidden Single: r1c7=3
Hidden Single: r6c5=7
Hidden Single: r3c4=7
Hidden Single: r6c9=6
Naked Single: r6c3=4
Hidden Single: r9c9=9
Full House: r8c7=8
Full House: r8c2=9
Naked Single: r9c4=2
Naked Single: r7c3=8
Full House: r7c5=9
Full House: r9c6=8
Naked Single: r5c4=9
Naked Single: r1c3=9
Full House: r3c3=6
Naked Single: r4c5=3
Full House: r3c5=8
Naked Single: r1c4=5
Full House: r2c4=6
Naked Single: r5c7=4
Full House: r4c7=9
Full House: r3c7=5
Full House: r5c6=2
Naked Single: r2c1=5
Naked Single: r6c6=5
Full House: r4c6=4
Full House: r6c2=3
Naked Single: r3c9=4
Full House: r3c6=3
Full House: r2c6=9
Full House: r2c2=8
Full House: r1c1=4
Full House: r1c9=8
Naked Single: r4c1=6
Full House: r4c2=5
Full House: r9c2=6
Full House: r9c1=3
|
normal_sudoku_2669
|
6......9..2...4.63..9.6.5....3.2..862.6.58.14.8..4..5..6...2.75....7....7..51....
|
647835291125794863839261547453129786276358914981647352364982175518473629792516438
|
Basic 9x9 Sudoku 2669
|
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 .
. 2 . . . 4 . 6 3
. . 9 . 6 . 5 . .
. . 3 . 2 . . 8 6
2 . 6 . 5 8 . 1 4
. 8 . . 4 . . 5 .
. 6 . . . 2 . 7 5
. . . . 7 . . . .
7 . . 5 1 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
647835291125794863839261547453129786276358914981647352364982175518473629792516438 #1 Extreme (18428) bf
Hidden Single: r1c1=6
Brute Force: r5c8=1
Hidden Single: r6c8=5
Locked Candidates Type 1 (Pointing): 3 in b6 => r789c7<>3
2-String Kite: 5 in r1c6,r5c2 (connected by r4c6,r5c5) => r1c2<>5
Forcing Chain Contradiction in r7c3 => r6c4<>7
r6c4=7 r6c3<>7 r6c3=1 r7c3<>1
r6c4=7 r6c4<>6 r8c4=6 r8c4<>4 r7c4=4 r7c3<>4
r6c4=7 r6c4<>6 r8c4=6 r8c4<>8 r7c45=8 r7c3<>8
Forcing Net Contradiction in c4 => r6c4=6
r6c4<>6 r8c4=6 (r8c4<>8) r8c4<>4 r7c4=4 (r7c7<>4) (r7c3<>4) r7c4<>8 r7c5=8 (r7c7<>8) r7c3<>8 r7c3=1 r7c7<>1 r7c7=9 (r4c7<>9 r4c7=7 r2c7<>7) (r8c9<>9) r9c9<>9 r6c9=9 r6c1<>9 r6c1=1 r6c3<>1 r6c3=7 r2c3<>7 r2c4=7
r6c4<>6 r8c4=6 (r8c4<>8) r8c4<>4 r7c4=4 (r7c7<>4) (r7c3<>4) r7c4<>8 r7c5=8 (r7c7<>8) r7c3<>8 r7c3=1 r7c7<>1 r7c7=9 (r4c7<>9 r4c7=7 r5c7<>7) (r8c9<>9) r9c9<>9 r6c9=9 r6c1<>9 r6c1=1 r6c3<>1 r6c3=7 r5c2<>7 r5c4=7
Forcing Net Verity => r4c1<>1
r1c2=7 (r1c6<>7) (r1c9<>7) (r1c3<>7) r2c3<>7 r6c3=7 (r6c6<>7) r6c9<>7 r3c9=7 (r2c7<>7 r2c4=7 r4c4<>7) r3c6<>7 r4c6=7 r4c7<>7 r4c7=9 r4c4<>9 r4c4=1 r4c1<>1
r3c2=7 (r3c6<>7) (r3c9<>7) (r1c3<>7) r2c3<>7 r6c3=7 (r6c6<>7) r6c9<>7 r1c9=7 r1c6<>7 r4c6=7 (r4c4<>7) r4c7<>7 r4c7=9 r4c4<>9 r4c4=1 r4c1<>1
r4c2=7 r6c3<>7 r6c3=1 r4c1<>1
r5c2=7 r6c3<>7 r6c3=1 r4c1<>1
Forcing Net Contradiction in c4 => r4c1<>9
r4c1=9 (r4c7<>9 r4c7=7 r2c7<>7) r6c1<>9 r6c1=1 r6c3<>1 r6c3=7 r2c3<>7 r2c4=7
r4c1=9 (r4c7<>9 r4c7=7 r5c7<>7) r6c1<>9 r6c1=1 r6c3<>1 r6c3=7 r5c2<>7 r5c4=7
Forcing Net Verity => r1c3<>5
r4c2=9 (r4c7<>9 r4c7=7 r2c7<>7) r6c1<>9 r6c1=1 r6c3<>1 r6c3=7 r2c3<>7 r2c4=7 r2c4<>9 r2c5=9 r2c5<>5 r1c56=5 r1c3<>5
r5c2=9 r5c2<>5 r5c5=5 r4c6<>5 r1c6=5 r1c3<>5
r8c2=9 (r8c6<>9) (r8c9<>9) (r7c1<>9) r8c1<>9 r6c1=9 (r6c6<>9) r6c9<>9 r9c9=9 r9c6<>9 r4c6=9 r4c6<>5 r1c6=5 r1c3<>5
r9c2=9 (r9c6<>9) (r9c9<>9) (r7c1<>9) r8c1<>9 r6c1=9 (r6c6<>9) r6c9<>9 r8c9=9 r8c6<>9 r4c6=9 r4c6<>5 r1c6=5 r1c3<>5
Locked Candidates Type 1 (Pointing): 5 in b1 => r2c5<>5
Forcing Net Verity => r1c6<>7
r4c2=9 (r4c7<>9 r4c7=7 r2c7<>7) r6c1<>9 r6c1=1 r6c3<>1 r6c3=7 r2c3<>7 r2c4=7 r1c6<>7
r5c2=9 r5c2<>5 r5c5=5 r1c5<>5 r1c6=5 r1c6<>7
r8c2=9 (r8c6<>9) (r8c9<>9) (r7c1<>9) r8c1<>9 r6c1=9 (r6c6<>9) r6c9<>9 r9c9=9 r9c6<>9 r4c6=9 r4c6<>5 r1c6=5 r1c6<>7
r9c2=9 (r9c6<>9) (r9c9<>9) (r7c1<>9) r8c1<>9 r6c1=9 (r6c6<>9) r6c9<>9 r8c9=9 r8c6<>9 r4c6=9 r4c6<>5 r1c6=5 r1c6<>7
Forcing Net Verity => r1c6=5
r4c2=9 (r4c2<>7) (r4c7<>9 r4c7=7 r4c6<>7) r6c1<>9 r6c1=1 r6c3<>1 r6c3=7 (r6c6<>7) (r1c3<>7) (r5c2<>7) r6c6<>7 r3c6=7 r3c2<>7 r1c2=7 (r1c9<>7) r2c3<>7 r6c3=7 (r6c6<>7) (r1c3<>7) (r5c2<>7) r6c9<>7 r3c9=7 r3c6<>7 r4c6=7 r4c6<>5 r1c6=5
r5c2=9 r5c2<>5 r5c5=5 r1c5<>5 r1c6=5
r8c2=9 (r8c6<>9) (r8c9<>9) (r7c1<>9) r8c1<>9 r6c1=9 (r6c6<>9) r6c9<>9 r9c9=9 r9c6<>9 r4c6=9 r4c6<>5 r1c6=5
r9c2=9 (r9c6<>9) (r9c9<>9) (r7c1<>9) r8c1<>9 r6c1=9 (r6c6<>9) r6c9<>9 r8c9=9 r8c6<>9 r4c6=9 r4c6<>5 r1c6=5
Hidden Single: r5c5=5
Naked Triple: 1,7,9 in r5c2,r6c13 => r4c2<>1, r4c2<>7, r4c2<>9
Locked Candidates Type 1 (Pointing): 1 in b4 => r6c6<>1
Finned Franken Swordfish: 7 r24b4 c347 fr4c6 fr5c2 => r5c4<>7
AIC: 9 9- r4c7 -7- r5c7 =7= r5c2 =9= r6c1 -9 => r6c79<>9
Locked Candidates Type 1 (Pointing): 9 in b6 => r789c7<>9
Sashimi X-Wing: 9 r67 c16 fr7c4 fr7c5 => r89c6<>9
Locked Pair: 3,6 in r89c6 => r36c6,r7c45,r8c4<>3
Hidden Single: r6c7=3
Hidden Single: r5c4=3
Hidden Single: r7c1=3
Hidden Single: r1c5=3
Hidden Single: r6c9=2
Hidden Single: r3c2=3
Locked Candidates Type 1 (Pointing): 7 in b6 => r12c7<>7
Locked Candidates Type 2 (Claiming): 9 in r7 => r8c4<>9
Locked Candidates Type 2 (Claiming): 9 in c6 => r4c4<>9
Naked Triple: 1,7,8 in r13c9,r2c7 => r1c7<>1, r1c7<>8
Skyscraper: 7 in r2c4,r6c6 (connected by r26c3) => r3c6,r4c4<>7
Naked Single: r3c6=1
Naked Single: r4c4=1
X-Wing: 1 c29 r18 => r18c3,r8c17<>1
Uniqueness Test 4: 8/9 in r2c45,r7c45 => r27c4<>8
XY-Chain: 8 8- r3c1 -4- r4c1 -5- r4c2 -4- r9c2 -9- r9c9 -8 => r3c9<>8
Naked Single: r3c9=7
XY-Wing: 2/8/4 in r3c48,r8c4 => r8c8<>4
XY-Chain: 4 4- r8c4 -8- r7c5 -9- r2c5 -8- r2c7 -1- r1c9 -8- r9c9 -9- r9c2 -4 => r8c123<>4
XY-Chain: 8 8- r2c7 -1- r1c9 -8- r9c9 -9- r9c2 -4- r4c2 -5- r4c1 -4- r3c1 -8 => r2c13<>8
Turbot Fish: 8 r2c7 =8= r2c5 -8- r7c5 =8= r8c4 => r8c7<>8
AIC: 2/4 2- r1c7 -4- r3c8 =4= r3c1 -4- r4c1 -5- r4c2 =5= r8c2 =1= r8c9 -1- r1c9 -8- r2c7 =8= r2c5 -8- r7c5 =8= r8c4 =4= r8c7 -4 => r8c7<>2, r1c7<>4
Naked Single: r1c7=2
Naked Single: r3c8=4
Naked Single: r3c1=8
Full House: r3c4=2
Hidden Single: r4c1=4
Naked Single: r4c2=5
XY-Wing: 5/9/1 in r28c1,r8c2 => r1c2<>1
Hidden Single: r1c9=1
Full House: r2c7=8
Naked Single: r2c5=9
Full House: r7c5=8
Naked Single: r2c4=7
Full House: r1c4=8
Naked Single: r8c4=4
Full House: r7c4=9
Naked Single: r8c7=6
Naked Single: r8c6=3
Full House: r9c6=6
Naked Single: r9c7=4
Naked Single: r8c8=2
Full House: r9c8=3
Naked Single: r7c7=1
Full House: r7c3=4
Naked Single: r9c2=9
Naked Single: r1c3=7
Full House: r1c2=4
Naked Single: r5c2=7
Full House: r8c2=1
Full House: r5c7=9
Full House: r4c7=7
Full House: r4c6=9
Full House: r6c6=7
Naked Single: r8c1=5
Naked Single: r9c9=8
Full House: r8c9=9
Full House: r8c3=8
Full House: r9c3=2
Naked Single: r6c3=1
Full House: r2c3=5
Full House: r2c1=1
Full House: r6c1=9
|
normal_sudoku_2222
|
.3.18.42....4.971314..2385..7..4.23.6......48.14...675.8.3.4.97...2.83644...7..82
|
539187426826459713147623859978546231652731948314892675281364597795218364463975182
|
Basic 9x9 Sudoku 2222
|
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 8 . 4 2 .
. . . 4 . 9 7 1 3
1 4 . . 2 3 8 5 .
. 7 . . 4 . 2 3 .
6 . . . . . . 4 8
. 1 4 . . . 6 7 5
. 8 . 3 . 4 . 9 7
. . . 2 . 8 3 6 4
4 . . . 7 . . 8 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
539187426826459713147623859978546231652731948314892675281364597795218364463975182 #1 Easy (418)
Hidden Single: r3c2=4
Hidden Single: r4c5=4
Hidden Single: r2c7=7
Hidden Single: r2c9=3
Hidden Single: r4c8=3
Hidden Single: r8c6=8
Hidden Single: r1c8=2
Hidden Single: r9c9=2
Hidden Single: r3c8=5
Full House: r8c8=6
Hidden Single: r9c1=4
Hidden Single: r8c9=4
Hidden Single: r6c7=6
Naked Single: r6c6=2
Hidden Single: r9c3=3
Hidden Single: r6c1=3
Naked Single: r6c5=9
Full House: r6c4=8
Hidden Single: r4c9=1
Full House: r5c7=9
Hidden Single: r5c5=3
Hidden Single: r9c4=9
Hidden Single: r5c6=1
Hidden Single: r8c2=9
Hidden Single: r9c7=1
Full House: r7c7=5
Naked Single: r7c1=2
Hidden Single: r5c4=7
Naked Single: r3c4=6
Full House: r4c4=5
Full House: r4c6=6
Naked Single: r2c5=5
Full House: r1c6=7
Full House: r9c6=5
Full House: r9c2=6
Naked Single: r3c9=9
Full House: r1c9=6
Full House: r3c3=7
Naked Single: r2c1=8
Naked Single: r8c5=1
Full House: r7c5=6
Full House: r7c3=1
Naked Single: r2c2=2
Full House: r2c3=6
Full House: r5c2=5
Full House: r5c3=2
Naked Single: r4c1=9
Full House: r4c3=8
Naked Single: r8c3=5
Full House: r1c3=9
Full House: r1c1=5
Full House: r8c1=7
|
normal_sudoku_885
|
4..27.1....1.3...2..2..5.6.95.4..2..1..56298.2.8.1...5.147...2.7...2.....29..17..
|
436278159571639842892145367953487216147562983268913475314796528785324691629851734
|
Basic 9x9 Sudoku 885
|
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 . . 2 7 . 1 . .
. . 1 . 3 . . . 2
. . 2 . . 5 . 6 .
9 5 . 4 . . 2 . .
1 . . 5 6 2 9 8 .
2 . 8 . 1 . . . 5
. 1 4 7 . . . 2 .
7 . . . 2 . . . .
. 2 9 . . 1 7 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
436278159571639842892145367953487216147562983268913475314796528785324691629851734 #1 Extreme (30956) bf
Forcing Net Contradiction in r8 => r2c9<>9
r2c9=9 (r2c8<>9 r8c8=9 r8c8<>5) (r2c9<>7) r2c9<>2 r2c1=2 (r2c1<>5 r1c3=5 r8c3<>5) (r2c1<>5) (r3c1<>2) r3c3<>2 r3c9=2 r3c9<>7 r2c8=7 r2c8<>5 r2c7=5 r8c7<>5 r8c5=5 r8c5<>4
r2c9=9 (r2c9<>4) (r2c9<>7) r2c9<>2 r2c1=2 (r2c1<>5) (r3c1<>2) r3c3<>2 r3c9=2 r3c9<>7 r2c8=7 (r2c8<>4) r2c8<>5 r2c7=5 r2c7<>4 r2c6=4 r8c6<>4
r2c9=9 (r2c9<>4) (r2c9<>7) r2c9<>2 r2c1=2 (r2c1<>5) (r3c1<>2) r3c3<>2 r3c9=2 (r3c9<>4) r3c9<>7 r2c8=7 (r2c8<>4) r2c8<>5 r2c7=5 r2c7<>4 r2c6=4 r3c5<>4 r3c7=4 r8c7<>4
r2c9=9 (r1c8<>9) r2c8<>9 r8c8=9 r8c8<>4
r2c9=9 (r1c8<>9) r2c8<>9 r8c8=9 r8c8<>1 r8c9=1 r8c9<>4
Forcing Net Contradiction in c3 => r8c9<>3
r8c9=3 (r8c3<>3) r8c9<>1 r4c9=1 r4c9<>6 r4c3=6 r8c3<>6 r8c3=5 r1c3<>5 r1c8=5 r2c8<>5 r2c7=5 r1c8<>5 r1c3=5
r8c9=3 (r8c3<>3) r8c9<>1 r4c9=1 r4c9<>6 r4c3=6 r8c3<>6 r8c3=5
Brute Force: r5c8=8
Forcing Net Contradiction in r8 => r8c5<>8
r8c5=8 (r8c5<>2 r8c6=2 r8c6<>4 r2c6=4 r2c7<>4) (r8c4<>8) (r9c4<>8) r4c5<>8 r4c5=1 r3c5<>1 r3c4=1 r3c4<>8 r2c4=8 r2c7<>8 r2c7=5 r1c8<>5 r1c3=5 r8c3<>5
r8c5=8 r8c5<>5
r8c5=8 (r8c5<>2 r8c6=2 r8c6<>4 r2c6=4 r2c7<>4) (r8c4<>8) (r9c4<>8) r4c5<>8 r4c5=1 r3c5<>1 r3c4=1 r3c4<>8 r2c4=8 r2c7<>8 r2c7=5 r8c7<>5
r8c5=8 (r4c5<>8 r4c5=1 r6c5<>1 r6c8=1 r6c8<>4) (r8c5<>4) r8c5<>2 r8c6=2 r8c6<>4 r2c6=4 (r2c8<>4) r3c5<>4 r9c5=4 r9c8<>4 r8c8=4 r8c8<>5
Brute Force: r5c6=2
Hidden Single: r3c3=2
Hidden Single: r6c1=2
Hidden Single: r8c5=2
Hidden Single: r2c9=2
Locked Candidates Type 1 (Pointing): 7 in b1 => r56c2<>7
Hidden Rectangle: 1/9 in r3c45,r6c45 => r3c4<>9
Finned X-Wing: 5 r18 c38 fr8c7 => r9c8<>5
Forcing Chain Contradiction in c4 => r3c4=1
r3c4<>1 r6c4=1 r6c4<>3
r3c4<>1 r3c4=8 r3c1<>8 r3c1=3 r79c1<>3 r8c23=3 r8c4<>3
r3c4<>1 r3c5=1 r3c5<>4 r9c5=4 r9c8<>4 r9c8=3 r9c4<>3
Forcing Chain Contradiction in c7 => r3c5<>8
r3c5=8 r3c1<>8 r3c1=3 r3c7<>3
r3c5=8 r4c5<>8 r4c6=8 r4c6<>3 r6c46=3 r6c7<>3
r3c5=8 r3c5<>4 r9c5=4 r9c8<>4 r9c8=3 r7c7<>3
r3c5=8 r3c5<>4 r9c5=4 r9c8<>4 r9c8=3 r8c7<>3
Forcing Chain Contradiction in r3c7 => r8c7<>3
r8c7=3 r3c7<>3
r8c7=3 r9c8<>3 r9c8=4 r9c5<>4 r3c5=4 r3c7<>4
r8c7=3 r8c23<>3 r79c1=3 r3c1<>3 r3c1=8 r3c7<>8
Forcing Net Contradiction in c9 => r4c5=8
r4c5<>8 (r4c5=1 r6c5<>1 r6c5=9 r6c4<>9) r4c6=8 (r7c6<>8) (r1c6<>8) r2c6<>8 r2c4=8 (r9c4<>8 r9c4=6 r7c6<>6) r2c4<>9 r8c4=9 r7c6<>9 r7c6=3 (r7c1<>3) (r7c7<>3) r9c4<>3 r6c4=3 (r6c7<>3) (r8c4<>3) r6c7<>3 r3c7=3 r3c1<>3 r9c1=3 r9c8<>3 r9c8=4 (r2c8<>4) r8c9<>4 r8c6=4 (r8c7<>4) (r8c8<>4) r2c6<>4 r2c7=4 r6c7<>4 r6c7=6 r4c9<>6
r4c5<>8 (r4c5=1 r6c5<>1 r6c5=9 r7c5<>9) (r4c5=1 r6c5<>1 r6c5=9 r6c4<>9) r4c6=8 (r1c6<>8) r2c6<>8 r2c4=8 r2c4<>9 r8c4=9 r7c6<>9 r7c9=9 r7c9<>6
r4c5<>8 r4c5=1 r4c9<>1 r8c9=1 r8c9<>6
r4c5<>8 (r4c5=1 r6c5<>1 r6c5=9 r6c4<>9 r6c4=3 r9c4<>3) r4c6=8 (r1c6<>8) r2c6<>8 r2c4=8 r9c4<>8 r9c4=6 r9c9<>6
Hidden Single: r6c5=1
Almost Locked Set XY-Wing: A=r8c23467 {345689}, B=r9c58 {345}, C=r7c5 {59}, X,Y=5,9, Z=3 => r8c8<>3
Forcing Chain Verity => r7c6<>3
r3c7=3 r3c1<>3 r79c1=3 r8c23<>3 r8c46=3 r7c6<>3
r6c7=3 r6c4<>3 r89c4=3 r7c6<>3
r7c7=3 r7c6<>3
Grouped Discontinuous Nice Loop: 9 r2c4 -9- r6c4 -3- r89c4 =3= r8c6 =4= r2c6 -4- r3c5 -9- r2c4 => r2c4<>9
Forcing Chain Contradiction in c4 => r2c1<>8
r2c1=8 r2c4<>8
r2c1=8 r79c1<>8 r8c2=8 r8c4<>8
r2c1=8 r3c1<>8 r3c1=3 r79c1<>3 r8c23=3 r8c46<>3 r9c4=3 r9c4<>8
Grouped Discontinuous Nice Loop: 6 r8c6 -6- r1c6 =6= r1c23 -6- r2c1 -5- r9c1 =5= r9c5 =4= r8c6 => r8c6<>6
Forcing Chain Contradiction in r3c7 => r3c2<>8
r3c2=8 r3c1<>8 r3c1=3 r3c7<>3
r3c2=8 r3c1<>8 r3c1=3 r7c1<>3 r7c79=3 r9c8<>3 r9c8=4 r9c5<>4 r3c5=4 r3c7<>4
r3c2=8 r3c7<>8
Forcing Chain Contradiction in r3c7 => r3c9<>8
r3c9=8 r3c1<>8 r3c1=3 r3c7<>3
r3c9=8 r3c1<>8 r3c1=3 r7c1<>3 r7c79=3 r9c8<>3 r9c8=4 r9c5<>4 r3c5=4 r3c7<>4
r3c9=8 r3c7<>8
Empty Rectangle: 8 in b7 (r3c17) => r8c7<>8
Forcing Chain Contradiction in r8c7 => r1c2<>6
r1c2=6 r2c1<>6 r2c1=5 r9c1<>5 r9c5=5 r9c5<>4 r8c6=4 r8c7<>4
r1c2=6 r2c1<>6 r2c1=5 r1c3<>5 r8c3=5 r8c7<>5
r1c2=6 r6c2<>6 r6c7=6 r8c7<>6
Forcing Chain Contradiction in r1 => r1c3<>3
r1c3=3 r3c1<>3 r3c1=8 r1c2<>8
r1c3=3 r1c3<>6 r1c6=6 r1c6<>8
r1c3=3 r1c3<>5 r8c3=5 r8c78<>5 r7c7=5 r7c7<>8 r23c7=8 r1c9<>8
Naked Pair: 5,6 in r1c3,r2c1 => r2c2<>6
2-String Kite: 6 in r4c9,r8c2 (connected by r4c3,r6c2) => r8c9<>6
Forcing Chain Contradiction in c4 => r4c8=1
r4c8<>1 r4c9=1 r4c9<>6 r4c3=6 r1c3<>6 r1c6=6 r2c4<>6
r4c8<>1 r4c9=1 r4c9<>6 r4c3=6 r6c2<>6 r8c2=6 r8c4<>6
r4c8<>1 r4c9=1 r4c9<>6 r4c3=6 r6c2<>6 r8c2=6 r8c2<>8 r79c1=8 r3c1<>8 r3c1=3 r79c1<>3 r8c23=3 r8c46<>3 r9c4=3 r9c4<>6
Hidden Single: r8c9=1
Finned Franken Swordfish: 8 r18b9 c269 fr7c7 fr8c4 => r7c6<>8
XYZ-Wing: 6/8/9 in r17c6,r2c4 => r2c6<>6
2-String Kite: 6 in r2c1,r7c6 (connected by r1c6,r2c4) => r7c1<>6
Empty Rectangle: 6 in b7 (r2c14) => r8c4<>6
X-Wing: 6 c14 r29 => r9c9<>6
Sue de Coq: r7c79 - {35689} (r7c56 - {569}, r9c89 - {348}) => r8c78<>4, r7c1<>5
Hidden Single: r8c6=4
Naked Single: r9c5=5
Naked Single: r7c5=9
Full House: r3c5=4
Naked Single: r7c6=6
Hidden Single: r7c7=5
Naked Single: r8c7=6
Naked Single: r8c8=9
Hidden Single: r2c1=5
Naked Single: r1c3=6
Hidden Single: r8c3=5
Hidden Single: r6c4=9
Hidden Single: r2c4=6
Hidden Single: r4c9=6
Hidden Single: r9c1=6
Hidden Single: r6c2=6
Hidden Single: r1c8=5
Hidden Single: r5c2=4
Hidden Single: r9c9=4
Naked Single: r9c8=3
Full House: r7c9=8
Full House: r9c4=8
Full House: r7c1=3
Full House: r8c4=3
Full House: r3c1=8
Full House: r8c2=8
Naked Single: r3c7=3
Naked Single: r1c9=9
Naked Single: r6c7=4
Full House: r2c7=8
Naked Single: r1c2=3
Full House: r1c6=8
Full House: r2c6=9
Naked Single: r3c9=7
Full House: r2c8=4
Full House: r6c8=7
Full House: r2c2=7
Full House: r3c2=9
Full House: r5c9=3
Full House: r6c6=3
Full House: r5c3=7
Full House: r4c6=7
Full House: r4c3=3
|
normal_sudoku_920
|
..4.6.25.6..42.89.92....461716..2945.491567.2..2..4.1.49...7....37.....4.6..4.179
|
874961253651423897923578461716832945349156782582794316495217638137689524268345179
|
Basic 9x9 Sudoku 920
|
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 . 2 5 .
6 . . 4 2 . 8 9 .
9 2 . . . . 4 6 1
7 1 6 . . 2 9 4 5
. 4 9 1 5 6 7 . 2
. . 2 . . 4 . 1 .
4 9 . . . 7 . . .
. 3 7 . . . . . 4
. 6 . . 4 . 1 7 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
874961253651423897923578461716832945349156782582794316495217638137689524268345179 #1 Extreme (2080)
Hidden Single: r5c3=9
Hidden Single: r9c2=6
Hidden Single: r4c8=4
Hidden Single: r9c9=9
Hidden Single: r2c4=4
Hidden Single: r7c1=4
Hidden Single: r5c2=4
Hidden Single: r6c8=1
Hidden Single: r3c7=4
Hidden Single: r4c9=5
Hidden Single: r9c8=7
Hidden Single: r2c5=2
Hidden Single: r3c8=6
Hidden Single: r5c7=7
Hidden Single: r1c8=5
Hidden Single: r5c6=6
Locked Candidates Type 1 (Pointing): 1 in b2 => r8c6<>1
Locked Candidates Type 1 (Pointing): 3 in b3 => r67c9<>3
Locked Candidates Type 1 (Pointing): 3 in b4 => r1c1<>3
Locked Candidates Type 1 (Pointing): 3 in b9 => r7c45<>3
Locked Candidates Type 2 (Claiming): 7 in r3 => r1c4<>7
Locked Candidates Type 2 (Claiming): 3 in r4 => r6c45<>3
Locked Candidates Type 2 (Claiming): 8 in r4 => r6c45<>8
Continuous Nice Loop: 8 3= r6c1 =5= r6c2 =8= r1c2 -8- r1c1 -1- r8c1 =1= r8c5 -1- r7c5 -8- r7c9 -6- r6c9 =6= r6c7 =3= r6c1 =5 => r1c46,r37c3,r6c1,r7c48<>8
Hidden Single: r9c3=8
XY-Wing: 5/7/3 in r2c29,r3c3 => r2c3<>3
Hidden Single: r3c3=3
Hidden Single: r4c5=3
Full House: r4c4=8
Locked Candidates Type 1 (Pointing): 5 in b1 => r2c6<>5
XY-Wing: 3/6/5 in r6c17,r8c7 => r8c1<>5
Sue de Coq: r8c56 - {1589} (r8c18 - {128}, r789c4,r9c6 - {23569}) => r8c4<>2
XY-Chain: 5 5- r3c4 -7- r3c5 -8- r7c5 -1- r7c3 -5- r2c3 -1- r2c6 -3- r9c6 -5 => r3c6,r789c4<>5
Naked Single: r3c6=8
Naked Single: r3c5=7
Full House: r3c4=5
Naked Single: r6c5=9
Full House: r6c4=7
XY-Wing: 6/8/2 in r7c49,r8c8 => r7c8<>2
Naked Single: r7c8=3
Naked Single: r5c8=8
Full House: r5c1=3
Full House: r8c8=2
Naked Single: r6c9=6
Full House: r6c7=3
Naked Single: r6c1=5
Full House: r6c2=8
Naked Single: r8c1=1
Naked Single: r7c9=8
Naked Single: r9c1=2
Full House: r1c1=8
Full House: r7c3=5
Full House: r2c3=1
Naked Single: r1c2=7
Full House: r2c2=5
Naked Single: r8c5=8
Full House: r7c5=1
Naked Single: r9c4=3
Full House: r9c6=5
Naked Single: r7c7=6
Full House: r7c4=2
Full House: r8c7=5
Naked Single: r2c6=3
Full House: r2c9=7
Full House: r1c9=3
Naked Single: r1c4=9
Full House: r1c6=1
Full House: r8c6=9
Full House: r8c4=6
|
normal_sudoku_149
|
....63.....2.5.96865.82...4..3..6.....85.461......2.9...56...49..42157.67.6.4.251
|
841963572372451968659827134413796825298534617567182493125678349934215786786349251
|
Basic 9x9 Sudoku 149
|
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 3 . . .
. . 2 . 5 . 9 6 8
6 5 . 8 2 . . . 4
. . 3 . . 6 . . .
. . 8 5 . 4 6 1 .
. . . . . 2 . 9 .
. . 5 6 . . . 4 9
. . 4 2 1 5 7 . 6
7 . 6 . 4 . 2 5 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
841963572372451968659827134413796825298534617567182493125678349934215786786349251 #1 Extreme (2556)
Hidden Single: r6c6=2
Hidden Single: r2c5=5
Hidden Single: r9c8=5
Hidden Single: r7c9=9
Hidden Single: r9c5=4
Locked Candidates Type 1 (Pointing): 2 in b3 => r1c123<>2
Hidden Single: r2c3=2
Locked Candidates Type 1 (Pointing): 3 in b3 => r3c1<>3
Locked Candidates Type 1 (Pointing): 1 in b5 => r12c4<>1
Locked Candidates Type 1 (Pointing): 8 in b5 => r7c5<>8
Locked Candidates Type 1 (Pointing): 9 in b8 => r9c23<>9
Naked Single: r9c3=6
Hidden Single: r3c1=6
Hidden Single: r7c4=6
Locked Candidates Type 2 (Claiming): 9 in c3 => r1c12<>9
Locked Candidates Type 2 (Claiming): 9 in c5 => r4c4<>9
Locked Candidates Type 2 (Claiming): 3 in c9 => r56c7<>3
Naked Single: r5c7=6
Hidden Single: r6c2=6
Naked Triple: 3,8,9 in r8c12,r9c2 => r7c12<>3, r7c12<>8
XY-Chain: 1 1- r2c6 -7- r7c6 -8- r7c7 -3- r3c7 -1 => r3c6<>1
Hidden Single: r2c6=1
Empty Rectangle: 7 in b4 (r2c24) => r6c4<>7
XY-Chain: 3 3- r2c1 -4- r2c4 -7- r3c6 -9- r9c6 -8- r9c2 -3 => r2c2,r8c1<>3
Hidden Single: r2c1=3
XY-Chain: 7 7- r3c6 -9- r9c6 -8- r7c6 -7- r7c5 -3- r7c7 -8- r8c8 -3- r3c8 -7 => r3c3<>7
XY-Chain: 7 7- r2c2 -4- r2c4 -7- r3c6 -9- r3c3 -1- r6c3 -7 => r1c3,r45c2<>7
Hidden Single: r6c3=7
Locked Pair: 2,9 in r5c12 => r4c12,r5c5<>9, r4c12,r5c9<>2
Hidden Single: r4c5=9
Hidden Single: r6c5=8
Locked Candidates Type 2 (Claiming): 1 in c3 => r1c12<>1
XY-Wing: 1/4/7 in r24c2,r4c4 => r2c4<>7
Naked Single: r2c4=4
Full House: r2c2=7
2-String Kite: 7 in r3c8,r4c4 (connected by r1c4,r3c6) => r4c8<>7
Locked Candidates Type 1 (Pointing): 7 in b6 => r1c9<>7
Hidden Rectangle: 2/7 in r1c89,r4c89 => r4c9<>7
Hidden Single: r4c4=7
Naked Single: r1c4=9
Full House: r3c6=7
Naked Single: r5c5=3
Full House: r6c4=1
Full House: r9c4=3
Full House: r7c5=7
Naked Single: r1c3=1
Full House: r3c3=9
Naked Single: r3c8=3
Full House: r3c7=1
Naked Single: r7c6=8
Full House: r9c6=9
Full House: r9c2=8
Naked Single: r5c9=7
Naked Single: r1c7=5
Naked Single: r8c8=8
Full House: r7c7=3
Naked Single: r1c2=4
Full House: r1c1=8
Naked Single: r8c1=9
Full House: r8c2=3
Naked Single: r1c9=2
Full House: r1c8=7
Full House: r4c8=2
Naked Single: r6c7=4
Full House: r4c7=8
Naked Single: r4c2=1
Naked Single: r5c1=2
Full House: r5c2=9
Full House: r7c2=2
Full House: r7c1=1
Naked Single: r4c9=5
Full House: r4c1=4
Full House: r6c1=5
Full House: r6c9=3
|
normal_sudoku_5413
|
......5.....925.1.1.58.....7.32581.4218..7.53.54...7283.1...2.5.7253..4154.1.2...
|
986413572437925816125876439793258164218647953654391728361784295872539641549162387
|
Basic 9x9 Sudoku 5413
|
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 . .
. . . 9 2 5 . 1 .
1 . 5 8 . . . . .
7 . 3 2 5 8 1 . 4
2 1 8 . . 7 . 5 3
. 5 4 . . . 7 2 8
3 . 1 . . . 2 . 5
. 7 2 5 3 . . 4 1
5 4 . 1 . 2 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
986413572437925816125876439793258164218647953654391728361784295872539641549162387 #1 Extreme (15788) bf
Hidden Single: r1c7=5
Hidden Single: r4c1=7
Hidden Single: r8c4=5
Hidden Single: r4c5=5
Hidden Single: r8c9=1
Hidden Single: r7c3=1
Hidden Single: r9c6=2
Hidden Single: r4c4=2
Hidden Single: r2c8=1
Brute Force: r5c3=8
Finned Franken Swordfish: 6 r58b4 c167 fr4c2 fr5c4 fr5c5 => r4c6<>6
W-Wing: 9/6 in r5c7,r6c1 connected by 6 in r4c28 => r6c9<>9
Finned X-Wing: 9 c39 r19 fr3c9 => r1c8<>9
Sashimi Swordfish: 9 r568 c167 fr5c5 fr6c5 => r4c6<>9
Naked Single: r4c6=8
Hidden Single: r6c9=8
Naked Pair: 6,7 in r2c39 => r2c127<>6
Turbot Fish: 8 r1c8 =8= r2c7 -8- r8c7 =8= r8c1 => r1c1<>8
Almost Locked Set Chain: 6- r2c1279 {34678} -7- r2c3 {67} -6- r9c3 {69} -9- r29c9 {679} -6 => r13c9<>6
Forcing Chain Verity => r1c8<>6
r1c1=6 r1c8<>6
r6c1=6 r4c2<>6 r4c8=6 r1c8<>6
r8c1=6 r8c1<>8 r8c7=8 r2c7<>8 r1c8=8 r1c8<>6
Forcing Chain Contradiction in r8c1 => r3c7<>6
r3c7=6 r5c7<>6 r4c8=6 r4c2<>6 r6c1=6 r8c1<>6
r3c7=6 r3c7<>4 r2c7=4 r2c1<>4 r2c1=8 r8c1<>8
r3c7=6 r2c9<>6 r2c3=6 r9c3<>6 r9c3=9 r8c1<>9
Forcing Chain Contradiction in r8c1 => r3c7<>9
r3c7=9 r13c9<>9 r9c9=9 r9c3<>9 r9c3=6 r8c1<>6
r3c7=9 r3c7<>4 r2c7=4 r2c1<>4 r2c1=8 r8c1<>8
r3c7=9 r5c7<>9 r5c5=9 r6c56<>9 r6c1=9 r8c1<>9
Forcing Chain Verity => r8c1<>6
r5c7=9 r5c7<>6 r4c8=6 r4c2<>6 r6c1=6 r8c1<>6
r8c7=9 r8c7<>8 r8c1=8 r8c1<>6
r9c7=9 r9c3<>9 r9c3=6 r8c1<>6
Turbot Fish: 6 r4c8 =6= r4c2 -6- r7c2 =6= r9c3 => r9c8<>6
Sashimi X-Wing: 6 r58 c67 fr5c4 fr5c5 => r6c6<>6
Multi Colors 1: 6 (r1c1,r4c2,r5c7) / (r4c8,r6c1), (r2c3,r3c8,r9c9) / (r2c9) => r2c3,r3c8<>6
Naked Single: r2c3=7
Naked Single: r2c9=6
W-Wing: 9/6 in r1c3,r4c2 connected by 6 in r16c1 => r13c2<>9
Locked Candidates Type 1 (Pointing): 9 in b1 => r1c9<>9
Almost Locked Set XZ-Rule: A=r8c16 {689}, B=r1c13,r2c1 {4689}, X=8, Z=6 => r1c6<>6
Almost Locked Set XZ-Rule: A=r58c7 {689}, B=r8c1,r9c3 {689}, X=8, Z=6 => r9c7<>6
AIC: 9 9- r7c2 =9= r4c2 =6= r4c8 -6- r7c8 =6= r8c7 -6- r8c6 -9 => r7c56,r8c1<>9
Naked Single: r8c1=8
Naked Single: r2c1=4
Hidden Single: r3c7=4
Locked Pair: 6,9 in r1c13 => r1c245,r3c2<>6
Naked Pair: 6,9 in r58c7 => r9c7<>9
X-Wing: 6 c28 r47 => r7c456<>6
Naked Single: r7c6=4
Naked Single: r7c4=7
Naked Single: r7c5=8
Locked Candidates Type 2 (Claiming): 6 in c4 => r56c5<>6
Naked Pair: 6,9 in r7c8,r8c7 => r9c89<>9
Naked Single: r9c9=7
Naked Single: r1c9=2
Full House: r3c9=9
Hidden Single: r3c2=2
Remote Pair: 9/6 r6c1 -6- r4c2 -9- r4c8 -6- r5c7 -9- r8c7 -6- r7c8 -9- r7c2 -6- r9c3 -9- r9c5 -6- r8c6 => r5c5,r6c6<>9
Naked Single: r5c5=4
Naked Single: r5c4=6
Full House: r5c7=9
Full House: r4c8=6
Full House: r4c2=9
Full House: r6c1=6
Full House: r1c1=9
Naked Single: r6c4=3
Full House: r1c4=4
Naked Single: r8c7=6
Full House: r8c6=9
Full House: r9c5=6
Naked Single: r7c8=9
Full House: r7c2=6
Full House: r9c3=9
Full House: r1c3=6
Naked Single: r6c6=1
Full House: r6c5=9
Naked Single: r3c5=7
Full House: r1c5=1
Naked Single: r1c6=3
Full House: r3c6=6
Full House: r3c8=3
Naked Single: r1c2=8
Full House: r1c8=7
Full House: r2c7=8
Full House: r9c8=8
Full House: r2c2=3
Full House: r9c7=3
|
normal_sudoku_1309
|
.732.915.5..13..72....753.93.........87453....6....5379...1..23.3.5.291...139.7.5
|
673249158594138672218675349352967481187453296469821537945716823736582914821394765
|
Basic 9x9 Sudoku 1309
|
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 3 2 . 9 1 5 .
5 . . 1 3 . . 7 2
. . . . 7 5 3 . 9
3 . . . . . . . .
. 8 7 4 5 3 . . .
. 6 . . . . 5 3 7
9 . . . 1 . . 2 3
. 3 . 5 . 2 9 1 .
. . 1 3 9 . 7 . 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
673249158594138672218675349352967481187453296469821537945716823736582914821394765 #1 Extreme (35310) bf
Hidden Single: r6c8=3
Hidden Single: r1c3=3
Hidden Single: r3c6=5
Hidden Single: r2c8=7
Hidden Single: r7c9=3
Hidden Single: r9c4=3
Hidden Single: r9c5=9
Locked Candidates Type 1 (Pointing): 8 in b6 => r4c456<>8
Locked Candidates Type 1 (Pointing): 7 in b8 => r7c23<>7
Brute Force: r5c4=4
Locked Candidates Type 1 (Pointing): 7 in b5 => r4c23<>7
Hidden Single: r1c2=7
Locked Candidates Type 1 (Pointing): 4 in b6 => r4c23<>4
Forcing Net Contradiction in r8 => r4c9<>6
r4c9=6 (r1c9<>6) (r5c7<>6) (r5c8<>6) r5c9<>6 r5c5=6 r1c5<>6 r1c1=6 r8c1<>6
r4c9=6 (r5c7<>6 r5c7=2 r5c1<>2) r5c9<>6 r5c9=1 r5c1<>1 r5c1=7 r8c1<>7 r8c3=7 r8c3<>6
r4c9=6 (r5c7<>6) (r5c8<>6) r5c9<>6 r5c5=6 r8c5<>6
r4c9=6 r8c9<>6
Brute Force: r5c5=5
Locked Candidates Type 1 (Pointing): 6 in b5 => r4c78<>6
Forcing Net Contradiction in r3c8 => r8c3<>4
r8c3=4 (r9c2<>4 r9c2=2 r3c2<>2) (r6c3<>4 r6c1=4 r6c1<>1 r6c6=1 r4c6<>1) (r8c9<>4) r8c5<>4 r1c5=4 r1c9<>4 r4c9=4 r4c9<>1 r4c2=1 r3c2<>1 r3c2=4 r3c8<>4
r8c3=4 (r7c2<>4 r7c2=5 r4c2<>5 r4c3=5 r4c3<>9) (r8c3<>7 r8c1=7 r5c1<>7 r5c3=7 r5c3<>9 r5c8=9 r4c8<>9) (r6c3<>4 r6c1=4 r6c1<>1 r6c6=1 r4c6<>1) (r8c9<>4) r8c5<>4 r1c5=4 r1c9<>4 r4c9=4 r4c9<>1 r4c2=1 r4c2<>9 r4c4=9 r6c4<>9 r6c4=8 r3c4<>8 r3c4=6 r3c8<>6
r8c3=4 (r8c5<>4 r1c5=4 r1c9<>4 r4c9=4 r4c8<>4) r8c3<>7 r8c1=7 r5c1<>7 r5c3=7 r5c3<>9 r5c8=9 r4c8<>9 r4c8=8 r3c8<>8
Brute Force: r5c3=7
Hidden Single: r8c1=7
Hidden Single: r5c8=9
Empty Rectangle: 6 in b7 (r39c8) => r3c3<>6
Finned Jellyfish: 6 r2578 c3679 fr7c4 fr8c5 => r9c6<>6
Discontinuous Nice Loop: 2 r3c2 -2- r9c2 =2= r9c1 -2- r5c1 -1- r3c1 =1= r3c2 => r3c2<>2
Forcing Chain Contradiction in r2c3 => r1c1<>4
r1c1=4 r2c3<>4
r1c1=4 r3c123<>4 r3c8=4 r3c8<>6 r9c8=6 r9c1<>6 r13c1=6 r2c3<>6
r1c1=4 r1c5<>4 r8c5=4 r9c6<>4 r9c6=8 r9c1<>8 r13c1=8 r2c3<>8
r1c1=4 r2c2<>4 r2c2=9 r2c3<>9
X-Wing: 4 r18 c59 => r4c9<>4
Forcing Chain Contradiction in r2c3 => r1c5<>8
r1c5=8 r1c5<>4 r2c6=4 r2c3<>4
r1c5=8 r1c1<>8 r1c1=6 r2c3<>6
r1c5=8 r1c5<>4 r8c5=4 r9c6<>4 r9c6=8 r9c1<>8 r13c1=8 r2c3<>8
r1c5=8 r1c5<>4 r2c6=4 r2c2<>4 r2c2=9 r2c3<>9
Discontinuous Nice Loop: 2 r4c2 -2- r4c5 =2= r6c5 =8= r8c5 -8- r9c6 -4- r9c2 -2- r4c2 => r4c2<>2
Hidden Single: r9c2=2
Discontinuous Nice Loop: 6 r8c9 -6- r5c9 =6= r5c7 =2= r4c7 -2- r4c5 -6- r1c5 -4- r1c9 =4= r8c9 => r8c9<>6
Discontinuous Nice Loop: 4 r9c8 -4- r8c9 -8- r8c3 -6- r9c1 =6= r9c8 => r9c8<>4
Finned Franken Swordfish: 8 r19b2 c168 fr1c9 fr3c4 => r3c8<>8
XY-Wing: 6/8/4 in r39c8,r8c9 => r1c9<>4
Hidden Single: r1c5=4
Hidden Single: r8c9=4
Skyscraper: 6 in r1c9,r9c8 (connected by r19c1) => r3c8<>6
Naked Single: r3c8=4
Naked Single: r3c2=1
Naked Single: r4c8=8
Full House: r9c8=6
Full House: r7c7=8
Naked Single: r4c9=1
Naked Single: r2c7=6
Full House: r1c9=8
Full House: r5c9=6
Full House: r1c1=6
Naked Single: r2c6=8
Full House: r3c4=6
Naked Single: r5c7=2
Full House: r4c7=4
Full House: r5c1=1
Naked Single: r6c6=1
Naked Single: r9c6=4
Full House: r9c1=8
Naked Single: r7c4=7
Naked Single: r3c1=2
Full House: r3c3=8
Full House: r6c1=4
Naked Single: r8c3=6
Full House: r8c5=8
Full House: r7c6=6
Full House: r4c6=7
Naked Single: r4c4=9
Full House: r6c4=8
Naked Single: r6c5=2
Full House: r4c5=6
Full House: r6c3=9
Naked Single: r4c2=5
Full House: r4c3=2
Naked Single: r2c3=4
Full House: r2c2=9
Full House: r7c2=4
Full House: r7c3=5
|
normal_sudoku_1054
|
953...16...8391.....7.65.93..951.6....2....5..45..6.1.2.1639.473.6.5.9.15.418...6
|
953874162628391475417265893739518624162943758845726319281639547376452981594187236
|
Basic 9x9 Sudoku 1054
|
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 5 3 . . . 1 6 .
. . 8 3 9 1 . . .
. . 7 . 6 5 . 9 3
. . 9 5 1 . 6 . .
. . 2 . . . . 5 .
. 4 5 . . 6 . 1 .
2 . 1 6 3 9 . 4 7
3 . 6 . 5 . 9 . 1
5 . 4 1 8 . . . 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
953874162628391475417265893739518624162943758845726319281639547376452981594187236 #1 Hard (1194)
Naked Single: r3c3=7
Naked Single: r1c3=3
Naked Single: r6c3=5
Full House: r8c3=6
Hidden Single: r3c6=5
Hidden Single: r3c8=9
Hidden Single: r2c4=3
Hidden Single: r9c1=5
Hidden Single: r7c4=6
Hidden Single: r9c9=6
Hidden Single: r1c1=9
Hidden Single: r9c4=1
Hidden Single: r8c9=1
Hidden Single: r8c5=5
Naked Single: r7c5=3
Naked Single: r7c6=9
Naked Single: r7c2=8
Full House: r7c7=5
Naked Single: r8c2=7
Full House: r9c2=9
Naked Single: r4c2=3
Hidden Single: r2c9=5
Hidden Single: r6c7=3
Naked Single: r9c7=2
Naked Single: r8c8=8
Full House: r9c8=3
Full House: r9c6=7
Hidden Single: r5c6=3
Naked Pair: 7,8 in r46c1 => r5c1<>7, r5c1<>8
2-String Kite: 4 in r1c5,r4c9 (connected by r4c6,r5c5) => r1c9<>4
Locked Candidates Type 1 (Pointing): 4 in b3 => r5c7<>4
Locked Candidates Type 2 (Claiming): 4 in r1 => r3c4<>4
W-Wing: 2/7 in r4c8,r6c5 connected by 7 in r46c1 => r4c6,r6c9<>2
W-Wing: 8/7 in r5c7,r6c1 connected by 7 in r4c18 => r6c9<>8
Naked Single: r6c9=9
Hidden Single: r5c4=9
Locked Candidates Type 2 (Claiming): 8 in r5 => r4c9<>8
XY-Wing: 2/4/8 in r14c9,r4c6 => r1c6<>8
Hidden Single: r4c6=8
Naked Single: r4c1=7
Naked Single: r4c8=2
Full House: r2c8=7
Full House: r4c9=4
Naked Single: r6c1=8
Naked Single: r2c7=4
Naked Single: r5c9=8
Full House: r1c9=2
Full House: r3c7=8
Full House: r5c7=7
Naked Single: r2c1=6
Full House: r2c2=2
Naked Single: r1c6=4
Full House: r8c6=2
Full House: r8c4=4
Naked Single: r3c4=2
Naked Single: r5c5=4
Naked Single: r5c1=1
Full House: r3c1=4
Full House: r3c2=1
Full House: r5c2=6
Naked Single: r1c5=7
Full House: r1c4=8
Full House: r6c4=7
Full House: r6c5=2
|
normal_sudoku_1793
|
785931..6...68..7.94675...8..439..8..9.176542.7.248.......1.83.....2...4.17.6....
|
785931426123684975946752318264395781398176542571248693652419837839527164417863259
|
Basic 9x9 Sudoku 1793
|
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.
|
7 8 5 9 3 1 . . 6
. . . 6 8 . . 7 .
9 4 6 7 5 . . . 8
. . 4 3 9 . . 8 .
. 9 . 1 7 6 5 4 2
. 7 . 2 4 8 . . .
. . . . 1 . 8 3 .
. . . . 2 . . . 4
. 1 7 . 6 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
785931426123684975946752318264395781398176542571248693652419837839527164417863259 #1 Easy (304)
Naked Single: r5c8=4
Naked Single: r5c5=7
Hidden Single: r1c1=7
Hidden Single: r3c9=8
Hidden Single: r6c4=2
Hidden Single: r7c5=1
Hidden Single: r1c2=8
Hidden Single: r6c6=8
Hidden Single: r9c5=6
Hidden Single: r6c5=4
Naked Single: r1c5=3
Naked Single: r1c9=6
Naked Single: r3c5=5
Full House: r4c5=9
Full House: r4c6=5
Naked Single: r1c8=2
Full House: r1c7=4
Naked Single: r3c6=2
Full House: r2c6=4
Naked Single: r3c8=1
Full House: r3c7=3
Naked Single: r2c7=9
Full House: r2c9=5
Naked Single: r9c7=2
Naked Single: r9c9=9
Naked Single: r7c9=7
Naked Single: r9c6=3
Naked Single: r9c8=5
Naked Single: r4c9=1
Full House: r6c9=3
Naked Single: r7c6=9
Full House: r8c6=7
Naked Single: r8c8=6
Full House: r6c8=9
Full House: r8c7=1
Naked Single: r6c7=6
Full House: r4c7=7
Naked Single: r6c3=1
Full House: r6c1=5
Naked Single: r7c3=2
Naked Single: r2c3=3
Naked Single: r2c2=2
Full House: r2c1=1
Naked Single: r5c3=8
Full House: r5c1=3
Full House: r8c3=9
Naked Single: r4c2=6
Full House: r4c1=2
Naked Single: r8c1=8
Naked Single: r7c2=5
Full House: r8c2=3
Full House: r8c4=5
Naked Single: r9c1=4
Full House: r7c1=6
Full House: r7c4=4
Full House: r9c4=8
|
normal_sudoku_5986
|
..238..547...54...54..129..6572.8.....4..152721....8....5.2..31.7...3...32.1.....
|
192386754786954312543712986657238149834691527219475863965827431471563298328149675
|
Basic 9x9 Sudoku 5986
|
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 3 8 . . 5 4
7 . . . 5 4 . . .
5 4 . . 1 2 9 . .
6 5 7 2 . 8 . . .
. . 4 . . 1 5 2 7
2 1 . . . . 8 . .
. . 5 . 2 . . 3 1
. 7 . . . 3 . . .
3 2 . 1 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
192386754786954312543712986657238149834691527219475863965827431471563298328149675 #1 Extreme (12672) bf
Hidden Single: r3c1=5
Grouped Discontinuous Nice Loop: 9 r4c4 -9- r4c89 =9= r6c89 -9- r6c1 -2- r6c4 =2= r4c4 => r4c4<>9
Forcing Net Contradiction in c4 => r4c4<>8
r4c4=8 r4c4<>4
r4c4=8 r4c4<>2 r4c2=2 r6c1<>2 r6c4=2 r6c4<>4
r4c4=8 r4c4<>2 r4c2=2 r6c1<>2 r8c1=2 r8c1<>4 r7c1=4 r7c4<>4
r4c4=8 (r4c4<>5) r4c4<>2 r4c2=2 (r6c1<>2 r6c4=2 r6c4<>5) r4c2<>5 r5c2=5 r5c4<>5 r8c4=5 r8c4<>4
Forcing Net Verity => r6c4<>6
r7c7=4 (r9c8<>4 r9c5=4 r6c5<>4) (r9c8<>4 r9c5=4 r4c5<>4) (r4c7<>4) r7c1<>4 r8c1=4 r8c1<>2 r6c1=2 r4c2<>2 r4c4=2 r4c4<>4 r4c8=4 r6c8<>4 r6c4=4 r6c4<>6
r7c7=6 r5c7<>6 r5c45=6 r6c4<>6
r7c7=7 (r7c4<>7) r9c8<>7 r3c8=7 r3c4<>7 r6c4=7 r6c4<>6
Brute Force: r5c7=5
Hidden Single: r4c2=5
Hidden Single: r4c4=2
Hidden Single: r9c2=2
Hidden Single: r6c1=2
Locked Candidates Type 1 (Pointing): 8 in b4 => r5c45<>8
Locked Candidates Type 1 (Pointing): 6 in b6 => r6c56<>6
W-Wing: 9/3 in r4c9,r6c3 connected by 3 in r3c39 => r6c89<>9
Locked Candidates Type 1 (Pointing): 9 in b6 => r4c56<>9
Naked Single: r4c6=8
Finned Swordfish: 8 r157 c124 fr1c5 => r23c4<>8
Hidden Single: r1c5=8
Naked Pair: 6,9 in r25c4 => r378c4<>6, r678c4<>9
Naked Single: r3c4=7
Hidden Single: r1c7=7
Hidden Single: r9c8=7
Hidden Single: r7c6=7
Hidden Single: r1c1=1
Hidden Single: r6c5=7
Hidden Single: r8c3=1
Locked Pair: 4,6 in r79c7 => r28c7,r8c89,r9c9<>6, r48c7,r8c8<>4
Naked Single: r8c7=2
Hidden Single: r8c5=6
Hidden Single: r2c9=2
Hidden Single: r5c4=6
Naked Single: r2c4=9
Full House: r1c6=6
Full House: r1c2=9
Hidden Single: r7c1=9
Naked Single: r5c1=8
Full House: r8c1=4
Naked Single: r5c2=3
Full House: r5c5=9
Full House: r6c3=9
Naked Single: r6c6=5
Full House: r9c6=9
Naked Single: r9c5=4
Full House: r4c5=3
Full House: r6c4=4
Naked Single: r7c4=8
Full House: r8c4=5
Naked Single: r9c7=6
Naked Single: r4c7=1
Naked Single: r4c9=9
Full House: r4c8=4
Naked Single: r6c8=6
Full House: r6c9=3
Naked Single: r7c2=6
Full House: r7c7=4
Full House: r9c3=8
Full House: r2c7=3
Full House: r2c2=8
Full House: r9c9=5
Naked Single: r8c9=8
Full House: r3c9=6
Full House: r8c8=9
Naked Single: r3c8=8
Full House: r2c8=1
Full House: r2c3=6
Full House: r3c3=3
|
normal_sudoku_1755
|
.15..283..3...621926....7.48.6..794.3.....6...9.62.5..1..27.3656..35.42.5.3.681.7
|
915742836437586219268913754856137942342895671791624583184279365679351428523468197
|
Basic 9x9 Sudoku 1755
|
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 . . 2 8 3 .
. 3 . . . 6 2 1 9
2 6 . . . . 7 . 4
8 . 6 . . 7 9 4 .
3 . . . . . 6 . .
. 9 . 6 2 . 5 . .
1 . . 2 7 . 3 6 5
6 . . 3 5 . 4 2 .
5 . 3 . 6 8 1 . 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
915742836437586219268913754856137942342895671791624583184279365679351428523468197 #1 Easy (258)
Naked Single: r4c1=8
Naked Single: r6c7=5
Naked Single: r2c7=2
Naked Single: r5c7=6
Full House: r8c7=4
Hidden Single: r1c6=2
Hidden Single: r7c8=6
Hidden Single: r9c5=6
Hidden Single: r8c1=6
Hidden Single: r2c2=3
Naked Single: r2c9=9
Naked Single: r1c8=3
Naked Single: r9c9=7
Naked Single: r1c9=6
Full House: r3c8=5
Naked Single: r8c9=8
Full House: r9c8=9
Naked Single: r8c2=7
Naked Single: r9c4=4
Full House: r9c2=2
Naked Single: r8c3=9
Full House: r8c6=1
Full House: r7c6=9
Naked Single: r4c2=5
Naked Single: r3c3=8
Naked Single: r3c6=3
Naked Single: r4c4=1
Naked Single: r5c2=4
Full House: r7c2=8
Full House: r7c3=4
Naked Single: r6c6=4
Full House: r5c6=5
Naked Single: r3c4=9
Full House: r3c5=1
Naked Single: r4c5=3
Full House: r4c9=2
Naked Single: r6c1=7
Naked Single: r2c3=7
Naked Single: r1c4=7
Naked Single: r1c5=4
Full House: r1c1=9
Full House: r2c1=4
Naked Single: r5c4=8
Full House: r2c4=5
Full House: r2c5=8
Full House: r5c5=9
Naked Single: r5c9=1
Full House: r6c9=3
Naked Single: r6c3=1
Full House: r6c8=8
Full House: r5c8=7
Full House: r5c3=2
|
normal_sudoku_1815
|
.32.1..7.71...9.839.837.2.137..4.....8195374....7.183..2318..971.7.9.3.889..37...
|
632518974714269583958374261379846125281953746546721839423185697167492358895637412
|
Basic 9x9 Sudoku 1815
|
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 2 . 1 . . 7 .
7 1 . . . 9 . 8 3
9 . 8 3 7 . 2 . 1
3 7 . . 4 . . . .
. 8 1 9 5 3 7 4 .
. . . 7 . 1 8 3 .
. 2 3 1 8 . . 9 7
1 . 7 . 9 . 3 . 8
8 9 . . 3 7 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
632518974714269583958374261379846125281953746546721839423185697167492358895637412 #1 Extreme (26812) bf
Hidden Single: r1c2=3
Hidden Single: r1c5=1
Hidden Single: r2c1=7
Hidden Single: r9c6=7
Hidden Single: r8c9=8
Hidden Single: r8c1=1
Hidden Single: r3c1=9
Hidden Single: r6c8=3
Hidden Single: r5c6=3
Hidden Single: r7c3=3
Hidden Single: r7c5=8
Hidden Single: r8c7=3
Naked Triple: 4,5,6 in r368c2 => r4c2<>5, r45c2<>6, r5c2<>4
Brute Force: r5c4=9
Hidden Single: r8c5=9
Hidden Single: r5c2=8
Naked Single: r4c2=7
Hidden Single: r5c7=7
Grouped Discontinuous Nice Loop: 6 r6c9 -6- r6c5 -2- r6c1 =2= r5c1 =6= r5c89 -6- r6c9 => r6c9<>6
Brute Force: r5c8=4
Finned X-Wing: 4 r38 c26 fr8c4 => r7c6<>4
2-String Kite: 4 in r1c9,r7c1 (connected by r7c7,r9c9) => r1c1<>4
Forcing Net Verity => r1c4<>4
r1c9=4 r1c4<>4
r1c9=5 (r1c1<>5 r1c1=6 r3c2<>6) (r1c9<>4 r9c9=4 r7c7<>4 r7c1=4 r6c1<>4 r6c1=5 r6c2<>5) (r1c9<>4 r9c9=4 r9c3<>4) (r2c7<>5) r3c8<>5 r3c8=6 r2c7<>6 r2c7=4 r2c3<>4 r6c3=4 r6c2<>4 r6c2=6 r6c5<>6 (r6c5=2 r4c6<>2 r8c6=2 r8c8<>2) r2c5=6 r3c6<>6 r3c8=6 r8c8<>6 r8c8=5 r7c7<>5 r7c1=5 r7c1<>4 r7c7=4 r9c9<>4 r1c9=4 r1c4<>4
r1c9=6 (r3c8<>6) (r1c1<>6 r1c1=5 r2c3<>5) (r2c7<>6) r3c8<>6 r3c8=5 (r8c8<>5) r2c7<>5 (r2c4=5 r2c4<>2) (r2c4=5 r2c4<>6) (r2c4=5 r8c4<>5) r2c7=4 r2c3<>4 (r6c3=4 r6c3<>5) r2c3=6 (r9c3<>6 r9c3=5 r4c3<>5) r3c2<>6 r3c6=6 r7c6<>6 r7c6=5 r8c6<>5 r8c2=5 r9c3<>5 r2c3=5 r2c4<>5 r2c4=4 r1c4<>4
r1c9=9 (r6c9<>9 r6c3=9 r6c3<>4) r1c9<>4 r9c9=4 (r7c7<>4) (r9c7<>4) r9c3<>4 r2c3=4 r2c7<>4 r1c7=4 r1c4<>4
Forcing Net Verity => r1c6<>4
r1c9=4 r1c6<>4
r1c9=5 (r1c1<>5 r1c1=6 r1c4<>6 r1c4=8 r4c4<>8 r4c6=8 r4c6<>2 r8c6=2 r8c8<>2) (r1c1<>5 r1c1=6 r3c2<>6) (r1c9<>4 r9c9=4 r7c7<>4 r7c1=4 r6c1<>4 r6c1=5 r6c2<>5) (r1c9<>4 r9c9=4 r9c3<>4) (r2c7<>5) r3c8<>5 r3c8=6 r2c7<>6 r2c7=4 r2c3<>4 r6c3=4 r6c2<>4 r6c2=6 r6c5<>6 r2c5=6 r3c6<>6 r3c8=6 r8c8<>6 r8c8=5 r7c7<>5 r7c1=5 r7c1<>4 r7c7=4 r9c9<>4 r1c9=4 r1c6<>4
r1c9=6 (r3c8<>6 r3c8=5 r2c7<>5 r2c4=5 r2c4<>2) (r3c8<>6 r3c8=5 r2c7<>5 r2c4=5 r2c4<>6) (r3c8<>6 r3c8=5 r2c7<>5 r2c7=4 r2c3<>4 r2c3=6 r9c3<>6 r9c3=5 r4c3<>5) (r3c8<>6 r3c8=5 r2c7<>5 r2c7=4 r2c3<>4 r6c3=4 r6c3<>5) (r3c8<>6 r3c8=5 r2c7<>5 r2c4=5 r8c4<>5) (r3c8<>6 r3c8=5 r8c8<>5) (r3c8<>6 r3c8=5 r3c6<>5) (r1c9<>4) r1c9<>9 r1c7=9 r1c7<>4 r1c6=4 r3c6<>4 r3c6=6 r7c6<>6 r7c6=5 r8c6<>5 r8c2=5 r9c3<>5 r2c3=5 r2c4<>5 r2c4=4 r1c6<>4
r1c9=9 (r6c9<>9 r6c3=9 r6c3<>4) r1c9<>4 r9c9=4 (r7c7<>4) (r9c7<>4) r9c3<>4 r2c3=4 r2c7<>4 r1c7=4 r1c6<>4
Locked Candidates Type 2 (Claiming): 4 in r1 => r2c7<>4
Naked Pair: 5,6 in r2c7,r3c8 => r1c79<>5, r1c79<>6
Grouped Discontinuous Nice Loop: 6 r6c1 -6- r6c5 =6= r2c5 -6- r1c46 =6= r1c1 -6- r6c1 => r6c1<>6
Almost Locked Set XY-Wing: A=r5c9 {26}, B=r27c7 {456}, C=r157c1 {2456}, X,Y=2,4, Z=6 => r4c7<>6
Finned Franken Swordfish: 5 r17b3 c167 fr1c4 fr3c8 => r3c6<>5
W-Wing: 6/5 in r1c1,r2c7 connected by 5 in r3c28 => r2c3<>6
Sashimi Swordfish: 6 r127 c167 fr1c4 fr2c4 fr2c5 => r3c6<>6
Naked Single: r3c6=4
Hidden Single: r2c3=4
Grouped Discontinuous Nice Loop: 6 r4c8 -6- r5c9 =6= r5c1 -6- r46c3 =6= r9c3 -6- r9c9 =6= r45c9 -6- r4c8 => r4c8<>6
Locked Candidates Type 1 (Pointing): 6 in b6 => r9c9<>6
Forcing Chain Verity => r6c2<>5
r2c7=5 r3c8<>5 r3c2=5 r6c2<>5
r4c7=5 r46c9<>5 r9c9=5 r9c3<>5 r46c3=5 r6c2<>5
r7c7=5 r7c7<>4 r7c1=4 r6c1<>4 r6c2=4 r6c2<>5
r9c7=5 r9c3<>5 r46c3=5 r6c2<>5
W-Wing: 6/5 in r1c1,r9c3 connected by 5 in r38c2 => r7c1<>6
Turbot Fish: 6 r3c8 =6= r3c2 -6- r8c2 =6= r9c3 => r9c8<>6
Sashimi X-Wing: 6 r27 c67 fr2c4 fr2c5 => r1c6<>6
Discontinuous Nice Loop: 2 r8c4 -2- r8c6 =2= r4c6 -2- r6c5 -6- r6c2 -4- r8c2 =4= r8c4 => r8c4<>2
Discontinuous Nice Loop: 6 r8c4 -6- r7c6 -5- r7c1 -4- r8c2 =4= r8c4 => r8c4<>6
Almost Locked Set XZ-Rule: A=r27c7 {456}, B=r7c1,r9c3 {456}, X=4, Z=6 => r9c7<>6
AIC: 5 5- r7c6 -6- r7c7 =6= r2c7 =5= r3c8 -5- r3c2 =5= r8c2 -5 => r7c1,r8c46<>5
Naked Single: r7c1=4
Naked Single: r8c4=4
Hidden Single: r6c2=4
Naked Pair: 5,6 in r27c7 => r49c7<>5
X-Wing: 5 r38 c28 => r49c8<>5
Locked Candidates Type 1 (Pointing): 5 in b6 => r9c9<>5
Locked Triple: 1,2,4 in r9c789 => r8c8,r9c4<>2
Hidden Single: r8c6=2
Remote Pair: 5/6 r1c1 -6- r3c2 -5- r3c8 -6- r2c7 -5- r7c7 -6- r8c8 -5- r8c2 -6- r9c3 -5- r9c4 -6- r7c6 => r1c6,r2c4<>5, r2c4<>6
Naked Single: r1c6=8
Naked Single: r2c4=2
Naked Single: r4c6=6
Full House: r7c6=5
Full House: r7c7=6
Full House: r9c4=6
Naked Single: r2c5=6
Full House: r6c5=2
Full House: r4c4=8
Full House: r2c7=5
Full House: r1c4=5
Naked Single: r8c8=5
Full House: r8c2=6
Full House: r9c3=5
Full House: r3c2=5
Full House: r3c8=6
Full House: r1c1=6
Naked Single: r6c1=5
Full House: r5c1=2
Full House: r5c9=6
Naked Single: r4c3=9
Full House: r6c3=6
Full House: r6c9=9
Naked Single: r4c7=1
Naked Single: r1c9=4
Full House: r1c7=9
Full House: r9c7=4
Naked Single: r4c8=2
Full House: r4c9=5
Full House: r9c9=2
Full House: r9c8=1
|
normal_sudoku_618
|
...1..536...786........5....2.41936..41..38..639578241......415174.52..3.5.341...
|
897124536315786924462935178528419367741263859639578241283697415174852693956341782
|
Basic 9x9 Sudoku 618
|
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 3 6
. . . 7 8 6 . . .
. . . . . 5 . . .
. 2 . 4 1 9 3 6 .
. 4 1 . . 3 8 . .
6 3 9 5 7 8 2 4 1
. . . . . . 4 1 5
1 7 4 . 5 2 . . 3
. 5 . 3 4 1 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
897124536315786924462935178528419367741263859639578241283697415174852693956341782 #1 Hard (948)
Naked Single: r6c4=5
Hidden Single: r6c9=1
Hidden Single: r8c1=1
Hidden Single: r9c6=1
Hidden Single: r4c7=3
Hidden Single: r7c9=5
Hidden Single: r3c6=5
Hidden Single: r8c3=4
Hidden Single: r9c5=4
Hidden Single: r4c8=6
Hidden Single: r5c6=3
Naked Single: r5c2=4
Naked Single: r6c5=7
Naked Single: r6c2=3
Full House: r6c8=4
Naked Single: r4c6=9
Naked Single: r1c6=4
Full House: r7c6=7
Naked Single: r4c9=7
Naked Single: r5c9=9
Full House: r5c8=5
Naked Single: r5c1=7
Hidden Single: r3c5=3
Hidden Single: r1c3=7
Locked Candidates Type 1 (Pointing): 8 in b3 => r3c123<>8
Locked Candidates Type 1 (Pointing): 2 in b9 => r9c13<>2
Naked Pair: 1,9 in r2c27 => r2c18<>9
Naked Single: r2c8=2
Naked Single: r2c9=4
Naked Single: r3c9=8
Full House: r9c9=2
Hidden Single: r3c1=4
Naked Triple: 6,8,9 in r7c2,r9c13 => r7c13<>8, r7c1<>9, r7c3<>6
Skyscraper: 9 in r7c5,r9c1 (connected by r1c15) => r7c2<>9
Hidden Single: r9c1=9
Locked Candidates Type 1 (Pointing): 9 in b9 => r8c4<>9
XY-Wing: 6/8/9 in r17c2,r7c5 => r1c5<>9
Naked Single: r1c5=2
Full House: r3c4=9
Naked Single: r1c1=8
Full House: r1c2=9
Naked Single: r5c5=6
Full House: r5c4=2
Full House: r7c5=9
Naked Single: r3c8=7
Naked Single: r4c1=5
Full House: r4c3=8
Naked Single: r2c2=1
Naked Single: r3c7=1
Full House: r2c7=9
Naked Single: r9c8=8
Full House: r8c8=9
Naked Single: r2c1=3
Full House: r2c3=5
Full House: r7c1=2
Naked Single: r9c3=6
Full House: r9c7=7
Full House: r8c7=6
Full House: r8c4=8
Full House: r7c4=6
Naked Single: r3c2=6
Full House: r3c3=2
Full House: r7c3=3
Full House: r7c2=8
|
normal_sudoku_2350
|
64...9.5...74.....1...6.......3.6..89..148.2..6..52.....4.....7...8..3...1..2..9.
|
648239751527481639139567482452396178973148526861752943384915267296874315715623894
|
Basic 9x9 Sudoku 2350
|
puzzles5_forum_hardest_1905_11+
|
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 4 . . . 9 . 5 .
. . 7 4 . . . . .
1 . . . 6 . . . .
. . . 3 . 6 . . 8
9 . . 1 4 8 . 2 .
. 6 . . 5 2 . . .
. . 4 . . . . . 7
. . . 8 . . 3 . .
. 1 . . 2 . . 9 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
648239751527481639139567482452396178973148526861752943384915267296874315715623894 #1 Extreme (39452) bf
Locked Candidates Type 1 (Pointing): 8 in b5 => r5c23<>8
Brute Force: r5c5=4
Hidden Single: r5c6=8
Brute Force: r5c4=1
Hidden Single: r4c6=6
Discontinuous Nice Loop: 9 r3c7 -9- r3c3 =9= r8c3 =6= r9c3 -6- r9c4 =6= r7c4 =9= r6c4 -9- r4c5 =9= r4c7 -9- r3c7 => r3c7<>9
Grouped Discontinuous Nice Loop: 3 r3c3 -3- r5c3 -5- r4c123 =5= r4c7 =9= r4c5 -9- r6c4 =9= r7c4 =6= r9c4 -6- r9c3 =6= r8c3 =9= r3c3 => r3c3<>3
Almost Locked Set XY-Wing: A=r5c23 {357}, B=r6c4 {79}, C=r4c12358 {124579}, X,Y=5,9, Z=7 => r6c1<>7
Forcing Chain Contradiction in r8c5 => r3c3<>5
r3c3=5 r2c12<>5 r2c6=5 r2c6<>1 r12c5=1 r8c5<>1
r3c3=5 r3c3<>9 r8c3=9 r8c3<>6 r9c3=6 r9c4<>6 r7c4=6 r7c4<>9 r6c4=9 r6c4<>7 r4c5=7 r8c5<>7
r3c3=5 r3c3<>9 r8c3=9 r8c5<>9
Forcing Chain Contradiction in r8 => r4c1<>7
r4c1=7 r89c1<>7 r8c2=7 r8c2<>9
r4c1=7 r4c5<>7 r4c5=9 r6c4<>9 r7c4=9 r7c4<>6 r9c4=6 r9c3<>6 r8c3=6 r8c3<>9
r4c1=7 r4c5<>7 r4c5=9 r8c5<>9
Locked Candidates Type 1 (Pointing): 7 in b4 => r8c2<>7
Forcing Chain Contradiction in r1c3 => r4c7<>4
r4c7=4 r4c7<>9 r4c5=9 r4c5<>7 r6c4=7 r1c4<>7 r1c4=2 r1c3<>2
r4c7=4 r4c7<>5 r4c123=5 r5c3<>5 r5c3=3 r1c3<>3
r4c7=4 r4c1<>4 r6c1=4 r6c1<>8 r6c3=8 r1c3<>8
Forcing Chain Contradiction in c3 => r6c1<>3
r6c1=3 r5c3<>3 r5c3=5 r4c123<>5 r4c7=5 r4c7<>9 r4c5=9 r4c5<>7 r6c4=7 r1c4<>7 r1c4=2 r1c3<>2
r6c1=3 r5c3<>3 r5c3=5 r4c123<>5 r4c7=5 r4c7<>9 r4c5=9 r6c4<>9 r7c4=9 r7c4<>6 r9c4=6 r9c3<>6 r8c3=6 r8c3<>9 r3c3=9 r3c3<>2
r6c1=3 r6c1<>8 r6c3=8 r6c3<>1 r4c3=1 r4c3<>2
r6c1=3 r5c3<>3 r5c3=5 r4c123<>5 r4c7=5 r4c7<>9 r4c5=9 r6c4<>9 r7c4=9 r7c4<>6 r9c4=6 r9c3<>6 r8c3=6 r8c3<>2
Forcing Chain Contradiction in c3 => r5c9<>3
r5c9=3 r5c3<>3 r5c3=5 r4c123<>5 r4c7=5 r4c7<>9 r4c5=9 r4c5<>7 r6c4=7 r1c4<>7 r1c4=2 r1c3<>2
r5c9=3 r5c3<>3 r5c3=5 r4c123<>5 r4c7=5 r4c7<>9 r4c5=9 r6c4<>9 r7c4=9 r7c4<>6 r9c4=6 r9c3<>6 r8c3=6 r8c3<>9 r3c3=9 r3c3<>2
r5c9=3 r5c23<>3 r6c3=3 r6c3<>1 r4c3=1 r4c3<>2
r5c9=3 r5c3<>3 r5c3=5 r4c123<>5 r4c7=5 r4c7<>9 r4c5=9 r6c4<>9 r7c4=9 r7c4<>6 r9c4=6 r9c3<>6 r8c3=6 r8c3<>2
Locked Candidates Type 1 (Pointing): 3 in b6 => r6c3<>3
Forcing Net Contradiction in r1c5 => r2c1<>8
r2c1=8 (r6c1<>8 r6c1=4 r4c1<>4 r4c8=4 r4c8<>7) (r2c8<>8) (r2c2<>8) r3c2<>8 r7c2=8 r7c8<>8 r3c8=8 r3c8<>7 r6c8=7 (r6c8<>3 r6c9=3 r1c9<>3) r5c7<>7 r5c2=7 r5c2<>3 r5c3=3 r1c3<>3 r1c5=3
r2c1=8 r2c5<>8 r1c5=8
Forcing Net Contradiction in r4 => r3c3<>8
r3c3=8 r6c3<>8 r6c3=1 r4c3<>1
r3c3=8 (r3c2<>8 r7c2=8 r7c2<>9) r3c3<>9 r8c3=9 r8c3<>6 r9c3=6 r9c4<>6 r7c4=6 r7c4<>9 r7c5=9 r4c5<>9 r4c7=9 r4c7<>1
r3c3=8 (r3c2<>8 r7c2=8 r7c8<>8) r3c3<>9 r8c3=9 r8c3<>6 r9c3=6 r9c4<>6 r7c4=6 r7c8<>6 r7c8=1 r4c8<>1
Forcing Net Verity => r2c7<>8
r1c3=2 (r2c1<>2) (r2c2<>2) (r3c3<>2 r3c3=9 r2c2<>9) r1c4<>2 r1c4=7 r6c4<>7 r6c4=9 r4c5<>9 r4c7=9 r2c7<>9 r2c9=9 r2c9<>2 r2c7=2 r2c7<>8
r1c3=3 r5c3<>3 r5c2=3 r5c2<>7 r5c7=7 (r1c7<>7) (r6c7<>7) r6c8<>7 r6c4=7 r1c4<>7 r1c5=7 r1c5<>8 r2c5=8 r2c7<>8
r1c3=8 r1c5<>8 r2c5=8 r2c7<>8
Forcing Net Contradiction in r5c3 => r4c7<>7
r4c7=7 (r6c8<>7 r6c4=7 r1c4<>7 r1c5=7 r1c5<>8 r2c5=8 r2c8<>8) (r6c8<>7 r6c4=7 r1c4<>7 r1c4=2 r1c3<>2) r5c7<>7 r5c2=7 r5c2<>3 r5c3=3 r1c3<>3 r1c3=8 (r2c2<>8) r3c2<>8 r7c2=8 r7c8<>8 r3c8=8 r3c8<>7 r13c7=7 r4c7<>7
Forcing Net Verity => r5c2<>5
r1c3=2 r1c4<>2 r1c4=7 r6c4<>7 r4c5=7 r4c2<>7 r5c2=7 r5c2<>5
r1c3=3 r5c3<>3 r5c3=5 r5c2<>5
r1c3=8 (r1c5<>8 r2c5=8 r2c8<>8) (r2c2<>8) r3c2<>8 r7c2=8 r7c8<>8 r3c8=8 r3c8<>7 r13c7=7 r5c7<>7 r5c2=7 r5c2<>5
Forcing Net Verity => r7c2<>3
r9c6=3 (r9c6<>7) r9c6<>4 r8c6=4 r8c6<>7 r3c6=7 (r1c4<>7 r1c4=2 r1c3<>2) (r1c4<>7) r1c5<>7 r1c7=7 r5c7<>7 r5c2=7 r5c2<>3 r5c3=3 r1c3<>3 r1c3=8 (r2c2<>8) r3c2<>8 r7c2=8 r7c2<>3
r9c6<>3 r7c56=3 r7c2<>3
Forcing Net Verity => r2c1<>3
r1c3=2 r1c4<>2 r1c4=7 r6c4<>7 r4c5=7 r4c2<>7 r5c2=7 r5c2<>3 r23c2=3 r2c1<>3
r1c3=3 r2c1<>3
r1c3=8 (r1c5<>8 r2c5=8 r2c8<>8) (r2c2<>8) r3c2<>8 r7c2=8 r7c8<>8 r3c8=8 r3c8<>7 r13c7=7 r5c7<>7 r5c2=7 r5c2<>3 r23c2=3 r2c1<>3
Locked Candidates Type 2 (Claiming): 3 in c1 => r9c3<>3
Discontinuous Nice Loop: 7 r8c6 -7- r8c1 =7= r9c1 =3= r9c6 =4= r8c6 => r8c6<>7
Forcing Chain Contradiction in r1c3 => r4c1<>5
r4c1=5 r2c1<>5 r2c1=2 r1c3<>2
r4c1=5 r5c3<>5 r5c3=3 r1c3<>3
r4c1=5 r4c1<>4 r6c1=4 r6c1<>8 r6c3=8 r1c3<>8
Forcing Chain Contradiction in r1c3 => r9c1<>8
r9c1=8 r9c1<>3 r9c6=3 r9c6<>7 r3c6=7 r1c4<>7 r1c4=2 r1c3<>2
r9c1=8 r9c1<>3 r9c6=3 r9c6<>7 r3c6=7 r3c8<>7 r13c7=7 r5c7<>7 r5c2=7 r5c2<>3 r5c3=3 r1c3<>3
r9c1=8 r6c1<>8 r6c3=8 r1c3<>8
Forcing Chain Contradiction in b9 => r8c9<>6
r8c9=6 r8c9<>2 r7c7=2 r7c7<>5
r8c9=6 r8c9<>5
r8c9=6 r8c3<>6 r9c3=6 r9c3<>8 r9c7=8 r9c7<>5
r8c9=6 r5c9<>6 r5c9=5 r9c9<>5
Forcing Net Contradiction in r1c3 => r3c3=9
r3c3<>9 r3c3=2 r1c3<>2
r3c3<>9 r8c3=9 (r7c2<>9) r8c3<>6 r8c8=6 (r7c7<>6) r7c8<>6 r7c4=6 r7c4<>9 r7c5=9 r4c5<>9 r4c5=7 r4c2<>7 r5c2=7 r5c2<>3 r5c3=3 r1c3<>3
r3c3<>9 r8c3=9 r8c3<>6 r8c8=6 (r7c8<>6) (r9c7<>6) (r9c9<>6) (r7c7<>6) r7c8<>6 r7c4=6 (r7c4<>9 r7c5=9 r4c5<>9 r4c5=7 r4c8<>7) r9c4<>6 r9c3=6 r9c3<>8 r9c7=8 r7c8<>8 r7c8=1 r4c8<>1 r4c8=4 (r6c7<>4) (r6c8<>4) r6c9<>4 r6c1=4 r6c1<>8 r6c3=8 r1c3<>8
Forcing Net Contradiction in r8 => r5c2=7
r5c2<>7 r5c7=7 r8c3=6
r5c2<>7 r5c7=7 (r4c8<>7) r6c8<>7 r3c8=7 r3c6<>7 r9c6=7 (r8c5<>7 r8c5=1 r8c8<>1) r9c6<>4 r8c6=4 r8c8<>4 r8c8=6
Hidden Single: r5c3=3
Locked Candidates Type 1 (Pointing): 5 in b4 => r4c7<>5
Almost Locked Set XZ-Rule: A=r1c347 {1278}, B=r4c57 {179}, X=1, Z=7 => r1c5<>7
Forcing Chain Contradiction in r7c5 => r2c9<>1
r2c9=1 r2c6<>1 r12c5=1 r7c5<>1
r2c9=1 r2c9<>9 r2c7=9 r4c7<>9 r4c5=9 r4c5<>7 r8c5=7 r8c1<>7 r9c1=7 r9c1<>3 r9c6=3 r7c5<>3
r2c9=1 r2c9<>9 r2c7=9 r4c7<>9 r4c5=9 r7c5<>9
Forcing Chain Contradiction in r1c7 => r6c7<>1
r6c7=1 r1c7<>1
r6c7=1 r6c3<>1 r6c3=8 r1c3<>8 r1c3=2 r1c7<>2
r6c7=1 r6c3<>1 r6c3=8 r1c3<>8 r1c3=2 r1c4<>2 r1c4=7 r1c7<>7
r6c7=1 r6c3<>1 r6c3=8 r9c3<>8 r9c7=8 r1c7<>8
Forcing Chain Contradiction in r1 => r6c8<>1
r6c8=1 r6c3<>1 r6c3=8 r1c3<>8
r6c8=1 r6c8<>3 r6c9=3 r1c9<>3 r1c5=3 r1c5<>8
r6c8=1 r6c3<>1 r6c3=8 r9c3<>8 r9c7=8 r1c7<>8
Forcing Chain Contradiction in r9c3 => r8c1<>5
r8c1=5 r9c3<>5
r8c1=5 r8c1<>7 r8c5=7 r4c5<>7 r4c5=9 r6c4<>9 r7c4=9 r7c4<>6 r9c4=6 r9c3<>6
r8c1=5 r2c1<>5 r2c1=2 r1c3<>2 r1c3=8 r9c3<>8
Forcing Chain Contradiction in r8c5 => r2c6<>5
r2c6=5 r2c6<>1 r12c5=1 r8c5<>1
r2c6=5 r2c1<>5 r2c1=2 r8c1<>2 r8c1=7 r8c5<>7
r2c6=5 r2c1<>5 r2c1=2 r1c3<>2 r1c3=8 r23c2<>8 r7c2=8 r7c2<>9 r8c2=9 r8c5<>9
Locked Candidates Type 1 (Pointing): 5 in b2 => r3c2<>5
Naked Triple: 1,3,8 in r12c5,r2c6 => r3c6<>3
Grouped Discontinuous Nice Loop: 8 r2c8 -8- r2c5 =8= r1c5 =3= r1c9 -3- r3c89 =3= r3c2 =8= r3c78 -8- r2c8 => r2c8<>8
Forcing Chain Contradiction in c8 => r2c9=9
r2c9<>9 r6c9=9 r6c4<>9 r6c4=7 r1c4<>7 r1c4=2 r1c3<>2 r1c3=8 r9c3<>8 r9c7=8 r7c8<>8 r3c8=8 r3c8<>4
r2c9<>9 r2c7=9 r4c7<>9 r4c5=9 r4c5<>7 r4c8=7 r4c8<>4
r2c9<>9 r6c9=9 r6c9<>3 r6c8=3 r6c8<>4
r2c9<>9 r2c7=9 r4c7<>9 r4c5=9 r4c5<>7 r8c5=7 r8c1<>7 r9c1=7 r9c1<>3 r9c6=3 r9c6<>4 r8c6=4 r8c8<>4
Grouped Discontinuous Nice Loop: 2 r8c2 =9= r7c2 =8= r23c2 -8- r1c3 -2- r2c12 =2= r2c7 -2- r7c7 =2= r8c9 -2- r8c2 => r8c2<>2
Forcing Chain Contradiction in r6c7 => r4c1=4
r4c1<>4 r4c8=4 r6c7<>4
r4c1<>4 r6c1=4 r6c1<>8 r7c1=8 r7c8<>8 r3c8=8 r3c8<>7 r13c7=7 r6c7<>7
r4c1<>4 r4c8=4 r4c8<>7 r4c5=7 r4c5<>9 r4c7=9 r6c7<>9
Naked Single: r6c1=8
Naked Single: r6c3=1
Discontinuous Nice Loop: 1 r2c8 -1- r2c6 -3- r9c6 =3= r9c1 =7= r8c1 -7- r8c5 =7= r4c5 -7- r4c8 -1- r2c8 => r2c8<>1
Discontinuous Nice Loop: 2 r7c2 -2- r4c2 =2= r4c3 -2- r1c3 -8- r9c3 =8= r7c2 => r7c2<>2
Discontinuous Nice Loop: 1 r8c6 -1- r8c9 =1= r1c9 =3= r1c5 -3- r2c6 -1- r8c6 => r8c6<>1
Grouped AIC: 3/8 8- r2c5 =8= r2c2 -8- r1c3 -2- r2c12 =2= r2c7 -2- r7c7 =2= r8c9 =1= r1c9 =3= r1c5 -3 => r2c5<>3, r1c5<>8
Hidden Single: r2c5=8
X-Wing: 8 r19 c37 => r37c7<>8
Grouped Discontinuous Nice Loop: 1 r7c8 -1- r4c8 -7- r4c5 =7= r8c5 =1= r7c56 -1- r7c8 => r7c8<>1
Continuous Nice Loop: 2/3/6 8= r3c2 =3= r2c2 -3- r2c8 -6- r7c8 -8- r7c2 =8= r3c2 =3 => r3c2<>2, r2c6<>3, r8c8<>6
Naked Single: r2c6=1
Naked Single: r1c5=3
Hidden Single: r8c3=6
Locked Candidates Type 1 (Pointing): 2 in b7 => r2c1<>2
Naked Single: r2c1=5
XY-Chain: 5 5- r8c6 -4- r8c8 -1- r4c8 -7- r4c5 -9- r6c4 -7- r1c4 -2- r1c3 -8- r9c3 -5 => r8c2,r9c46<>5
Naked Single: r8c2=9
Sue de Coq: r8c89 - {1245} (r8c15 - {127}, r7c8,r9c79 - {4568}) => r7c7<>5, r7c7<>6
Sue de Coq: r89c9 - {12456} (r5c9 - {56}, r7c7,r8c8 - {124}) => r9c7<>4
XY-Chain: 3 3- r2c8 -6- r2c7 -2- r7c7 -1- r8c8 -4- r8c6 -5- r3c6 -7- r1c4 -2- r1c3 -8- r3c2 -3 => r2c2,r3c89<>3
Naked Single: r2c2=2
Naked Single: r1c3=8
Full House: r3c2=3
Naked Single: r2c7=6
Full House: r2c8=3
Naked Single: r4c2=5
Full House: r4c3=2
Full House: r9c3=5
Full House: r7c2=8
Naked Single: r5c7=5
Full House: r5c9=6
Naked Single: r9c7=8
Naked Single: r7c8=6
Naked Single: r9c9=4
Naked Single: r3c9=2
Naked Single: r6c9=3
Naked Single: r8c8=1
Naked Single: r1c9=1
Full House: r8c9=5
Full House: r7c7=2
Naked Single: r4c8=7
Naked Single: r8c5=7
Naked Single: r1c7=7
Full House: r1c4=2
Naked Single: r8c6=4
Full House: r8c1=2
Naked Single: r7c1=3
Full House: r9c1=7
Naked Single: r4c5=9
Full House: r4c7=1
Full House: r6c4=7
Full House: r7c5=1
Naked Single: r6c8=4
Full House: r3c8=8
Full House: r3c7=4
Full House: r6c7=9
Naked Single: r9c4=6
Full House: r9c6=3
Naked Single: r7c6=5
Full House: r3c6=7
Full House: r3c4=5
Full House: r7c4=9
|
normal_sudoku_5523
|
..314.2.5.5..9.........6.3781.4....3..4...51.32....4......7...6..286.3..9......5.
|
683147295157293684249586137816452973794638512325719468431975826572861349968324751
|
Basic 9x9 Sudoku 5523
|
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 4 . 2 . 5
. 5 . . 9 . . . .
. . . . . 6 . 3 7
8 1 . 4 . . . . 3
. . 4 . . . 5 1 .
3 2 . . . . 4 . .
. . . . 7 . . . 6
. . 2 8 6 . 3 . .
9 . . . . . . 5 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
683147295157293684249586137816452973794638512325719468431975826572861349968324751 #1 Extreme (14246) bf
Locked Candidates Type 1 (Pointing): 4 in b3 => r2c1<>4
Almost Locked Set XZ-Rule: A=r1c1 {67}, B=r2c3789 {14678}, X=7, Z=6 => r2c1<>6
Brute Force: r5c7=5
Hidden Single: r1c9=5
Locked Candidates Type 1 (Pointing): 5 in b4 => r7c3<>5
Naked Pair: 6,7 in r15c1 => r28c1<>7, r8c1<>6
Forcing Chain Contradiction in r5c2 => r1c8<>6
r1c8=6 r1c1<>6 r5c1=6 r5c2<>6
r1c8=6 r2c7<>6 r4c7=6 r4c7<>7 r9c7=7 r9c3<>7 r89c2=7 r5c2<>7
r1c8=6 r1c8<>9 r1c2=9 r5c2<>9
Locked Candidates Type 1 (Pointing): 6 in b3 => r2c3<>6
Finned Swordfish: 6 r158 c125 fr5c4 => r46c5<>6
Grouped Discontinuous Nice Loop: 7 r5c2 -7- r5c1 -6- r46c3 =6= r9c3 =7= r89c2 -7- r5c2 => r5c2<>7
Forcing Chain Contradiction in c4 => r1c8=9
r1c8<>9 r1c8=8 r1c6<>8 r1c6=7 r2c4<>7
r1c8<>9 r1c8=8 r1c6<>8 r1c6=7 r1c1<>7 r5c1=7 r5c4<>7
r1c8<>9 r1c2=9 r5c2<>9 r5c2=6 r5c45<>6 r6c4=6 r6c4<>7
2-String Kite: 9 in r4c7,r8c6 (connected by r7c7,r8c9) => r4c6<>9
AIC: 6 6- r5c2 -9- r4c3 =9= r4c7 =7= r9c7 -7- r8c8 =7= r8c2 =6= r8c5 -6 => r5c5,r8c2<>6
Hidden Single: r8c5=6
Naked Pair: 4,7 in r8c28 => r8c169<>4
XYZ-Wing: 1/8/9 in r37c7,r8c9 => r9c7<>1
Discontinuous Nice Loop: 1 r2c9 -1- r3c7 -8- r9c7 -7- r8c8 -4- r2c8 =4= r2c9 => r2c9<>1
Locked Candidates Type 1 (Pointing): 1 in b3 => r7c7<>1
XY-Wing: 8/9/1 in r7c37,r8c9 => r8c1<>1
Naked Single: r8c1=5
Continuous Nice Loop: 1/8/9 9= r3c2 =4= r3c1 -4- r7c1 -1- r7c3 -8- r7c7 -9- r4c7 =9= r4c3 -9- r3c3 =9= r3c2 =4 => r7c6,r9c3<>1, r37c2,r7c8<>8, r6c3<>9
Empty Rectangle: 8 in b3 (r7c37) => r2c3<>8
Finned X-Wing: 9 r68 c69 fr6c4 => r5c6<>9
AIC: 7 7- r1c6 -8- r1c2 =8= r9c2 -8- r7c3 -1- r2c3 -7 => r1c12,r2c46<>7
Naked Single: r1c1=6
Naked Single: r1c2=8
Full House: r1c6=7
Naked Single: r5c1=7
Hidden Single: r2c3=7
Hidden Single: r6c4=7
Hidden Single: r5c4=6
Naked Single: r5c2=9
Naked Single: r3c2=4
Naked Single: r7c2=3
Naked Single: r8c2=7
Full House: r9c2=6
Naked Single: r8c8=4
Naked Single: r9c3=8
Naked Single: r7c8=2
Naked Single: r7c3=1
Full House: r7c1=4
Naked Single: r9c7=7
Naked Single: r9c9=1
Naked Single: r3c3=9
Naked Single: r8c9=9
Full House: r7c7=8
Full House: r8c6=1
Naked Single: r6c9=8
Naked Single: r3c7=1
Naked Single: r2c9=4
Full House: r5c9=2
Naked Single: r6c8=6
Naked Single: r2c7=6
Full House: r2c8=8
Full House: r4c7=9
Full House: r4c8=7
Naked Single: r3c1=2
Full House: r2c1=1
Naked Single: r6c3=5
Full House: r4c3=6
Naked Single: r3c4=5
Full House: r3c5=8
Naked Single: r6c5=1
Full House: r6c6=9
Naked Single: r7c4=9
Full House: r7c6=5
Naked Single: r5c5=3
Full House: r5c6=8
Naked Single: r4c6=2
Full House: r4c5=5
Full House: r9c5=2
Naked Single: r2c6=3
Full House: r2c4=2
Full House: r9c4=3
Full House: r9c6=4
|
normal_sudoku_1610
|
.3..2.7.9745.9.621....7.4...6..89572287..519..5.7.28..5.6.3.2...1..579....4...3..
|
631524789745893621928671435463189572287345196159762843576938214312457968894216357
|
Basic 9x9 Sudoku 1610
|
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 . 7 . 9
7 4 5 . 9 . 6 2 1
. . . . 7 . 4 . .
. 6 . . 8 9 5 7 2
2 8 7 . . 5 1 9 .
. 5 . 7 . 2 8 . .
5 . 6 . 3 . 2 . .
. 1 . . 5 7 9 . .
. . 4 . . . 3 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
631524789745893621928671435463189572287345196159762843576938214312457968894216357 #1 Unfair (700)
Naked Single: r2c5=9
Naked Single: r4c7=5
Naked Single: r6c7=8
Naked Single: r1c7=7
Full House: r7c7=2
Hidden Single: r2c8=2
Hidden Single: r6c6=2
Hidden Single: r6c2=5
Hidden Single: r3c5=7
Hidden Single: r5c3=7
Hidden Single: r5c2=8
Naked Single: r1c2=3
Hidden Single: r5c8=9
Locked Candidates Type 1 (Pointing): 3 in b3 => r3c46<>3
Hidden Single: r2c6=3
Full House: r2c4=8
Locked Candidates Type 2 (Claiming): 4 in c5 => r45c4<>4
Hidden Single: r4c1=4
Discontinuous Nice Loop: 5/6/8 r9c9 =7= r9c2 =2= r9c4 =9= r7c4 -9- r7c2 -7- r7c9 =7= r9c9 => r9c9<>5, r9c9<>6, r9c9<>8
Naked Single: r9c9=7
Hidden Single: r9c8=5
Naked Single: r1c8=8
Naked Single: r1c3=1
Naked Single: r3c8=3
Full House: r3c9=5
Naked Single: r1c1=6
Naked Single: r4c3=3
Full House: r4c4=1
Naked Single: r1c6=4
Full House: r1c4=5
Naked Single: r6c3=9
Full House: r6c1=1
Naked Single: r3c4=6
Full House: r3c6=1
Naked Single: r5c4=3
Naked Single: r7c6=8
Full House: r9c6=6
Naked Single: r7c9=4
Naked Single: r9c5=1
Naked Single: r5c9=6
Full House: r5c5=4
Full House: r6c5=6
Naked Single: r7c4=9
Naked Single: r7c8=1
Full House: r7c2=7
Naked Single: r8c8=6
Full House: r6c8=4
Full House: r6c9=3
Full House: r8c9=8
Naked Single: r9c4=2
Full House: r8c4=4
Naked Single: r8c1=3
Full House: r8c3=2
Full House: r3c3=8
Naked Single: r9c2=9
Full House: r3c2=2
Full House: r3c1=9
Full House: r9c1=8
|
normal_sudoku_1160
|
..93.6857..68...41..3....2...8....3.9352614784217.....59417..8.3.2.5.....674.....
|
149326857256897341783514926678945132935261478421783569594172683312658794867439215
|
Basic 9x9 Sudoku 1160
|
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 3 . 6 8 5 7
. . 6 8 . . . 4 1
. . 3 . . . . 2 .
. . 8 . . . . 3 .
9 3 5 2 6 1 4 7 8
4 2 1 7 . . . . .
5 9 4 1 7 . . 8 .
3 . 2 . 5 . . . .
. 6 7 4 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
149326857256897341783514926678945132935261478421783569594172683312658794867439215 #1 Medium (344)
Naked Single: r7c1=5
Naked Single: r7c3=4
Naked Single: r9c3=7
Naked Single: r7c2=9
Naked Single: r5c3=5
Full House: r2c3=6
Naked Single: r5c4=2
Naked Single: r5c8=7
Naked Single: r1c8=5
Naked Single: r5c2=3
Full House: r5c7=4
Naked Single: r1c9=7
Naked Single: r6c2=2
Naked Single: r1c7=8
Naked Single: r4c2=7
Full House: r4c1=6
Naked Single: r2c2=5
Hidden Single: r2c7=3
Hidden Single: r4c7=1
Hidden Single: r8c4=6
Hidden Single: r8c9=4
Hidden Single: r8c7=7
Hidden Single: r4c9=2
Hidden Single: r6c8=6
Locked Candidates Type 1 (Pointing): 9 in b3 => r3c456<>9
Naked Single: r3c4=5
Full House: r4c4=9
Naked Single: r4c5=4
Full House: r4c6=5
Naked Single: r3c5=1
Naked Single: r1c5=2
Naked Single: r1c1=1
Full House: r1c2=4
Naked Single: r2c5=9
Naked Single: r9c1=8
Full House: r8c2=1
Full House: r3c2=8
Naked Single: r2c6=7
Full House: r2c1=2
Full House: r3c1=7
Full House: r3c6=4
Naked Single: r9c5=3
Full House: r6c5=8
Full House: r6c6=3
Naked Single: r8c8=9
Full House: r8c6=8
Full House: r9c8=1
Naked Single: r7c6=2
Full House: r9c6=9
Naked Single: r9c9=5
Full House: r9c7=2
Naked Single: r7c7=6
Full House: r7c9=3
Naked Single: r6c9=9
Full House: r3c9=6
Full House: r3c7=9
Full House: r6c7=5
|
normal_sudoku_2652
|
9....46..3....8...6.1..7.855..241.9.194...5.228.....147...62...4.2......856479123
|
978524631325618749641397285563241897194783562287956314739162458412835976856479123
|
Basic 9x9 Sudoku 2652
|
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 . . . . 4 6 . .
3 . . . . 8 . . .
6 . 1 . . 7 . 8 5
5 . . 2 4 1 . 9 .
1 9 4 . . . 5 . 2
2 8 . . . . . 1 4
7 . . . 6 2 . . .
4 . 2 . . . . . .
8 5 6 4 7 9 1 2 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
978524631325618749641397285563241897194783562287956314739162458412835976856479123 #1 Easy (318)
Naked Single: r9c8=2
Hidden Single: r4c6=1
Naked Single: r9c6=9
Naked Single: r9c1=8
Full House: r9c7=1
Hidden Single: r5c3=4
Hidden Single: r6c1=2
Hidden Single: r1c6=4
Naked Single: r1c1=9
Naked Single: r3c3=1
Naked Single: r8c1=4
Full House: r3c1=6
Hidden Single: r5c9=2
Hidden Single: r7c6=2
Hidden Single: r1c3=8
Hidden Single: r4c2=6
Hidden Single: r7c3=9
Naked Single: r7c9=8
Naked Single: r4c9=7
Naked Single: r7c7=4
Naked Single: r1c9=1
Naked Single: r4c3=3
Full House: r4c7=8
Full House: r6c3=7
Full House: r2c3=5
Naked Single: r6c7=3
Full House: r5c8=6
Naked Single: r7c8=5
Naked Single: r2c9=9
Full House: r8c9=6
Naked Single: r5c6=3
Naked Single: r8c8=7
Full House: r8c7=9
Naked Single: r3c7=2
Full House: r2c7=7
Naked Single: r5c5=8
Full House: r5c4=7
Naked Single: r8c6=5
Full House: r6c6=6
Naked Single: r1c8=3
Full House: r2c8=4
Naked Single: r3c2=4
Naked Single: r1c4=5
Naked Single: r2c2=2
Full House: r1c2=7
Full House: r1c5=2
Naked Single: r6c4=9
Full House: r6c5=5
Naked Single: r2c5=1
Full House: r2c4=6
Naked Single: r3c4=3
Full House: r3c5=9
Full House: r8c5=3
Naked Single: r7c4=1
Full House: r7c2=3
Full House: r8c2=1
Full House: r8c4=8
|
normal_sudoku_1718
|
.7....4....21...8.9...6...3.2...9.....945182.8..23...95.......8.48...7....63...5.
|
173892465652143987984765213425689371739451826861237549517924638348516792296378154
|
Basic 9x9 Sudoku 1718
|
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 . .
. . 2 1 . . . 8 .
9 . . . 6 . . . 3
. 2 . . . 9 . . .
. . 9 4 5 1 8 2 .
8 . . 2 3 . . . 9
5 . . . . . . . 8
. 4 8 . . . 7 . .
. . 6 3 . . . 5 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
173892465652143987984765213425689371739451826861237549517924638348516792296378154 #1 Extreme (31052) bf
Finned X-Wing: 2 r37 c67 fr7c5 => r89c6<>2
Forcing Net Verity => r3c4<>8
r9c6=4 (r3c6<>4) (r6c6<>4) (r7c4<>4) (r7c5<>4) r7c6<>4 r7c8=4 r6c8<>4 r6c3=4 r3c3<>4 r3c4=4 r3c4<>8
r9c6=7 (r3c6<>7) (r6c6<>7) (r7c4<>7) (r7c5<>7) r7c6<>7 r7c3=7 r6c3<>7 r6c8=7 r3c8<>7 r3c4=7 r3c4<>8
r9c6=8 r9c2<>8 r3c2=8 r3c4<>8
Forcing Net Verity => r8c4<>8
r9c6=4 (r7c5<>4) (r9c5<>4) (r3c6<>4) (r6c6<>4) (r7c4<>4) (r7c5<>4) r7c6<>4 r7c8=4 r6c8<>4 r6c3=4 r3c3<>4 r3c4=4 r2c5<>4 r4c5=4 r4c5<>8 r45c4=8 r8c4<>8
r9c6=7 (r7c5<>7) (r9c5<>7) (r3c6<>7) (r6c6<>7) (r7c4<>7) (r7c5<>7) r7c6<>7 r7c3=7 r6c3<>7 r6c8=7 r3c8<>7 r3c4=7 r2c5<>7 r4c5=7 r4c5<>8 r45c4=8 r8c4<>8
r9c6=8 r8c4<>8
Brute Force: r5c3=9
Brute Force: r5c4=4
Hidden Single: r5c7=8
Locked Candidates Type 1 (Pointing): 3 in b6 => r4c13<>3
Finned Swordfish: 4 r367 c368 fr7c5 => r9c6<>4
Forcing Chain Contradiction in r6 => r1c3<>8
r1c3=8 r8c3<>8 r9c2=8 r9c6<>8 r9c6=7 r9c1<>7 r7c3=7 r6c3<>7
r1c3=8 r1c4<>8 r4c4=8 r4c4<>6 r6c6=6 r6c6<>7
r1c3=8 r1c456<>8 r3c6=8 r3c6<>4 r3c3=4 r6c3<>4 r6c8=4 r6c8<>7
Locked Candidates Type 1 (Pointing): 8 in b1 => r3c6<>8
Forcing Chain Contradiction in r6 => r3c2<>1
r3c2=1 r3c2<>8 r9c2=8 r9c6<>8 r9c6=7 r9c1<>7 r7c3=7 r6c3<>7
r3c2=1 r3c2<>8 r9c2=8 r9c6<>8 r9c6=7 r6c6<>7
r3c2=1 r3c8<>1 r3c8=7 r6c8<>7
Forcing Chain Contradiction in c8 => r3c6<>7
r3c6=7 r3c8<>7
r3c6=7 r6c6<>7 r4c45=7 r4c8<>7
r3c6=7 r3c6<>4 r3c3=4 r6c3<>4 r6c8=4 r6c8<>7
Forcing Chain Contradiction in c4 => r4c1<>7
r4c1=7 r5c1<>7 r5c9=7 r2c9<>7 r3c8=7 r3c4<>7
r4c1=7 r4c4<>7
r4c1=7 r9c1<>7 r7c3=7 r7c4<>7
Forcing Chain Contradiction in r8 => r4c7<>6
r4c7=6 r5c9<>6 r5c9=7 r5c1<>7 r9c1=7 r9c1<>2 r8c1=2 r8c1<>3
r4c7=6 r5c9<>6 r5c9=7 r5c1<>7 r9c1=7 r9c6<>7 r9c6=8 r9c2<>8 r8c3=8 r8c3<>3
r4c7=6 r4c7<>3 r4c8=3 r8c8<>3
Forcing Chain Contradiction in c4 => r4c9<>7
r4c9=7 r2c9<>7 r3c8=7 r3c4<>7
r4c9=7 r4c4<>7
r4c9=7 r5c9<>7 r5c1=7 r9c1<>7 r7c3=7 r7c4<>7
Forcing Chain Contradiction in r8 => r8c8<>1
r8c8=1 r3c8<>1 r3c8=7 r2c9<>7 r5c9=7 r5c1<>7 r9c1=7 r9c1<>2 r8c1=2 r8c1<>3
r8c8=1 r3c8<>1 r3c8=7 r3c4<>7 r3c4=5 r3c2<>5 r3c2=8 r3c3<>8 r8c3=8 r8c3<>3
r8c8=1 r8c8<>3
Forcing Net Contradiction in r9c2 => r3c2=8
r3c2<>8 r9c2=8
r3c2<>8 (r3c3=8 r3c3<>4 r3c6=4 r2c5<>4 r2c5=9 r9c5<>9) (r3c3=8 r3c3<>4 r3c6=4 r2c6<>4 r2c1=4 r4c1<>4) r9c2=8 (r9c2<>1) r9c2<>9 r7c2=9 r7c2<>1 r6c2=1 r4c1<>1 r4c1=6 r2c7=9 r9c7<>9 r9c2=9
Hidden Single: r8c3=8
Discontinuous Nice Loop: 5 r2c6 -5- r3c4 -7- r3c8 =7= r2c9 -7- r5c9 =7= r5c1 -7- r9c1 =7= r7c3 =3= r1c3 -3- r1c6 =3= r2c6 => r2c6<>5
Almost Locked Set XY-Wing: A=r124c1 {1346}, B=r579c2 {1369}, C=r5c19 {367}, X,Y=3,6, Z=1 => r89c1<>1
Almost Locked Set XY-Wing: A=r8c14569 {123569}, B=r9c127 {1279}, C=r1245c1 {13467}, X,Y=3,7, Z=9 => r9c5<>9
Almost Locked Set Chain: 9- r8c14569 {123569} -3- r1245c1 {13467} -7- r89c1 {237} -3- r7c23,r9c2 {1379} -7- r78c4,r8c6 {5679} -9 => r7c5<>9
Forcing Chain Contradiction in r3c3 => r1c3<>1
r1c3=1 r3c3<>1
r1c3=1 r1c1<>1 r4c1=1 r4c1<>4 r2c1=4 r3c3<>4
r1c3=1 r1c3<>3 r7c3=3 r7c3<>7 r9c1=7 r5c1<>7 r5c9=7 r2c9<>7 r3c8=7 r3c4<>7 r3c4=5 r3c3<>5
Forcing Chain Verity => r4c7=3
r2c7=6 r1c89<>6 r1c1=6 r1c1<>1 r3c3=1 r3c8<>1 r3c8=7 r2c9<>7 r5c9=7 r5c1<>7 r9c1=7 r9c1<>2 r8c1=2 r8c1<>3 r8c8=3 r4c8<>3 r4c7=3
r6c7=6 r5c9<>6 r5c9=7 r5c1<>7 r9c1=7 r9c1<>2 r8c1=2 r8c1<>3 r8c8=3 r4c8<>3 r4c7=3
r7c7=6 r7c7<>3 r4c7=3
2-String Kite: 5 in r2c2,r4c9 (connected by r4c3,r6c2) => r2c9<>5
Naked Pair: 6,7 in r25c9 => r148c9<>6
2-String Kite: 6 in r1c1,r5c9 (connected by r1c8,r2c9) => r5c1<>6
Naked Triple: 2,3,7 in r589c1 => r12c1<>3
XYZ-Wing: 1/2/9 in r8c9,r9c27 => r9c9<>1
Finned Swordfish: 6 r148 c148 fr8c6 => r7c4<>6
Sue de Coq: r1c89 - {12569} (r1c3456 - {23589}, r2c9,r3c8 - {167}) => r2c7<>6, r3c7<>1
2-String Kite: 1 in r3c8,r4c1 (connected by r1c1,r3c3) => r4c8<>1
XY-Chain: 1 1- r3c8 -7- r2c9 -6- r5c9 -7- r5c1 -3- r8c1 -2- r8c9 -1 => r1c9,r7c8<>1
Locked Candidates Type 1 (Pointing): 1 in b3 => r6c8<>1
Naked Pair: 2,5 in r1c9,r3c7 => r2c7<>5
Naked Single: r2c7=9
Hidden Single: r2c2=5
Naked Single: r1c3=3
Hidden Single: r9c2=9
Hidden Single: r2c6=3
Locked Candidates Type 1 (Pointing): 6 in b1 => r4c1<>6
Locked Candidates Type 1 (Pointing): 1 in b7 => r7c57<>1
Naked Pair: 1,2 in r8c9,r9c7 => r7c7,r9c9<>2
Naked Single: r7c7=6
Naked Single: r9c9=4
Locked Candidates Type 2 (Claiming): 2 in r7 => r89c5<>2
Hidden Pair: 2,4 in r7c56 => r7c56<>7
Hidden Pair: 5,6 in r8c46 => r8c4<>9
Skyscraper: 7 in r5c1,r6c6 (connected by r9c16) => r6c3<>7
Skyscraper: 7 in r3c4,r6c6 (connected by r36c8) => r4c4<>7
W-Wing: 6/1 in r1c8,r6c2 connected by 1 in r14c1 => r6c8<>6
W-Wing: 1/7 in r3c8,r7c3 connected by 7 in r37c4 => r3c3<>1
Naked Single: r3c3=4
Naked Single: r2c1=6
Full House: r1c1=1
Naked Single: r2c9=7
Full House: r2c5=4
Naked Single: r1c8=6
Naked Single: r4c1=4
Naked Single: r3c8=1
Naked Single: r5c9=6
Naked Single: r7c5=2
Naked Single: r4c8=7
Naked Single: r5c2=3
Full House: r5c1=7
Naked Single: r7c6=4
Naked Single: r4c5=8
Naked Single: r6c8=4
Naked Single: r7c2=1
Full House: r6c2=6
Naked Single: r9c1=2
Full House: r8c1=3
Full House: r7c3=7
Naked Single: r1c5=9
Naked Single: r4c4=6
Full House: r6c6=7
Naked Single: r9c7=1
Naked Single: r8c8=9
Full House: r7c8=3
Full House: r7c4=9
Full House: r8c9=2
Naked Single: r8c5=1
Full House: r9c5=7
Full House: r9c6=8
Naked Single: r8c4=5
Full House: r8c6=6
Naked Single: r6c7=5
Full House: r3c7=2
Full House: r1c9=5
Full House: r4c9=1
Full House: r6c3=1
Full House: r4c3=5
Naked Single: r1c4=8
Full House: r3c4=7
Full House: r3c6=5
Full House: r1c6=2
|
normal_sudoku_1798
|
67.93....92156.34783....9..1....3.2.34....7..5.27...347....6..325637941841.2...7.
|
675934182921568347834127965197843526348652791562791834789416253256379418413285679
|
Basic 9x9 Sudoku 1798
|
puzzles5_forum_hardest_1905_11+
|
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 . 9 3 . . . .
9 2 1 5 6 . 3 4 7
8 3 . . . . 9 . .
1 . . . . 3 . 2 .
3 4 . . . . 7 . .
5 . 2 7 . . . 3 4
7 . . . . 6 . . 3
2 5 6 3 7 9 4 1 8
4 1 . 2 . . . 7 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
675934182921568347834127965197843526348652791562791834789416253256379418413285679 #1 Easy (244)
Full House: r8c1=2
Hidden Single: r2c7=3
Hidden Single: r1c1=6
Hidden Single: r4c6=3
Hidden Single: r1c4=9
Naked Single: r1c2=7
Naked Single: r2c1=9
Naked Single: r3c2=3
Naked Single: r2c3=1
Naked Single: r9c1=4
Full House: r7c1=7
Naked Single: r2c9=7
Full House: r2c6=8
Naked Single: r6c6=1
Naked Single: r9c6=5
Naked Single: r5c6=2
Naked Single: r9c5=8
Naked Single: r9c7=6
Naked Single: r1c6=4
Full House: r3c6=7
Naked Single: r6c5=9
Naked Single: r6c7=8
Full House: r6c2=6
Naked Single: r9c9=9
Full House: r9c3=3
Naked Single: r1c3=5
Full House: r3c3=4
Naked Single: r3c4=1
Full House: r3c5=2
Naked Single: r5c5=5
Naked Single: r4c7=5
Naked Single: r7c8=5
Full House: r7c7=2
Full House: r1c7=1
Naked Single: r1c8=8
Full House: r1c9=2
Naked Single: r7c4=4
Full House: r7c5=1
Full House: r4c5=4
Naked Single: r4c9=6
Naked Single: r3c8=6
Full House: r3c9=5
Full House: r5c8=9
Full House: r5c9=1
Naked Single: r4c4=8
Full House: r5c4=6
Full House: r5c3=8
Naked Single: r4c2=9
Full House: r4c3=7
Full House: r7c3=9
Full House: r7c2=8
|
normal_sudoku_889
|
7..3...6..6..57..8.3..6.7..652...849847529613319846527.7..1.9..4......8...3..5.72
|
785394261264157398931268754652731849847529613319846527578412936426973185193685472
|
Basic 9x9 Sudoku 889
|
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 . . 3 . . . 6 .
. 6 . . 5 7 . . 8
. 3 . . 6 . 7 . .
6 5 2 . . . 8 4 9
8 4 7 5 2 9 6 1 3
3 1 9 8 4 6 5 2 7
. 7 . . 1 . 9 . .
4 . . . . . . 8 .
. . 3 . . 5 . 7 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
785394261264157398931268754652731849847529613319846527578412936426973185193685472 #1 Medium (304)
Naked Single: r5c2=4
Naked Single: r5c8=1
Naked Single: r5c5=2
Full House: r5c7=6
Naked Single: r6c3=9
Naked Single: r9c8=7
Naked Single: r4c7=8
Naked Single: r4c2=5
Naked Single: r6c1=3
Full House: r6c9=7
Full House: r4c1=6
Full House: r4c9=9
Hidden Single: r1c1=7
Hidden Single: r9c4=6
Hidden Single: r9c7=4
Hidden Single: r9c1=1
Locked Candidates Type 1 (Pointing): 9 in b7 => r1c2<>9
Hidden Single: r1c5=9
Naked Single: r9c5=8
Full House: r9c2=9
Naked Single: r8c2=2
Full House: r1c2=8
Naked Single: r7c1=5
Naked Single: r8c6=3
Naked Single: r7c8=3
Naked Single: r7c9=6
Naked Single: r8c3=6
Full House: r7c3=8
Naked Single: r4c6=1
Naked Single: r8c5=7
Full House: r4c5=3
Full House: r4c4=7
Naked Single: r8c7=1
Full House: r8c9=5
Full House: r8c4=9
Naked Single: r2c8=9
Full House: r3c8=5
Naked Single: r1c7=2
Full House: r2c7=3
Naked Single: r2c1=2
Full House: r3c1=9
Naked Single: r1c6=4
Naked Single: r1c9=1
Full House: r1c3=5
Full House: r3c9=4
Naked Single: r2c4=1
Full House: r2c3=4
Full House: r3c3=1
Naked Single: r7c6=2
Full House: r3c6=8
Full House: r3c4=2
Full House: r7c4=4
|
normal_sudoku_929
|
97.35......87.2.39321..46758....7.93......7...971.......9278.6.7.264.9.8.8...9.27
|
974356812568712439321894675815467293643925781297183546159278364732641958486539127
|
Basic 9x9 Sudoku 929
|
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 7 . 3 5 . . . .
. . 8 7 . 2 . 3 9
3 2 1 . . 4 6 7 5
8 . . . . 7 . 9 3
. . . . . . 7 . .
. 9 7 1 . . . . .
. . 9 2 7 8 . 6 .
7 . 2 6 4 . 9 . 8
. 8 . . . 9 . 2 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
974356812568712439321894675815467293643925781297183546159278364732641958486539127 #1 Hard (862)
Hidden Single: r7c3=9
Hidden Single: r8c3=2
Locked Candidates Type 1 (Pointing): 5 in b1 => r2c7<>5
Locked Candidates Type 1 (Pointing): 3 in b4 => r5c456<>3
Naked Triple: 1,3,5 in r8c6,r9c45 => r7c456<>3, r7c46<>5, r7c56<>1
Naked Single: r7c6=8
Naked Single: r3c6=4
Naked Single: r2c4=7
Naked Single: r3c9=5
Naked Single: r7c4=2
Naked Single: r7c5=7
Hidden Single: r5c7=7
Hidden Single: r3c8=7
Locked Candidates Type 1 (Pointing): 8 in b3 => r1c4<>8
Naked Single: r1c4=3
Naked Single: r9c4=5
Naked Single: r4c4=4
Locked Candidates Type 2 (Claiming): 5 in c3 => r45c2,r56c1<>5
W-Wing: 5/6 in r4c3,r5c6 connected by 6 in r1c36 => r5c3<>5
Hidden Single: r4c3=5
XY-Wing: 2/6/1 in r24c5,r4c7 => r2c7<>1
Naked Single: r2c7=4
Hidden Single: r2c5=1
Naked Single: r1c6=6
Naked Single: r9c5=3
Full House: r8c6=1
Naked Single: r1c3=4
Naked Single: r5c6=5
Full House: r6c6=3
Naked Single: r9c7=1
Naked Single: r8c8=5
Full House: r8c2=3
Naked Single: r9c3=6
Full House: r5c3=3
Full House: r9c1=4
Naked Single: r4c7=2
Naked Single: r7c9=4
Full House: r7c7=3
Naked Single: r1c7=8
Full House: r6c7=5
Naked Single: r4c5=6
Full House: r4c2=1
Naked Single: r6c9=6
Naked Single: r1c8=1
Full House: r1c9=2
Full House: r5c9=1
Naked Single: r7c2=5
Full House: r7c1=1
Naked Single: r6c1=2
Naked Single: r2c2=6
Full House: r2c1=5
Full House: r5c1=6
Full House: r5c2=4
Naked Single: r6c5=8
Full House: r6c8=4
Full House: r5c8=8
Naked Single: r3c5=9
Full House: r3c4=8
Full House: r5c4=9
Full House: r5c5=2
|
normal_sudoku_2265
|
5..9..2.4..6..35.94..52..16982..5..115..7...27....2.583..2..6.5..5..6..3641359827
|
518967234276413589439528716982635471153874962764192358397281645825746193641359827
|
Basic 9x9 Sudoku 2265
|
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 . . 2 . 4
. . 6 . . 3 5 . 9
4 . . 5 2 . . 1 6
9 8 2 . . 5 . . 1
1 5 . . 7 . . . 2
7 . . . . 2 . 5 8
3 . . 2 . . 6 . 5
. . 5 . . 6 . . 3
6 4 1 3 5 9 8 2 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
518967234276413589439528716982635471153874962764192358397281645825746193641359827 #1 Unfair (1656)
Naked Single: r3c9=6
Naked Single: r1c9=4
Full House: r7c9=5
Naked Single: r9c8=2
Naked Single: r9c3=1
Naked Single: r9c1=6
Naked Single: r5c1=1
Hidden Single: r6c8=5
Hidden Single: r4c3=2
Naked Single: r6c1=7
Hidden Single: r6c6=2
Hidden Single: r3c4=5
Naked Single: r9c4=3
Full House: r9c5=5
Hidden Single: r1c1=5
Hidden Single: r6c2=6
Hidden Single: r6c5=9
Hidden Single: r8c7=1
Hidden Single: r1c5=6
Hidden Single: r6c4=1
Hidden Single: r4c5=3
Hidden Single: r5c7=9
Locked Candidates Type 1 (Pointing): 3 in b4 => r13c3<>3
Locked Candidates Type 1 (Pointing): 4 in b9 => r45c8<>4
Hidden Rectangle: 7/9 in r3c23,r7c23 => r3c3<>7
Finned X-Wing: 8 c15 r28 fr7c5 => r8c4<>8
XY-Chain: 8 8- r3c6 -7- r3c7 -3- r6c7 -4- r6c3 -3- r5c3 -4- r5c6 -8 => r17c6<>8
Locked Candidates Type 1 (Pointing): 8 in b8 => r2c5<>8
XY-Chain: 7 7- r1c3 -8- r2c1 -2- r8c1 -8- r8c5 -4- r2c5 -1- r1c6 -7 => r1c28<>7
XY-Wing: 3/8/7 in r1c38,r3c7 => r3c2<>7
Sue de Coq: r1c23 - {1378} (r1c6 - {17}, r2c1,r3c23 - {2389}) => r2c2<>2
Hidden Single: r2c1=2
Full House: r8c1=8
Naked Single: r8c5=4
Naked Single: r2c5=1
Full House: r7c5=8
Naked Single: r8c4=7
Full House: r7c6=1
Naked Single: r8c8=9
Full House: r7c8=4
Full House: r8c2=2
Naked Single: r1c6=7
Naked Single: r2c2=7
Naked Single: r1c3=8
Naked Single: r3c6=8
Full House: r2c4=4
Full House: r2c8=8
Full House: r5c6=4
Naked Single: r7c2=9
Full House: r7c3=7
Naked Single: r1c8=3
Full House: r1c2=1
Full House: r3c2=3
Full House: r3c3=9
Full House: r3c7=7
Naked Single: r4c4=6
Full House: r5c4=8
Naked Single: r5c3=3
Full House: r5c8=6
Full House: r4c8=7
Full House: r4c7=4
Full House: r6c3=4
Full House: r6c7=3
|
normal_sudoku_4525
|
.....93589..835.7..38.7.6...9...8.3.21...386..8..1...4.6...7.8.15..8.2..8..5.....
|
741269358926835471538471629694758132217943865385612794462197583159386247873524916
|
Basic 9x9 Sudoku 4525
|
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 5 8
9 . . 8 3 5 . 7 .
. 3 8 . 7 . 6 . .
. 9 . . . 8 . 3 .
2 1 . . . 3 8 6 .
. 8 . . 1 . . . 4
. 6 . . . 7 . 8 .
1 5 . . 8 . 2 . .
8 . . 5 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
741269358926835471538471629694758132217943865385612794462197583159386247873524916 #1 Extreme (3366)
Turbot Fish: 1 r3c8 =1= r9c8 -1- r9c6 =1= r7c4 => r3c4<>1
X-Chain: 1 r1c3 =1= r1c4 -1- r7c4 =1= r9c6 -1- r9c8 =1= r3c8 => r3c3<>1
Discontinuous Nice Loop: 9 r9c9 -9- r8c8 -4- r8c6 -6- r8c9 =6= r9c9 => r9c9<>9
Forcing Chain Contradiction in r7 => r3c1=5
r3c1<>5 r3c1=4 r7c1<>4
r3c1<>5 r3c1=4 r4c1<>4 r45c3=4 r7c3<>4
r3c1<>5 r3c1=4 r1c123<>4 r1c45=4 r23c6<>4 r89c6=4 r7c4<>4
r3c1<>5 r3c1=4 r1c123<>4 r1c45=4 r23c6<>4 r89c6=4 r7c5<>4
r3c1<>5 r3c1=4 r3c8<>4 r2c7=4 r7c7<>4
Forcing Chain Contradiction in c6 => r3c3<>2
r3c3=2 r1c23<>2 r1c45=2 r2c6<>2
r3c3=2 r3c6<>2
r3c3=2 r3c8<>2 r6c8=2 r6c6<>2
r3c3=2 r7c3<>2 r7c45=2 r9c6<>2
Discontinuous Nice Loop: 4 r2c4 -4- r2c7 =4= r3c8 -4- r3c3 -8- r3c4 =8= r2c4 => r2c4<>4
Discontinuous Nice Loop: 4 r2c5 -4- r2c7 =4= r3c8 -4- r3c3 -8- r3c4 =8= r2c4 =3= r2c5 => r2c5<>4
Discontinuous Nice Loop: 4 r2c6 -4- r2c7 =4= r3c8 -4- r3c3 -8- r3c4 =8= r2c4 =3= r2c5 =5= r2c6 => r2c6<>4
Finned Swordfish: 4 c268 r389 fr1c2 fr2c2 => r3c3<>4
Naked Single: r3c3=8
Hidden Single: r6c2=8
Hidden Single: r2c4=8
Hidden Single: r5c7=8
Hidden Single: r8c2=5
Hidden Single: r2c5=3
Hidden Single: r2c6=5
Hidden Single: r2c3=6
Hidden Single: r1c3=1
Hidden Single: r7c4=1
Hidden Single: r3c6=1
Hidden Single: r8c4=3
Hidden Single: r9c8=1
Locked Candidates Type 1 (Pointing): 2 in b1 => r9c2<>2
Locked Candidates Type 1 (Pointing): 9 in b8 => r5c5<>9
Locked Candidates Type 2 (Claiming): 4 in c6 => r79c5<>4
Sashimi X-Wing: 4 r27 c27 fr7c1 fr7c3 => r9c2<>4
Naked Single: r9c2=7
Hidden Single: r1c1=7
Hidden Single: r8c9=7
Hidden Single: r8c6=6
Naked Single: r6c6=2
Full House: r9c6=4
Naked Single: r6c8=9
Naked Single: r9c7=9
Naked Single: r5c9=5
Naked Single: r8c8=4
Full House: r3c8=2
Full House: r8c3=9
Naked Single: r9c5=2
Full House: r7c5=9
Naked Single: r5c5=4
Naked Single: r6c7=7
Naked Single: r7c9=3
Naked Single: r7c7=5
Full House: r9c9=6
Full House: r9c3=3
Naked Single: r2c9=1
Naked Single: r3c4=4
Full House: r3c9=9
Full House: r2c7=4
Full House: r4c7=1
Full House: r4c9=2
Full House: r2c2=2
Full House: r1c2=4
Naked Single: r1c5=6
Full House: r1c4=2
Full House: r4c5=5
Naked Single: r5c3=7
Full House: r5c4=9
Naked Single: r6c4=6
Full House: r4c4=7
Naked Single: r7c1=4
Full House: r7c3=2
Naked Single: r6c3=5
Full House: r4c3=4
Full House: r6c1=3
Full House: r4c1=6
|
normal_sudoku_6765
|
1....3.7..7.6.1...4.3.7.....47.6..1...8417..5.1..3..4..3..9.468...3.4..99.4..623.
|
192853674875641923463972581347569812628417395519238746231795468786324159954186237
|
Basic 9x9 Sudoku 6765
|
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 . 7 .
. 7 . 6 . 1 . . .
4 . 3 . 7 . . . .
. 4 7 . 6 . . 1 .
. . 8 4 1 7 . . 5
. 1 . . 3 . . 4 .
. 3 . . 9 . 4 6 8
. . . 3 . 4 . . 9
9 . 4 . . 6 2 3 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
192853674875641923463972581347569812628417395519238746231795468786324159954186237 #1 Extreme (22202) bf
Grouped Discontinuous Nice Loop: 9 r1c7 -9- r2c78 =9= r2c3 -9- r6c3 =9= r5c2 -9- r5c8 =9= r456c7 -9- r1c7 => r1c7<>9
Grouped Discontinuous Nice Loop: 9 r3c7 -9- r2c78 =9= r2c3 -9- r6c3 =9= r5c2 -9- r5c8 =9= r456c7 -9- r3c7 => r3c7<>9
Brute Force: r5c6=7
Hidden Single: r8c6=4
Hidden Single: r9c6=6
Hidden Pair: 1,4 in r5c45 => r5c45<>2, r5c4<>9
Almost Locked Set XZ-Rule: A=r8c123578 {1235678}, B=r9c258 {1358}, X=3, Z=1 => r8c4<>1
Brute Force: r5c5=1
Naked Single: r5c4=4
Naked Pair: 5,8 in r9c25 => r9c48<>5, r9c489<>8
Naked Single: r9c8=3
Hidden Single: r8c4=3
Locked Candidates Type 1 (Pointing): 5 in b9 => r8c1235<>5
Naked Triple: 2,5,8 in r7c6,r89c5 => r7c4<>2, r7c4<>5, r7c4<>8
Empty Rectangle: 8 in b1 (r9c25) => r2c5<>8
Uniqueness Test 1: 1/7 in r7c49,r9c49 => r7c9<>1, r7c9<>7
Naked Single: r7c9=8
Naked Single: r8c8=5
Locked Candidates Type 1 (Pointing): 8 in b6 => r123c7<>8
Locked Candidates Type 1 (Pointing): 8 in b8 => r1c5<>8
Sue de Coq: r456c7 - {36789} (r138c7 - {1567}, r4c9,r5c8 - {239}) => r6c9<>2, r2c7<>5
Sashimi X-Wing: 5 r29 c25 fr2c1 fr2c3 => r13c2<>5
Hidden Single: r9c2=5
Naked Single: r9c5=8
Naked Single: r8c5=2
Naked Single: r7c6=5
Locked Candidates Type 1 (Pointing): 5 in b5 => r13c4<>5
Hidden Single: r3c7=5
Naked Single: r1c7=6
Hidden Single: r3c9=1
Naked Single: r9c9=7
Full House: r8c7=1
Full House: r9c4=1
Full House: r7c4=7
Naked Single: r6c9=6
Naked Single: r8c3=6
Naked Single: r7c1=2
Full House: r7c3=1
Naked Single: r8c2=8
Full House: r8c1=7
Naked Single: r6c1=5
Naked Single: r2c1=8
Naked Single: r4c1=3
Full House: r5c1=6
Naked Single: r4c9=2
Naked Single: r1c9=4
Full House: r2c9=3
Naked Single: r5c8=9
Naked Single: r1c5=5
Full House: r2c5=4
Naked Single: r2c7=9
Naked Single: r2c8=2
Full House: r2c3=5
Full House: r3c8=8
Naked Single: r4c7=8
Naked Single: r5c2=2
Full House: r5c7=3
Full House: r6c7=7
Full House: r6c3=9
Full House: r1c3=2
Naked Single: r4c6=9
Full House: r4c4=5
Naked Single: r1c2=9
Full House: r1c4=8
Full House: r3c2=6
Naked Single: r3c6=2
Full House: r3c4=9
Full House: r6c4=2
Full House: r6c6=8
|
normal_sudoku_2188
|
4...3859.9.....32.563...8148..45.1737....12..1..7..6.96..24593.351...4822.....76.
|
472138596918564327563927814829456173746391258135782649687245931351679482294813765
|
Basic 9x9 Sudoku 2188
|
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 5 9 .
9 . . . . . 3 2 .
5 6 3 . . . 8 1 4
8 . . 4 5 . 1 7 3
7 . . . . 1 2 . .
1 . . 7 . . 6 . 9
6 . . 2 4 5 9 3 .
3 5 1 . . . 4 8 2
2 . . . . . 7 6 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
472138596918564327563927814829456173746391258135782649687245931351679482294813765 #1 Easy (208)
Naked Single: r4c8=7
Naked Single: r7c1=6
Naked Single: r3c7=8
Naked Single: r4c9=3
Naked Single: r8c1=3
Naked Single: r3c8=1
Naked Single: r7c7=9
Naked Single: r9c1=2
Naked Single: r8c7=4
Full House: r5c7=2
Naked Single: r3c1=5
Full House: r6c1=1
Naked Single: r8c8=8
Naked Single: r3c4=9
Naked Single: r7c9=1
Full House: r9c9=5
Naked Single: r8c4=6
Naked Single: r5c9=8
Naked Single: r1c4=1
Naked Single: r5c4=3
Naked Single: r2c4=5
Full House: r9c4=8
Naked Single: r6c6=2
Naked Single: r3c6=7
Full House: r3c5=2
Naked Single: r6c5=8
Naked Single: r2c5=6
Full House: r2c6=4
Naked Single: r8c6=9
Full House: r8c5=7
Naked Single: r2c9=7
Full House: r1c9=6
Naked Single: r5c5=9
Full House: r4c6=6
Full House: r9c5=1
Full House: r9c6=3
Naked Single: r2c3=8
Full House: r2c2=1
Naked Single: r5c2=4
Naked Single: r7c3=7
Full House: r7c2=8
Naked Single: r5c8=5
Full House: r5c3=6
Full House: r6c8=4
Naked Single: r6c2=3
Full House: r6c3=5
Naked Single: r9c2=9
Full House: r9c3=4
Naked Single: r1c3=2
Full House: r1c2=7
Full House: r4c2=2
Full House: r4c3=9
|
normal_sudoku_1754
|
..971...84...6.975...49..6......76....79248533.518679..36.71.8...86....7...8.92.6
|
659712348412368975873495162984537621167924853325186794536271489298643517741859236
|
Basic 9x9 Sudoku 1754
|
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 7 1 . . . 8
4 . . . 6 . 9 7 5
. . . 4 9 . . 6 .
. . . . . 7 6 . .
. . 7 9 2 4 8 5 3
3 . 5 1 8 6 7 9 .
. 3 6 . 7 1 . 8 .
. . 8 6 . . . . 7
. . . 8 . 9 2 . 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
659712348412368975873495162984537621167924853325186794536271489298643517741859236 #1 Easy (326)
Naked Single: r5c6=4
Naked Single: r6c5=8
Naked Single: r6c4=1
Naked Single: r5c4=9
Hidden Single: r4c6=7
Hidden Single: r2c5=6
Hidden Single: r9c9=6
Hidden Single: r4c7=6
Hidden Single: r9c4=8
Hidden Single: r2c7=9
Hidden Single: r3c5=9
Hidden Single: r8c9=7
Hidden Single: r3c4=4
Hidden Single: r7c9=9
Hidden Single: r7c7=4
Naked Single: r1c7=3
Naked Single: r3c7=1
Full House: r8c7=5
Naked Single: r3c9=2
Full House: r1c8=4
Naked Single: r3c3=3
Naked Single: r6c9=4
Full House: r4c9=1
Full House: r6c2=2
Full House: r4c8=2
Naked Single: r4c3=4
Naked Single: r9c3=1
Full House: r2c3=2
Naked Single: r9c8=3
Full House: r8c8=1
Naked Single: r2c4=3
Naked Single: r2c6=8
Full House: r2c2=1
Naked Single: r4c4=5
Full House: r4c5=3
Full House: r7c4=2
Full House: r7c1=5
Naked Single: r3c6=5
Full House: r1c6=2
Full House: r8c6=3
Naked Single: r5c2=6
Full House: r5c1=1
Naked Single: r8c5=4
Full House: r9c5=5
Naked Single: r1c1=6
Full House: r1c2=5
Naked Single: r9c1=7
Full House: r9c2=4
Naked Single: r8c2=9
Full House: r8c1=2
Naked Single: r3c1=8
Full House: r3c2=7
Full House: r4c2=8
Full House: r4c1=9
|
normal_sudoku_5732
|
31.8...95.8.1..23..25.931.883..1952..9.53..81.51...3.9.4.....1.17..4.9..563971842
|
317862495489157236625493178836719524294536781751284369948325617172648953563971842
|
Basic 9x9 Sudoku 5732
|
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 1 . 8 . . . 9 5
. 8 . 1 . . 2 3 .
. 2 5 . 9 3 1 . 8
8 3 . . 1 9 5 2 .
. 9 . 5 3 . . 8 1
. 5 1 . . . 3 . 9
. 4 . . . . . 1 .
1 7 . . 4 . 9 . .
5 6 3 9 7 1 8 4 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
317862495489157236625493178836719524294536781751284369948325617172648953563971842 #1 Extreme (3496)
Naked Single: r9c2=6
Naked Single: r8c2=7
Naked Single: r9c7=8
Naked Single: r7c2=4
Naked Single: r9c9=2
Full House: r9c6=1
Naked Single: r1c2=1
Full House: r6c2=5
Hidden Single: r3c9=8
Hidden Single: r6c7=3
Hidden Single: r1c8=9
Hidden Single: r3c3=5
Hidden Single: r1c1=3
Hidden Single: r4c6=9
Hidden Single: r7c8=1
Hidden Single: r2c4=1
Hidden Single: r6c3=1
Hidden Single: r4c7=5
Hidden Single: r8c8=5
Empty Rectangle: 7 in b2 (r36c8) => r6c6<>7
Hidden Rectangle: 5/6 in r2c56,r7c56 => r7c6<>6
Hidden Rectangle: 3/6 in r7c49,r8c49 => r7c4<>6
Finned X-Wing: 4 r36 c14 fr6c6 => r4c4<>4
2-String Kite: 4 in r1c7,r4c3 (connected by r4c9,r5c7) => r1c3<>4
Forcing Chain Contradiction in r3c4 => r4c9<>6
r4c9=6 r4c9<>4 r2c9=4 r1c7<>4 r1c6=4 r3c4<>4
r4c9=6 r6c8<>6 r3c8=6 r3c4<>6
r4c9=6 r4c4<>6 r4c4=7 r3c4<>7
W-Wing: 7/6 in r3c8,r7c7 connected by 6 in r5c7,r6c8 => r1c7<>7
Finned Franken Swordfish: 6 r34b6 c148 fr4c3 fr5c7 => r5c1<>6
Grouped AIC: 7 7- r1c3 -6- r23c1 =6= r6c1 -6- r6c8 -7- r3c8 =7= r2c9 -7 => r2c13<>7
Finned Swordfish: 7 r124 c369 fr4c4 => r5c6<>7
Locked Candidates Type 1 (Pointing): 7 in b5 => r3c4<>7
Finned Swordfish: 7 c148 r346 fr5c1 => r4c3<>7
W-Wing: 6/4 in r1c7,r4c3 connected by 4 in r24c9 => r1c3<>6
Naked Single: r1c3=7
Hidden Single: r2c6=7
Hidden Single: r3c8=7
Full House: r6c8=6
Hidden Single: r2c5=5
Hidden Single: r7c6=5
Locked Candidates Type 1 (Pointing): 6 in b4 => r2c3<>6
X-Wing: 6 c57 r17 => r1c6,r7c9<>6
XYZ-Wing: 2/4/8 in r16c6,r6c5 => r5c6<>2
Locked Candidates Type 1 (Pointing): 2 in b5 => r6c1<>2
W-Wing: 6/4 in r4c3,r5c6 connected by 4 in r4c9,r5c7 => r4c4,r5c3<>6
Naked Single: r4c4=7
Naked Single: r4c9=4
Full House: r4c3=6
Full House: r5c7=7
Naked Single: r2c9=6
Full House: r1c7=4
Full House: r7c7=6
Naked Single: r8c9=3
Full House: r7c9=7
Naked Single: r1c6=2
Full House: r1c5=6
Full House: r3c4=4
Full House: r3c1=6
Naked Single: r6c4=2
Naked Single: r6c5=8
Full House: r7c5=2
Naked Single: r7c4=3
Full House: r8c4=6
Full House: r8c6=8
Full House: r8c3=2
Naked Single: r6c6=4
Full House: r5c6=6
Full House: r6c1=7
Naked Single: r7c1=9
Full House: r7c3=8
Naked Single: r5c3=4
Full House: r2c3=9
Full House: r2c1=4
Full House: r5c1=2
|
normal_sudoku_327
|
.6..8.5.9.......6......6.875..8.2....231.497..4..9...82..31.....75.48.9...1..5...
|
462781539758923461319456287597832614823164975146597328284319756675248193931675842
|
Basic 9x9 Sudoku 327
|
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 . 5 . 9
. . . . . . . 6 .
. . . . . 6 . 8 7
5 . . 8 . 2 . . .
. 2 3 1 . 4 9 7 .
. 4 . . 9 . . . 8
2 . . 3 1 . . . .
. 7 5 . 4 8 . 9 .
. . 1 . . 5 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
462781539758923461319456287597832614823164975146597328284319756675248193931675842 #1 Extreme (41676) bf
Hidden Pair: 4,8 in r4c4,r5c6 => r4c4<>6, r4c4,r5c6<>7
Brute Force: r5c6=4
Naked Single: r4c4=8
Brute Force: r5c7=9
Forcing Chain Contradiction in c3 => r2c3<>9
r2c3=9 r2c3<>8
r2c3=9 r23c1<>9 r9c1=9 r9c1<>4 r7c3=4 r7c3<>8
r2c3=9 r2c6<>9 r7c6=9 r7c6<>8 r8c6=8 r8c3<>8
Brute Force: r5c8=7
Forcing Net Contradiction in r9 => r2c2<>9
r2c2=9 (r9c2<>9) r2c6<>9 r7c6=9 r9c4<>9 r9c1=9 r9c1<>6
r2c2=9 (r2c6<>9 r7c6=9 r7c6<>7) r4c2<>9 r4c3=9 r4c3<>7 r4c5=7 (r9c5<>7) r7c5<>7 r7c7=7 r9c7<>7 r9c4=7 r9c4<>6
r2c2=9 r2c6<>9 r7c6=9 (r9c4<>9 r9c1=9 r9c1<>4 r7c3=4 r7c8<>4) (r7c6<>1) r7c6<>8 r8c6=8 r8c6<>1 r7c5=1 r7c8<>1 r7c8=5 r6c8<>5 r6c4=5 r5c5<>5 r5c5=6 r9c5<>6
r2c2=9 (r2c6<>9 r7c6=9 r9c4<>9 r9c1=9 r9c1<>4 r7c3=4 r7c3<>6) (r2c6<>9 r7c6=9 r7c6<>8 r8c6=8 r8c6<>1 r7c5=1 r7c5<>6) (r2c6<>9 r7c6=9 r7c6<>7) r4c2<>9 r4c3=9 r4c3<>7 r4c5=7 r7c5<>7 r7c7=7 r7c7<>6 r7c9=6 r9c7<>6
r2c2=9 (r2c6<>9 r7c6=9 r9c4<>9 r9c1=9 r9c1<>4 r7c3=4 r7c3<>6) (r2c6<>9 r7c6=9 r7c6<>8 r8c6=8 r8c6<>1 r7c5=1 r7c5<>6) (r2c6<>9 r7c6=9 r7c6<>7) r4c2<>9 r4c3=9 r4c3<>7 r4c5=7 r7c5<>7 r7c7=7 r7c7<>6 r7c9=6 r9c9<>6
Forcing Net Contradiction in r6c1 => r7c7<>4
r7c7=4 (r7c7<>7) (r7c7<>8) (r9c9<>4 r9c1=4 r9c1<>8) r7c7<>7 r9c7=7 r9c7<>8 r9c2=8 (r7c2<>8) r7c3<>8 r7c6=8 r7c6<>7 r7c5=7 r4c5<>7 r4c3=7 r4c3<>9 r4c2=9 r4c2<>1 r6c1=1
r7c7=4 (r9c9<>4 r9c1=4 r9c1<>6) (r9c9<>4 r9c1=4 r9c1<>3) (r9c9<>4 r9c1=4 r9c1<>8) r7c7<>7 r9c7=7 r9c7<>8 r9c2=8 (r5c2<>8 r5c1=8 r5c1<>6) r9c2<>3 r8c1=3 r8c1<>6 r6c1=6
Forcing Net Contradiction in b8 => r7c8<>1
r7c8=1 (r1c8<>1) (r8c7<>1) r8c9<>1 r8c6=1 r1c6<>1 r1c1=1 (r2c2<>1) r3c2<>1 r4c2=1 r4c2<>9 r4c3=9 r4c3<>7 r4c5=7 r7c5<>7
r7c8=1 (r8c7<>1) r8c9<>1 r8c6=1 r8c6<>8 r7c6=8 r7c6<>7
r7c8=1 (r8c7<>1) r8c9<>1 r8c6=1 r8c6<>8 r7c6=8 r7c6<>9 r2c6=9 (r2c4<>9) r3c4<>9 r9c4=9 r9c4<>7
r7c8=1 (r1c8<>1) (r8c7<>1) r8c9<>1 r8c6=1 r1c6<>1 r1c1=1 (r2c2<>1) r3c2<>1 r4c2=1 r4c2<>9 r4c3=9 r4c3<>7 r4c5=7 r9c5<>7
Discontinuous Nice Loop: 8 r9c1 -8- r5c1 -6- r5c5 -5- r5c9 =5= r6c8 -5- r7c8 -4- r7c3 =4= r9c1 => r9c1<>8
Forcing Net Verity => r3c2<>2
r9c8=2 (r1c8<>2) (r8c7<>2) r8c9<>2 r8c4=2 r1c4<>2 r1c3=2 r3c2<>2
r9c8=3 (r6c8<>3) (r1c8<>3) (r8c7<>3) r8c9<>3 r8c1=3 (r3c1<>3) r1c1<>3 r1c6=3 (r3c5<>3) r6c6<>3 r6c7=3 r3c7<>3 r3c2=3 r3c2<>2
r9c8=4 r7c8<>4 r7c8=5 r6c8<>5 r6c4=5 r5c5<>5 r5c9=5 r5c9<>2 r5c2=2 r3c2<>2
Forcing Net Contradiction in r9c5 => r3c2<>9
r3c2=9 (r2c1<>9) r3c1<>9 r9c1=9 (r9c1<>6) r9c1<>4 r7c3=4 (r7c3<>6) r7c8<>4 r7c8=5 r8c9<>5 r8c3=5 r8c3<>6 r8c1=6 r8c4<>6 r8c4=2 r9c5<>2
r3c2=9 (r2c1<>9) r3c1<>9 r9c1=9 r9c1<>4 r7c3=4 r7c8<>4 r7c8=5 r6c8<>5 r6c4=5 r5c5<>5 r5c5=6 r9c5<>6
r3c2=9 r4c2<>9 r4c3=9 r4c3<>7 r4c5=7 r9c5<>7
Forcing Net Contradiction in r1c6 => r7c5<>6
r7c5=6 r7c5<>1 r23c5=1 r1c6<>1
r7c5=6 (r8c4<>6 r8c4=2 r9c5<>2 r9c5=7 r4c5<>7 r4c5=3 r4c8<>3) r5c5<>6 r5c5=5 r6c4<>5 r6c8=5 r7c8<>5 r7c8=4 r4c8<>4 r4c8=1 (r1c8<>1) (r6c7<>1) r6c8<>1 r6c1=1 r1c1<>1 r1c6=1
AIC: 8 8- r8c6 -1- r7c5 -7- r7c7 =7= r9c7 =8= r9c2 -8 => r8c13<>8
Almost Locked Set XY-Wing: A=r9c124589 {2346789}, B=r23468c7 {123468}, C=r7c5,r8c6 {178}, X,Y=7,8, Z=2,3,4,6 => r9c7<>2, r9c7<>3, r9c7<>4, r9c7<>6
Forcing Net Contradiction in r5c1 => r5c1=8
r5c1<>8 (r5c2=8 r9c2<>8 r9c2=9 r4c2<>9 r4c2=1 r4c8<>1) r5c1=6 r5c5<>6 r5c5=5 r6c4<>5 r6c8=5 r7c8<>5 r7c8=4 r4c8<>4 r4c8=3 (r1c8<>3) (r6c7<>3) r6c8<>3 r6c6=3 r1c6<>3 r1c1=3 r8c1<>3 r8c1=6 r5c1<>6 r5c1=8
Naked Single: r5c2=2
Almost Locked Set XY-Wing: A=r468c3 {5679}, B=r4c789,r5c9 {13456}, C=r4c2 {19}, X,Y=1,9, Z=5 => r8c9<>5
Hidden Single: r8c3=5
AIC: 1/7 1- r7c5 -7- r4c5 =7= r4c3 =9= r4c2 -9- r7c2 -8- r9c2 =8= r9c7 =7= r7c7 -7 => r7c7<>1, r7c5<>7
Naked Single: r7c5=1
Naked Single: r8c6=8
Hidden Pair: 7,8 in r79c7 => r7c7<>6
Naked Triple: 7,8,9 in r7c267 => r7c3<>8, r7c3<>9
Hidden Single: r2c3=8
Discontinuous Nice Loop: 6 r4c5 -6- r5c5 =6= r5c9 -6- r7c9 =6= r7c3 -6- r6c3 -7- r4c3 =7= r4c5 => r4c5<>6
Naked Pair: 3,7 in r4c5,r6c6 => r6c4<>7
Finned X-Wing: 6 r47 c39 fr4c7 => r5c9<>6
Naked Single: r5c9=5
Full House: r5c5=6
Naked Single: r6c4=5
Hidden Single: r7c8=5
XY-Chain: 6 6- r7c9 -4- r7c3 -6- r6c3 -7- r6c6 -3- r4c5 -7- r9c5 -2- r8c4 -6 => r8c79<>6
Locked Candidates Type 1 (Pointing): 6 in b9 => r4c9<>6
Grouped Discontinuous Nice Loop: 3 r9c1 -3- r8c1 -6- r8c4 -2- r9c5 -7- r4c5 =7= r4c3 =9= r4c2 -9- r79c2 =9= r9c1 => r9c1<>3
Almost Locked Set XY-Wing: A=r4c25789 {134679}, B=r1238c4 {24679}, C=r79c2,r8c1 {3689}, X,Y=6,9, Z=7 => r2c5<>7
Forcing Chain Contradiction in c1 => r4c7=6
r4c7<>6 r4c3=6 r6c1<>6
r4c7<>6 r4c3=6 r4c3<>7 r4c5=7 r9c5<>7 r9c5=2 r8c4<>2 r8c4=6 r8c1<>6
r4c7<>6 r4c3=6 r4c3<>9 r4c2=9 r79c2<>9 r9c1=9 r9c1<>6
Locked Candidates Type 2 (Claiming): 4 in c7 => r1c8,r2c9<>4
Forcing Chain Verity => r1c1<>1
r2c7=3 r2c7<>4 r3c7=4 r3c7<>1 r3c12=1 r1c1<>1
r3c7=3 r3c7<>1 r3c12=1 r1c1<>1
r6c7=3 r6c6<>3 r6c6=7 r4c5<>7 r4c3=7 r4c3<>9 r4c2=9 r4c2<>1 r6c1=1 r1c1<>1
r8c7=3 r8c1<>3 r8c1=6 r8c4<>6 r8c4=2 r9c5<>2 r9c5=7 r4c5<>7 r4c3=7 r4c3<>9 r4c2=9 r4c2<>1 r6c1=1 r1c1<>1
Almost Locked Set Chain: 2- r1c134 {2347} -3- r8c1 {36} -6- r12369c1 {134679} -3- r234c2 {1359} -9- r1467c3 {24679} -2 => r1c8<>2
Discontinuous Nice Loop: 1 r6c8 -1- r6c1 =1= r4c2 =9= r4c3 =7= r4c5 -7- r9c5 -2- r9c8 =2= r6c8 => r6c8<>1
Finned X-Wing: 1 r36 c17 fr3c2 => r2c1<>1
AIC: 7/8 8- r9c7 =8= r9c2 -8- r7c2 -9- r4c2 -1- r4c8 =1= r1c8 -1- r1c6 =1= r2c6 =9= r7c6 =7= r7c7 -7 => r9c7<>7, r7c7<>8
Naked Single: r9c7=8
Naked Single: r7c7=7
Naked Single: r7c6=9
Naked Single: r7c2=8
Discontinuous Nice Loop: 7 r2c4 -7- r9c4 =7= r9c5 -7- r4c5 =7= r4c3 =9= r3c3 -9- r3c4 =9= r2c4 => r2c4<>7
AIC: 7 7- r1c4 =7= r9c4 -7- r9c5 =7= r4c5 -7- r4c3 -9- r4c2 -1- r4c8 =1= r1c8 -1- r1c6 =1= r2c6 =7= r2c1 -7 => r1c13,r2c6<>7
Hidden Single: r2c1=7
Hidden Single: r2c4=9
Hidden Single: r2c7=4
XY-Wing: 3/6/4 in r18c1,r7c3 => r13c3,r9c1<>4
Naked Single: r1c3=2
Naked Single: r3c3=9
Naked Single: r4c3=7
Naked Single: r4c5=3
Full House: r6c6=7
Naked Single: r6c3=6
Full House: r7c3=4
Full House: r7c9=6
Naked Single: r6c1=1
Full House: r4c2=9
Naked Single: r9c2=3
Naked Single: r8c1=6
Full House: r9c1=9
Naked Single: r8c4=2
Naked Single: r3c4=4
Naked Single: r9c5=7
Full House: r9c4=6
Full House: r1c4=7
Naked Single: r3c1=3
Full House: r1c1=4
Bivalue Universal Grave + 1 => r2c9<>2, r2c9<>3
Naked Single: r2c9=1
Naked Single: r1c8=3
Full House: r3c7=2
Full House: r1c6=1
Full House: r2c6=3
Naked Single: r2c2=5
Full House: r2c5=2
Full House: r3c5=5
Full House: r3c2=1
Naked Single: r4c9=4
Full House: r4c8=1
Naked Single: r8c9=3
Full House: r9c9=2
Full House: r8c7=1
Full House: r6c7=3
Full House: r6c8=2
Full House: r9c8=4
|
normal_sudoku_2510
|
...7......2..9...8.....314...9..5.34...97.5..5..34.91.1....74....6.89.2..9.6..8..
|
914758263623491758857263149279815634431976582568342917182537496746189325395624871
|
Basic 9x9 Sudoku 2510
|
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 . . . . .
. 2 . . 9 . . . 8
. . . . . 3 1 4 .
. . 9 . . 5 . 3 4
. . . 9 7 . 5 . .
5 . . 3 4 . 9 1 .
1 . . . . 7 4 . .
. . 6 . 8 9 . 2 .
. 9 . 6 . . 8 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
914758263623491758857263149279815634431976582568342917182537496746189325395624871 #1 Extreme (16782) bf
Brute Force: r5c4=9
Hidden Single: r8c6=9
Hidden Pair: 6,9 in r7c89 => r7c89<>5, r7c8<>8, r7c9<>3
Locked Candidates Type 1 (Pointing): 8 in b9 => r9c13<>8
Discontinuous Nice Loop: 2 r6c7 -2- r5c9 -6- r7c9 -9- r6c9 =9= r6c7 => r6c7<>2
Empty Rectangle: 2 in b5 (r14c7) => r1c6<>2
Discontinuous Nice Loop: 6/7/8 r6c7 =9= r6c9 -9- r7c9 -6- r5c9 -2- r4c7 =2= r1c7 =9= r6c7 => r6c7<>6, r6c7<>7, r6c7<>8
Naked Single: r6c7=9
Finned Swordfish: 8 r167 c236 fr1c1 => r3c23<>8
Forcing Chain Contradiction in c1 => r4c5<>2
r4c5=2 r4c1<>2
r4c5=2 r13c5<>2 r3c4=2 r3c4<>8 r3c1=8 r3c1<>9 r3c9=9 r7c9<>9 r7c9=6 r5c9<>6 r5c9=2 r5c1<>2
r4c5=2 r56c6<>2 r9c6=2 r9c1<>2
Forcing Chain Verity => r5c2<>8
r5c6=2 r5c9<>2 r5c9=6 r5c8<>6 r5c8=8 r5c2<>8
r6c6=2 r6c6<>8 r6c23=8 r5c2<>8
r9c6=2 r7c45<>2 r7c3=2 r7c3<>8 r7c2=8 r5c2<>8
Forcing Net Verity => r5c8=8
r9c7=3 (r8c7<>3 r8c7=7 r9c8<>7 r2c8=7 r2c8<>5 r1c8=5 r1c5<>5) (r9c5<>3 r7c5=3 r7c5<>5) r9c7<>8 (r9c8=8 r9c8<>5) r4c7=8 (r4c4<>8 r3c4=8 r3c4<>2) r4c7<>2 r1c7=2 r3c9<>2 r3c5=2 r3c5<>5 r9c5=5 (r8c4<>5 r2c4=5 r7c4<>5 r7c4=2 r4c4<>2) r9c9<>5 r8c9=5 r8c9<>1 r8c4=1 r4c4<>1 r4c4=8 r4c7<>8 r9c7=8 r9c8<>8 r5c8=8
r9c7=7 (r8c7<>7 r8c7=3 r9c9<>3 r1c9=3 r1c9<>9) (r9c8<>7 r2c8=7 r2c8<>5) r9c7<>8 r9c8=8 r9c8<>5 r1c8=5 r1c8<>9 r1c1=9 r1c1<>8 r5c1=8 (r6c3<>8 r6c6=8 r6c6<>2) (r6c3<>8) r3c1<>8 r3c4=8 (r3c1<>8) r4c4<>8 r4c7=8 (r4c1<>8) (r4c2<>8) (r4c1<>8) r4c7<>7 r6c9=7 r6c3<>7 r6c3=2 (r4c1<>2) r5c1<>2 r9c1=2 r9c6<>2 r5c6=2 r5c9<>2 r5c9=6 r5c8<>6 r5c8=8
r9c7=8 r9c8<>8 r5c8=8
Hidden Single: r9c7=8
Forcing Chain Verity => r5c3<>2
r5c6=2 r5c3<>2
r6c6=2 r6c6<>8 r1c6=8 r3c4<>8 r3c1=8 r3c1<>9 r3c9=9 r7c9<>9 r7c9=6 r5c9<>6 r5c9=2 r5c3<>2
r9c6=2 r9c1<>2 r45c1=2 r5c3<>2
Forcing Chain Contradiction in r5c6 => r6c6<>6
r6c6=6 r4c5<>6 r4c5=1 r5c6<>1
r6c6=6 r6c6<>8 r1c6=8 r3c4<>8 r3c1=8 r3c1<>9 r3c9=9 r7c9<>9 r7c9=6 r5c9<>6 r5c9=2 r5c6<>2
r6c6=6 r5c6<>6
Discontinuous Nice Loop: 8 r6c2 -8- r6c6 =8= r1c6 -8- r3c4 =8= r3c1 =9= r3c9 -9- r7c9 -6- r6c9 =6= r6c2 => r6c2<>8
Almost Locked Set Chain: 7- r3c23 {567} -6- r6c2 {67} -7- r6c369 {2678} -6- r7c23459 {235689} -9- r7c8 {69} -6- r129c8 {5679} -9- r1c123,r2c13,r3c23 {13456789} -7 => r3c1<>7
Almost Locked Set Chain: 5- r3c23 {567} -6- r6c2 {67} -7- r6c369 {2678} -6- r7c23459 {235689} -9- r7c8 {69} -6- r129c8 {5679} -9- r1c123,r2c13,r3c23 {13456789} -8- r1c56,r2c46,r3c5 {124568} -5 => r3c4<>5
Grouped Discontinuous Nice Loop: 5 r9c5 -5- r9c89 =5= r8c9 =1= r8c4 =4= r2c4 =5= r78c4 -5- r9c5 => r9c5<>5
Forcing Chain Contradiction in r3 => r1c7=2
r1c7<>2 r4c7=2 r4c7<>6 r56c9=6 r7c9<>6 r7c9=9 r3c9<>9 r3c1=9 r3c1<>6
r1c7<>2 r4c7=2 r4c7<>7 r6c9=7 r6c9<>6 r6c2=6 r3c2<>6
r1c7<>2 r4c7=2 r5c9<>2 r5c9=6 r5c6<>6 r4c5=6 r3c5<>6
r1c7<>2 r4c7=2 r4c7<>6 r12c7=6 r3c9<>6
Turbot Fish: 6 r2c7 =6= r4c7 -6- r4c5 =6= r5c6 => r2c6<>6
Finned Swordfish: 2 r347 c145 fr7c3 => r9c1<>2
Locked Candidates Type 1 (Pointing): 2 in b7 => r6c3<>2
Continuous Nice Loop: 1/4/6 8= r1c6 =6= r5c6 -6- r5c9 -2- r6c9 =2= r6c6 =8= r1c6 =6 => r1c6<>1, r1c6<>4, r5c12<>6
Locked Candidates Type 1 (Pointing): 4 in b2 => r2c13<>4
Continuous Nice Loop: 6/9 9= r3c1 =8= r3c4 -8- r1c6 -6- r5c6 =6= r5c9 -6- r7c9 -9- r3c9 =9= r3c1 =8 => r16c9,r3c1<>6, r1c9<>9
Hidden Single: r6c2=6
Locked Pair: 5,7 in r3c23 => r1c23,r2c3,r3c59<>5, r2c13,r3c9<>7
Naked Pair: 6,9 in r37c9 => r5c9<>6
Naked Single: r5c9=2
Naked Single: r6c9=7
Full House: r4c7=6
Naked Single: r6c3=8
Full House: r6c6=2
Naked Single: r4c5=1
Naked Single: r4c2=7
Naked Single: r4c4=8
Full House: r5c6=6
Full House: r4c1=2
Naked Single: r3c2=5
Naked Single: r3c4=2
Naked Single: r1c6=8
Naked Single: r3c3=7
Naked Single: r3c5=6
Naked Single: r7c4=5
Naked Single: r1c5=5
Naked Single: r3c9=9
Full House: r3c1=8
Naked Single: r1c9=3
Naked Single: r1c8=6
Naked Single: r7c9=6
Naked Single: r2c7=7
Full House: r2c8=5
Full House: r8c7=3
Naked Single: r7c8=9
Full House: r9c8=7
Naked Single: r8c2=4
Naked Single: r1c2=1
Naked Single: r8c1=7
Naked Single: r8c4=1
Full House: r2c4=4
Full House: r8c9=5
Full House: r2c6=1
Full House: r9c6=4
Full House: r9c9=1
Naked Single: r9c1=3
Naked Single: r1c3=4
Full House: r1c1=9
Naked Single: r2c3=3
Full House: r2c1=6
Full House: r5c1=4
Naked Single: r5c2=3
Full House: r7c2=8
Full House: r5c3=1
Naked Single: r7c3=2
Full House: r7c5=3
Full House: r9c5=2
Full House: r9c3=5
|
normal_sudoku_2743
|
.82.45691..192837595..16....95..4..3.48..9..6.73...9...26....34.1..6..29.......67
|
382745691461928375957316482695874213148239756273651948826197534714563829539482167
|
Basic 9x9 Sudoku 2743
|
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 2 . 4 5 6 9 1
. . 1 9 2 8 3 7 5
9 5 . . 1 6 . . .
. 9 5 . . 4 . . 3
. 4 8 . . 9 . . 6
. 7 3 . . . 9 . .
. 2 6 . . . . 3 4
. 1 . . 6 . . 2 9
. . . . . . . 6 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
382745691461928375957316482695874213148239756273651948826197534714563829539482167 #1 Easy (314)
Naked Single: r2c5=2
Naked Single: r1c9=1
Naked Single: r1c7=6
Naked Single: r2c9=5
Naked Single: r1c8=9
Hidden Single: r4c2=9
Hidden Single: r4c9=3
Hidden Single: r2c3=1
Hidden Single: r9c8=6
Hidden Single: r3c2=5
Hidden Single: r9c9=7
Hidden Single: r7c3=6
Naked Single: r7c2=2
Naked Single: r5c2=4
Naked Single: r2c2=6
Full House: r9c2=3
Full House: r2c1=4
Naked Single: r3c3=7
Full House: r1c1=3
Full House: r1c4=7
Full House: r3c4=3
Naked Single: r8c3=4
Full House: r9c3=9
Hidden Single: r7c5=9
Hidden Single: r3c7=4
Naked Single: r3c8=8
Full House: r3c9=2
Full House: r6c9=8
Naked Single: r4c8=1
Naked Single: r6c5=5
Naked Single: r5c8=5
Full House: r6c8=4
Naked Single: r9c5=8
Naked Single: r4c5=7
Full House: r5c5=3
Naked Single: r8c4=5
Naked Single: r9c1=5
Naked Single: r4c7=2
Full House: r5c7=7
Naked Single: r7c4=1
Naked Single: r8c7=8
Naked Single: r9c7=1
Full House: r7c7=5
Naked Single: r4c1=6
Full House: r4c4=8
Naked Single: r5c4=2
Full House: r5c1=1
Full House: r6c1=2
Naked Single: r7c6=7
Full House: r7c1=8
Full House: r8c1=7
Full House: r8c6=3
Naked Single: r9c6=2
Full House: r6c6=1
Full House: r6c4=6
Full House: r9c4=4
|
normal_sudoku_3338
|
..3.92176...8.72...7...358.3.9..4....6.3254972.79863.1..62.97.57...68923.....1...
|
583492176691857234472613589359174862168325497247986351836249715714568923925731648
|
Basic 9x9 Sudoku 3338
|
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 . 9 2 1 7 6
. . . 8 . 7 2 . .
. 7 . . . 3 5 8 .
3 . 9 . . 4 . . .
. 6 . 3 2 5 4 9 7
2 . 7 9 8 6 3 . 1
. . 6 2 . 9 7 . 5
7 . . . 6 8 9 2 3
. . . . . 1 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
583492176691857234472613589359174862168325497247986351836249715714568923925731648 #1 Easy (234)
Naked Single: r1c6=2
Naked Single: r8c6=8
Naked Single: r1c7=1
Naked Single: r8c7=9
Naked Single: r2c7=2
Hidden Single: r5c4=3
Hidden Single: r6c3=7
Naked Single: r6c5=8
Naked Single: r6c6=6
Naked Single: r3c6=3
Full House: r2c6=7
Naked Single: r6c4=9
Naked Single: r6c8=5
Full House: r6c2=4
Naked Single: r4c8=6
Naked Single: r4c7=8
Full House: r4c9=2
Full House: r9c7=6
Naked Single: r9c8=4
Naked Single: r2c8=3
Full House: r7c8=1
Full House: r9c9=8
Hidden Single: r9c2=2
Naked Single: r9c3=5
Naked Single: r8c2=1
Naked Single: r9c1=9
Naked Single: r9c4=7
Full House: r9c5=3
Naked Single: r4c2=5
Naked Single: r8c3=4
Full House: r8c4=5
Full House: r7c5=4
Naked Single: r4c4=1
Full House: r4c5=7
Naked Single: r1c2=8
Naked Single: r2c2=9
Full House: r7c2=3
Full House: r7c1=8
Naked Single: r2c3=1
Naked Single: r1c4=4
Full House: r1c1=5
Full House: r3c4=6
Naked Single: r3c5=1
Full House: r2c5=5
Naked Single: r2c9=4
Full House: r2c1=6
Full House: r3c9=9
Naked Single: r5c1=1
Full House: r5c3=8
Full House: r3c3=2
Full House: r3c1=4
|
normal_sudoku_6894
|
.46.832.118.2...362.316.......31.......65.3.73.......5.348.6...62..31.8.8.142.6.3
|
746983251185247936293165748579312864412658397368794125934876512627531489851429673
|
Basic 9x9 Sudoku 6894
|
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 . 8 3 2 . 1
1 8 . 2 . . . 3 6
2 . 3 1 6 . . . .
. . . 3 1 . . . .
. . . 6 5 . 3 . 7
3 . . . . . . . 5
. 3 4 8 . 6 . . .
6 2 . . 3 1 . 8 .
8 . 1 4 2 . 6 . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
746983251185247936293165748579312864412658397368794125934876512627531489851429673 #1 Extreme (28444) bf
Hidden Single: r6c1=3
Hidden Single: r3c1=2
Hidden Single: r3c4=1
Hidden Single: r1c5=8
Hidden Single: r2c1=1
Hidden Single: r9c1=8
Hidden Single: r8c5=3
Hidden Single: r8c1=6
Hidden Single: r2c8=3
Hidden Single: r2c9=6
Brute Force: r5c4=6
Brute Force: r5c5=5
Finned Franken Swordfish: 5 r17b8 c148 fr7c7 fr9c6 => r9c8<>5
Forcing Net Contradiction in r7c7 => r7c9=2
r7c9<>2 r7c9=9 (r9c8<>9 r9c8=7 r1c8<>7) (r9c8<>9 r9c8=7 r9c2<>7) (r7c1<>9) r7c5<>9 r7c5=7 r7c1<>7 r7c1=5 r9c2<>5 r9c2=9 (r3c2<>9) r9c2<>5 r9c6=5 r8c4<>5 r1c4=5 r1c4<>7 r1c1=7 r3c2<>7 r3c2=5 (r3c8<>5) (r2c3<>5) r9c2<>5 r9c6=5 r2c6<>5 r2c7=5 r1c8<>5 r7c8=5 r7c8<>2 r7c9=2
Forcing Net Verity => r3c2<>5
r9c2=5 r3c2<>5
r9c2=7 (r7c1<>7) (r9c8<>7 r9c8=9 r1c8<>9) r9c2<>5 r9c6=5 r8c4<>5 r1c4=5 r1c4<>9 r1c1=9 r7c1<>9 r7c1=5 (r4c1<>5) (r7c8<>5 r8c7=5 r2c7<>5) r9c2<>5 r9c6=5 r2c6<>5 r2c3=5 r4c3<>5 r4c2=5 r3c2<>5
r9c2=9 (r7c1<>9) (r9c8<>9 r9c8=7 r1c8<>7) r9c2<>5 r9c6=5 r8c4<>5 r1c4=5 r1c4<>7 r1c1=7 r7c1<>7 r7c1=5 (r4c1<>5) (r7c8<>5 r8c7=5 r2c7<>5) r9c2<>5 r9c6=5 r2c6<>5 r2c3=5 r4c3<>5 r4c2=5 r3c2<>5
Turbot Fish: 5 r2c3 =5= r1c1 -5- r1c4 =5= r8c4 => r8c3<>5
Forcing Chain Contradiction in r1 => r9c2<>7
r9c2=7 r3c2<>7 r3c2=9 r1c1<>9
r9c2=7 r9c2<>5 r9c6=5 r8c4<>5 r1c4=5 r1c4<>9
r9c2=7 r9c8<>7 r9c8=9 r1c8<>9
Discontinuous Nice Loop: 7 r8c4 -7- r8c3 -9- r9c2 -5- r9c6 =5= r8c4 => r8c4<>7
Grouped Discontinuous Nice Loop: 7 r6c3 -7- r8c3 =7= r8c7 -7- r9c8 =7= r9c6 -7- r4c6 =7= r4c123 -7- r6c3 => r6c3<>7
Almost Locked Set XZ-Rule: A=r7c15 {579}, B=r9c28 {579}, X=5, Z=7 => r7c78<>7
Finned Franken Swordfish: 7 c14b8 r147 fr6c4 fr9c6 => r4c6<>7
Locked Candidates Type 1 (Pointing): 7 in b5 => r6c2<>7
Forcing Chain Contradiction in r1 => r8c4=5
r8c4<>5 r9c6=5 r9c2<>5 r9c2=9 r3c2<>9 r3c2=7 r1c1<>7
r8c4<>5 r1c4=5 r1c4<>7
r8c4<>5 r8c7=5 r8c7<>7 r9c8=7 r1c8<>7
Hidden Single: r9c2=5
Naked Pair: 7,9 in r7c15 => r7c78<>9
Empty Rectangle: 9 in b5 (r9c68) => r6c8<>9
Grouped Discontinuous Nice Loop: 8 r4c3 -8- r4c79 =8= r6c7 =1= r7c7 =5= r7c8 -5- r1c8 =5= r1c1 -5- r4c1 =5= r4c3 => r4c3<>8
Finned Franken Swordfish: 9 r89b5 c36b9 fr6c4 fr6c5 => r6c3<>9
Finned Franken Swordfish: 9 c29b7 r348 fr5c2 fr6c2 fr7c1 => r4c1<>9
Finned Franken Swordfish: 9 c14b8 r157 fr6c4 fr9c6 => r5c6<>9
Grouped Discontinuous Nice Loop: 9 r6c2 -9- r5c123 =9= r5c8 -9- r9c8 =9= r9c6 -9- r4c6 =9= r6c456 -9- r6c2 => r6c2<>9
Almost Locked Set XY-Wing: A=r135679c8 {1245679}, B=r4c79,r6c7 {1489}, C=r6c2 {16}, X,Y=1,6, Z=4,9 => r4c8<>4, r4c8<>9
Forcing Chain Verity => r1c1<>9
r1c8=7 r1c8<>5 r1c1=5 r1c1<>9
r3c8=7 r3c2<>7 r3c2=9 r1c1<>9
r9c8=7 r9c8<>9 r9c6=9 r7c5<>9 r7c1=9 r1c1<>9
Skyscraper: 9 in r1c4,r9c6 (connected by r19c8) => r23c6<>9
W-Wing: 7/9 in r6c4,r7c5 connected by 9 in r1c4,r2c5 => r6c5<>7
Turbot Fish: 7 r2c5 =7= r7c5 -7- r7c1 =7= r8c3 => r2c3<>7
W-Wing: 4/9 in r5c1,r6c5 connected by 9 in r7c15 => r5c6<>4
XY-Wing: 5/7/9 in r1c14,r2c3 => r2c5<>9
Hidden Single: r1c4=9
Full House: r6c4=7
W-Wing: 9/7 in r3c2,r9c8 connected by 7 in r1c18 => r3c8<>9
XY-Wing: 5/7/9 in r17c1,r2c3 => r8c3<>9
Naked Single: r8c3=7
Full House: r7c1=9
Naked Single: r5c1=4
Naked Single: r7c5=7
Full House: r9c6=9
Full House: r9c8=7
Naked Single: r2c5=4
Full House: r6c5=9
Naked Single: r1c8=5
Full House: r1c1=7
Full House: r4c1=5
Naked Single: r3c8=4
Naked Single: r7c8=1
Full House: r7c7=5
Naked Single: r3c2=9
Full House: r2c3=5
Naked Single: r3c9=8
Naked Single: r5c2=1
Naked Single: r2c6=7
Full House: r2c7=9
Full House: r3c7=7
Full House: r3c6=5
Naked Single: r6c2=6
Full House: r4c2=7
Naked Single: r8c7=4
Full House: r8c9=9
Full House: r4c9=4
Naked Single: r6c8=2
Naked Single: r4c7=8
Full House: r6c7=1
Naked Single: r4c8=6
Full House: r5c8=9
Naked Single: r6c3=8
Full House: r6c6=4
Naked Single: r4c6=2
Full House: r4c3=9
Full House: r5c3=2
Full House: r5c6=8
|
normal_sudoku_199
|
....14..6.5.2...8.4....5..9.2.5...9...3.6...2......1..2.8.59.7.9657....837....9..
|
837914526659237481412685739126578394793461852584392167248159673965743218371826945
|
Basic 9x9 Sudoku 199
|
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 . 2 . . . 8 .
4 . . . . 5 . . 9
. 2 . 5 . . . 9 .
. . 3 . 6 . . . 2
. . . . . . 1 . .
2 . 8 . 5 9 . 7 .
9 6 5 7 . . . . 8
3 7 . . . . 9 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
837914526659237481412685739126578394793461852584392167248159673965743218371826945 #1 Extreme (7726)
Hidden Single: r8c1=9
Finned Swordfish: 6 r347 c347 fr4c1 => r6c3<>6
Discontinuous Nice Loop: 4 r6c8 -4- r5c8 -5- r5c1 =5= r6c1 =6= r6c8 => r6c8<>4
Almost Locked Set XY-Wing: A=r6c234569 {2345789}, B=r13589c8 {123456}, C=r9c34569 {124568}, X,Y=5,6, Z=3 => r6c8<>3
Grouped Discontinuous Nice Loop: 3 r1c4 -3- r7c4 =3= r7c79 -3- r8c8 =3= r13c8 -3- r2c79 =3= r2c56 -3- r1c4 => r1c4<>3
Grouped Discontinuous Nice Loop: 3 r3c4 -3- r7c4 =3= r7c79 -3- r8c8 =3= r13c8 -3- r2c79 =3= r2c56 -3- r3c4 => r3c4<>3
Discontinuous Nice Loop: 2 r9c6 -2- r6c6 =2= r6c5 =9= r2c5 -9- r1c4 -8- r3c4 -6- r2c6 =6= r9c6 => r9c6<>2
Grouped Discontinuous Nice Loop: 8 r5c2 -8- r3c2 =8= r1c12 -8- r1c4 -9- r5c4 =9= r5c2 => r5c2<>8
Grouped Discontinuous Nice Loop: 8 r5c4 -8- r3c4 -6- r2c6 =6= r9c6 =8= r456c6 -8- r5c4 => r5c4<>8
Grouped Discontinuous Nice Loop: 8 r6c4 -8- r3c4 -6- r2c6 =6= r9c6 =8= r456c6 -8- r6c4 => r6c4<>8
Grouped Discontinuous Nice Loop: 8 r6c5 -8- r456c6 =8= r9c6 =6= r2c6 -6- r3c4 -8- r1c4 -9- r2c5 =9= r6c5 => r6c5<>8
Almost Locked Set XZ-Rule: A=r1c4 {89}, B=r1c13,r2c13,r3c3 {126789}, X=8, Z=9 => r1c2<>9
Locked Candidates Type 1 (Pointing): 9 in b1 => r6c3<>9
Almost Locked Set XY-Wing: A=r7c129 {1234}, B=r123458c7 {2345678}, C=r46c9,r56c8 {34567}, X,Y=3,6, Z=2,4 => r7c7<>2, r7c7<>4
Hidden Single: r7c1=2
Discontinuous Nice Loop: 7 r2c3 -7- r1c1 -8- r1c4 -9- r1c3 =9= r2c3 => r2c3<>7
Grouped Discontinuous Nice Loop: 1 r5c2 -1- r5c4 =1= r79c4 -1- r8c6 =1= r8c8 -1- r3c8 =1= r2c9 -1- r2c1 =1= r45c1 -1- r5c2 => r5c2<>1
Turbot Fish: 1 r2c9 =1= r3c8 -1- r3c2 =1= r7c2 => r7c9<>1
AIC: 4 4- r2c7 =4= r2c9 =1= r9c9 =5= r9c8 -5- r5c8 -4 => r45c7<>4
Grouped Discontinuous Nice Loop: 3 r2c7 -3- r4c7 =3= r46c9 -3- r7c9 -4- r2c9 =4= r2c7 => r2c7<>3
Grouped Discontinuous Nice Loop: 7 r3c3 -7- r6c3 -4- r9c3 =4= r7c2 -4- r7c9 -3- r46c9 =3= r4c7 =8= r5c7 =5= r1c7 =7= r1c13 -7- r3c3 => r3c3<>7
Grouped Discontinuous Nice Loop: 7 r6c5 -7- r6c3 -4- r9c3 -1- r7c2 =1= r3c2 =8= r1c12 -8- r1c4 -9- r2c5 =9= r6c5 => r6c5<>7
Grouped Discontinuous Nice Loop: 7 r6c6 -7- r6c3 -4- r9c3 -1- r7c2 =1= r3c2 =8= r1c12 -8- r1c4 -9- r2c5 =9= r6c5 =2= r6c6 => r6c6<>7
Finned Franken Swordfish: 4 r48b7 c359 fr7c2 fr8c7 fr8c8 => r7c9<>4
Naked Single: r7c9=3
Naked Single: r7c7=6
Hidden Single: r4c7=3
Hidden Single: r6c4=3
Hidden Single: r6c8=6
Hidden Single: r5c7=8
Hidden Single: r1c7=5
Locked Candidates Type 1 (Pointing): 7 in b6 => r2c9<>7
Locked Candidates Type 2 (Claiming): 7 in r1 => r2c1<>7
Locked Candidates Type 2 (Claiming): 3 in r2 => r3c5<>3
Sue de Coq: r45c1 - {15678} (r2c1 - {16}, r56c2,r6c13 - {45789}) => r4c3<>4, r4c3<>7
Sashimi X-Wing: 4 r48 c59 fr8c7 fr8c8 => r9c9<>4
XY-Chain: 8 8- r1c2 -3- r1c8 -2- r3c7 -7- r3c5 -8 => r1c4,r3c2<>8
Naked Single: r1c4=9
Hidden Single: r2c3=9
Hidden Single: r6c5=9
Hidden Single: r5c2=9
Hidden Single: r6c6=2
Locked Candidates Type 1 (Pointing): 4 in b4 => r6c9<>4
Locked Candidates Type 1 (Pointing): 8 in b5 => r4c1<>8
Naked Pair: 1,4 in r57c4 => r9c4<>1, r9c4<>4
XY-Chain: 3 3- r2c5 -7- r2c7 -4- r2c9 -1- r9c9 -5- r6c9 -7- r6c3 -4- r9c3 -1- r7c2 -4- r7c4 -1- r8c6 -3 => r2c6,r8c5<>3
Hidden Single: r2c5=3
Hidden Single: r8c6=3
Hidden Single: r8c8=1
Naked Single: r9c9=5
Naked Single: r6c9=7
Naked Single: r4c9=4
Full House: r2c9=1
Full House: r5c8=5
Naked Single: r6c3=4
Naked Single: r2c1=6
Naked Single: r6c2=8
Full House: r6c1=5
Naked Single: r9c3=1
Full House: r7c2=4
Full House: r7c4=1
Naked Single: r2c6=7
Full House: r2c7=4
Naked Single: r1c2=3
Full House: r3c2=1
Naked Single: r3c3=2
Naked Single: r4c3=6
Full House: r1c3=7
Full House: r1c1=8
Full House: r1c8=2
Naked Single: r5c4=4
Naked Single: r3c5=8
Full House: r3c4=6
Full House: r9c4=8
Naked Single: r5c6=1
Full House: r5c1=7
Full House: r4c1=1
Naked Single: r8c7=2
Full House: r3c7=7
Full House: r3c8=3
Full House: r9c8=4
Full House: r8c5=4
Naked Single: r4c5=7
Full House: r4c6=8
Full House: r9c6=6
Full House: r9c5=2
|
normal_sudoku_1632
|
.81....7....8.91...5.........29854315483217969134672..2.5.7...98....3..71...9...4
|
381546972726839145459712863672985431548321796913467258265174389894253617137698524
|
Basic 9x9 Sudoku 1632
|
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 1 . . . . 7 .
. . . 8 . 9 1 . .
. 5 . . . . . . .
. . 2 9 8 5 4 3 1
5 4 8 3 2 1 7 9 6
9 1 3 4 6 7 2 . .
2 . 5 . 7 . . . 9
8 . . . . 3 . . 7
1 . . . 9 . . . 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
381546972726839145459712863672985431548321796913467258265174389894253617137698524 #1 Easy (346)
Naked Single: r6c5=6
Naked Single: r6c6=7
Naked Single: r5c6=1
Naked Single: r6c1=9
Naked Single: r4c4=9
Full House: r5c4=3
Naked Single: r5c9=6
Naked Single: r4c9=1
Naked Single: r5c8=9
Naked Single: r5c7=7
Full House: r5c2=4
Hidden Single: r1c2=8
Hidden Single: r9c1=1
Hidden Single: r3c4=7
Hidden Single: r7c6=4
Hidden Single: r8c3=4
Hidden Single: r2c2=2
Hidden Single: r1c7=9
Hidden Single: r8c2=9
Hidden Single: r3c3=9
Hidden Single: r3c5=1
Naked Single: r8c5=5
Naked Single: r8c7=6
Hidden Single: r9c6=8
Hidden Single: r1c4=5
Hidden Single: r9c7=5
Naked Single: r9c8=2
Naked Single: r8c8=1
Full House: r8c4=2
Naked Single: r9c4=6
Full House: r7c4=1
Naked Single: r7c8=8
Full House: r7c7=3
Full House: r3c7=8
Full House: r7c2=6
Naked Single: r9c3=7
Full House: r2c3=6
Full House: r9c2=3
Full House: r4c2=7
Full House: r4c1=6
Naked Single: r6c8=5
Full House: r6c9=8
Naked Single: r2c8=4
Full House: r3c8=6
Naked Single: r2c5=3
Full House: r1c5=4
Naked Single: r3c6=2
Full House: r1c6=6
Naked Single: r2c1=7
Full House: r2c9=5
Naked Single: r1c1=3
Full House: r1c9=2
Full House: r3c9=3
Full House: r3c1=4
|
normal_sudoku_2100
|
785...6.3426.73..89135...4.8.74.....2.4..98..159....3..923......71...38.348..192.
|
785214693426973518913586247837425169264139875159867432692348751571692384348751926
|
Basic 9x9 Sudoku 2100
|
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.
|
7 8 5 . . . 6 . 3
4 2 6 . 7 3 . . 8
9 1 3 5 . . . 4 .
8 . 7 4 . . . . .
2 . 4 . . 9 8 . .
1 5 9 . . . . 3 .
. 9 2 3 . . . . .
. 7 1 . . . 3 8 .
3 4 8 . . 1 9 2 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
785214693426973518913586247837425169264139875159867432692348751571692384348751926 #1 Hard (1340)
Naked Single: r1c3=5
Naked Single: r2c3=6
Naked Single: r2c2=2
Naked Single: r3c3=3
Full House: r3c1=9
Naked Single: r4c3=7
Naked Single: r5c3=4
Full House: r8c3=1
Hidden Single: r4c1=8
Hidden Single: r8c7=3
Hidden Single: r9c2=4
Hidden Single: r5c1=2
Hidden Single: r9c1=3
Locked Candidates Type 1 (Pointing): 2 in b3 => r3c56<>2
Locked Pair: 6,8 in r3c56 => r2c4,r3c9<>8
Hidden Single: r2c9=8
Hidden Single: r6c4=8
Hidden Single: r4c9=9
Skyscraper: 7 in r7c8,r9c4 (connected by r5c48) => r7c6,r9c9<>7
Hidden Single: r6c6=7
Hidden Single: r9c4=7
X-Wing: 6 r69 c59 => r34578c5,r578c9<>6
Naked Single: r3c5=8
Naked Single: r3c6=6
Hidden Single: r7c6=8
W-Wing: 5/6 in r7c1,r9c5 connected by 6 in r8c14 => r7c5<>5
Naked Single: r7c5=4
Hidden Single: r1c6=4
Hidden Single: r6c7=4
Hidden Single: r8c9=4
XY-Wing: 2/6/5 in r4c6,r69c5 => r45c5,r8c6<>5
Naked Single: r8c6=2
Full House: r4c6=5
Hidden Single: r1c4=2
Naked Triple: 1,2,6 in r4c78,r6c9 => r5c89<>1, r5c8<>6
Hidden Single: r7c9=1
Locked Candidates Type 1 (Pointing): 1 in b6 => r4c5<>1
W-Wing: 7/5 in r5c8,r7c7 connected by 5 in r2c78 => r7c8<>7
Hidden Single: r7c7=7
Naked Single: r3c7=2
Full House: r3c9=7
Naked Single: r4c7=1
Full House: r2c7=5
Naked Single: r5c9=5
Naked Single: r4c8=6
Naked Single: r5c8=7
Full House: r6c9=2
Full House: r9c9=6
Full House: r7c8=5
Full House: r6c5=6
Full House: r9c5=5
Full House: r7c1=6
Full House: r8c1=5
Naked Single: r4c2=3
Full House: r4c5=2
Full House: r5c2=6
Naked Single: r5c4=1
Full House: r5c5=3
Naked Single: r8c5=9
Full House: r1c5=1
Full House: r2c4=9
Full House: r8c4=6
Full House: r1c8=9
Full House: r2c8=1
|
normal_sudoku_1041
|
.4.....8.7..5.8..2832.4....37...2...68...52.3.2.3.6.7...8...75...389712.217654938
|
145269387796538412832741695379482561681975243524316879968123754453897126217654938
|
Basic 9x9 Sudoku 1041
|
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 . . . . . 8 .
7 . . 5 . 8 . . 2
8 3 2 . 4 . . . .
3 7 . . . 2 . . .
6 8 . . . 5 2 . 3
. 2 . 3 . 6 . 7 .
. . 8 . . . 7 5 .
. . 3 8 9 7 1 2 .
2 1 7 6 5 4 9 3 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
145269387796538412832741695379482561681975243524316879968123754453897126217654938 #1 Medium (540)
Hidden Single: r3c1=8
Hidden Single: r4c1=3
Hidden Single: r9c3=7
Hidden Single: r9c5=5
Hidden Single: r8c6=7
Hidden Single: r9c8=3
Naked Single: r9c6=4
Naked Single: r9c1=2
Naked Single: r9c4=6
Full House: r9c9=8
Hidden Single: r7c3=8
Hidden Single: r8c8=2
Hidden Single: r6c2=2
Hidden Single: r5c7=2
Hidden Single: r8c2=5
Naked Single: r8c1=4
Full House: r8c9=6
Full House: r7c9=4
Naked Single: r7c1=9
Full House: r7c2=6
Full House: r2c2=9
Locked Pair: 1,8 in r46c5 => r1257c5,r45c4<>1
Naked Single: r5c5=7
Locked Candidates Type 1 (Pointing): 5 in b1 => r1c79<>5
Locked Candidates Type 1 (Pointing): 9 in b5 => r13c4<>9
Locked Candidates Type 2 (Claiming): 6 in r3 => r12c7,r2c8<>6
Naked Single: r1c7=3
Naked Single: r2c7=4
Naked Single: r2c8=1
Naked Single: r2c3=6
Full House: r2c5=3
Naked Single: r7c5=2
Naked Single: r1c5=6
Naked Single: r7c4=1
Full House: r7c6=3
Naked Single: r3c4=7
Naked Single: r1c4=2
Hidden Single: r6c3=4
Hidden Single: r5c3=1
Naked Single: r1c3=5
Full House: r1c1=1
Full House: r6c1=5
Full House: r4c3=9
Naked Single: r1c6=9
Full House: r1c9=7
Full House: r3c6=1
Naked Single: r6c7=8
Naked Single: r4c4=4
Full House: r5c4=9
Full House: r5c8=4
Naked Single: r6c5=1
Full House: r4c5=8
Full House: r6c9=9
Naked Single: r4c8=6
Full House: r3c8=9
Naked Single: r3c9=5
Full House: r3c7=6
Full House: r4c7=5
Full House: r4c9=1
|
normal_sudoku_1146
|
5432..76..9.53.4.28126.4.3....4.6.2..257.........2..74..4.6..5.35...2146.6..45.97
|
543219768796538412812674935178456329425793681639821574984167253357982146261345897
|
Basic 9x9 Sudoku 1146
|
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 4 3 2 . . 7 6 .
. 9 . 5 3 . 4 . 2
8 1 2 6 . 4 . 3 .
. . . 4 . 6 . 2 .
. 2 5 7 . . . . .
. . . . 2 . . 7 4
. . 4 . 6 . . 5 .
3 5 . . . 2 1 4 6
. 6 . . 4 5 . 9 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
543219768796538412812674935178456329425793681639821574984167253357982146261345897 #1 Easy (396)
Naked Single: r1c2=4
Hidden Single: r3c3=2
Hidden Single: r8c2=5
Hidden Single: r8c8=4
Hidden Single: r2c4=5
Hidden Single: r4c8=2
Hidden Single: r8c9=6
Hidden Single: r3c4=6
Naked Single: r3c8=3
Hidden Single: r6c5=2
Hidden Single: r1c8=6
Hidden Single: r3c6=4
Hidden Single: r4c4=4
Hidden Single: r6c7=5
Naked Single: r3c7=9
Naked Single: r3c5=7
Full House: r3c9=5
Hidden Single: r4c5=5
Hidden Single: r5c1=4
Hidden Single: r5c7=6
Hidden Single: r7c6=7
Naked Single: r7c2=8
Naked Single: r6c2=3
Full House: r4c2=7
Naked Single: r7c9=3
Naked Single: r9c3=1
Naked Single: r7c7=2
Full House: r9c7=8
Full House: r4c7=3
Naked Single: r9c1=2
Full House: r9c4=3
Naked Single: r7c1=9
Full House: r7c4=1
Full House: r8c3=7
Naked Single: r4c1=1
Naked Single: r2c3=6
Full House: r2c1=7
Full House: r6c1=6
Hidden Single: r5c6=3
Hidden Single: r6c6=1
Naked Single: r2c6=8
Full House: r1c6=9
Full House: r2c8=1
Full House: r1c5=1
Full House: r1c9=8
Full House: r5c8=8
Naked Single: r4c9=9
Full House: r4c3=8
Full House: r5c9=1
Full House: r5c5=9
Full House: r6c3=9
Full House: r6c4=8
Full House: r8c5=8
Full House: r8c4=9
|
normal_sudoku_5224
|
..7..8..45...3.....2.....5.7..9..3....23.1..6.9.8...1.2...1...7.7...64....4.8..6.
|
937658124546132978128749653781965342452371896693824715269413587875296431314587269
|
Basic 9x9 Sudoku 5224
|
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 . . 4
5 . . . 3 . . . .
. 2 . . . . . 5 .
7 . . 9 . . 3 . .
. . 2 3 . 1 . . 6
. 9 . 8 . . . 1 .
2 . . . 1 . . . 7
. 7 . . . 6 4 . .
. . 4 . 8 . . 6 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
937658124546132978128749653781965342452371896693824715269413587875296431314587269 #1 Extreme (27970) bf
Brute Force: r5c4=3
Hidden Single: r6c4=8
Locked Candidates Type 1 (Pointing): 6 in b5 => r13c5<>6
Finned Swordfish: 3 r368 c139 fr8c8 => r9c9<>3
Forcing Net Contradiction in c5 => r2c4<>4
r2c4=4 (r3c5<>4) r7c4<>4 r7c4=5 (r8c5<>5) r8c4<>5 r8c4=2 r8c5<>2 r8c5=9 r3c5<>9 r3c5=7
r2c4=4 (r3c6<>4 r3c1=4 r6c1<>4) r7c4<>4 (r7c4=5 r1c4<>5 r1c5=5 r5c5<>5) r7c6=4 r6c6<>4 r6c5=4 r5c5<>4 r5c5=7
Forcing Net Contradiction in r7c7 => r2c4<>7
r2c4=7 r9c4<>7 r9c6=7 (r6c6<>7 r6c5=7 r6c5<>2) (r6c6<>7 r6c5=7 r6c5<>6 r4c5=6 r4c5<>2) (r9c6<>9) r9c6<>3 r7c6=3 r7c6<>9 r8c5=9 r8c5<>2 r1c5=2 r1c5<>5 r1c4=5 (r9c4<>5) r8c4<>5 r8c4=2 r9c4<>2 r9c4=7 r2c4<>7
Forcing Net Contradiction in c5 => r4c5<>4
r4c5=4 (r3c5<>4) r4c8<>4 r5c8=4 (r5c8<>7) r5c8<>9 r5c7=9 r5c7<>7 r5c5=7 r3c5<>7 r3c5=9
r4c5=4 (r4c8<>4 r5c8=4 r5c1<>4 r5c1=8 r5c2<>8 r5c2=5 r4c3<>5) (r4c8<>4 r5c8=4 r5c1<>4 r5c1=8 r4c2<>8) (r4c8<>4 r5c8=4 r5c1<>4 r5c1=8 r5c2<>8) (r4c2<>4) (r6c5<>4) r6c6<>4 r6c1=4 (r6c1<>3 r6c3=3 r6c3<>5) r5c2<>4 r2c2=4 r2c2<>8 r7c2=8 r7c2<>6 r7c3=6 r7c3<>5 r8c3=5 (r8c5<>5) r8c4<>5 r8c4=2 r8c5<>2 r8c5=9
Forcing Net Contradiction in c8 => r6c5<>5
r6c5=5 (r6c5<>2) (r6c5<>6 r4c5=6 r4c5<>2) r1c5<>5 r1c4=5 r8c4<>5 r8c4=2 r8c5<>2 r1c5=2 r1c8<>2
r6c5=5 (r6c7<>5) r6c9<>5 r6c9=2 r6c7<>2 r6c7=7 r5c8<>7 r2c8=7 r2c8<>2
r6c5=5 r6c9<>5 r6c9=2 r4c8<>2
r6c5=5 r1c5<>5 r1c4=5 r8c4<>5 r8c4=2 r8c8<>2
Forcing Net Contradiction in r1 => r8c9<>5
r8c9=5 (r8c9<>1) (r6c9<>5 r6c9=2 r9c9<>2) r8c4<>5 r8c4=2 (r8c5<>2 r8c5=9 r9c6<>9) (r9c4<>2) r9c6<>2 r9c7=2 (r9c7<>9) r9c7<>1 r9c9=1 r9c9<>9 r9c1=9 r1c1<>9
r8c9=5 (r8c5<>5) r8c4<>5 r8c4=2 r8c5<>2 r8c5=9 r1c5<>9
r8c9=5 (r6c9<>5 r6c9=2 r2c9<>2) (r6c9<>5 r6c9=2 r4c9<>2 r4c9=8 r2c9<>8) (r8c9<>1) (r6c9<>5 r6c9=2 r9c9<>2) r8c4<>5 r8c4=2 (r9c4<>2) r9c6<>2 r9c7=2 r9c7<>1 r9c9=1 r2c9<>1 r2c9=9 r1c7<>9
r8c9=5 (r6c9<>5 r6c9=2 r2c9<>2) (r6c9<>5 r6c9=2 r4c9<>2 r4c9=8 r2c9<>8) (r8c9<>1) (r6c9<>5 r6c9=2 r9c9<>2) r8c4<>5 r8c4=2 (r9c4<>2) r9c6<>2 r9c7=2 r9c7<>1 r9c9=1 r2c9<>1 r2c9=9 r1c8<>9
Forcing Chain Contradiction in r5 => r9c2<>5
r9c2=5 r5c2<>5
r9c2=5 r8c3<>5 r8c45=5 r79c6<>5 r46c6=5 r5c5<>5
r9c2=5 r9c9<>5 r79c7=5 r5c7<>5
Forcing Chain Contradiction in r1c2 => r4c3<>6
r4c3=6 r4c3<>1 r4c2=1 r1c2<>1
r4c3=6 r4c3<>1 r4c2=1 r9c2<>1 r9c2=3 r1c2<>3
r4c3=6 r7c3<>6 r7c2=6 r1c2<>6
Forcing Net Contradiction in r1 => r7c4=4
r7c4<>4 r7c6=4 r7c6<>3 r9c6=3 (r9c1<>3) r9c2<>3 r9c2=1 r9c1<>1 r9c1=9 r1c1<>9
r7c4<>4 r7c4=5 r1c4<>5 r1c5=5 r1c5<>9
r7c4<>4 (r7c4=5 r8c4<>5 r8c4=2 r8c5<>2 r8c5=9 r8c9<>9) r7c6=4 r7c6<>3 r9c6=3 r9c2<>3 r9c2=1 (r9c1<>1 r9c1=9 r9c9<>9) (r8c1<>1) r8c3<>1 r8c9=1 r8c9<>3 r3c9=3 r3c9<>9 r2c9=9 r1c7<>9
r7c4<>4 (r7c4=5 r1c4<>5 r1c5=5 r1c5<>2 r2c6=2 r2c8<>2) (r7c4=5 r8c4<>5 r8c4=2 r8c8<>2) r7c6=4 (r4c6<>4) r2c6<>4 r2c2=4 r4c2<>4 r4c8=4 r4c8<>2 r1c8=2 r1c8<>9
Forcing Net Contradiction in r1 => r2c2<>1
r2c2=1 (r2c2<>4 r2c6=4 r3c6<>4 r3c1=4 r3c1<>3) (r2c2<>4 r2c6=4 r3c6<>4 r3c1=4 r3c1<>6) (r1c2<>1) r9c2<>1 r9c2=3 (r8c1<>3) (r9c1<>3) r1c2<>3 r1c2=6 r1c1<>6 r6c1=6 r6c1<>3 r1c1=3 r1c1<>9
r2c2=1 (r2c2<>8) r2c2<>4 r2c6=4 (r3c5<>4) r3c6<>4 r3c1=4 r5c1<>4 r5c1=8 (r4c2<>8) r5c2<>8 r7c2=8 (r7c2<>5) r7c2<>6 r7c3=6 r7c3<>5 r8c3=5 (r8c5<>5) r8c4<>5 r8c4=2 r8c5<>2 r8c5=9 r1c5<>9
r2c2=1 (r9c2<>1 r9c2=3 r9c6<>3 r7c6=3 r7c8<>3) (r2c2<>8) r2c2<>4 r2c6=4 (r3c5<>4) r3c6<>4 r3c1=4 r5c1<>4 r5c1=8 (r4c2<>8) r5c2<>8 r7c2=8 r7c8<>8 r7c8=9 r5c8<>9 r5c7=9 r1c7<>9
r2c2=1 (r9c2<>1 r9c2=3 r9c6<>3 r7c6=3 r7c8<>3) (r2c2<>8) r2c2<>4 r2c6=4 (r3c5<>4) r3c6<>4 r3c1=4 r5c1<>4 r5c1=8 (r4c2<>8) r5c2<>8 r7c2=8 r7c8<>8 r7c8=9 r1c8<>9
Forcing Net Contradiction in r1 => r3c9<>1
r3c9=1 (r1c7<>1) (r2c7<>1) r3c7<>1 r9c7=1 (r9c1<>1) r9c2<>1 r9c2=3 r9c1<>3 r9c1=9 r1c1<>9
r3c9=1 (r3c9<>3 r8c9=3 r7c8<>3) (r1c7<>1) (r2c7<>1) r3c7<>1 r9c7=1 r9c2<>1 r9c2=3 (r9c1<>3 r9c1=9 r9c6<>9) (r7c2<>3) r7c3<>3 r7c6=3 r7c6<>9 r8c5=9 r1c5<>9
r3c9=1 (r3c9<>9) (r3c9<>3 r8c9=3 r8c9<>9) (r1c7<>1) (r2c7<>1) r3c7<>1 r9c7=1 (r9c1<>1) r9c2<>1 r9c2=3 r9c1<>3 r9c1=9 r9c9<>9 r2c9=9 r1c7<>9
r3c9=1 r3c9<>3 r8c9=3 (r7c8<>3) r8c8<>3 r1c8=3 r1c8<>9
Forcing Net Contradiction in r1 => r2c9<>1
r2c9=1 (r1c7<>1) (r2c7<>1) r3c7<>1 r9c7=1 (r9c1<>1) r9c2<>1 r9c2=3 r9c1<>3 r9c1=9 r1c1<>9
r2c9=1 (r1c7<>1) (r2c7<>1) r3c7<>1 r9c7=1 r9c2<>1 r9c2=3 (r9c1<>3 r9c1=9 r9c6<>9) r9c6<>3 r7c6=3 r7c6<>9 r8c5=9 r1c5<>9
r2c9=1 (r2c9<>9) (r1c7<>1) (r2c7<>1) r3c7<>1 r9c7=1 r9c2<>1 r9c2=3 (r9c1<>3 r9c1=9 r9c9<>9) (r9c1<>3 r9c1=9 r9c6<>9) r9c6<>3 r7c6=3 r7c6<>9 r8c5=9 r8c9<>9 r3c9=9 r1c7<>9
r2c9=1 (r2c9<>9) (r1c7<>1) (r2c7<>1) r3c7<>1 r9c7=1 r9c2<>1 r9c2=3 (r9c1<>3 r9c1=9 r9c9<>9) (r9c1<>3 r9c1=9 r9c6<>9) r9c6<>3 r7c6=3 r7c6<>9 r8c5=9 r8c9<>9 r3c9=9 r1c8<>9
Locked Candidates Type 1 (Pointing): 1 in b3 => r9c7<>1
Forcing Net Contradiction in r1c8 => r2c8<>9
r2c8=9 (r2c9<>9) (r5c8<>9 r5c7=9 r5c7<>8) r2c8<>7 r5c8=7 (r5c8<>8) r5c8<>4 r4c8=4 r4c8<>8 r4c9=8 r2c9<>8 r2c9=2 r1c8<>2
r2c8=9 (r3c9<>9) (r5c8<>9 r5c7=9 r5c7<>8) r2c8<>7 r5c8=7 (r5c8<>8) r5c8<>4 r4c8=4 r4c8<>8 r4c9=8 r3c9<>8 r3c9=3 r1c8<>3
r2c8=9 r1c8<>9
Forcing Net Contradiction in r1 => r3c9<>8
r3c9=8 r3c9<>3 r8c9=3 r8c9<>1 r9c9=1 (r9c1<>1) r9c2<>1 r9c2=3 r9c1<>3 r9c1=9 r1c1<>9
r3c9=8 r3c9<>3 r8c9=3 (r7c8<>3) r8c9<>1 r9c9=1 r9c2<>1 r9c2=3 (r9c1<>3 r9c1=9 r9c6<>9) (r7c2<>3) r7c3<>3 r7c6=3 r7c6<>9 r8c5=9 r1c5<>9
r3c9=8 (r3c9<>9) r3c9<>3 r8c9=3 (r8c9<>9) r8c9<>1 r9c9=1 r9c9<>9 r2c9=9 r1c7<>9
r3c9=8 r3c9<>3 r8c9=3 (r7c8<>3) r8c8<>3 r1c8=3 r1c8<>9
Forcing Net Contradiction in b2 => r3c9=3
r3c9<>3 (r3c9=9 r1c7<>9) (r3c9=9 r1c8<>9) r8c9=3 r8c9<>1 r9c9=1 (r9c1<>1) r9c2<>1 r9c2=3 r9c1<>3 r9c1=9 r1c1<>9 r1c5=9
r3c9<>3 r8c9=3 r3c9<>3 r3c9=9 (r2c7<>9) r2c9<>9 r2c6=9
Almost Locked Set XZ-Rule: A=r8c13459 {123589}, B=r9c1279 {12359}, X=3, Z=2 => r8c8<>2
Almost Locked Set XY-Wing: A=r1c8,r2c9 {289}, B=r7c78,r8c8,r9c7 {23589}, C=r4689c9 {12589}, X,Y=8,9, Z=2 => r12c7<>2
Forcing Net Verity => r1c8=2
r1c8=2 r1c8=2
r2c8=2 r1c8<>2 r1c8=9 (r7c8<>9) (r2c9<>9 r2c9=8 r2c7<>8) (r2c9<>9 r2c9=8 r3c7<>8) r5c8<>9 r5c7=9 r5c7<>8 r7c7=8 r7c8<>8 r7c8=3 r7c6<>3 r9c6=3 r9c2<>3 r9c2=1 (r9c1<>1 r9c1=9 r9c9<>9) (r8c1<>1) r8c3<>1 r8c9=1 r8c9<>9 r2c9=9 r1c8<>9 r1c8=2
r4c8=2 (r6c9<>2 r6c9=5 r4c9<>5 r4c9=8 r8c9<>8) (r6c9<>2 r6c9=5 r6c3<>5) (r6c7<>2 r9c7=2 r9c7<>5 r7c7=5 r7c3<>5) r4c8<>4 r5c8=4 (r5c2<>4) r5c1<>4 r5c1=8 (r8c1<>8) r5c2<>8 r5c2=5 r4c3<>5 r8c3=5 r8c3<>8 r8c8=8 r8c8<>3 r7c8=3 r7c6<>3 r9c6=3 r9c2<>3 r9c2=1 (r9c1<>1 r9c1=9 r9c9<>9) (r8c1<>1) r8c3<>1 r8c9=1 r8c9<>9 r2c9=9 r1c8<>9 r1c8=2
Almost Locked Set XZ-Rule: A=r1c5 {59}, B=r2346c6 {24579}, X=9, Z=5 => r45c5<>5
Locked Candidates Type 1 (Pointing): 5 in b5 => r79c6<>5
Almost Locked Set XZ-Rule: A=r5c5 {47}, B=r6c679 {2457}, X=4, Z=7 => r6c5<>7
Skyscraper: 7 in r2c8,r3c5 (connected by r5c58) => r2c6,r3c7<>7
Discontinuous Nice Loop: 2 r9c4 -2- r9c7 =2= r6c7 =7= r6c6 -7- r9c6 =7= r9c4 => r9c4<>2
Almost Locked Set XZ-Rule: A=r7c678 {3589}, B=r9c1279 {12359}, X=5, Z=3 => r7c23<>3
Almost Locked Set XY-Wing: A=r7c678 {3589}, B=r8c13459 {123589}, C=r9c1279 {12359}, X,Y=3,5, Z=8 => r8c8<>8
Discontinuous Nice Loop: 5 r6c3 -5- r5c2 =5= r5c7 =9= r5c8 -9- r8c8 -3- r8c3 =3= r6c3 => r6c3<>5
Almost Locked Set XY-Wing: A=r8c45,r9c4 {2579}, B=r7c78,r8c8 {3589}, C=r9c12679 {123579}, X,Y=5,7, Z=9 => r8c9<>9
Forcing Chain Contradiction in c7 => r6c3=3
r6c3<>3 r8c3=3 r8c8<>3 r8c8=9 r5c8<>9 r5c7=9 r5c7<>5
r6c3<>3 r6c1=3 r6c1<>4 r6c56=4 r5c5<>4 r5c5=7 r6c6<>7 r6c7=7 r6c7<>5
r6c3<>3 r8c3=3 r8c3<>5 r7c23=5 r7c7<>5
r6c3<>3 r6c1=3 r6c1<>4 r6c56=4 r5c5<>4 r5c5=7 r6c6<>7 r6c7=7 r6c7<>2 r9c7=2 r9c7<>5
Forcing Chain Contradiction in c3 => r2c8=7
r2c8<>7 r2c7=7 r6c7<>7 r6c6=7 r6c6<>5 r4c6=5 r4c3<>5
r2c8<>7 r5c8=7 r5c5<>7 r5c5=4 r6c56<>4 r6c1=4 r6c1<>6 r4c2=6 r7c2<>6 r7c3=6 r7c3<>5
r2c8<>7 r2c7=7 r6c7<>7 r6c6=7 r9c6<>7 r9c4=7 r9c4<>5 r8c45=5 r8c3<>5
Forcing Chain Contradiction in c3 => r5c5=7
r5c5<>7 r5c7=7 r5c7<>5 r5c2=5 r4c3<>5
r5c5<>7 r5c5=4 r6c56<>4 r6c1=4 r6c1<>6 r4c2=6 r7c2<>6 r7c3=6 r7c3<>5
r5c5<>7 r3c5=7 r3c4<>7 r9c4=7 r9c4<>5 r8c45=5 r8c3<>5
Hidden Single: r6c7=7
Hidden Single: r9c7=2
Discontinuous Nice Loop: 9 r2c6 -9- r2c9 =9= r9c9 =5= r9c4 -5- r8c4 -2- r2c4 =2= r2c6 => r2c6<>9
Naked Triple: 2,4,5 in r246c6 => r3c6<>4
Discontinuous Nice Loop: 4 r4c2 -4- r4c8 =4= r5c8 =9= r5c7 =5= r7c7 -5- r9c9 =5= r9c4 -5- r8c4 -2- r2c4 =2= r2c6 =4= r2c2 -4- r4c2 => r4c2<>4
Discontinuous Nice Loop: 9 r3c7 -9- r3c6 -7- r3c4 =7= r9c4 =5= r9c9 =9= r2c9 -9- r3c7 => r3c7<>9
Discontinuous Nice Loop: 2 r6c6 -2- r2c6 -4- r2c2 =4= r5c2 =5= r5c7 -5- r6c9 =5= r6c6 => r6c6<>2
Discontinuous Nice Loop: 3 r7c8 -3- r7c6 =3= r9c6 =7= r9c4 =5= r9c9 -5- r7c7 =5= r5c7 =9= r5c8 -9- r8c8 -3- r7c8 => r7c8<>3
Hidden Single: r7c6=3
Hidden Single: r8c8=3
Hidden Rectangle: 1/3 in r1c12,r9c12 => r1c1<>1
Finned Swordfish: 9 r257 c378 fr2c9 => r1c7<>9
Locked Candidates Type 1 (Pointing): 9 in b3 => r2c3<>9
2-String Kite: 9 in r1c1,r9c6 (connected by r1c5,r3c6) => r9c1<>9
Locked Pair: 1,3 in r9c12 => r8c13,r9c9<>1
Hidden Single: r8c9=1
Locked Candidates Type 1 (Pointing): 8 in b9 => r7c23<>8
Uniqueness Test 4: 1/3 in r1c12,r9c12 => r1c2<>1
Finned X-Wing: 8 c29 r24 fr5c2 => r4c3<>8
Sue de Coq: r45c2 - {14568} (r179c2 - {1356}, r5c1 - {48}) => r6c1<>4, r2c2<>6
Naked Single: r6c1=6
Hidden Single: r4c5=6
Locked Candidates Type 1 (Pointing): 4 in b4 => r5c8<>4
Hidden Single: r4c8=4
XY-Chain: 9 9- r3c5 -4- r6c5 -2- r6c9 -5- r9c9 -9- r9c6 -7- r3c6 -9 => r1c5,r3c13<>9
Naked Single: r1c5=5
Hidden Single: r1c1=9
Naked Single: r8c1=8
Naked Single: r5c1=4
Naked Single: r3c1=1
Full House: r9c1=3
Naked Single: r9c2=1
Hidden Single: r1c2=3
Hidden Single: r3c5=4
Naked Single: r2c6=2
Naked Single: r6c5=2
Full House: r8c5=9
Naked Single: r4c6=5
Full House: r6c6=4
Full House: r6c9=5
Naked Single: r8c3=5
Full House: r8c4=2
Naked Single: r9c6=7
Full House: r3c6=9
Full House: r9c4=5
Full House: r9c9=9
Naked Single: r4c2=8
Naked Single: r4c3=1
Full House: r4c9=2
Full House: r2c9=8
Full House: r5c2=5
Naked Single: r7c2=6
Full House: r2c2=4
Full House: r7c3=9
Naked Single: r7c8=8
Full House: r5c8=9
Full House: r7c7=5
Full House: r5c7=8
Naked Single: r2c3=6
Full House: r3c3=8
Naked Single: r3c7=6
Full House: r3c4=7
Naked Single: r2c4=1
Full House: r1c4=6
Full House: r1c7=1
Full House: r2c7=9
|
normal_sudoku_178
|
79.416.2.4..892...862375419.8..21.561.6.5....5...381.......37....8.49.6565.28....
|
793416528415892637862375419984721356136954872527638194249563781378149265651287943
|
Basic 9x9 Sudoku 178
|
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 9 . 4 1 6 . 2 .
4 . . 8 9 2 . . .
8 6 2 3 7 5 4 1 9
. 8 . . 2 1 . 5 6
1 . 6 . 5 . . . .
5 . . . 3 8 1 . .
. . . . . 3 7 . .
. . 8 . 4 9 . 6 5
6 5 . 2 8 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
793416528415892637862375419984721356136954872527638194249563781378149265651287943 #1 Easy (244)
Naked Single: r1c6=6
Naked Single: r3c3=2
Naked Single: r1c5=1
Naked Single: r3c2=6
Naked Single: r3c5=7
Full House: r3c7=4
Naked Single: r2c6=2
Full House: r2c5=9
Naked Single: r8c5=4
Naked Single: r4c5=2
Naked Single: r7c6=3
Naked Single: r9c5=8
Full House: r7c5=6
Naked Single: r9c6=7
Full House: r5c6=4
Naked Single: r8c4=1
Full House: r7c4=5
Hidden Single: r6c4=6
Hidden Single: r2c7=6
Hidden Single: r4c3=4
Hidden Single: r8c2=7
Naked Single: r6c2=2
Naked Single: r5c2=3
Naked Single: r2c2=1
Full House: r7c2=4
Naked Single: r4c1=9
Full House: r6c3=7
Naked Single: r4c4=7
Full House: r4c7=3
Full House: r5c4=9
Naked Single: r7c1=2
Full House: r8c1=3
Full House: r8c7=2
Naked Single: r6c9=4
Full House: r6c8=9
Naked Single: r9c7=9
Naked Single: r5c7=8
Full House: r1c7=5
Naked Single: r7c8=8
Naked Single: r9c3=1
Full House: r7c3=9
Full House: r7c9=1
Naked Single: r5c8=7
Full House: r5c9=2
Naked Single: r1c3=3
Full House: r1c9=8
Full House: r2c3=5
Naked Single: r9c9=3
Full House: r2c9=7
Full House: r2c8=3
Full House: r9c8=4
|
normal_sudoku_385
|
.....8.....96.4.8..6..3...45.6..7.1..7.3.98.69.....47..2...3..8..58.......7.2.1..
|
743298561159674382862135794536487219274319856918562473621753948395841627487926135
|
Basic 9x9 Sudoku 385
|
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 6 . 4 . 8 .
. 6 . . 3 . . . 4
5 . 6 . . 7 . 1 .
. 7 . 3 . 9 8 . 6
9 . . . . . 4 7 .
. 2 . . . 3 . . 8
. . 5 8 . . . . .
. . 7 . 2 . 1 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
743298561159674382862135794536487219274319856918562473621753948395841627487926135 #1 Extreme (22204) bf
Brute Force: r5c6=9
Forcing Chain Contradiction in r9c9 => r5c1<>8
r5c1=8 r5c7<>8 r4c7=8 r4c7<>3 r46c9=3 r9c9<>3
r5c1=8 r6c23<>8 r6c5=8 r6c5<>6 r6c6=6 r9c6<>6 r9c6=5 r9c9<>5
r5c1=8 r5c7<>8 r4c7=8 r4c7<>9 r4c9=9 r9c9<>9
Forcing Chain Contradiction in r9c9 => r5c3<>8
r5c3=8 r5c7<>8 r4c7=8 r4c7<>3 r46c9=3 r9c9<>3
r5c3=8 r6c23<>8 r6c5=8 r6c5<>6 r6c6=6 r9c6<>6 r9c6=5 r9c9<>5
r5c3=8 r5c7<>8 r4c7=8 r4c7<>9 r4c9=9 r9c9<>9
Forcing Chain Contradiction in r9 => r9c8<>5
r9c8=5 r5c8<>5 r5c8=2 r5c13<>2 r6c3=2 r6c3<>8 r3c3=8 r3c1<>8 r9c1=8 r9c1<>3
r9c8=5 r5c8<>5 r5c8=2 r5c13<>2 r6c3=2 r6c3<>3 r46c2=3 r9c2<>3
r9c8=5 r9c8<>3
r9c8=5 r5c8<>5 r5c8=2 r5c13<>2 r6c3=2 r6c3<>3 r1c3=3 r1c8<>3 r89c8=3 r9c9<>3
Forcing Net Contradiction in r9c4 => r3c1<>2
r3c1=2 r3c6<>2 r6c6=2 r4c4<>2 r4c4=4 r9c4<>4
r3c1=2 (r1c3<>2) (r3c3<>2) r3c6<>2 r6c6=2 (r6c6<>5) (r6c6<>6 r6c5=6 r6c5<>5) r6c3<>2 r5c3=2 r5c8<>2 r5c8=5 r6c9<>5 r6c4=5 r9c4<>5
r3c1=2 (r1c3<>2) (r3c3<>2) r3c6<>2 r6c6=2 (r6c6<>6 r6c5=6 r6c5<>8 r6c2=8 r6c2<>1) (r6c6<>6 r6c5=6 r6c5<>1) (r6c6<>1) (r4c4<>2 r4c4=4 r5c5<>4) (r4c4<>2 r4c4=4 r4c5<>4 r4c5=8 r5c5<>8) r6c3<>2 r5c3=2 r5c8<>2 r5c8=5 (r6c9<>5 r6c9=3 r6c3<>3 r1c3=3 r1c1<>3) (r6c9<>5 r6c9=3 r6c3<>3 r1c3=3 r2c1<>3) r5c5<>5 r5c5=1 r6c4<>1 r6c3=1 (r7c3<>1 r7c3=4 r9c2<>4) r6c3<>8 r3c3=8 r3c1<>8 r9c1=8 (r9c2<>8) r9c1<>3 r8c1=3 r9c2<>3 r9c2=9 r9c4<>9
Forcing Net Contradiction in c9 => r3c6<>1
r3c6=1 r3c6<>2 r6c6=2 r4c4<>2 r4c4=4 (r4c2<>4) r4c5<>4 r4c5=8 r4c2<>8 r4c2=3 (r6c2<>3) r6c3<>3 r6c9=3
r3c6=1 (r8c6<>1 r8c6=6 r9c6<>6 r9c6=5 r9c9<>5) (r8c6<>1 r8c6=6 r9c6<>6 r9c6=5 r9c4<>5) r3c6<>2 r6c6=2 r4c4<>2 r4c4=4 r9c4<>4 r9c4=9 r9c9<>9 r9c9=3
Forcing Chain Contradiction in c2 => r6c4<>1
r6c4=1 r3c4<>1 r3c13=1 r1c2<>1
r6c4=1 r3c4<>1 r3c13=1 r2c2<>1
r6c4=1 r6c2<>1
r6c4=1 r6c6<>1 r8c6=1 r8c2<>1
Grouped AIC: 5 5- r5c8 -2- r4c79 =2= r4c4 -2- r6c4 -5 => r5c5,r6c9<>5
Almost Locked Set XZ-Rule: A=r5c8 {25}, B=r469c9 {2359}, X=2, Z=5 => r7c8<>5
Forcing Chain Contradiction in c6 => r5c8=5
r5c8<>5 r5c8=2 r4c79<>2 r4c4=2 r6c6<>2 r3c6=2 r3c6<>5
r5c8<>5 r5c8=2 r4c79<>2 r4c4=2 r6c4<>2 r6c4=5 r6c6<>5
r5c8<>5 r5c7=5 r7c7<>5 r9c9=5 r9c6<>5
Almost Locked Set XY-Wing: A=r7c138 {1469}, B=r9c6 {56}, C=r3c68 {259}, X,Y=5,9, Z=6 => r7c5<>6
Hidden Rectangle: 1/6 in r6c56,r8c56 => r6c5<>1
Almost Locked Set XY-Wing: A=r7c138 {1469}, B=r89c6 {156}, C=r3c68 {259}, X,Y=5,9, Z=1 => r7c45,r8c12<>1
Locked Candidates Type 2 (Claiming): 1 in c4 => r12c5<>1
Grouped Discontinuous Nice Loop: 9 r3c4 -9- r3c8 -2- r3c46 =2= r1c4 =1= r3c4 => r3c4<>9
Locked Candidates Type 1 (Pointing): 9 in b2 => r1c789<>9
Almost Locked Set XY-Wing: A=r3c68 {259}, B=r469c4 {2459}, C=r689c6 {1256}, X,Y=2,5, Z=9 => r9c8<>9
Almost Locked Set Chain: 2- r5c135 {1248} -8- r124678c5 {1456789} -1- r89c6 {156} -5- r469c9 {2359} -2 => r5c7<>2
Naked Single: r5c7=8
Locked Candidates Type 2 (Claiming): 2 in r5 => r6c3<>2
Almost Locked Set Chain: 7- r2c5 {57} -5- r3c6 {25} -2- r3c8 {29} -9- r7c138 {1469} -4- r127c5 {4579} -7 => r8c5<>7
Locked Candidates Type 1 (Pointing): 7 in b8 => r7c7<>7
Almost Locked Set XZ-Rule: A=r7c1378 {14569}, B=r469c9 {2359}, X=5, Z=9 => r8c9<>9
Forcing Chain Contradiction in r3 => r4c5=8
r4c5<>8 r4c5=4 r4c4<>4 r4c4=2 r6c4<>2 r6c4=5 r3c4<>5
r4c5<>8 r4c5=4 r4c4<>4 r4c4=2 r6c6<>2 r3c6=2 r3c6<>5
r4c5<>8 r6c5=8 r6c5<>6 r6c6=6 r9c6<>6 r9c6=5 r9c9<>5 r7c7=5 r3c7<>5
Grouped Discontinuous Nice Loop: 1 r1c3 -1- r12c2 =1= r6c2 =8= r6c3 =3= r1c3 => r1c3<>1
Grouped Discontinuous Nice Loop: 1 r3c1 -1- r12c2 =1= r6c2 =8= r6c3 -8- r3c3 =8= r3c1 => r3c1<>1
Grouped Discontinuous Nice Loop: 4 r7c4 -4- r4c4 =4= r5c5 =1= r8c5 -1- r8c6 -6- r9c6 -5- r9c9 =5= r7c7 -5- r3c7 =5= r3c46 -5- r2c5 -7- r7c5 =7= r7c4 => r7c4<>4
Almost Locked Set XY-Wing: A=r4689c2 {13489}, B=r1357c3 {12348}, C=r6c34569 {123568}, X,Y=1,8, Z=3 => r12c2<>3
Discontinuous Nice Loop: 7 r3c4 -7- r2c5 -5- r2c2 -1- r3c3 =1= r3c4 => r3c4<>7
Grouped Discontinuous Nice Loop: 7 r2c1 -7- r2c5 -5- r3c46 =5= r3c7 =7= r3c1 -7- r2c1 => r2c1<>7
Grouped Discontinuous Nice Loop: 1 r1c1 -1- r12c2 =1= r6c2 =8= r6c3 -8- r3c3 =8= r3c1 =7= r1c1 => r1c1<>1
Almost Locked Set Chain: 3- r6c4569 {12356} -1- r8c6 {16} -6- r9c6 {56} -5- r469c9 {2359} -3 => r128c9<>3
Discontinuous Nice Loop: 5 r2c7 -5- r7c7 =5= r9c9 -5- r9c6 -6- r8c6 -1- r8c5 =1= r5c5 =4= r4c4 -4- r4c2 -3- r6c3 =3= r1c3 -3- r2c1 =3= r2c7 => r2c7<>5
Grouped Discontinuous Nice Loop: 7 r2c7 -7- r2c5 -5- r3c46 =5= r3c7 -5- r7c7 =5= r9c9 -5- r9c6 -6- r8c6 -1- r8c5 =1= r5c5 =4= r4c4 -4- r4c2 -3- r6c3 =3= r1c3 -3- r2c1 =3= r2c7 => r2c7<>7
Forcing Chain Contradiction in r3 => r1c3=3
r1c3<>3 r6c3=3 r6c3<>8 r3c3=8 r3c3<>1 r3c4=1 r3c4<>5
r1c3<>3 r6c3=3 r6c9<>3 r6c9=2 r6c6<>2 r3c6=2 r3c6<>5
r1c3<>3 r6c3=3 r4c2<>3 r4c2=4 r4c4<>4 r5c5=4 r5c5<>1 r8c5=1 r8c6<>1 r8c6=6 r9c6<>6 r9c6=5 r9c9<>5 r7c7=5 r3c7<>5
Hidden Single: r2c7=3
Locked Candidates Type 1 (Pointing): 3 in b4 => r89c2<>3
Locked Candidates Type 1 (Pointing): 3 in b6 => r9c9<>3
Sue de Coq: r7c78 - {4569} (r7c13 - {146}, r9c9 - {59}) => r8c78<>9, r7c5<>4
Naked Triple: 5,7,9 in r127c5 => r6c5<>5, r8c5<>9
Naked Single: r6c5=6
Hidden Single: r8c2=9
Skyscraper: 4 in r7c3,r8c5 (connected by r5c35) => r8c1<>4
XY-Wing: 1/4/8 in r67c3,r9c2 => r6c2<>8
Hidden Single: r6c3=8
Hidden Single: r9c2=8
Hidden Single: r3c1=8
Hidden Single: r3c7=7
Hidden Single: r1c1=7
Hidden Single: r2c5=7
Hidden Single: r8c9=7
Hidden Single: r3c8=9
Hidden Single: r7c4=7
Hidden Single: r1c2=4
Naked Single: r4c2=3
Naked Single: r6c2=1
Full House: r2c2=5
Hidden Single: r4c4=4
Naked Single: r5c5=1
Naked Single: r8c5=4
Hidden Single: r6c9=3
Hidden Single: r8c6=1
Hidden Single: r9c6=6
Locked Candidates Type 1 (Pointing): 5 in b3 => r1c45<>5
Naked Single: r1c5=9
Full House: r7c5=5
Full House: r9c4=9
Naked Single: r9c9=5
Hidden Single: r7c7=9
Naked Single: r4c7=2
Full House: r4c9=9
Naked Single: r8c7=6
Full House: r1c7=5
Naked Single: r7c8=4
Naked Single: r8c1=3
Full House: r8c8=2
Full House: r9c8=3
Full House: r9c1=4
Full House: r1c8=6
Naked Single: r7c3=1
Full House: r7c1=6
Naked Single: r5c1=2
Full House: r2c1=1
Full House: r3c3=2
Full House: r5c3=4
Full House: r2c9=2
Full House: r1c9=1
Full House: r1c4=2
Naked Single: r3c6=5
Full House: r3c4=1
Full House: r6c4=5
Full House: r6c6=2
|
normal_sudoku_866
|
92..7..4.5...8.29.748.9256..1.2...8...54.8.29.9...1.5...9...812...81.975...92.634
|
921576348536184297748392561413259786675438129892761453359647812264813975187925634
|
Basic 9x9 Sudoku 866
|
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 2 . . 7 . . 4 .
5 . . . 8 . 2 9 .
7 4 8 . 9 2 5 6 .
. 1 . 2 . . . 8 .
. . 5 4 . 8 . 2 9
. 9 . . . 1 . 5 .
. . 9 . . . 8 1 2
. . . 8 1 . 9 7 5
. . . 9 2 . 6 3 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
921576348536184297748392561413259786675438129892761453359647812264813975187925634 #1 Easy (306)
Naked Single: r7c8=1
Naked Single: r8c7=9
Full House: r7c7=8
Naked Single: r3c8=6
Naked Single: r1c8=4
Naked Single: r5c8=2
Full House: r6c8=5
Hidden Single: r1c1=9
Hidden Single: r6c2=9
Hidden Single: r2c7=2
Hidden Single: r2c5=8
Hidden Single: r9c5=2
Hidden Single: r3c5=9
Hidden Single: r5c7=1
Naked Single: r1c7=3
Naked Single: r3c9=1
Full House: r3c4=3
Naked Single: r1c9=8
Full House: r2c9=7
Hidden Single: r4c6=9
Hidden Single: r9c1=1
Naked Single: r9c3=7
Naked Single: r9c6=5
Full House: r9c2=8
Naked Single: r1c6=6
Naked Single: r1c3=1
Full House: r1c4=5
Naked Single: r2c4=1
Full House: r2c6=4
Naked Single: r8c6=3
Full House: r7c6=7
Naked Single: r8c2=6
Naked Single: r7c4=6
Full House: r6c4=7
Full House: r7c5=4
Naked Single: r2c2=3
Full House: r2c3=6
Naked Single: r6c7=4
Full House: r4c7=7
Naked Single: r7c1=3
Full House: r7c2=5
Full House: r5c2=7
Naked Single: r5c1=6
Full House: r5c5=3
Naked Single: r4c1=4
Naked Single: r6c5=6
Full House: r4c5=5
Naked Single: r4c3=3
Full House: r4c9=6
Full House: r6c9=3
Naked Single: r8c1=2
Full House: r6c1=8
Full House: r6c3=2
Full House: r8c3=4
|
normal_sudoku_2618
|
.36.4.....91.3.......5.7.9336.7..9.19..1.8367.173..8.5.7.....3...94732.6.23....79
|
536941782791832654482567193368754921945128367217396845674219538859473216123685479
|
Basic 9x9 Sudoku 2618
|
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 6 . 4 . . . .
. 9 1 . 3 . . . .
. . . 5 . 7 . 9 3
3 6 . 7 . . 9 . 1
9 . . 1 . 8 3 6 7
. 1 7 3 . . 8 . 5
. 7 . . . . . 3 .
. . 9 4 7 3 2 . 6
. 2 3 . . . . 7 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
536941782791832654482567193368754921945128367217396845674219538859473216123685479 #1 Hard (924)
Hidden Single: r2c2=9
Hidden Single: r4c7=9
Hidden Single: r8c6=3
Hidden Single: r6c4=3
Hidden Single: r8c3=9
Hidden Single: r4c4=7
Locked Pair: 2,4 in r46c8 => r128c8,r5c79<>2, r2c8,r5c79<>4
Hidden Single: r8c7=2
Locked Triple: 2,4,8 in r3c123 => r12c1,r3c59<>2, r12c1,r3c59<>8, r2c1,r3c79<>4
Naked Single: r3c9=3
Naked Single: r5c9=7
Naked Single: r5c7=3
Hidden Single: r7c2=7
Hidden Single: r6c3=7
Hidden Single: r4c2=6
Hidden Single: r4c3=8
Locked Pair: 2,5 in r45c5 => r46c6,r67c5<>2, r4c6,r79c5<>5
Naked Single: r4c6=4
Naked Single: r4c8=2
Full House: r4c5=5
Full House: r6c8=4
Naked Single: r5c5=2
Naked Single: r6c1=2
Hidden Single: r3c3=2
Locked Candidates Type 1 (Pointing): 5 in b1 => r789c1<>5
Locked Candidates Type 1 (Pointing): 8 in b2 => r79c4<>8
Naked Single: r9c4=6
Hidden Single: r7c1=6
XY-Wing: 4/5/8 in r7c39,r8c2 => r8c8<>8
Hidden Single: r7c9=8
Naked Single: r1c9=2
Full House: r2c9=4
Hidden Single: r9c5=8
W-Wing: 1/9 in r1c6,r7c5 connected by 9 in r6c56 => r3c5,r79c6<>1
Naked Single: r3c5=6
Naked Single: r9c6=5
Naked Single: r2c6=2
Naked Single: r3c7=1
Naked Single: r6c5=9
Full House: r6c6=6
Full House: r7c5=1
Naked Single: r2c4=8
Naked Single: r7c6=9
Full House: r1c6=1
Full House: r1c4=9
Full House: r7c4=2
Naked Single: r9c7=4
Full House: r9c1=1
Naked Single: r2c8=5
Naked Single: r7c7=5
Full House: r8c8=1
Full House: r1c8=8
Full House: r7c3=4
Full House: r5c3=5
Full House: r5c2=4
Naked Single: r8c1=8
Full House: r8c2=5
Full House: r3c2=8
Full House: r3c1=4
Naked Single: r1c7=7
Full House: r1c1=5
Full House: r2c1=7
Full House: r2c7=6
|
normal_sudoku_6925
|
.9.6....1..4..56......8..2.7...5...4.6.748.1...2.637..8..5...97.2.4..1....38.....
|
397624851284195673156387429738251964569748312412963785841536297625479138973812546
|
Basic 9x9 Sudoku 6925
|
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 . 6 . . . . 1
. . 4 . . 5 6 . .
. . . . 8 . . 2 .
7 . . . 5 . . . 4
. 6 . 7 4 8 . 1 .
. . 2 . 6 3 7 . .
8 . . 5 . . . 9 7
. 2 . 4 . . 1 . .
. . 3 8 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
397624851284195673156387429738251964569748312412963785841536297625479138973812546 #1 Extreme (15640) bf
Brute Force: r5c6=8
Hidden Single: r9c4=8
Hidden Single: r7c4=5
Locked Candidates Type 1 (Pointing): 4 in b5 => r1c5<>4
Locked Candidates Type 1 (Pointing): 3 in b8 => r12c5<>3
X-Wing: 8 c37 r14 => r14c8,r4c2<>8
Discontinuous Nice Loop: 2/9 r5c5 =4= r5c1 =3= r4c2 -3- r4c8 -6- r4c6 =6= r6c5 =4= r5c5 => r5c5<>2, r5c5<>9
Naked Single: r5c5=4
Locked Candidates Type 1 (Pointing): 2 in b5 => r4c7<>2
Almost Locked Set XY-Wing: A=r5c13 {359}, B=r6c24589 {145689}, C=r47c2 {134}, X,Y=3,4, Z=5,9 => r6c1<>5, r6c1<>9
Forcing Chain Contradiction in r1c6 => r4c4<>9
r4c4=9 r4c4<>2 r4c6=2 r1c6<>2
r4c4=9 r6c45<>9 r6c9=9 r45c7<>9 r3c7=9 r3c7<>4 r3c6=4 r1c6<>4
r4c4=9 r4c4<>2 r2c4=2 r1c5<>2 r1c5=7 r1c6<>7
Forcing Chain Verity => r7c5<>6
r1c1=3 r5c1<>3 r4c2=3 r4c8<>3 r4c8=6 r4c6<>6 r6c5=6 r7c5<>6
r1c7=3 r7c7<>3 r7c5=3 r7c5<>6
r1c8=3 r4c8<>3 r4c8=6 r4c6<>6 r6c5=6 r7c5<>6
Forcing Chain Contradiction in c9 => r8c8<>6
r8c8=6 r4c8<>6 r4c8=3 r4c2<>3 r5c1=3 r1c1<>3 r1c78=3 r2c9<>3
r8c8=6 r4c8<>6 r4c8=3 r4c2<>3 r5c1=3 r1c1<>3 r1c78=3 r3c9<>3
r8c8=6 r4c8<>6 r4c8=3 r5c9<>3
r8c8=6 r8c8<>8 r8c9=8 r8c9<>3
Forcing Chain Contradiction in c9 => r9c5<>6
r9c5=6 r6c5<>6 r4c6=6 r4c8<>6 r4c8=3 r4c2<>3 r5c1=3 r1c1<>3 r1c78=3 r2c9<>3
r9c5=6 r6c5<>6 r4c6=6 r4c8<>6 r4c8=3 r4c2<>3 r5c1=3 r1c1<>3 r1c78=3 r3c9<>3
r9c5=6 r6c5<>6 r4c6=6 r4c8<>6 r4c8=3 r5c9<>3
r9c5=6 r9c89<>6 r8c9=6 r8c9<>3
Forcing Net Contradiction in r8c6 => r4c8=6
r4c8<>6 r4c6=6 r8c6<>6
r4c8<>6 (r4c6=6 r7c6<>6 r7c3=6 r7c3<>1 r3c3=1 r3c3<>7) r4c8=3 (r1c8<>3) (r5c7<>3) r5c9<>3 r5c1=3 r1c1<>3 r1c7=3 r1c7<>8 r1c3=8 r1c3<>7 r8c3=7 r8c6<>7
r4c8<>6 (r4c8=3 r5c9<>3 r5c1=3 r5c1<>9) (r4c8=3 r4c2<>3 r4c2=1 r6c1<>1) (r4c8=3 r4c2<>3 r4c2=1 r4c3<>1) r4c6=6 r7c6<>6 r7c3=6 (r3c3<>6 r3c1=6 r3c1<>1) r7c3<>1 r3c3=1 r2c1<>1 r9c1=1 r9c1<>9 r8c1=9 r8c6<>9
Hidden Single: r6c5=6
Empty Rectangle: 9 in b3 (r6c49) => r3c4<>9
Discontinuous Nice Loop: 3 r2c2 -3- r4c2 =3= r4c7 =8= r4c3 -8- r1c3 =8= r2c2 => r2c2<>3
Discontinuous Nice Loop: 5 r5c9 -5- r6c8 -8- r8c8 =8= r8c9 =6= r9c9 =2= r5c9 => r5c9<>5
Grouped Discontinuous Nice Loop: 3 r1c7 -3- r45c7 =3= r5c9 =2= r9c9 =6= r8c9 =8= r8c8 =3= r12c8 -3- r1c7 => r1c7<>3
Grouped Discontinuous Nice Loop: 3 r3c2 -3- r3c4 -1- r6c4 =1= r4c46 -1- r4c2 -3- r3c2 => r3c2<>3
Hidden Single: r4c2=3
Locked Pair: 5,9 in r5c13 => r5c7,r6c2<>5, r4c3,r5c79<>9
Finned X-Wing: 5 c27 r39 fr1c7 => r3c9<>5
XY-Wing: 1/3/9 in r3c49,r6c4 => r6c9<>9
Hidden Single: r6c4=9
Hidden Single: r4c7=9
Hidden Single: r4c3=8
Hidden Single: r1c7=8
Hidden Single: r2c2=8
Locked Pair: 3,9 in r23c9 => r12c8,r3c7,r58c9<>3
Naked Single: r5c9=2
Naked Single: r2c8=7
Naked Single: r5c7=3
Hidden Single: r1c1=3
Hidden Single: r8c8=3
Hidden Single: r7c5=3
Hidden Single: r2c1=2
Hidden Single: r8c9=8
Naked Single: r6c9=5
Full House: r6c8=8
Naked Single: r9c9=6
Hidden Single: r4c4=2
Full House: r4c6=1
Hidden Single: r9c5=1
Naked Single: r2c5=9
Naked Single: r2c9=3
Full House: r2c4=1
Full House: r3c9=9
Full House: r3c4=3
Naked Single: r8c5=7
Full House: r1c5=2
Hidden Single: r9c2=7
Hidden Single: r3c2=5
Naked Single: r1c3=7
Naked Single: r3c7=4
Full House: r1c8=5
Full House: r1c6=4
Full House: r3c6=7
Full House: r9c8=4
Naked Single: r7c7=2
Full House: r9c7=5
Naked Single: r7c6=6
Naked Single: r9c1=9
Full House: r9c6=2
Full House: r8c6=9
Naked Single: r7c3=1
Full House: r7c2=4
Full House: r6c2=1
Full House: r6c1=4
Naked Single: r5c1=5
Full House: r5c3=9
Naked Single: r3c3=6
Full House: r3c1=1
Full House: r8c1=6
Full House: r8c3=5
|
normal_sudoku_2487
|
73.4.2...5..3...4242.6..39...27.513.3.5..428....23.9.......3....57.4...38635.74..
|
739452861586319742421678395692785134375194286148236957214963578957841623863527419
|
Basic 9x9 Sudoku 2487
|
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.
|
7 3 . 4 . 2 . . .
5 . . 3 . . . 4 2
4 2 . 6 . . 3 9 .
. . 2 7 . 5 1 3 .
3 . 5 . . 4 2 8 .
. . . 2 3 . 9 . .
. . . . . 3 . . .
. 5 7 . 4 . . . 3
8 6 3 5 . 7 4 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
739452861586319742421678395692785134375194286148236957214963578957841623863527419 #1 Medium (804)
Hidden Single: r3c2=2
Hidden Single: r5c7=2
Naked Single: r9c7=4
Hidden Single: r2c1=5
Hidden Single: r1c4=4
Hidden Single: r9c3=3
Hidden Single: r7c6=3
Hidden Single: r4c8=3
Hidden Single: r2c8=4
Hidden Single: r3c7=3
Hidden Single: r1c2=3
Hidden Single: r5c1=3
Locked Candidates Type 1 (Pointing): 6 in b1 => r6c3<>6
Locked Candidates Type 2 (Claiming): 8 in c4 => r7c5,r8c6<>8
Naked Pair: 1,8 in r3c36 => r3c59<>1, r3c59<>8
Locked Candidates Type 1 (Pointing): 1 in b3 => r1c35<>1
Hidden Triple: 1,8,9 in r179c9 => r17c9<>5, r17c9<>6, r7c9<>7
Locked Candidates Type 2 (Claiming): 6 in c9 => r6c8<>6
Hidden Pair: 5,7 in r7c78 => r7c78<>6, r7c7<>8, r7c8<>1, r7c8<>2
Hidden Single: r7c5=6
Hidden Single: r5c9=6
Naked Single: r4c9=4
Hidden Single: r6c6=6
Naked Single: r6c1=1
Hidden Single: r7c1=2
Naked Single: r8c1=9
Full House: r4c1=6
Naked Single: r8c6=1
Naked Single: r3c6=8
Full House: r2c6=9
Naked Single: r8c4=8
Naked Single: r3c3=1
Naked Single: r1c5=5
Naked Single: r7c4=9
Full House: r5c4=1
Full House: r9c5=2
Naked Single: r8c7=6
Full House: r8c8=2
Naked Single: r2c2=8
Naked Single: r7c3=4
Full House: r7c2=1
Naked Single: r3c5=7
Full House: r2c5=1
Full House: r3c9=5
Naked Single: r5c5=9
Full House: r4c5=8
Full House: r4c2=9
Full House: r5c2=7
Full House: r6c2=4
Full House: r6c3=8
Naked Single: r9c8=1
Full House: r9c9=9
Naked Single: r1c7=8
Naked Single: r2c3=6
Full House: r2c7=7
Full House: r1c3=9
Full House: r7c7=5
Naked Single: r7c9=8
Full House: r7c8=7
Naked Single: r6c9=7
Full House: r1c9=1
Full House: r1c8=6
Full House: r6c8=5
|
normal_sudoku_1222
|
.46.18....5.973614.31264....29.5....317.9.54..8....7...6..8...5.7...9..619..25.37
|
946518273852973614731264958629457381317896542485132769263781495578349126194625837
|
Basic 9x9 Sudoku 1222
|
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 . 1 8 . . .
. 5 . 9 7 3 6 1 4
. 3 1 2 6 4 . . .
. 2 9 . 5 . . . .
3 1 7 . 9 . 5 4 .
. 8 . . . . 7 . .
. 6 . . 8 . . . 5
. 7 . . . 9 . . 6
1 9 . . 2 5 . 3 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
946518273852973614731264958629457381317896542485132769263781495578349126194625837 #1 Unfair (1480)
Naked Single: r1c5=1
Hidden Single: r3c2=3
Hidden Single: r5c2=1
Hidden Single: r8c2=7
Hidden Single: r5c3=7
Hidden Single: r5c7=5
Locked Candidates Type 1 (Pointing): 1 in b9 => r4c7<>1
Locked Candidates Type 2 (Claiming): 6 in r5 => r4c46,r6c456<>6
Hidden Single: r3c5=6
Hidden Single: r2c7=6
Hidden Single: r3c6=4
Hidden Single: r9c6=5
Naked Single: r9c2=9
Full House: r2c2=5
Naked Single: r2c4=9
Full House: r1c4=5
Hidden Single: r9c4=6
Naked Single: r5c4=8
Naked Single: r5c9=2
Full House: r5c6=6
Hidden Single: r3c8=5
Hidden Single: r6c6=2
Hidden Single: r3c1=7
Hidden Single: r1c8=7
Hidden Single: r1c1=9
Naked Single: r1c9=3
Full House: r1c7=2
Hidden Single: r4c7=3
2-String Kite: 4 in r4c1,r8c5 (connected by r4c4,r6c5) => r8c1<>4
W-Wing: 2/8 in r2c3,r8c8 connected by 8 in r9c37 => r8c3<>2
XY-Wing: 2/4/8 in r27c1,r9c3 => r2c3,r8c1<>8
Naked Single: r2c3=2
Full House: r2c1=8
Uniqueness Test 2: 3/4 in r6c45,r8c45 => r47c4<>1
XYZ-Wing: 3/4/7 in r47c4,r8c5 => r8c4<>4
XY-Chain: 6 6- r4c1 -4- r7c1 -2- r7c8 -9- r6c8 -6 => r4c8,r6c1<>6
Naked Single: r4c8=8
Naked Single: r4c9=1
Naked Single: r8c8=2
Naked Single: r4c6=7
Full House: r7c6=1
Naked Single: r6c9=9
Full House: r3c9=8
Full House: r6c8=6
Full House: r7c8=9
Full House: r3c7=9
Naked Single: r8c1=5
Naked Single: r4c4=4
Full House: r4c1=6
Naked Single: r8c4=3
Naked Single: r7c7=4
Naked Single: r6c1=4
Full House: r7c1=2
Full House: r6c3=5
Naked Single: r6c5=3
Full House: r6c4=1
Full House: r7c4=7
Full House: r8c5=4
Full House: r7c3=3
Naked Single: r9c7=8
Full House: r8c7=1
Full House: r8c3=8
Full House: r9c3=4
|
normal_sudoku_1308
|
4.18...2..8..2.4....2..48.31.4..8.7272.1..594.9.24.....4.7..2.62.7.8..4...94.2...
|
471835629386921457952674813164598372728163594593247168845719236217386945639452781
|
Basic 9x9 Sudoku 1308
|
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 . 1 8 . . . 2 .
. 8 . . 2 . 4 . .
. . 2 . . 4 8 . 3
1 . 4 . . 8 . 7 2
7 2 . 1 . . 5 9 4
. 9 . 2 4 . . . .
. 4 . 7 . . 2 . 6
2 . 7 . 8 . . 4 .
. . 9 4 . 2 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
471835629386921457952674813164598372728163594593247168845719236217386945639452781 #1 Extreme (26602) bf
Hidden Single: r5c2=2
Hidden Single: r1c4=8
Hidden Single: r9c4=4
Hidden Single: r2c5=2
Hidden Single: r8c1=2
Hidden Single: r7c2=4
Finned X-Wing: 1 r37 c58 fr7c6 => r9c5<>1
Brute Force: r5c8=9
Locked Candidates Type 1 (Pointing): 9 in b9 => r8c46<>9
Forcing Net Verity => r1c5<>9
r1c7=9 r1c5<>9
r1c9=9 r1c5<>9
r2c7=9 (r2c7<>1) (r2c7<>7) r2c7<>4 r2c9=4 (r2c9<>1) r2c9<>7 r2c6=7 r2c6<>1 r2c8=1 (r7c8<>1) r3c8<>1 r3c5=1 r7c5<>1 r7c6=1 r7c6<>9 r7c5=9 r1c5<>9
r2c9=9 (r2c9<>1) (r2c9<>7) r2c9<>4 r2c7=4 (r2c7<>1) r2c7<>7 r2c6=7 r2c6<>1 r2c8=1 (r7c8<>1) r3c8<>1 r3c5=1 r7c5<>1 r7c6=1 r7c6<>9 r7c5=9 r1c5<>9
Forcing Net Contradiction in r2 => r2c7<>6
r2c7=6 (r2c7<>1) (r2c7<>7) r2c7<>4 r2c9=4 (r2c9<>1) r2c9<>7 r2c6=7 r2c6<>1 r2c8=1 (r7c8<>1) r3c8<>1 r3c5=1 (r3c5<>9) r7c5<>1 r7c6=1 r7c6<>9 r7c5=9 r4c5<>9 r4c4=9 r3c4<>9 r3c1=9 r2c1<>9
r2c7=6 (r2c7<>1) (r2c7<>7) r2c7<>4 r2c9=4 (r2c9<>1) r2c9<>7 r2c6=7 r2c6<>1 r2c8=1 (r7c8<>1) r3c8<>1 r3c5=1 r7c5<>1 r7c6=1 r7c6<>9 r12c6=9 r2c4<>9
r2c7=6 (r2c7<>7) r2c7<>4 r2c9=4 r2c9<>7 r2c6=7 r2c6<>9
r2c7=6 r2c7<>9
r2c7=6 r2c7<>4 r2c9=4 r2c9<>9
Forcing Net Contradiction in r2 => r2c9<>5
r2c9=5 (r2c9<>1) (r2c9<>7) r2c9<>4 r2c7=4 (r2c7<>1) r2c7<>7 r2c6=7 r2c6<>1 r2c8=1 (r7c8<>1) r3c8<>1 r3c5=1 (r3c5<>9) r7c5<>1 r7c6=1 r7c6<>9 r7c5=9 r4c5<>9 r4c4=9 r3c4<>9 r3c1=9 r2c1<>9
r2c9=5 (r2c9<>1) (r2c9<>7) r2c9<>4 r2c7=4 (r2c7<>1) r2c7<>7 r2c6=7 r2c6<>1 r2c8=1 (r7c8<>1) r3c8<>1 r3c5=1 r7c5<>1 r7c6=1 r7c6<>9 r12c6=9 r2c4<>9
r2c9=5 (r2c9<>7) r2c9<>4 r2c7=4 r2c7<>7 r2c6=7 r2c6<>9
r2c9=5 r2c9<>4 r2c7=4 r2c7<>9
r2c9=5 r2c9<>9
Forcing Net Contradiction in r9 => r6c5<>3
r6c5=3 (r4c4<>3) (r4c5<>3) (r5c5<>3) r5c6<>3 (r5c6=6 r8c6<>6) (r5c6=6 r4c4<>6) (r5c6=6 r4c5<>6) r5c3=3 r4c2<>3 r4c7=3 r4c7<>6 r4c2=6 (r9c2<>6) r8c2<>6 r8c4=6 r9c5<>6 r9c1=6 r9c1<>3
r6c5=3 (r1c5<>3) (r4c4<>3) (r4c4<>3) (r4c5<>3) (r5c5<>3) r5c6<>3 (r5c6=6 r8c6<>6) (r5c6=6 r4c4<>6) (r5c6=6 r4c5<>6) r5c3=3 r4c2<>3 r4c7=3 r4c7<>6 r4c2=6 r8c2<>6 r8c4=6 r8c4<>3 r2c4=3 r1c6<>3 r1c2=3 r9c2<>3
r6c5=3 r9c5<>3
r6c5=3 (r4c4<>3) (r4c5<>3) (r5c5<>3) r5c6<>3 r5c3=3 r4c2<>3 r4c7=3 r9c7<>3
r6c5=3 (r6c5<>4 r5c5=4 r5c9<>4 r5c9=8 r9c9<>8) (r4c4<>3) (r4c5<>3) (r5c5<>3) r5c6<>3 (r5c6=6 r8c6<>6) (r5c6=6 r4c4<>6) (r5c6=6 r4c5<>6) r5c3=3 r4c2<>3 r4c7=3 r4c7<>6 r4c2=6 (r9c2<>6) r8c2<>6 r8c4=6 r9c5<>6 r9c1=6 r9c1<>8 r9c8=8 r9c8<>3
Forcing Net Contradiction in c4 => r6c6<>3
r6c6=3 (r8c6<>3) (r4c4<>3) (r4c5<>3) (r5c5<>3) r5c6<>3 (r5c6=6 r8c6<>6) (r5c6=6 r4c4<>6) (r5c6=6 r4c5<>6) r5c3=3 r4c2<>3 r4c7=3 (r8c7<>3) r4c7<>6 r4c2=6 r8c2<>6 r8c4=6 r8c4<>3 r8c2=3 r1c2<>3 r1c56=3 r2c4<>3
r6c6=3 r4c4<>3
r6c6=3 (r4c4<>3) (r4c5<>3) (r5c5<>3) r5c6<>3 (r5c6=6 r8c6<>6) (r5c6=6 r4c4<>6) (r5c6=6 r4c5<>6) r5c3=3 r4c2<>3 r4c7=3 r4c7<>6 r4c2=6 r8c2<>6 r8c4=6 r8c4<>3
Forcing Net Contradiction in r8 => r6c6<>6
r6c6=6 (r1c6<>6) (r4c4<>6) (r4c5<>6) (r5c5<>6) r5c6<>6 (r5c6=3 r1c6<>3) (r5c6=3 r4c4<>3) (r5c6=3 r4c5<>3) r5c3=6 r4c2<>6 r4c7=6 (r1c7<>6) r4c7<>3 r4c2=3 r1c2<>3 r1c5=3 r1c5<>6 r1c2=6 r8c2<>6
r6c6=6 (r4c4<>6) (r4c5<>6) (r5c5<>6) r5c6<>6 (r5c6=3 r4c4<>3) (r5c6=3 r1c6<>3) (r5c6=3 r4c4<>3) (r5c6=3 r4c5<>3) r5c3=6 r4c2<>6 r4c7=6 r4c7<>3 r4c2=3 r1c2<>3 r1c5=3 r2c4<>3 r8c4=3 r8c4<>6
r6c6=6 r8c6<>6
Forcing Net Verity => r7c6<>5
r2c6=1 (r7c6<>1) r3c5<>1 r3c8=1 r7c8<>1 r7c5=1 r7c5<>9 r7c6=9 r7c6<>5
r2c7=1 (r2c7<>7) r2c7<>4 r2c9=4 r2c9<>7 r2c6=7 r6c6<>7 r6c6=5 r7c6<>5
r2c8=1 (r7c8<>1) r3c8<>1 r3c5=1 r7c5<>1 r7c6=1 r7c6<>5
r2c9=1 (r2c9<>7) r2c9<>4 r2c7=4 r2c7<>7 r2c6=7 r6c6<>7 r6c6=5 r7c6<>5
Brute Force: r5c9=4
Hidden Single: r2c7=4
Hidden Single: r6c5=4
Hidden Single: r5c3=8
Hidden Single: r6c6=7
Hidden Single: r2c9=7
Hidden Single: r9c7=7
Locked Candidates Type 1 (Pointing): 1 in b3 => r679c8<>1
Locked Candidates Type 1 (Pointing): 9 in b3 => r1c6<>9
Locked Candidates Type 1 (Pointing): 5 in b5 => r4c2<>5
Locked Candidates Type 2 (Claiming): 3 in r5 => r4c45<>3
Locked Candidates Type 2 (Claiming): 6 in r5 => r4c45<>6
Locked Candidates Type 2 (Claiming): 1 in r7 => r8c6<>1
Naked Triple: 3,5,6 in r8c46,r9c5 => r7c56<>3, r7c5<>5
Naked Triple: 3,5,6 in r158c6 => r2c6<>3, r2c6<>5, r2c6<>6
Empty Rectangle: 3 in b1 (r28c4) => r8c2<>3
Finned Jellyfish: 3 r1458 c2567 fr8c4 => r9c5<>3
Locked Candidates Type 1 (Pointing): 3 in b8 => r8c7<>3
Locked Candidates Type 1 (Pointing): 3 in b9 => r6c8<>3
Finned Jellyfish: 6 r1458 c2567 fr8c4 => r9c5<>6
Naked Single: r9c5=5
Naked Single: r4c5=9
Naked Single: r4c4=5
Naked Single: r7c5=1
Naked Single: r7c6=9
Naked Single: r2c6=1
Hidden Single: r1c6=5
Naked Single: r1c9=9
Naked Single: r1c7=6
Naked Single: r2c8=5
Full House: r3c8=1
Naked Single: r4c7=3
Full House: r4c2=6
Naked Single: r6c7=1
Full House: r8c7=9
Naked Single: r6c9=8
Full House: r6c8=6
Naked Single: r9c9=1
Full House: r8c9=5
Naked Single: r9c2=3
Naked Single: r8c2=1
Naked Single: r1c2=7
Full House: r1c5=3
Full House: r3c2=5
Naked Single: r7c3=5
Naked Single: r9c8=8
Full House: r7c8=3
Full House: r7c1=8
Full House: r9c1=6
Naked Single: r5c5=6
Full House: r3c5=7
Full House: r5c6=3
Full House: r8c6=6
Full House: r8c4=3
Naked Single: r6c3=3
Full House: r2c3=6
Full House: r6c1=5
Naked Single: r3c1=9
Full House: r2c1=3
Full House: r2c4=9
Full House: r3c4=6
|
normal_sudoku_1295
|
948753621..39...7.72.8....9.9734..1.8.41...9....598.....9.3.1..471.89.3.3..4..9..
|
948753621513926478726814359697342815854167293132598764289635147471289536365471982
|
Basic 9x9 Sudoku 1295
|
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 8 7 5 3 6 2 1
. . 3 9 . . . 7 .
7 2 . 8 . . . . 9
. 9 7 3 4 . . 1 .
8 . 4 1 . . . 9 .
. . . 5 9 8 . . .
. . 9 . 3 . 1 . .
4 7 1 . 8 9 . 3 .
3 . . 4 . . 9 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
948753621513926478726814359697342815854167293132598764289635147471289536365471982 #1 Medium (452)
Hidden Single: r6c5=9
Hidden Single: r8c3=1
Naked Single: r1c3=8
Naked Single: r1c8=2
Naked Single: r1c4=7
Hidden Single: r4c2=9
Hidden Single: r3c4=8
Hidden Single: r3c1=7
Hidden Single: r3c9=9
Hidden Single: r1c1=9
Locked Candidates Type 1 (Pointing): 1 in b1 => r2c569<>1
Hidden Single: r1c9=1
Full House: r1c6=3
Hidden Single: r3c7=3
Locked Candidates Type 1 (Pointing): 7 in b5 => r5c79<>7
Hidden Single: r6c7=7
Hidden Single: r2c7=4
Naked Single: r3c8=5
Full House: r2c9=8
Naked Single: r3c3=6
Naked Single: r3c5=1
Full House: r3c6=4
Naked Single: r6c3=2
Full House: r9c3=5
Hidden Single: r4c7=8
Hidden Single: r9c6=1
Hidden Single: r7c1=2
Naked Single: r7c4=6
Full House: r8c4=2
Naked Single: r7c2=8
Full House: r9c2=6
Naked Single: r8c7=5
Full House: r5c7=2
Full House: r8c9=6
Naked Single: r9c5=7
Full House: r7c6=5
Naked Single: r7c8=4
Full House: r7c9=7
Naked Single: r9c8=8
Full House: r9c9=2
Full House: r6c8=6
Naked Single: r4c9=5
Naked Single: r5c5=6
Full House: r2c5=2
Full House: r2c6=6
Naked Single: r6c1=1
Naked Single: r4c1=6
Full House: r4c6=2
Full House: r5c6=7
Full House: r2c1=5
Full House: r2c2=1
Naked Single: r5c9=3
Full House: r5c2=5
Full House: r6c2=3
Full House: r6c9=4
|
normal_sudoku_2464
|
.9.27.6.8..26..79......924.21.59.87....78231..7...6529.2.9..1.735......2..1.2....
|
594271638132648795687359241216593874945782316873416529428935167359167482761824953
|
Basic 9x9 Sudoku 2464
|
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 . 2 7 . 6 . 8
. . 2 6 . . 7 9 .
. . . . . 9 2 4 .
2 1 . 5 9 . 8 7 .
. . . 7 8 2 3 1 .
. 7 . . . 6 5 2 9
. 2 . 9 . . 1 . 7
3 5 . . . . . . 2
. . 1 . 2 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
594271638132648795687359241216593874945782316873416529428935167359167482761824953 #1 Extreme (3672)
Hidden Single: r4c8=7
Hidden Single: r5c6=2
Hidden Single: r6c8=2
Hidden Single: r3c7=2
Hidden Single: r1c4=2
Hidden Single: r4c7=8
Hidden Single: r9c5=2
Hidden Single: r3c6=9
Hidden Single: r2c8=9
Locked Candidates Type 1 (Pointing): 4 in b6 => r9c9<>4
Locked Candidates Type 1 (Pointing): 6 in b6 => r9c9<>6
Naked Pair: 4,6 in r5c29 => r5c13<>4, r5c13<>6
Naked Triple: 4,6,8 in r7c13,r9c2 => r8c3,r9c1<>4, r8c3,r9c1<>6, r8c3,r9c1<>8
Skyscraper: 1 in r1c1,r4c2 (connected by r14c6) => r23c2,r6c1<>1
Hidden Single: r4c2=1
Locked Candidates Type 1 (Pointing): 3 in b4 => r13c3<>3
Empty Rectangle: 3 in b9 (r1c68) => r9c6<>3
Discontinuous Nice Loop: 4 r8c5 -4- r8c7 -9- r8c3 -7- r3c3 =7= r3c1 =6= r7c1 -6- r7c5 =6= r8c5 => r8c5<>4
Discontinuous Nice Loop: 8 r8c6 -8- r8c8 -6- r8c5 =6= r7c5 -6- r7c1 =6= r3c1 =7= r3c3 -7- r8c3 =7= r8c6 => r8c6<>8
Discontinuous Nice Loop: 3 r9c8 -3- r1c8 =3= r1c6 -3- r4c6 =3= r4c3 =6= r5c2 -6- r9c2 =6= r9c8 => r9c8<>3
Grouped Discontinuous Nice Loop: 8 r7c8 -8- r8c8 -6- r9c8 =6= r9c2 =8= r7c13 -8- r7c8 => r7c8<>8
Finned Swordfish: 8 r267 c136 fr2c2 => r3c13<>8
Almost Locked Set XZ-Rule: A=r1c13,r23c1,r3c3 {145678}, B=r5c123,r6c1 {45689}, X=8, Z=6 => r3c2<>6
Hidden Pair: 6,7 in r3c13 => r3c1<>1, r3c13<>5
Grouped Discontinuous Nice Loop: 3 r3c9 -3- r1c8 -5- r1c3 =5= r5c3 =9= r8c3 =7= r8c6 =1= r12c6 -1- r3c45 =1= r3c9 => r3c9<>3
Forcing Chain Contradiction in r7c8 => r1c3=4
r1c3<>4 r1c3=5 r1c8<>5 r1c8=3 r7c8<>3
r1c3<>4 r1c3=5 r5c3<>5 r5c3=9 r5c1<>9 r9c1=9 r9c1<>7 r9c6=7 r9c6<>5 r7c56=5 r7c8<>5
r1c3<>4 r1c3=5 r5c3<>5 r5c3=9 r5c1<>9 r9c1=9 r9c1<>7 r3c1=7 r3c1<>6 r7c1=6 r7c8<>6
Hidden Single: r5c3=5
Naked Single: r5c1=9
Naked Single: r9c1=7
Naked Single: r3c1=6
Naked Single: r8c3=9
Naked Single: r3c3=7
Naked Single: r8c7=4
Full House: r9c7=9
Hidden Single: r8c6=7
Locked Pair: 3,8 in r23c2 => r2c1,r9c2<>8
Locked Candidates Type 1 (Pointing): 8 in b7 => r7c6<>8
Locked Candidates Type 2 (Claiming): 1 in c6 => r23c5,r3c4<>1
Hidden Single: r3c9=1
Hidden Single: r3c5=5
Skyscraper: 4 in r7c1,r9c4 (connected by r6c14) => r7c56,r9c2<>4
Naked Single: r9c2=6
Naked Single: r5c2=4
Full House: r5c9=6
Full House: r4c9=4
Naked Single: r7c3=8
Full House: r7c1=4
Naked Single: r6c1=8
Naked Single: r4c6=3
Full House: r4c3=6
Full House: r6c3=3
Naked Single: r1c6=1
Naked Single: r7c6=5
Naked Single: r1c1=5
Full House: r1c8=3
Full House: r2c1=1
Full House: r2c9=5
Full House: r9c9=3
Naked Single: r7c8=6
Full House: r7c5=3
Naked Single: r8c8=8
Full House: r9c8=5
Naked Single: r2c5=4
Naked Single: r8c4=1
Full House: r8c5=6
Full House: r6c5=1
Full House: r6c4=4
Naked Single: r2c6=8
Full House: r2c2=3
Full House: r3c4=3
Full House: r9c4=8
Full House: r9c6=4
Full House: r3c2=8
|
normal_sudoku_2022
|
...83...5..2.1.6..1....7.3.321......9.732.4...64....23.1..9.3.....5....76....3.8.
|
496832175732415698185967234321674859957328416864159723518796342243581967679243581
|
Basic 9x9 Sudoku 2022
|
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 3 . . . 5
. . 2 . 1 . 6 . .
1 . . . . 7 . 3 .
3 2 1 . . . . . .
9 . 7 3 2 . 4 . .
. 6 4 . . . . 2 3
. 1 . . 9 . 3 . .
. . . 5 . . . . 7
6 . . . . 3 . 8 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
496832175732415698185967234321674859957328416864159723518796342243581967679243581 #1 Extreme (19032) bf
Finned Swordfish: 1 r168 c678 fr6c4 => r45c6<>1
Brute Force: r5c3=7
Hidden Single: r4c3=1
2-String Kite: 3 in r1c5,r5c2 (connected by r4c5,r5c4) => r1c2<>3
X-Chain: 3 r5c2 =3= r5c4 -3- r2c4 =3= r1c5 -3- r1c3 =3= r8c3 => r8c2<>3
Forcing Chain Contradiction in r5 => r8c2<>8
r8c2=8 r5c2<>8
r8c2=8 r8c5<>8 r46c5=8 r5c6<>8
r8c2=8 r78c3<>8 r3c3=8 r3c7<>8 r46c7=8 r5c9<>8
Almost Locked Set XZ-Rule: A=r1246c1 {34578}, B=r18c2 {479}, X=7, Z=4 => r23c2<>4
Forcing Chain Contradiction in r5 => r9c2<>5
r9c2=5 r5c2<>5
r9c2=5 r79c3<>5 r3c3=5 r3c5<>5 r2c6=5 r5c6<>5
r9c2=5 r9c7<>5 r7c8=5 r5c8<>5
Naked Triple: 4,7,9 in r189c2 => r2c2<>7, r23c2<>9
Forcing Chain Contradiction in r5 => r5c6<>5
r5c6=5 r2c6<>5 r3c5=5 r3c2<>5 r3c2=8 r5c2<>8
r5c6=5 r5c6<>8
r5c6=5 r2c6<>5 r3c5=5 r3c2<>5 r3c2=8 r3c7<>8 r46c7=8 r5c9<>8
Discontinuous Nice Loop: 9 r8c3 -9- r9c3 -5- r9c7 =5= r7c8 -5- r5c8 =5= r5c2 =3= r2c2 -3- r1c3 =3= r8c3 => r8c3<>9
Grouped Discontinuous Nice Loop: 4 r1c5 -4- r9c5 -7- r9c2 =7= r1c2 =9= r89c2 -9- r9c3 -5- r9c7 =5= r7c8 -5- r5c8 =5= r5c2 =3= r5c4 -3- r2c4 =3= r1c5 => r1c5<>4
Forcing Chain Contradiction in r8c5 => r8c3=3
r8c3<>3 r8c3=8 r7c3<>8 r7c3=5 r9c3<>5 r9c3=9 r8c2<>9 r8c2=4 r8c5<>4
r8c3<>3 r1c3=3 r1c5<>3 r1c5=6 r8c5<>6
r8c3<>3 r8c3=8 r8c5<>8
AIC: 3 3- r1c5 -6- r1c3 -9- r9c3 -5- r9c7 =5= r7c8 -5- r5c8 =5= r5c2 =3= r2c2 -3 => r1c1,r2c4<>3
Hidden Single: r1c5=3
Forcing Chain Contradiction in r7 => r2c2=3
r2c2<>3 r5c2=3 r5c2<>5 r46c1=5 r7c1<>5
r2c2<>3 r5c2=3 r5c2<>8 r46c1=8 r78c1<>8 r7c3=8 r7c3<>5
r2c2<>3 r5c2=3 r5c2<>5 r5c8=5 r7c8<>5
Hidden Single: r4c1=3
Hidden Single: r5c4=3
Locked Candidates Type 1 (Pointing): 1 in b5 => r6c7<>1
2-String Kite: 8 in r2c9,r5c2 (connected by r2c1,r3c2) => r5c9<>8
Grouped Discontinuous Nice Loop: 4 r8c5 -4- r8c2 -9- r9c3 -5- r9c7 =5= r7c8 -5- r5c8 =5= r5c2 =8= r5c6 -8- r46c5 =8= r8c5 => r8c5<>4
Forcing Chain Contradiction in r7 => r2c9=8
r2c9<>8 r2c1=8 r6c1<>8 r6c1=5 r7c1<>5
r2c9<>8 r2c1=8 r3c3<>8 r7c3=8 r7c3<>5
r2c9<>8 r2c1=8 r6c1<>8 r6c1=5 r5c2<>5 r5c8=5 r7c8<>5
Discontinuous Nice Loop: 5 r4c7 -5- r5c8 =5= r5c2 =8= r6c1 -8- r6c7 =8= r4c7 => r4c7<>5
Grouped Discontinuous Nice Loop: 9 r1c6 -9- r1c23 =9= r3c3 -9- r3c7 -2- r3c4 =2= r1c6 => r1c6<>9
Grouped Discontinuous Nice Loop: 7 r4c4 -7- r7c4 =7= r7c1 -7- r9c2 =7= r1c2 =9= r89c2 -9- r9c3 -5- r9c7 =5= r6c7 =7= r4c78 -7- r4c4 => r4c4<>7
Grouped Discontinuous Nice Loop: 9 r4c4 -9- r4c9 -6- r4c456 =6= r5c6 =8= r5c2 =5= r3c2 -5- r3c5 =5= r2c6 =9= r23c4 -9- r4c4 => r4c4<>9
Grouped Discontinuous Nice Loop: 9 r9c9 -9- r9c3 -5- r9c7 =5= r6c7 -5- r6c1 -8- r5c2 =8= r5c6 =6= r4c456 -6- r4c9 -9- r9c9 => r9c9<>9
Almost Locked Set XZ-Rule: A=r9c5 {47}, B=r2347c4 {24679}, X=7, Z=4 => r9c4<>4
Almost Locked Set XZ-Rule: A=r1389c7 {12579}, B=r89c2,r9c3 {4579}, X=5, Z=7 => r1c2<>7
Hidden Single: r9c2=7
Naked Single: r9c5=4
Hidden Single: r7c4=7
Naked Pair: 1,2 in r9c49 => r9c7<>1, r9c7<>2
2-String Kite: 9 in r1c2,r9c7 (connected by r8c2,r9c3) => r1c7<>9
Sue de Coq: r78c6 - {1268} (r5c6 - {68}, r9c4 - {12}) => r14c6<>6, r46c6<>8
Hidden Single: r1c3=6
XY-Chain: 6 6- r4c4 -4- r2c4 -9- r6c4 -1- r9c4 -2- r9c9 -1- r5c9 -6 => r4c89,r5c6<>6
Naked Single: r4c9=9
Naked Single: r5c6=8
Naked Single: r5c2=5
Full House: r6c1=8
Naked Single: r3c2=8
Hidden Single: r4c7=8
Hidden Single: r8c5=8
Hidden Single: r7c3=8
Naked Pair: 5,7 in r6c57 => r6c6<>5
Swordfish: 5 r369 c357 => r4c5<>5
W-Wing: 2/4 in r1c6,r8c1 connected by 4 in r18c2 => r8c6<>2
XYZ-Wing: 4/5/9 in r2c46,r4c6 => r1c6<>4
Naked Single: r1c6=2
Naked Single: r7c6=6
Naked Single: r8c6=1
Full House: r9c4=2
Naked Single: r6c6=9
Naked Single: r9c9=1
Naked Single: r6c4=1
Naked Single: r5c9=6
Full House: r5c8=1
Hidden Single: r8c8=6
Hidden Single: r1c7=1
Hidden Single: r6c7=7
Full House: r4c8=5
Full House: r6c5=5
Naked Single: r4c6=4
Full House: r2c6=5
Naked Single: r7c8=4
Naked Single: r3c5=6
Full House: r4c5=7
Full House: r4c4=6
Naked Single: r7c9=2
Full House: r3c9=4
Full House: r7c1=5
Naked Single: r8c7=9
Full House: r9c7=5
Full House: r9c3=9
Full House: r3c7=2
Full House: r3c3=5
Full House: r3c4=9
Full House: r2c4=4
Naked Single: r8c2=4
Full House: r1c2=9
Full House: r8c1=2
Naked Single: r2c1=7
Full House: r1c1=4
Full House: r1c8=7
Full House: r2c8=9
|
normal_sudoku_6295
|
.1.2.4..8...3...6.....7.2..1..7.86.5.75612.....8..371259.4.......1..9..448..3..2.
|
716254398259381467843976251124798635375612849968543712592467183631829574487135926
|
Basic 9x9 Sudoku 6295
|
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 . 2 . 4 . . 8
. . . 3 . . . 6 .
. . . . 7 . 2 . .
1 . . 7 . 8 6 . 5
. 7 5 6 1 2 . . .
. . 8 . . 3 7 1 2
5 9 . 4 . . . . .
. . 1 . . 9 . . 4
4 8 . . 3 . . 2 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
716254398259381467843976251124798635375612849968543712592467183631829574487135926 #1 Extreme (14306) bf
Brute Force: r5c2=7
Naked Single: r5c6=2
Hidden Single: r4c4=7
Hidden Single: r6c9=2
Hidden Single: r6c8=1
Hidden Single: r4c7=6
Locked Candidates Type 2 (Claiming): 4 in r5 => r4c8<>4
Naked Pair: 3,9 in r4c8,r5c9 => r5c78<>3, r5c78<>9
2-String Kite: 2 in r1c4,r7c3 (connected by r7c5,r8c4) => r1c3<>2
Turbot Fish: 7 r2c9 =7= r1c8 -7- r8c8 =7= r8c1 => r2c1<>7
Finned Swordfish: 6 r168 c125 fr1c3 => r3c12<>6
Sue de Coq: r123c3 - {234679} (r9c3 - {67}, r2c12,r3c12 - {234589}) => r1c1<>2, r1c1<>3, r1c1<>9, r7c3<>6, r7c3<>7
Locked Candidates Type 1 (Pointing): 2 in b1 => r2c5<>2
AIC: 2/8 2- r7c5 =2= r7c3 -2- r8c1 =2= r2c1 =8= r2c5 -8- r3c4 =8= r8c4 -8 => r8c4<>2, r7c5<>8
Hidden Single: r1c4=2
Locked Candidates Type 1 (Pointing): 8 in b8 => r8c78<>8
AIC: 6/7 7- r7c6 =7= r9c6 -7- r9c3 -6- r9c9 =6= r7c9 -6 => r7c6<>6, r7c9<>7
Discontinuous Nice Loop: 5 r2c5 -5- r6c5 =5= r6c4 =9= r3c4 =8= r2c5 => r2c5<>5
Discontinuous Nice Loop: 9 r2c9 -9- r5c9 =9= r5c1 -9- r6c1 -6- r1c1 -7- r1c8 =7= r2c9 => r2c9<>9
Discontinuous Nice Loop: 1 r7c6 -1- r9c4 -5- r6c4 -9- r6c1 -6- r6c2 =6= r8c2 -6- r9c3 -7- r9c6 =7= r7c6 => r7c6<>1
Naked Single: r7c6=7
Locked Candidates Type 1 (Pointing): 1 in b8 => r9c79<>1
Naked Triple: 3,5,9 in r189c7 => r2c7<>5, r2c7<>9, r7c7<>3
X-Wing: 7 r29 c39 => r1c3<>7
Empty Rectangle: 3 in b7 (r18c7) => r1c3<>3
Locked Candidates Type 1 (Pointing): 3 in b1 => r3c89<>3
XY-Chain: 7 7- r1c1 -6- r6c1 -9- r5c1 -3- r5c9 -9- r3c9 -1- r2c9 -7 => r1c8,r2c3<>7
Hidden Single: r1c1=7
Hidden Single: r8c8=7
Hidden Single: r2c9=7
Hidden Single: r9c3=7
Locked Candidates Type 1 (Pointing): 6 in b7 => r8c5<>6
Locked Candidates Type 1 (Pointing): 5 in b9 => r1c7<>5
XY-Chain: 4 4- r2c7 -1- r3c9 -9- r5c9 -3- r5c1 -9- r6c1 -6- r6c2 -4 => r2c2<>4
AIC: 1 1- r2c6 -5- r2c2 -2- r2c1 =2= r8c1 -2- r8c5 =2= r7c5 =6= r7c9 =1= r3c9 -1 => r2c7,r3c46<>1
Naked Single: r2c7=4
Naked Single: r5c7=8
Naked Single: r5c8=4
Naked Single: r7c7=1
Hidden Single: r2c6=1
Hidden Single: r3c9=1
Hidden Single: r9c4=1
Hidden Single: r7c8=8
Hidden Single: r2c2=5
Skyscraper: 3 in r5c1,r7c3 (connected by r57c9) => r4c3,r8c1<>3
Swordfish: 3 r148 c278 => r3c2<>3
Naked Single: r3c2=4
Naked Single: r6c2=6
Naked Single: r6c1=9
Naked Single: r5c1=3
Full House: r5c9=9
Full House: r4c8=3
Naked Single: r6c4=5
Full House: r6c5=4
Full House: r4c5=9
Naked Single: r3c1=8
Naked Single: r4c2=2
Full House: r4c3=4
Full House: r8c2=3
Naked Single: r9c9=6
Full House: r7c9=3
Naked Single: r8c4=8
Full House: r3c4=9
Naked Single: r2c5=8
Naked Single: r2c1=2
Full House: r2c3=9
Full House: r8c1=6
Full House: r7c3=2
Full House: r7c5=6
Naked Single: r8c7=5
Full House: r8c5=2
Full House: r9c6=5
Full House: r1c5=5
Full House: r9c7=9
Full House: r3c6=6
Full House: r1c7=3
Naked Single: r3c8=5
Full House: r1c8=9
Full House: r1c3=6
Full House: r3c3=3
|
normal_sudoku_4530
|
.37.58.198.1...57.59.71....9.527183..13.8....7829...51.7814.........71..15..2....
|
237458619861392574594716328945271836613584297782963451378145962429637185156829743
|
Basic 9x9 Sudoku 4530
|
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 . 5 8 . 1 9
8 . 1 . . . 5 7 .
5 9 . 7 1 . . . .
9 . 5 2 7 1 8 3 .
. 1 3 . 8 . . . .
7 8 2 9 . . . 5 1
. 7 8 1 4 . . . .
. . . . . 7 1 . .
1 5 . . 2 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
237458619861392574594716328945271836613584297782963451378145962429637185156829743 #1 Extreme (14002) bf
Hidden Single: r1c3=7
Hidden Single: r6c2=8
Hidden Single: r2c1=8
Hidden Single: r4c5=7
Hidden Single: r1c8=1
Hidden Single: r9c1=1
Hidden Single: r4c3=5
Hidden Single: r7c2=7
Hidden Single: r4c6=1
Hidden Single: r3c5=1
Hidden Single: r4c1=9
Brute Force: r6c3=2
Finned Franken Swordfish: 4 r16b4 c147 fr4c2 fr6c6 => r4c4<>4
W-Wing: 6/4 in r5c1,r6c7 connected by 4 in r4c29 => r5c789<>6
Sashimi Swordfish: 6 r156 c147 fr5c6 fr6c5 fr6c6 => r4c4<>6
Naked Single: r4c4=2
Naked Pair: 4,6 in r4c9,r6c7 => r5c789<>4
Forcing Chain Contradiction in r2 => r1c1<>4
r1c1=4 r1c1<>2 r2c2=2 r2c2<>6
r1c1=4 r1c4<>4 r1c4=6 r2c4<>6
r1c1=4 r1c4<>4 r1c4=6 r2c5<>6
r1c1=4 r1c4<>4 r1c4=6 r2c6<>6
r1c1=4 r5c1<>4 r5c1=6 r4c2<>6 r4c9=6 r2c9<>6
Skyscraper: 4 in r1c4,r6c6 (connected by r16c7) => r23c6,r5c4<>4
2-String Kite: 4 in r4c9,r8c1 (connected by r4c2,r5c1) => r8c9<>4
Turbot Fish: 4 r3c3 =4= r2c2 -4- r4c2 =4= r4c9 => r3c9<>4
Discontinuous Nice Loop: 6 r8c2 -6- r4c2 =6= r5c1 -6- r1c1 -2- r2c2 =2= r8c2 => r8c2<>6
Grouped Discontinuous Nice Loop: 4 r9c9 -4- r4c9 =4= r4c2 -4- r2c2 =4= r3c3 -4- r3c8 =4= r89c8 -4- r9c9 => r9c9<>4
Almost Locked Set XZ-Rule: A=r16c7 {246}, B=r1c1,r3c3 {246}, X=2, Z=4 => r3c7<>4
Empty Rectangle: 4 in b7 (r3c38) => r8c8<>4
Locked Candidates Type 1 (Pointing): 4 in b9 => r9c3<>4
Discontinuous Nice Loop: 9 r9c8 -9- r9c3 -6- r3c3 -4- r3c8 =4= r9c8 => r9c8<>9
Forcing Chain Verity => r1c1=2
r2c2=4 r2c2<>2 r1c1=2
r2c4=4 r1c4<>4 r1c4=6 r1c1<>6 r1c1=2
r2c9=4 r4c9<>4 r4c9=6 r4c2<>6 r2c2=6 r2c2<>2 r1c1=2
Hidden Single: r8c2=2
Naked Pair: 4,6 in r16c7 => r379c7<>6, r9c7<>4
Hidden Single: r9c8=4
Hidden Single: r3c3=4
Full House: r2c2=6
Full House: r4c2=4
Full House: r4c9=6
Full House: r5c1=6
Naked Single: r6c7=4
Naked Single: r5c4=5
Naked Single: r7c1=3
Full House: r8c1=4
Naked Single: r1c7=6
Full House: r1c4=4
Naked Single: r5c6=4
Naked Single: r2c4=3
Naked Single: r2c5=9
Naked Single: r2c6=2
Full House: r2c9=4
Full House: r3c6=6
Naked Single: r6c6=3
Full House: r6c5=6
Full House: r8c5=3
Naked Single: r9c6=9
Full House: r7c6=5
Naked Single: r9c3=6
Full House: r8c3=9
Naked Single: r7c9=2
Naked Single: r9c4=8
Full House: r8c4=6
Naked Single: r5c9=7
Naked Single: r7c7=9
Full House: r7c8=6
Naked Single: r8c8=8
Full House: r8c9=5
Naked Single: r9c9=3
Full House: r3c9=8
Full House: r9c7=7
Naked Single: r5c7=2
Full House: r3c7=3
Full House: r3c8=2
Full House: r5c8=9
|
normal_sudoku_1711
|
3...8.762..15..493.6...4815...732..1...4982.672.651..9.4.21...8..7.6.1.49......37
|
354189762871526493269374815496732581135498276728651349643217958587963124912845637
|
Basic 9x9 Sudoku 1711
|
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 . . . 8 . 7 6 2
. . 1 5 . . 4 9 3
. 6 . . . 4 8 1 5
. . . 7 3 2 . . 1
. . . 4 9 8 2 . 6
7 2 . 6 5 1 . . 9
. 4 . 2 1 . . . 8
. . 7 . 6 . 1 . 4
9 . . . . . . 3 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
354189762871526493269374815496732581135498276728651349643217958587963124912845637 #1 Easy (212)
Naked Single: r5c5=9
Naked Single: r1c9=2
Naked Single: r6c6=1
Full House: r4c6=2
Naked Single: r1c5=8
Naked Single: r2c9=3
Naked Single: r9c9=7
Naked Single: r8c5=6
Naked Single: r2c4=5
Naked Single: r3c7=8
Full House: r2c7=4
Naked Single: r6c9=9
Full House: r4c9=1
Naked Single: r7c8=5
Naked Single: r9c5=4
Naked Single: r9c6=5
Naked Single: r1c6=9
Naked Single: r9c4=8
Naked Single: r3c1=2
Naked Single: r4c7=5
Naked Single: r6c7=3
Naked Single: r5c8=7
Naked Single: r7c1=6
Naked Single: r8c8=2
Naked Single: r9c7=6
Full House: r7c7=9
Naked Single: r1c2=5
Naked Single: r1c4=1
Full House: r1c3=4
Naked Single: r3c4=3
Full House: r8c4=9
Naked Single: r8c6=3
Full House: r7c6=7
Full House: r7c3=3
Full House: r2c6=6
Naked Single: r9c2=1
Full House: r9c3=2
Naked Single: r2c1=8
Naked Single: r3c3=9
Full House: r3c5=7
Full House: r2c2=7
Full House: r2c5=2
Naked Single: r6c3=8
Full House: r6c8=4
Full House: r4c8=8
Naked Single: r8c2=8
Full House: r8c1=5
Naked Single: r5c3=5
Full House: r4c3=6
Naked Single: r5c2=3
Full House: r4c2=9
Full House: r4c1=4
Full House: r5c1=1
|
normal_sudoku_1968
|
.3...1..2..29..14.1...2.8....8.1...4.1.7...2.4....631..51...46.7..1.52.9..3.9...1
|
834571692572968143169423875628319754315784926497256318951832467786145239243697581
|
Basic 9x9 Sudoku 1968
|
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 . . 2
. . 2 9 . . 1 4 .
1 . . . 2 . 8 . .
. . 8 . 1 . . . 4
. 1 . 7 . . . 2 .
4 . . . . 6 3 1 .
. 5 1 . . . 4 6 .
7 . . 1 . 5 2 . 9
. . 3 . 9 . . . 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
834571692572968143169423875628319754315784926497256318951832467786145239243697581 #1 Extreme (4168)
Hidden Single: r5c2=1
Hidden Single: r8c4=1
Locked Candidates Type 1 (Pointing): 8 in b6 => r78c9<>8
Sashimi X-Wing: 9 r67 c19 fr6c2 fr6c3 => r45c1<>9
Almost Locked Set XZ-Rule: A=r7c456 {2378}, B=r78c9,r8c78 {23789}, X=7, Z=8 => r8c5<>8
Forcing Chain Contradiction in r3 => r7c1=9
r7c1<>9 r1c1=9 r3c2<>9
r7c1<>9 r1c1=9 r3c3<>9
r7c1<>9 r7c9=9 r8c9<>9 r8c9=3 r8c8<>3 r3c8=3 r3c8<>9
r7c1<>9 r7c9=9 r3c9<>9
Locked Candidates Type 2 (Claiming): 2 in r7 => r9c46<>2
Locked Candidates Type 2 (Claiming): 8 in r7 => r9c46<>8
Grouped Discontinuous Nice Loop: 4 r3c6 -4- r3c2 =4= r89c2 -4- r8c3 -6- r8c5 =6= r9c4 =4= r13c4 -4- r3c6 => r3c6<>4
W-Wing: 7/3 in r3c6,r7c9 connected by 3 in r38c8 => r3c9,r7c6<>7
W-Wing: 3/7 in r3c6,r7c9 connected by 7 in r7c5,r9c6 => r3c9,r7c6<>3
AIC: 3/9 3- r8c8 =3= r3c8 -3- r3c6 -7- r9c6 =7= r7c5 -7- r7c9 -3- r8c9 -9 => r8c9<>3, r8c8<>9
Naked Single: r8c9=9
Naked Single: r8c7=2
Locked Candidates Type 2 (Claiming): 9 in r6 => r4c2,r5c3<>9
2-String Kite: 3 in r2c9,r8c5 (connected by r7c9,r8c8) => r2c5<>3
AIC: 3 3- r2c6 =3= r2c9 -3- r7c9 -7- r7c5 =7= r9c6 -7- r3c6 -3 => r3c4,r45c6<>3
Discontinuous Nice Loop: 7 r2c6 -7- r9c6 =7= r7c5 -7- r7c9 -3- r2c9 =3= r2c6 => r2c6<>7
Finned Swordfish: 7 r267 c259 fr6c3 => r4c2<>7
Locked Candidates Type 1 (Pointing): 7 in b4 => r6c9<>7
Naked Pair: 5,8 in r6c59 => r6c34<>5, r6c4<>8
Naked Single: r6c4=2
Naked Single: r4c6=9
Hidden Single: r7c6=2
Hidden Single: r5c7=9
Naked Triple: 5,6,8 in r356c9 => r2c9<>5, r2c9<>6
Empty Rectangle: 5 in b4 (r2c15) => r5c5<>5
Turbot Fish: 5 r2c1 =5= r2c5 -5- r6c5 =5= r4c4 => r4c1<>5
Locked Candidates Type 1 (Pointing): 5 in b4 => r5c9<>5
Turbot Fish: 5 r3c9 =5= r6c9 -5- r6c5 =5= r4c4 => r3c4<>5
Naked Pair: 4,6 in r39c4 => r1c4<>4, r1c4<>6
W-Wing: 5/8 in r1c4,r6c5 connected by 8 in r7c45 => r12c5,r4c4<>5
Naked Single: r4c4=3
Naked Single: r7c4=8
Naked Single: r1c4=5
Hidden Single: r2c1=5
Hidden Single: r6c5=5
Naked Single: r6c9=8
Naked Single: r5c9=6
Naked Single: r3c9=5
Naked Single: r5c1=3
Naked Single: r5c3=5
Hidden Single: r1c7=6
Naked Single: r1c1=8
Skyscraper: 6 in r8c3,r9c4 (connected by r3c34) => r8c5,r9c12<>6
Naked Single: r9c1=2
Full House: r4c1=6
Naked Single: r4c2=2
Hidden Single: r2c5=6
Naked Single: r2c2=7
Naked Single: r3c4=4
Full House: r9c4=6
Naked Single: r2c9=3
Full House: r2c6=8
Full House: r7c9=7
Full House: r7c5=3
Naked Single: r6c2=9
Full House: r6c3=7
Naked Single: r1c5=7
Full House: r3c6=3
Naked Single: r5c6=4
Full House: r5c5=8
Full House: r8c5=4
Full House: r9c6=7
Naked Single: r9c7=5
Full House: r4c7=7
Full House: r4c8=5
Naked Single: r3c2=6
Naked Single: r1c8=9
Full House: r1c3=4
Full House: r3c3=9
Full House: r8c3=6
Full House: r3c8=7
Naked Single: r9c8=8
Full House: r8c8=3
Full House: r8c2=8
Full House: r9c2=4
|
normal_sudoku_3738
|
..8159..4.4.....5......489.7..6......1.3.5..7.869.7..58...96.2..9...1..8..7.3....
|
628159374149783256573264891735618942914325687286947135851496723392571468467832519
|
Basic 9x9 Sudoku 3738
|
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 1 5 9 . . 4
. 4 . . . . . 5 .
. . . . . 4 8 9 .
7 . . 6 . . . . .
. 1 . 3 . 5 . . 7
. 8 6 9 . 7 . . 5
8 . . . 9 6 . 2 .
. 9 . . . 1 . . 8
. . 7 . 3 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
628159374149783256573264891735618942914325687286947135851496723392571468467832519 #1 Extreme (14822) bf
Brute Force: r5c4=3
Locked Candidates Type 1 (Pointing): 4 in b5 => r78c5<>4
Forcing Chain Contradiction in r2c4 => r1c6<>2
r1c6=2 r2c4<>2
r1c6=2 r3c4<>2 r3c4=7 r2c4<>7
r1c6=2 r4c6<>2 r4c6=8 r9c6<>8 r9c4=8 r2c4<>8
Forcing Chain Contradiction in r7 => r2c5<>2
r2c5=2 r3c4<>2 r3c4=7 r7c4<>7
r2c5=2 r2c5<>9 r7c5=9 r7c5<>7
r2c5=2 r3c4<>2 r3c4=7 r2c45<>7 r2c7=7 r7c7<>7
Forcing Chain Contradiction in r2c4 => r2c6<>2
r2c6=2 r2c4<>2
r2c6=2 r3c4<>2 r3c4=7 r2c4<>7
r2c6=2 r4c6<>2 r4c6=8 r9c6<>8 r9c4=8 r2c4<>8
Forcing Chain Contradiction in c2 => r2c1<>2
r2c1=2 r1c2<>2
r2c1=2 r3c2<>2
r2c1=2 r1c12<>2 r1c7=2 r456c7<>2 r4c9=2 r4c2<>2
r2c1=2 r1c12<>2 r1c7=2 r456c7<>2 r4c9=2 r4c6<>2 r9c6=2 r9c2<>2
Forcing Chain Contradiction in c2 => r2c3<>2
r2c3=2 r1c2<>2
r2c3=2 r3c2<>2
r2c3=2 r1c12<>2 r1c7=2 r456c7<>2 r4c9=2 r4c2<>2
r2c3=2 r1c12<>2 r1c7=2 r456c7<>2 r4c9=2 r4c6<>2 r9c6=2 r9c2<>2
Forcing Chain Contradiction in r7 => r1c7<>2
r1c7=2 r1c12<>2 r3c123=2 r3c4<>2 r3c4=7 r7c4<>7
r1c7=2 r456c7<>2 r4c9=2 r4c6<>2 r4c6=8 r45c5<>8 r2c5=8 r2c5<>9 r7c5=9 r7c5<>7
r1c7=2 r1c12<>2 r3c123=2 r3c4<>2 r3c4=7 r2c45<>7 r2c7=7 r7c7<>7
Locked Candidates Type 2 (Claiming): 2 in r1 => r3c123<>2
Almost Locked Set XY-Wing: A=r1c1278 {23679}, B=r3c45 {267}, C=r2c13,r3c123 {135679}, X,Y=7,9, Z=6 => r1c6<>6
Forcing Chain Contradiction in r7 => r3c4=2
r3c4<>2 r3c4=7 r7c4<>7
r3c4<>2 r3c4=7 r3c2<>7 r1c2=7 r1c2<>2 r1c1=2 r1c1<>9 r1c6=9 r2c5<>9 r7c5=9 r7c5<>7
r3c4<>2 r3c4=7 r2c45<>7 r2c7=7 r7c7<>7
XYZ-Wing: 6/7/9 in r37c5,r7c6 => r8c5<>6
Finned Swordfish: 6 r158 c178 fr1c2 => r23c1<>6
Hidden Triple: 2,6,7 in r1c12,r3c2 => r1c12,r3c2<>3, r1c1<>9, r3c2<>5
Hidden Single: r1c6=9
Naked Single: r7c6=6
Hidden Single: r7c5=9
Hidden Single: r2c6=3
Locked Pair: 1,9 in r2c13 => r2c79,r3c13<>1
Hidden Single: r3c9=1
Naked Single: r7c9=3
Naked Single: r7c2=5
Hidden Single: r4c2=3
Hidden Single: r4c3=5
Naked Single: r3c3=3
Naked Single: r3c1=5
Hidden Single: r8c1=3
Locked Candidates Type 1 (Pointing): 9 in b4 => r5c7<>9
Locked Candidates Type 1 (Pointing): 6 in b7 => r9c789<>6
Naked Single: r9c9=9
Naked Single: r4c9=2
Full House: r2c9=6
Naked Single: r4c6=8
Full House: r9c6=2
Naked Single: r8c5=7
Naked Single: r9c2=6
Naked Single: r2c5=8
Naked Single: r3c5=6
Full House: r3c2=7
Full House: r2c4=7
Full House: r1c2=2
Naked Single: r7c4=4
Naked Single: r2c7=2
Naked Single: r1c1=6
Naked Single: r7c3=1
Full House: r7c7=7
Naked Single: r8c4=5
Full House: r9c4=8
Naked Single: r2c3=9
Full House: r2c1=1
Naked Single: r9c1=4
Full House: r8c3=2
Full House: r5c3=4
Naked Single: r1c7=3
Full House: r1c8=7
Naked Single: r6c1=2
Full House: r5c1=9
Naked Single: r9c8=1
Full House: r9c7=5
Naked Single: r5c5=2
Naked Single: r5c7=6
Full House: r5c8=8
Naked Single: r4c8=4
Naked Single: r8c7=4
Full House: r8c8=6
Full House: r6c8=3
Naked Single: r4c5=1
Full House: r4c7=9
Full House: r6c7=1
Full House: r6c5=4
|
normal_sudoku_5716
|
.5.81.3.4..4....2..3......93.54...92.2619345.49.25.6.324.....355.......6.63..5.4.
|
957812364684739521132564879315486792726193458498257613241678935579341286863925147
|
Basic 9x9 Sudoku 5716
|
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 . 8 1 . 3 . 4
. . 4 . . . . 2 .
. 3 . . . . . . 9
3 . 5 4 . . . 9 2
. 2 6 1 9 3 4 5 .
4 9 . 2 5 . 6 . 3
2 4 . . . . . 3 5
5 . . . . . . . 6
. 6 3 . . 5 . 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
957812364684739521132564879315486792726193458498257613241678935579341286863925147 #1 Extreme (13692) bf
Hidden Single: r5c2=2
Hidden Single: r1c7=3
Hidden Single: r6c1=4
Hidden Single: r5c7=4
Hidden Single: r6c9=3
Hidden Single: r4c1=3
Hidden Single: r4c3=5
Hidden Single: r8c1=5
Brute Force: r5c4=1
Hidden Single: r5c5=9
Finned X-Wing: 1 c19 r29 fr3c1 => r2c2<>1
2-String Kite: 1 in r6c8,r8c2 (connected by r4c2,r6c3) => r8c8<>1
Forcing Chain Contradiction in r2c9 => r4c2<>7
r4c2=7 r4c2<>1 r4c7=1 r6c8<>1 r3c8=1 r2c9<>1
r4c2=7 r5c1<>7 r5c9=7 r2c9<>7
r4c2=7 r2c2<>7 r2c2=8 r2c9<>8
W-Wing: 8/7 in r5c9,r6c6 connected by 7 in r5c1,r6c3 => r6c8<>8
Almost Locked Set XY-Wing: A=r6c6 {78}, B=r8c28 {178}, C=r4c256 {1678}, X,Y=1,7, Z=8 => r8c6<>8
Finned Franken Swordfish: 8 c28b6 r248 fr3c8 fr5c9 => r2c9<>8
AIC: 7 7- r2c2 =7= r8c2 -7- r8c8 -8- r9c9 =8= r5c9 =7= r5c1 -7 => r123c1<>7
AIC: 1 1- r4c2 -8- r2c2 -7- r2c9 -1- r3c8 =1= r6c8 -1 => r4c7,r6c3<>1
Hidden Single: r4c2=1
Hidden Single: r6c8=1
Naked Pair: 7,8 in r8c28 => r8c34567<>7, r8c357<>8
Skyscraper: 8 in r2c2,r3c8 (connected by r8c28) => r2c7,r3c13<>8
Turbot Fish: 7 r4c7 =7= r5c9 -7- r5c1 =7= r9c1 => r9c7<>7
Empty Rectangle: 7 in b1 (r6c36) => r2c6<>7
W-Wing: 7/8 in r4c7,r8c8 connected by 8 in r3c78 => r7c7<>7
Turbot Fish: 7 r2c2 =7= r8c2 -7- r8c8 =7= r9c9 => r2c9<>7
Naked Single: r2c9=1
Naked Pair: 7,8 in r8c8,r9c9 => r79c7<>8
X-Wing: 7 c19 r59 => r9c45<>7
Naked Single: r9c4=9
Naked Single: r8c4=3
Hidden Single: r2c5=3
Locked Candidates Type 1 (Pointing): 9 in b7 => r1c3<>9
Locked Candidates Type 1 (Pointing): 7 in b8 => r7c3<>7
Remote Pair: 8/7 r2c2 -7- r8c2 -8- r8c8 -7- r9c9 -8- r5c9 -7- r5c1 => r2c1<>8
Hidden Single: r2c2=8
Full House: r8c2=7
Naked Single: r8c8=8
Naked Single: r9c9=7
Full House: r5c9=8
Full House: r4c7=7
Full House: r5c1=7
Full House: r6c3=8
Full House: r6c6=7
Naked Single: r2c7=5
Naked Single: r3c7=8
Hidden Single: r9c1=8
Naked Single: r9c5=2
Full House: r9c7=1
Naked Single: r8c5=4
Naked Single: r7c7=9
Full House: r8c7=2
Naked Single: r8c6=1
Full House: r8c3=9
Full House: r7c3=1
Hidden Single: r2c4=7
Naked Single: r3c5=6
Naked Single: r7c4=6
Full House: r3c4=5
Naked Single: r2c6=9
Full House: r2c1=6
Naked Single: r3c1=1
Full House: r1c1=9
Naked Single: r3c8=7
Full House: r1c8=6
Naked Single: r4c5=8
Full House: r4c6=6
Full House: r7c5=7
Full House: r7c6=8
Naked Single: r1c6=2
Full House: r1c3=7
Full House: r3c3=2
Full House: r3c6=4
|
normal_sudoku_6130
|
....78..6..624.7......1..429...341.8.8...5394.3498...7..145..7..5....4.134..9.6.5
|
492378516516249783873516942925734168187625394634981257261453879759862431348197625
|
Basic 9x9 Sudoku 6130
|
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 . . 6
. . 6 2 4 . 7 . .
. . . . 1 . . 4 2
9 . . . 3 4 1 . 8
. 8 . . . 5 3 9 4
. 3 4 9 8 . . . 7
. . 1 4 5 . . 7 .
. 5 . . . . 4 . 1
3 4 . . 9 . 6 . 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
492378516516249783873516942925734168187625394634981257261453879759862431348197625 #1 Extreme (13420) bf
Forcing Chain Contradiction in r1c5 => r9c4<>7
r9c4=7 r9c4<>5 r7c5=5 r2c5<>5 r2c5=4 r1c5<>4
r9c4=7 r9c4<>5 r7c5=5 r1c5<>5
r9c4=7 r45c4<>7 r5c5=7 r1c5<>7
Forcing Net Contradiction in c1 => r2c1<>4
r2c1=4 (r2c1<>8) (r2c2<>4 r9c2=4 r9c9<>4) r2c5<>4 r2c5=5 (r1c4<>5) r3c4<>5 r9c4=5 r9c9<>5 r9c9=8 r2c9<>8 r2c8=8 r2c8<>1 r1c8=1 r1c1<>1
r2c1=4 r2c1<>1
r2c1=4 r2c5<>4 r2c5=5 (r1c4<>5) r3c4<>5 r9c4=5 r9c4<>1 r5c4=1 r5c1<>1
r2c1=4 (r2c2<>4 r9c2=4 r9c9<>4) r2c5<>4 r2c5=5 (r1c4<>5) r3c4<>5 r9c4=5 r9c9<>5 r9c9=8 r4c9<>8 r4c9=5 (r6c7<>5) r6c8<>5 r6c1=5 r6c1<>1
Forcing Net Contradiction in c1 => r7c5<>6
r7c5=6 (r7c5<>5 r9c4=5 r9c9<>5) (r8c4<>6) (r8c5<>6) r8c6<>6 r8c1=6 r8c1<>4 r8c7=4 r9c9<>4 r9c9=8 (r2c9<>8) (r4c9<>8 r4c9=5 r6c8<>5 r6c1=5 r2c1<>5) (r4c9<>8 r4c9=5 r2c9<>5) r9c9<>4 r9c2=4 r2c2<>4 r2c5=4 r2c5<>5 r2c8=5 r2c8<>8 r2c1=8
r7c5=6 (r7c5<>8) (r7c5<>5 r9c4=5 r9c9<>5) (r8c4<>6) (r8c5<>6) r8c6<>6 r8c1=6 r8c1<>4 r8c7=4 r9c9<>4 r9c9=8 (r7c7<>8) r7c9<>8 r7c1=8
Forcing Net Contradiction in c1 => r9c9<>8
r9c9=8 r9c9<>4 r9c2=4 (r1c2<>4) r2c2<>4 r2c5=4 r1c5<>4 r1c1=4 r1c1<>1
r9c9=8 (r2c9<>8) (r4c9<>8 r4c9=5 r6c8<>5 r6c1=5 r2c1<>5) (r4c9<>8 r4c9=5 r2c9<>5) r9c9<>4 r9c2=4 r2c2<>4 r2c5=4 r2c5<>5 r2c8=5 r2c8<>8 r2c1=8 r2c1<>1
r9c9=8 (r9c9<>5) (r4c9<>8 r4c9=5 r6c8<>5 r6c1=5 r2c1<>5) (r4c9<>8 r4c9=5 r2c9<>5) r9c9<>4 r9c2=4 r2c2<>4 r2c5=4 r2c5<>5 r2c8=5 r9c8<>5 r9c4=5 r9c4<>1 r5c4=1 r5c1<>1
r9c9=8 r4c9<>8 r4c9=5 (r6c7<>5) r6c8<>5 r6c1=5 r6c1<>1
Brute Force: r5c7=3
Hidden Single: r6c2=3
Hidden Single: r5c9=4
Naked Single: r9c9=5
Naked Single: r4c9=8
Hidden Single: r8c7=4
Hidden Single: r9c2=4
Hidden Single: r5c8=9
Hidden Single: r7c5=5
Naked Single: r2c5=4
Naked Single: r1c5=7
Hidden Single: r6c5=8
Hidden Single: r1c1=4
Hidden Single: r8c3=9
Locked Candidates Type 1 (Pointing): 1 in b4 => r2c1<>1
Locked Candidates Type 1 (Pointing): 7 in b5 => r8c4<>7
Naked Pair: 3,9 in r2c69 => r2c2<>9, r2c8<>3
Naked Single: r2c2=1
Hidden Single: r1c8=1
Hidden Single: r8c8=3
Naked Single: r7c9=9
Full House: r2c9=3
Naked Single: r2c6=9
Hidden Single: r7c6=3
Naked Single: r3c6=6
Locked Candidates Type 1 (Pointing): 6 in b8 => r8c1<>6
Skyscraper: 5 in r2c1,r4c3 (connected by r24c8) => r13c3,r6c1<>5
Hidden Single: r4c3=5
Skyscraper: 8 in r2c8,r7c7 (connected by r27c1) => r3c7,r9c8<>8
Naked Single: r9c8=2
Full House: r7c7=8
Naked Single: r4c8=6
Naked Single: r4c4=7
Full House: r4c2=2
Naked Single: r6c8=5
Full House: r2c8=8
Full House: r6c7=2
Full House: r2c1=5
Naked Single: r1c2=9
Naked Single: r5c3=7
Naked Single: r7c2=6
Full House: r3c2=7
Full House: r7c1=2
Naked Single: r6c6=1
Full House: r6c1=6
Full House: r5c1=1
Naked Single: r1c7=5
Full House: r3c7=9
Naked Single: r9c3=8
Full House: r8c1=7
Full House: r3c1=8
Naked Single: r5c4=6
Full House: r5c5=2
Full House: r8c5=6
Naked Single: r9c6=7
Full House: r9c4=1
Full House: r8c6=2
Full House: r8c4=8
Naked Single: r1c4=3
Full House: r1c3=2
Full House: r3c3=3
Full House: r3c4=5
|
normal_sudoku_309
|
..61.8349.914376.8348..97...1.....7...4....3..5..1.98..85.4..93.698.3..7.3...186.
|
276158349591437628348269751913682475824975136657314982185746293469823517732591864
|
Basic 9x9 Sudoku 309
|
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 1 . 8 3 4 9
. 9 1 4 3 7 6 . 8
3 4 8 . . 9 7 . .
. 1 . . . . . 7 .
. . 4 . . . . 3 .
. 5 . . 1 . 9 8 .
. 8 5 . 4 . . 9 3
. 6 9 8 . 3 . . 7
. 3 . . . 1 8 6 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
276158349591437628348269751913682475824975136657314982185746293469823517732591864 #1 Hard (1340)
Hidden Single: r1c9=9
Hidden Single: r3c3=8
Hidden Single: r9c7=8
Hidden Single: r7c8=9
Hidden Single: r1c7=3
Hidden Single: r2c3=1
Hidden Single: r5c8=3
Hidden Single: r7c9=3
Hidden Single: r3c7=7
Hidden Single: r1c4=1
Hidden Single: r9c2=3
Hidden Single: r3c2=4
Hidden Single: r2c4=4
Hidden Single: r2c7=6
Locked Candidates Type 2 (Claiming): 5 in c6 => r4c45,r5c45<>5
Naked Pair: 2,5 in r18c5 => r3459c5<>2, r39c5<>5
Naked Single: r3c5=6
Naked Triple: 2,3,7 in r46c3,r5c2 => r456c1<>2, r56c1<>7
Naked Single: r6c1=6
Naked Pair: 8,9 in r4c15 => r4c4<>9
Naked Pair: 2,4 in r6c69 => r6c34<>2
Skyscraper: 7 in r6c3,r7c1 (connected by r67c4) => r9c3<>7
Naked Single: r9c3=2
Naked Single: r4c3=3
Full House: r6c3=7
Naked Single: r5c2=2
Full House: r1c2=7
Naked Single: r6c4=3
Naked Triple: 1,5,6 in r5c679 => r5c4<>6
XYZ-Wing: 1/2/5 in r7c7,r8c58 => r8c7<>2
Swordfish: 2 r128 c158 => r3c8<>2
Skyscraper: 2 in r3c4,r6c6 (connected by r36c9) => r4c4<>2
Naked Single: r4c4=6
Naked Single: r5c6=5
Naked Single: r5c7=1
Naked Single: r5c9=6
Naked Single: r7c7=2
Naked Single: r7c4=7
Naked Single: r7c6=6
Full House: r7c1=1
Naked Single: r5c4=9
Naked Single: r9c5=9
Naked Single: r8c1=4
Full House: r9c1=7
Naked Single: r4c5=8
Naked Single: r5c1=8
Full House: r4c1=9
Full House: r5c5=7
Naked Single: r9c4=5
Full House: r3c4=2
Full House: r8c5=2
Full House: r9c9=4
Full House: r1c5=5
Full House: r1c1=2
Full House: r2c1=5
Full House: r2c8=2
Naked Single: r8c7=5
Full House: r4c7=4
Full House: r8c8=1
Full House: r3c8=5
Full House: r3c9=1
Naked Single: r6c9=2
Full House: r4c9=5
Full House: r4c6=2
Full House: r6c6=4
|
normal_sudoku_2605
|
9176.5..8.36.1.759...97.163428..7.1..6.4.....37.1......82..15.........81....6...2
|
917635248236814759854972163428597316169423875375186924682341597743259681591768432
|
Basic 9x9 Sudoku 2605
|
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 7 6 . 5 . . 8
. 3 6 . 1 . 7 5 9
. . . 9 7 . 1 6 3
4 2 8 . . 7 . 1 .
. 6 . 4 . . . . .
3 7 . 1 . . . . .
. 8 2 . . 1 5 . .
. . . . . . . 8 1
. . . . 6 . . . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
917635248236814759854972163428597316169423875375186924682341597743259681591768432 #1 Hard (1116)
Hidden Single: r3c5=7
Hidden Single: r2c5=1
Hidden Single: r3c7=1
Locked Pair: 4,5 in r3c23 => r3c1<>5, r2c3,r3c69<>4
Naked Single: r3c9=3
Locked Candidates Type 1 (Pointing): 2 in b3 => r1c145<>2
Locked Candidates Type 2 (Claiming): 9 in c2 => r789c1,r89c3<>9
Locked Candidates Type 2 (Claiming): 8 in c5 => r56c6<>8
Naked Pair: 6,9 in r1c1,r2c3 => r2c1<>6, r2c1<>9
2-String Kite: 9 in r2c9,r5c1 (connected by r1c1,r2c3) => r5c9<>9
XY-Wing: 3/7/6 in r17c4,r7c1 => r1c1<>6
Naked Single: r1c1=9
Naked Single: r2c3=6
Hidden Single: r1c4=6
Hidden Single: r2c9=9
Hidden Single: r6c6=6
Hidden Single: r1c5=3
Hidden Single: r2c6=4
Skyscraper: 3 in r4c7,r7c8 (connected by r47c4) => r5c8,r89c7<>3
Skyscraper: 9 in r4c7,r7c8 (connected by r47c5) => r56c8,r89c7<>9
Naked Single: r9c7=4
Naked Single: r1c7=2
Full House: r1c8=4
Naked Single: r8c7=6
Naked Single: r6c8=2
Naked Single: r7c9=7
Naked Single: r5c8=7
Naked Single: r5c9=5
Naked Single: r7c1=6
Naked Single: r7c4=3
Naked Single: r4c9=6
Full House: r6c9=4
Naked Single: r5c1=1
Naked Single: r4c4=5
Naked Single: r7c8=9
Full House: r7c5=4
Full House: r9c8=3
Naked Single: r5c3=9
Full House: r6c3=5
Naked Single: r4c5=9
Full House: r4c7=3
Naked Single: r3c3=4
Naked Single: r9c3=1
Full House: r8c3=3
Naked Single: r6c5=8
Full House: r6c7=9
Full House: r5c7=8
Naked Single: r3c2=5
Naked Single: r5c5=2
Full House: r5c6=3
Full House: r8c5=5
Naked Single: r9c2=9
Full House: r8c2=4
Naked Single: r8c1=7
Full House: r9c1=5
Naked Single: r9c6=8
Full House: r9c4=7
Naked Single: r8c4=2
Full House: r2c4=8
Full House: r3c6=2
Full House: r8c6=9
Full House: r2c1=2
Full House: r3c1=8
|
normal_sudoku_6674
|
..8.314.714..758..7.3.8...5..7.5...8.8.7.26..69...8.7...68.37...7..6..8.8..5.7..6
|
958231467142675839763984125237456918481792653695318274526843791374169582819527346
|
Basic 9x9 Sudoku 6674
|
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 . 3 1 4 . 7
1 4 . . 7 5 8 . .
7 . 3 . 8 . . . 5
. . 7 . 5 . . . 8
. 8 . 7 . 2 6 . .
6 9 . . . 8 . 7 .
. . 6 8 . 3 7 . .
. 7 . . 6 . . 8 .
8 . . 5 . 7 . . 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
958231467142675839763984125237456918481792653695318274526843791374169582819527346 #1 Extreme (10646)
Hidden Single: r2c5=7
Hidden Single: r6c8=7
Hidden Single: r3c1=7
Hidden Single: r4c9=8
Hidden Single: r9c1=8
Hidden Single: r7c4=8
Hidden Single: r9c6=7
Locked Candidates Type 1 (Pointing): 2 in b2 => r8c4<>2
Finned Swordfish: 3 r258 c189 fr8c7 => r9c8<>3
Forcing Net Contradiction in b9 => r4c6=6
r4c6<>6 r4c4=6 (r1c4<>6) r2c4<>6 r2c8=6 r1c8<>6 r1c2=6 r1c2<>5 r7c2=5 r7c8<>5
r4c6<>6 (r4c4=6 r1c4<>6) r3c6=6 r2c4<>6 r2c8=6 (r2c8<>3 r2c9=3 r8c9<>3) (r2c8<>3) r1c8<>6 r1c2=6 r1c2<>5 r7c2=5 r7c8<>5 r5c8=5 r5c8<>3 r4c8=3 r4c2<>3 r9c2=3 r8c1<>3 r8c7=3 r8c7<>5
Forcing Chain Contradiction in c7 => r8c9<>9
r8c9=9 r8c6<>9 r3c6=9 r3c7<>9
r8c9=9 r8c46<>9 r79c5=9 r5c5<>9 r4c4=9 r4c7<>9
r8c9=9 r8c7<>9
r8c9=9 r9c7<>9
Forcing Net Contradiction in r7 => r1c4<>9
r1c4=9 (r1c1<>9) r3c6<>9 r8c6=9 r8c1<>9 r7c1=9
r1c4=9 (r1c1<>9) r3c6<>9 r8c6=9 (r7c5<>9) r8c1<>9 r7c1=9 r7c8<>9 r7c9=9
Almost Locked Set XZ-Rule: A=r12c4 {269}, B=r2c3,r3c2 {269}, X=9, Z=6 => r3c4<>6
Forcing Net Contradiction in r9 => r1c2<>2
r1c2=2 r9c2=3
r1c2=2 (r1c4<>2 r1c4=6 r2c4<>6 r2c8=6 r2c8<>3) r1c2<>5 r7c2=5 (r8c3<>5 r8c7=5 r8c7<>3) r7c8<>5 r5c8=5 r5c8<>3 r4c8=3 (r4c7<>3) r6c7<>3 r9c7=3
Forcing Net Contradiction in r7c8 => r6c9<>3
r6c9=3 (r6c9<>2) (r8c9<>3) (r5c8<>3) r5c9<>3 r5c1=3 r8c1<>3 r8c7=3 r8c7<>5 r6c7=5 r6c7<>2 r6c3=2 (r2c3<>2 r2c3=9 r1c1<>9 r1c8=9 r1c8<>6) r6c3<>5 r6c7=5 r5c8<>5 r7c8=5 r7c2<>5 r1c2=5 r1c2<>6 r1c4=6 r2c4<>6 r2c8=6 r2c8<>3 r2c9=3 r6c9<>3
Forcing Net Contradiction in r4c1 => r6c4<>1
r6c4=1 (r6c5<>1 r6c5=4 r6c9<>4 r6c9=2 r8c9<>2) (r8c4<>1) r6c4<>3 r6c7=3 (r5c9<>3 r5c1=3 r8c1<>3 r8c9=3 r8c9<>1) r6c7<>5 r8c7=5 (r8c7<>2) r8c7<>1 r8c3=1 r8c3<>2 r8c1=2 r4c1<>2
r6c4=1 r6c4<>3 r4c4=3 r4c1<>3
r6c4=1 (r8c4<>1) r6c4<>3 r6c7=3 (r5c9<>3 r5c1=3 r8c1<>3 r8c9=3 r8c9<>1) r6c7<>5 (r6c3=5 r5c3<>5) r8c7=5 r8c7<>1 r8c3=1 r5c3<>1 r5c3=4 r4c1<>4
Empty Rectangle: 1 in b4 (r48c4) => r8c3<>1
Forcing Chain Contradiction in r4 => r9c7<>1
r9c7=1 r9c3<>1 r79c2=1 r4c2<>1
r9c7=1 r8c79<>1 r8c4=1 r4c4<>1
r9c7=1 r4c7<>1
r9c7=1 r3c7<>1 r3c8=1 r4c8<>1
Forcing Chain Contradiction in r4 => r9c8<>1
r9c8=1 r9c3<>1 r79c2=1 r4c2<>1
r9c8=1 r8c79<>1 r8c4=1 r4c4<>1
r9c8=1 r3c8<>1 r3c7=1 r4c7<>1
r9c8=1 r4c8<>1
Forcing Net Contradiction in b5 => r6c4=3
r6c4<>3 r4c4=3 r4c4<>9
r6c4<>3 (r6c7=3 r5c8<>3 r2c8=3 r2c9<>3 r2c9=9 r7c9<>9) r6c4=4 r3c4<>4 r3c6=4 r8c6<>4 r8c6=9 r8c1<>9 r7c1=9 r1c1<>9 r1c8=9 r2c9<>9 r5c9=9 r5c5<>9
Forcing Net Contradiction in r4 => r5c8<>9
r5c8=9 (r5c8<>5 r7c8=5 r7c8<>4) (r5c8<>5 r7c8=5 r7c8<>1) (r4c7<>9) r4c8<>9 r4c4=9 (r2c4<>9 r2c9=9 r3c7<>9 r3c6=9 r8c6<>9 r8c6=4 r7c5<>4) r4c4<>1 r8c4=1 (r8c7<>1) r8c9<>1 r7c9=1 r7c9<>4 r7c1=4 r4c1<>4
r5c8=9 (r4c7<>9) r4c8<>9 r4c4=9 r4c4<>4
r5c8=9 (r1c8<>9 r1c1=9 r2c3<>9 r2c3=2 r6c3<>2 r6c9=2 r6c9<>4) (r5c8<>5 r7c8=5 r7c8<>1) (r4c7<>9) r4c8<>9 r4c4=9 (r2c4<>9 r2c9=9 r3c7<>9 r3c6=9 r8c6<>9 r8c6=4 r8c9<>4) r4c4<>1 r8c4=1 (r8c7<>1) r8c9<>1 r7c9=1 r7c9<>4 r5c9=4 r4c8<>4
Forcing Net Contradiction in b4 => r5c5<>1
r5c5=1 (r6c5<>1 r6c5=4 r9c5<>4) (r6c5<>1 r6c5=4 r6c9<>4) (r5c5<>9 r5c9=9 r5c9<>4) (r6c5<>1 r6c5=4 r4c4<>4) r4c4<>1 r8c4=1 r8c4<>4 r3c4=4 r3c6<>4 r8c6=4 r8c9<>4 r7c9=4 r9c8<>4 r9c3=4 r9c3<>1 r79c2=1 r4c2<>1
r5c5=1 r5c3<>1
r5c5=1 (r5c9<>1) (r6c5<>1 r6c5=4 r6c9<>4) (r5c5<>9 r5c9=9 r5c9<>4) (r6c5<>1 r6c5=4 r4c4<>4) r4c4<>1 r8c4=1 (r8c9<>1) r8c4<>4 r3c4=4 r3c6<>4 r8c6=4 r8c9<>4 r7c9=4 r7c9<>1 r6c9=1 r6c3<>1
Forcing Net Verity => r1c2=5
r1c1=9 r1c1<>5 r1c2=5
r7c1=9 (r8c1<>9) (r8c3<>9) (r7c5<>9) (r7c9<>9) r1c1<>9 r1c8=9 r2c9<>9 r5c9=9 (r4c7<>9 r4c4=9 r8c4<>9) r5c5<>9 r9c5=9 r8c6<>9 r8c7=9 r8c7<>5 r6c7=5 r5c8<>5 r7c8=5 r7c2<>5 r1c2=5
r8c1=9 (r8c1<>3 r9c2=3 r9c2<>1) (r8c4<>9) r8c6<>9 (r3c6=9 r3c4<>9 r4c4=9 r5c5<>9 r5c5=4 r5c3<>4) r8c6=4 r8c4<>4 r8c4=1 r9c5<>1 r9c3=1 r5c3<>1 r5c3=5 r5c8<>5 r7c8=5 r7c2<>5 r1c2=5
Hidden Single: r3c2=6
Hidden Rectangle: 2/6 in r1c48,r2c48 => r2c8<>2
Discontinuous Nice Loop: 2 r2c9 -2- r2c3 -9- r1c1 =9= r1c8 =6= r2c8 =3= r2c9 => r2c9<>2
Grouped Continuous Nice Loop: 2/4/9 2= r9c5 =1= r9c23 -1- r7c2 -2- r7c5 =2= r9c5 =1 => r7c189<>2, r9c5<>4, r9c5<>9
Sashimi Swordfish: 9 c359 r257 fr8c3 fr9c3 => r7c1<>9
Discontinuous Nice Loop: 4 r5c8 -4- r9c8 =4= r9c3 -4- r7c1 -5- r7c8 =5= r5c8 => r5c8<>4
Sashimi Swordfish: 4 c468 r348 fr7c8 fr9c8 => r8c9<>4
Finned Swordfish: 4 c359 r567 fr8c3 fr9c3 => r7c1<>4
Naked Single: r7c1=5
Hidden Single: r5c8=5
Hidden Single: r8c7=5
Hidden Single: r6c3=5
Locked Candidates Type 1 (Pointing): 2 in b4 => r4c78<>2
X-Wing: 3 r58 c19 => r2c9,r4c1<>3
Naked Single: r2c9=9
Naked Single: r2c3=2
Full House: r1c1=9
Naked Single: r2c4=6
Full House: r2c8=3
Naked Single: r1c4=2
Full House: r1c8=6
Hidden Single: r5c5=9
Hidden Single: r7c8=9
Hidden Single: r4c7=9
Hidden Single: r9c3=9
Naked Single: r8c3=4
Full House: r5c3=1
Naked Single: r8c6=9
Full House: r3c6=4
Full House: r3c4=9
Naked Single: r8c4=1
Full House: r4c4=4
Full House: r6c5=1
Naked Single: r9c5=2
Full House: r7c5=4
Naked Single: r4c1=2
Naked Single: r4c8=1
Full House: r4c2=3
Full House: r5c1=4
Full House: r8c1=3
Full House: r5c9=3
Full House: r8c9=2
Naked Single: r6c7=2
Full House: r6c9=4
Full House: r7c9=1
Full House: r7c2=2
Full House: r9c2=1
Naked Single: r9c7=3
Full House: r9c8=4
Full House: r3c8=2
Full House: r3c7=1
|
normal_sudoku_2103
|
342.1...7596..3..481764.9.362.8..7.1..142.3..45.1.7.9...43..8.5.3....47...5..4.39
|
342918567596273184817645923623859741971426358458137692764392815239581476185764239
|
Basic 9x9 Sudoku 2103
|
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 . 1 . . . 7
5 9 6 . . 3 . . 4
8 1 7 6 4 . 9 . 3
6 2 . 8 . . 7 . 1
. . 1 4 2 . 3 . .
4 5 . 1 . 7 . 9 .
. . 4 3 . . 8 . 5
. 3 . . . . 4 7 .
. . 5 . . 4 . 3 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
342918567596273184817645923623859741971426358458137692764392815239581476185764239 #1 Easy (284)
Naked Single: r2c1=5
Naked Single: r2c3=6
Naked Single: r1c2=4
Full House: r1c1=3
Naked Single: r6c1=4
Hidden Single: r4c7=7
Hidden Single: r3c5=4
Hidden Single: r3c9=3
Hidden Single: r7c4=3
Hidden Single: r5c4=4
Hidden Single: r7c3=4
Hidden Single: r1c9=7
Hidden Single: r1c7=5
Naked Single: r1c4=9
Naked Single: r3c8=2
Full House: r3c6=5
Naked Single: r1c6=8
Full House: r1c8=6
Naked Single: r2c7=1
Full House: r2c8=8
Naked Single: r4c6=9
Naked Single: r2c5=7
Full House: r2c4=2
Naked Single: r7c8=1
Naked Single: r5c8=5
Full House: r4c8=4
Naked Single: r4c3=3
Full House: r4c5=5
Naked Single: r5c6=6
Full House: r6c5=3
Naked Single: r8c4=5
Full House: r9c4=7
Naked Single: r6c3=8
Full House: r8c3=9
Naked Single: r5c9=8
Naked Single: r7c6=2
Full House: r8c6=1
Naked Single: r5c2=7
Full House: r5c1=9
Naked Single: r7c1=7
Naked Single: r8c1=2
Full House: r9c1=1
Naked Single: r7c2=6
Full House: r7c5=9
Full House: r9c2=8
Naked Single: r8c9=6
Full House: r6c9=2
Full House: r8c5=8
Full House: r9c5=6
Full House: r9c7=2
Full House: r6c7=6
|
normal_sudoku_5912
|
13.4.6...9.6.513.4.5493..6..43.....759..24638...3..4...69....4331.64.9.54.5.93..6
|
132476859986251374754938162643189527591724638278365491869517243317642985425893716
|
Basic 9x9 Sudoku 5912
|
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 3 . 4 . 6 . . .
9 . 6 . 5 1 3 . 4
. 5 4 9 3 . . 6 .
. 4 3 . . . . . 7
5 9 . . 2 4 6 3 8
. . . 3 . . 4 . .
. 6 9 . . . . 4 3
3 1 . 6 4 . 9 . 5
4 . 5 . 9 3 . . 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
132476859986251374754938162643189527591724638278365491869517243317642985425893716 #1 Extreme (37498) bf
Hidden Single: r1c2=3
Hidden Single: r2c3=6
Hidden Single: r8c4=6
Hidden Single: r9c1=4
Hidden Single: r6c4=3
Hidden Single: r8c1=3
Hidden Single: r7c9=3
Hidden Single: r9c5=9
Hidden Single: r3c2=5
Hidden Single: r2c9=4
Hidden Single: r3c3=4
Brute Force: r5c6=4
Hidden Single: r6c7=4
Hidden Single: r5c2=9
Brute Force: r5c7=6
Hidden Single: r9c9=6
Brute Force: r5c5=2
Finned Franken Swordfish: 2 r18b2 c368 fr1c7 fr1c9 fr2c4 => r2c8<>2
Forcing Chain Contradiction in r1c3 => r2c4<>7
r2c4=7 r2c4<>2 r2c2=2 r1c3<>2
r2c4=7 r5c4<>7 r5c3=7 r1c3<>7
r2c4=7 r1c5<>7 r1c5=8 r1c3<>8
Finned Franken Swordfish: 7 r28b2 c368 fr1c5 fr2c2 => r1c3<>7
Forcing Net Contradiction in c6 => r1c7<>2
r1c7=2 (r3c7<>2) (r3c9<>2) (r4c7<>2) (r1c9<>2) r3c9<>2 r6c9=2 r4c8<>2 r4c1=2 r3c1<>2 r3c6=2
r1c7=2 (r3c9<>2 r6c9=2 r4c8<>2 r4c1=2 r7c1<>2) (r7c7<>2) r1c7<>5 r1c8=5 r6c8<>5 r6c6=5 r7c6<>5 r7c4=5 r7c4<>2 r7c6=2
Forcing Net Verity => r1c7<>7
r1c5=7 r1c7<>7
r6c5=7 (r6c5<>6 r6c1=6 r6c1<>2) (r6c5<>6 r6c1=6 r6c1<>2) (r6c1<>7) r1c5<>7 (r1c5=8 r1c3<>8 r1c3=2 r6c3<>2) (r1c5=8 r1c3<>8 r1c3=2 r3c1<>2) r3c6=7 r3c1<>7 r7c1=7 r7c1<>2 r4c1=2 r6c2<>2 r6c8=2 r2c2=2 r2c2<>7 r2c8=7 r1c7<>7
r7c5=7 (r7c1<>7) r1c5<>7 r3c6=7 r3c1<>7 r6c1=7 (r6c1<>6 r6c5=6 r4c5<>6 r4c1=6 r4c1<>2) (r6c3<>7 r8c3=7 r8c8<>7) r3c1<>7 r2c2=7 r2c8<>7 r2c8=8 r8c8<>8 r8c8=2 r4c8<>2 r4c7=2 r4c7<>5 r1c7=5 r1c7<>7
Forcing Chain Contradiction in r8 => r6c5<>7
r6c5=7 r5c4<>7 r5c3=7 r8c3<>7
r6c5=7 r1c5<>7 r3c6=7 r8c6<>7
r6c5=7 r1c5<>7 r1c8=7 r8c8<>7
Forcing Net Contradiction in r7 => r1c5=7
r1c5<>7 (r7c5=7 r7c1<>7) (r1c5=8 r1c3<>8 r1c3=2 r3c1<>2) r3c6=7 r3c1<>7 r3c1=8 r7c1<>8 r7c1=2
r1c5<>7 (r1c5=8 r2c4<>8 r2c4=2 r7c4<>2) r1c8=7 (r8c8<>7) r2c8<>7 r2c8=8 r8c8<>8 r8c8=2 r7c7<>2 r7c6=2
W-Wing: 8/2 in r1c3,r3c6 connected by 2 in r2c24 => r3c1<>8
Sashimi Swordfish: 8 r138 c368 fr1c7 fr3c7 => r2c8<>8
Naked Single: r2c8=7
Hidden Single: r3c1=7
Skyscraper: 7 in r5c4,r8c6 (connected by r58c3) => r6c6,r79c4<>7
Hidden Single: r5c4=7
Full House: r5c3=1
XYZ-Wing: 1/2/8 in r29c4,r7c5 => r7c4<>8
Grouped Discontinuous Nice Loop: 2 r7c4 -2- r7c1 -8- r7c5 -1- r79c4 =1= r4c4 =5= r7c4 => r7c4<>2
Almost Locked Set XZ-Rule: A=r6c1235 {12678}, B=r7c15 {128}, X=1, Z=2 => r4c1<>2
Locked Candidates Type 1 (Pointing): 2 in b4 => r6c89<>2
Locked Candidates Type 2 (Claiming): 2 in c9 => r1c8,r3c7<>2
Hidden Rectangle: 6/8 in r4c15,r6c15 => r6c5<>8
Discontinuous Nice Loop: 8 r4c6 -8- r3c6 -2- r3c9 -1- r6c9 -9- r6c6 =9= r4c6 => r4c6<>8
Grouped AIC: 1/2 2- r9c4 =2= r2c4 =8= r3c6 -8- r3c7 -1- r79c7 =1= r9c8 -1 => r9c4<>1, r9c8<>2
Locked Candidates Type 1 (Pointing): 1 in b8 => r7c7<>1
Naked Pair: 2,8 in r29c4 => r4c4<>8
Hidden Pair: 6,8 in r4c15 => r4c5<>1
2-String Kite: 8 in r3c7,r9c4 (connected by r2c4,r3c6) => r9c7<>8
Uniqueness Test 4: 6/8 in r4c15,r6c15 => r6c1<>8
X-Wing: 8 c15 r47 => r7c67<>8
Locked Candidates Type 1 (Pointing): 8 in b9 => r1c8<>8
W-Wing: 9/5 in r1c8,r4c6 connected by 5 in r6c68 => r4c8<>9
Hidden Single: r4c6=9
Multi Colors 1: 8 (r1c3,r2c4,r3c7) / (r1c7,r2c2,r3c6,r9c4), (r4c1,r6c6,r7c5) / (r4c5,r7c1) => r8c3<>8
W-Wing: 2/7 in r7c7,r8c3 connected by 7 in r9c27 => r7c1,r8c8<>2
Naked Single: r7c1=8
Naked Single: r8c8=8
Naked Single: r4c1=6
Full House: r6c1=2
Naked Single: r7c5=1
Naked Single: r9c8=1
Naked Single: r4c5=8
Full House: r6c5=6
Naked Single: r7c4=5
Naked Single: r6c6=5
Full House: r4c4=1
Naked Single: r6c8=9
Naked Single: r1c8=5
Full House: r4c8=2
Full House: r4c7=5
Full House: r6c9=1
Naked Single: r1c7=8
Naked Single: r3c9=2
Full House: r1c9=9
Full House: r1c3=2
Full House: r3c7=1
Full House: r3c6=8
Full House: r2c2=8
Full House: r2c4=2
Full House: r9c4=8
Naked Single: r8c3=7
Full House: r6c3=8
Full House: r6c2=7
Full House: r8c6=2
Full House: r9c2=2
Full House: r7c6=7
Full House: r9c7=7
Full House: r7c7=2
|
normal_sudoku_5198
|
2.84.1.5...5..2...9..6..2...8..2.467629...5.8..7...92.85....6.2.962.8.757.25..894
|
268471359315982746974653281583129467629347518147865923851794632496238175732516894
|
Basic 9x9 Sudoku 5198
|
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 . 8 4 . 1 . 5 .
. . 5 . . 2 . . .
9 . . 6 . . 2 . .
. 8 . . 2 . 4 6 7
6 2 9 . . . 5 . 8
. . 7 . . . 9 2 .
8 5 . . . . 6 . 2
. 9 6 2 . 8 . 7 5
7 . 2 5 . . 8 9 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
268471359315982746974653281583129467629347518147865923851794632496238175732516894 #1 Extreme (23368) bf
Hidden Single: r1c1=2
Hidden Single: r6c8=2
Hidden Single: r4c5=2
Hidden Single: r9c3=2
Hidden Single: r7c1=8
Hidden Single: r8c9=5
Hidden Single: r8c2=9
Hidden Single: r9c7=8
Hidden Single: r8c3=6
Naked Triple: 1,3,4 in r369c9 => r12c9<>3, r2c9<>1, r2c9<>4
Brute Force: r5c1=6
Brute Force: r4c7=4
Locked Candidates Type 1 (Pointing): 4 in b4 => r6c56<>4
Skyscraper: 4 in r7c3,r9c9 (connected by r3c39) => r7c8,r9c2<>4
Hidden Single: r9c9=4
Naked Pair: 1,3 in r57c8 => r123c8<>3, r23c8<>1
Naked Single: r1c8=5
Empty Rectangle: 1 in b8 (r57c8) => r5c5<>1
Hidden Rectangle: 3/6 in r6c56,r9c56 => r6c5<>3
Finned Franken Swordfish: 3 r19b9 c257 fr7c8 fr9c6 => r7c5<>3
Forcing Chain Contradiction in r3c3 => r6c2<>1
r6c2=1 r6c9<>1 r3c9=1 r3c3<>1
r6c2=1 r4c3<>1 r4c3=3 r3c3<>3
r6c2=1 r6c2<>4 r23c2=4 r3c3<>4
Forcing Chain Contradiction in r3c3 => r6c2=4
r6c2<>4 r6c2=3 r4c3<>3 r4c3=1 r3c3<>1
r6c2<>4 r6c2=3 r6c9<>3 r3c9=3 r3c3<>3
r6c2<>4 r23c2=4 r3c3<>4
Discontinuous Nice Loop: 1 r8c1 -1- r9c2 =1= r9c5 =6= r6c5 =5= r3c5 =8= r3c8 =4= r3c3 -4- r7c3 =4= r8c1 => r8c1<>1
Finned Swordfish: 1 r289 c257 fr2c1 => r3c2<>1
W-Wing: 3/1 in r4c3,r6c9 connected by 1 in r3c39 => r6c1<>3
Locked Candidates Type 1 (Pointing): 3 in b4 => r4c46<>3
AIC: 1/3 1- r3c9 =1= r3c3 =4= r7c3 -4- r8c1 -3- r8c7 =3= r7c8 -3- r5c8 =3= r6c9 -3 => r6c9<>1, r3c9<>3
Naked Single: r6c9=3
Full House: r5c8=1
Naked Single: r3c9=1
Naked Single: r7c8=3
Full House: r8c7=1
W-Wing: 4/3 in r3c3,r8c1 connected by 3 in r4c13 => r2c1,r7c3<>4
Naked Single: r7c3=1
Naked Single: r4c3=3
Full House: r3c3=4
Naked Single: r9c2=3
Full House: r8c1=4
Full House: r8c5=3
Naked Single: r3c8=8
Full House: r2c8=4
Naked Single: r3c2=7
Naked Single: r9c6=6
Full House: r9c5=1
Naked Single: r1c2=6
Full House: r2c2=1
Full House: r2c1=3
Naked Single: r3c5=5
Full House: r3c6=3
Naked Single: r6c6=5
Naked Single: r1c9=9
Full House: r2c9=6
Naked Single: r2c7=7
Full House: r1c7=3
Full House: r1c5=7
Naked Single: r4c6=9
Naked Single: r6c1=1
Full House: r4c1=5
Full House: r4c4=1
Naked Single: r5c5=4
Naked Single: r6c4=8
Full House: r6c5=6
Naked Single: r5c6=7
Full House: r5c4=3
Full House: r7c6=4
Naked Single: r7c5=9
Full House: r2c5=8
Full House: r2c4=9
Full House: r7c4=7
|
normal_sudoku_3717
|
7..5....2.381..57..657..3....1.4.........2.156..851.2.8426.5.3.197483.5635621..8.
|
714539862238164579965728341521346798483972615679851423842695137197483256356217984
|
Basic 9x9 Sudoku 3717
|
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 . . 5 . . . . 2
. 3 8 1 . . 5 7 .
. 6 5 7 . . 3 . .
. . 1 . 4 . . . .
. . . . . 2 . 1 5
6 . . 8 5 1 . 2 .
8 4 2 6 . 5 . 3 .
1 9 7 4 8 3 . 5 6
3 5 6 2 1 . . 8 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
714539862238164579965728341521346798483972615679851423842695137197483256356217984 #1 Easy (378)
Hidden Single: r6c5=5
Hidden Single: r6c6=1
Hidden Single: r2c4=1
Hidden Single: r3c3=5
Hidden Single: r8c4=4
Naked Single: r8c6=3
Hidden Single: r2c7=5
Hidden Single: r8c8=5
Hidden Single: r7c3=2
Naked Single: r8c1=1
Naked Single: r7c2=4
Full House: r9c2=5
Naked Single: r8c9=6
Full House: r8c7=2
Naked Single: r1c2=1
Naked Single: r6c2=7
Naked Single: r5c2=8
Full House: r4c2=2
Hidden Single: r1c5=3
Hidden Single: r4c1=5
Hidden Single: r3c9=1
Hidden Single: r7c7=1
Hidden Single: r3c6=8
Hidden Single: r4c9=8
Hidden Single: r1c7=8
Hidden Single: r4c4=3
Full House: r5c4=9
Naked Single: r5c1=4
Naked Single: r5c3=3
Full House: r6c3=9
Full House: r1c3=4
Naked Single: r6c7=4
Full House: r6c9=3
Hidden Single: r1c8=6
Full House: r1c6=9
Naked Single: r4c8=9
Full House: r3c8=4
Full House: r2c9=9
Naked Single: r3c5=2
Full House: r3c1=9
Full House: r2c1=2
Naked Single: r9c6=7
Full House: r7c5=9
Full House: r7c9=7
Full House: r9c9=4
Full House: r9c7=9
Naked Single: r2c5=6
Full House: r2c6=4
Full House: r4c6=6
Full House: r5c5=7
Full House: r4c7=7
Full House: r5c7=6
|
normal_sudoku_6675
|
18..549.7.74.9851.9.5....488..9.14.541.58..9.25943687154....18..918.57..7.8....5.
|
182654937374298516965173248837921465416587392259436871543762189691845723728319654
|
Basic 9x9 Sudoku 6675
|
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 8 . . 5 4 9 . 7
. 7 4 . 9 8 5 1 .
9 . 5 . . . . 4 8
8 . . 9 . 1 4 . 5
4 1 . 5 8 . . 9 .
2 5 9 4 3 6 8 7 1
5 4 . . . . 1 8 .
. 9 1 8 . 5 7 . .
7 . 8 . . . . 5 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
182654937374298516965173248837921465416587392259436871543762189691845723728319654 #1 Extreme (4794)
Hidden Single: r1c6=4
Hidden Single: r5c1=4
Hidden Single: r4c4=9
Hidden Single: r6c7=8
Hidden Single: r6c9=1
Hidden Single: r2c8=1
Hidden Single: r6c3=9
Hidden Single: r5c4=5
Hidden Single: r7c1=5
Naked Single: r6c1=2
Full House: r6c2=5
Hidden Single: r8c7=7
Hidden Single: r1c2=8
Hidden Single: r2c7=5
Hidden Single: r9c8=5
Hidden Single: r5c5=8
Hidden Single: r8c4=8
Empty Rectangle: 2 in b2 (r39c2) => r9c4<>2
Finned Swordfish: 2 c267 r359 fr7c6 => r9c5<>2
Sashimi Swordfish: 2 r248 c589 fr2c4 => r3c5<>2
Grouped Discontinuous Nice Loop: 6 r7c4 =7= r3c4 =1= r3c5 =6= r123c4 -6- r7c4 => r7c4<>6
Finned Franken Swordfish: 3 c18b4 r148 fr2c1 fr5c3 => r1c3<>3
W-Wing: 6/3 in r4c2,r8c1 connected by 3 in r2c1,r3c2 => r9c2<>6
Sashimi Swordfish: 6 c128 r148 fr2c1 fr3c2 => r1c3<>6
Naked Single: r1c3=2
Hidden Single: r9c2=2
Hidden Rectangle: 3/9 in r7c69,r9c69 => r7c9<>3
Discontinuous Nice Loop: 6 r7c9 -6- r9c7 -3- r9c6 -9- r9c9 =9= r7c9 => r7c9<>6
Grouped Discontinuous Nice Loop: 3 r7c4 -3- r7c3 =3= r8c1 -3- r2c1 =3= r3c2 -3- r3c6 =3= r123c4 -3- r7c4 => r7c4<>3
Discontinuous Nice Loop: 7 r7c6 -7- r7c4 -2- r2c4 =2= r2c9 -2- r3c7 =2= r5c7 -2- r5c6 -7- r7c6 => r7c6<>7
Forcing Chain Contradiction in r4c8 => r2c4<>3
r2c4=3 r2c4<>2 r2c9=2 r3c7<>2 r5c7=2 r4c8<>2
r2c4=3 r1c4<>3 r1c8=3 r4c8<>3
r2c4=3 r2c1<>3 r2c1=6 r3c2<>6 r4c2=6 r4c8<>6
W-Wing: 6/3 in r1c8,r3c2 connected by 3 in r2c19 => r3c7<>6
Turbot Fish: 6 r1c8 =6= r2c9 -6- r2c1 =6= r8c1 => r8c8<>6
Finned X-Wing: 3 r28 c19 fr8c8 => r9c9<>3
Discontinuous Nice Loop: 3 r4c3 -3- r7c3 =3= r8c1 -3- r8c8 -2- r4c8 =2= r4c5 =7= r4c3 => r4c3<>3
Discontinuous Nice Loop: 2 r7c4 -2- r2c4 -6- r2c1 =6= r8c1 -6- r7c3 =6= r7c5 =7= r7c4 => r7c4<>2
Naked Single: r7c4=7
Locked Candidates Type 2 (Claiming): 2 in c4 => r3c6<>2
XY-Wing: 3/7/2 in r3c67,r5c6 => r5c7<>2
Hidden Single: r3c7=2
Hidden Single: r2c4=2
Remote Pair: 3/6 r1c8 -6- r2c9 -3- r2c1 -6- r8c1 => r8c8<>3
Naked Single: r8c8=2
Naked Single: r7c9=9
Hidden Single: r4c5=2
Full House: r5c6=7
Naked Single: r7c5=6
Naked Single: r3c6=3
Naked Single: r7c3=3
Full House: r7c6=2
Full House: r9c6=9
Full House: r8c1=6
Full House: r2c1=3
Full House: r3c2=6
Full House: r2c9=6
Full House: r4c2=3
Full House: r1c8=3
Full House: r1c4=6
Full House: r4c8=6
Full House: r4c3=7
Full House: r5c3=6
Naked Single: r8c5=4
Full House: r8c9=3
Naked Single: r3c4=1
Full House: r3c5=7
Full House: r9c5=1
Full House: r9c4=3
Naked Single: r9c9=4
Full House: r5c9=2
Full House: r5c7=3
Full House: r9c7=6
|
normal_sudoku_2952
|
.5.........97..1..6....2..3...9....75.74.3.181...783....5...642....4.8.18....6.3.
|
758139426239764185641582793483951267567423918192678354315897642926345871874216539
|
Basic 9x9 Sudoku 2952
|
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 . . . . . . .
. . 9 7 . . 1 . .
6 . . . . 2 . . 3
. . . 9 . . . . 7
5 . 7 4 . 3 . 1 8
1 . . . 7 8 3 . .
. . 5 . . . 6 4 2
. . . . 4 . 8 . 1
8 . . . . 6 . 3 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
758139426239764185641582793483951267567423918192678354315897642926345871874216539 #1 Extreme (23642) bf
Brute Force: r5c1=5
Naked Single: r5c6=3
Locked Candidates Type 1 (Pointing): 9 in b4 => r789c2<>9
Brute Force: r4c9=7
Turbot Fish: 7 r1c1 =7= r3c2 -7- r9c2 =7= r9c7 => r1c7<>7
Empty Rectangle: 6 in b6 (r16c4) => r1c8<>6
Forcing Net Contradiction in r7c8 => r1c9<>9
r1c9=9 (r9c9<>9) (r3c7<>9) r3c8<>9 r3c5=9 r9c5<>9 r9c7=9 (r5c7<>9 r5c7=2 r1c7<>2 r1c7=4 r1c6<>4) (r9c7<>5) r9c7<>7 r3c7=7 r3c7<>5 r4c7=5 r4c6<>5 r4c6=1 r1c6<>1 r1c6=9 r1c9<>9
XYZ-Wing: 4/5/6 in r12c9,r2c6 => r2c8<>4
Discontinuous Nice Loop: 4 r9c9 -4- r1c9 -6- r1c4 =6= r6c4 -6- r5c5 -2- r5c7 -9- r6c9 =9= r9c9 => r9c9<>4
Almost Locked Set XZ-Rule: A=r15c7 {249}, B=r129c9 {4569}, X=4, Z=9 => r9c7<>9
Forcing Chain Contradiction in r1c7 => r9c9=9
r9c9<>9 r6c9=9 r5c7<>9 r5c7=2 r1c7<>2
r9c9<>9 r6c9=9 r6c9<>4 r12c9=4 r1c7<>4
r9c9<>9 r9c5=9 r3c5<>9 r1c56=9 r1c7<>9
Grouped Discontinuous Nice Loop: 4 r2c1 -4- r2c6 -5- r2c9 =5= r6c9 =4= r12c9 -4- r3c78 =4= r3c23 -4- r2c1 => r2c1<>4
Grouped Discontinuous Nice Loop: 4 r2c2 -4- r2c6 -5- r2c9 =5= r6c9 =4= r12c9 -4- r3c78 =4= r3c23 -4- r2c2 => r2c2<>4
Finned Franken Swordfish: 5 c69b9 r248 fr6c9 fr9c7 => r4c7<>5
Naked Triple: 2,4,9 in r145c7 => r39c7<>4, r3c7<>9
Hidden Single: r7c8=4
Locked Candidates Type 2 (Claiming): 4 in r3 => r1c13<>4
Hidden Single: r4c1=4
Naked Single: r4c7=2
Naked Single: r5c7=9
Naked Single: r1c7=4
Naked Single: r1c9=6
Naked Single: r2c9=5
Full House: r6c9=4
Naked Single: r2c6=4
Naked Single: r3c7=7
Full House: r9c7=5
Full House: r8c8=7
Hidden Single: r6c2=9
Hidden Single: r6c4=6
Naked Single: r5c5=2
Full House: r5c2=6
Naked Single: r6c3=2
Full House: r6c8=5
Full House: r4c8=6
Naked Single: r9c5=1
Naked Single: r4c5=5
Full House: r4c6=1
Naked Single: r9c3=4
Naked Single: r9c4=2
Full House: r9c2=7
Naked Single: r1c6=9
Naked Single: r3c5=8
Naked Single: r7c6=7
Full House: r8c6=5
Naked Single: r1c5=3
Naked Single: r3c3=1
Naked Single: r3c8=9
Naked Single: r8c4=3
Naked Single: r1c4=1
Naked Single: r2c5=6
Full House: r7c5=9
Full House: r3c4=5
Full House: r3c2=4
Full House: r7c4=8
Naked Single: r1c3=8
Naked Single: r8c2=2
Naked Single: r8c3=6
Full House: r4c3=3
Full House: r8c1=9
Full House: r4c2=8
Naked Single: r7c1=3
Full House: r7c2=1
Full House: r2c2=3
Naked Single: r1c8=2
Full House: r1c1=7
Full House: r2c1=2
Full House: r2c8=8
|
normal_sudoku_6523
|
..1.9..359....38..3.8...9.4.1.9..3.78...3...959327...143....59.1.935.748.85..91.3
|
641897235972543816358612974214968357867135429593274681436781592129356748785429163
|
Basic 9x9 Sudoku 6523
|
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 . . 3 5
9 . . . . 3 8 . .
3 . 8 . . . 9 . 4
. 1 . 9 . . 3 . 7
8 . . . 3 . . . 9
5 9 3 2 7 . . . 1
4 3 . . . . 5 9 .
1 . 9 3 5 . 7 4 8
. 8 5 . . 9 1 . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
641897235972543816358612974214968357867135429593274681436781592129356748785429163 #1 Extreme (13776) bf
Hidden Single: r1c8=3
Hidden Single: r5c5=3
Hidden Single: r3c3=8
Hidden Single: r7c2=3
Hidden Single: r6c2=9
Hidden Single: r4c4=9
Hidden Single: r7c8=9
Hidden Single: r8c1=1
Hidden Single: r9c9=3
Hidden Single: r7c7=5
Hidden Single: r8c3=9
Hidden Single: r2c1=9
Brute Force: r4c9=7
Skyscraper: 7 in r8c7,r9c1 (connected by r1c17) => r8c2,r9c8<>7
Hidden Single: r8c7=7
Naked Pair: 2,6 in r1c7,r2c9 => r23c8<>2, r23c8<>6
Finned X-Wing: 2 r38 c26 fr3c5 => r1c6<>2
Finned X-Wing: 6 r38 c26 fr3c4 fr3c5 => r1c6<>6
Forcing Chain Contradiction in c5 => r1c4<>6
r1c4=6 r2c5<>6
r1c4=6 r3c5<>6
r1c4=6 r1c4<>8 r1c6=8 r46c6<>8 r4c5=8 r4c5<>6
r1c4=6 r3c456<>6 r3c2=6 r8c2<>6 r8c6=6 r7c5<>6
r1c4=6 r1c7<>6 r2c9=6 r7c9<>6 r9c8=6 r9c5<>6
Forcing Chain Contradiction in c1 => r4c8<>6
r4c8=6 r56c7<>6 r1c7=6 r1c1<>6
r4c8=6 r4c1<>6
r4c8=6 r6c78<>6 r6c6=6 r8c6<>6 r8c2=6 r9c1<>6
Forcing Chain Contradiction in r1c1 => r5c2<>2
r5c2=2 r5c7<>2 r1c7=2 r1c1<>2
r5c2=2 r4c1<>2 r4c1=6 r1c1<>6
r5c2=2 r5c2<>7 r123c2=7 r1c1<>7
Forcing Chain Contradiction in r7c3 => r1c1<>2
r1c1=2 r4c1<>2 r45c3=2 r7c3<>2
r1c1=2 r1c7<>2 r1c7=6 r2c9<>6 r7c9=6 r7c3<>6
r1c1=2 r1c1<>7 r9c1=7 r7c3<>7
W-Wing: 6/2 in r2c9,r8c2 connected by 2 in r1c27 => r2c2<>6
Multi Colors 1: 2 (r1c2,r2c9,r5c7,r9c8) / (r1c7,r7c9), (r8c2) / (r8c6) => r7c56<>2
W-Wing: 6/2 in r8c2,r9c8 connected by 2 in r7c39 => r9c1<>6
XY-Wing: 2/7/6 in r19c1,r8c2 => r13c2<>6
Locked Candidates Type 2 (Claiming): 6 in r3 => r2c45<>6
XY-Chain: 6 6- r1c1 -7- r9c1 -2- r9c8 -6- r7c9 -2- r2c9 -6 => r1c7,r2c3<>6
Naked Single: r1c7=2
Naked Single: r2c9=6
Full House: r7c9=2
Full House: r9c8=6
Naked Single: r6c8=8
Hidden Single: r1c1=6
Naked Single: r4c1=2
Full House: r9c1=7
Naked Single: r4c8=5
Naked Single: r7c3=6
Full House: r8c2=2
Full House: r8c6=6
Naked Single: r9c4=4
Full House: r9c5=2
Naked Single: r5c8=2
Naked Single: r4c3=4
Naked Single: r6c6=4
Full House: r6c7=6
Full House: r5c7=4
Naked Single: r4c6=8
Full House: r4c5=6
Naked Single: r5c3=7
Full House: r2c3=2
Full House: r5c2=6
Naked Single: r1c6=7
Naked Single: r3c5=1
Naked Single: r1c2=4
Full House: r1c4=8
Naked Single: r7c6=1
Naked Single: r2c4=5
Naked Single: r2c5=4
Full House: r7c5=8
Full House: r7c4=7
Naked Single: r3c8=7
Full House: r2c8=1
Full House: r2c2=7
Full House: r3c2=5
Naked Single: r5c6=5
Full House: r3c6=2
Full House: r3c4=6
Full House: r5c4=1
|
normal_sudoku_1239
|
.5.6..4.787...4..6..437.1.......6.....51.327.....2.69.5364...12..2..1...14....5..
|
359618427871254936264379185728946351695183274413725698536497812982561743147832569
|
Basic 9x9 Sudoku 1239
|
puzzles5_forum_hardest_1905_11+
|
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 . 6 . . 4 . 7
8 7 . . . 4 . . 6
. . 4 3 7 . 1 . .
. . . . . 6 . . .
. . 5 1 . 3 2 7 .
. . . . 2 . 6 9 .
5 3 6 4 . . . 1 2
. . 2 . . 1 . . .
1 4 . . . . 5 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
359618427871254936264379185728946351695183274413725698536497812982561743147832569 #1 Extreme (22982) bf
Locked Candidates Type 1 (Pointing): 1 in b1 => r46c3<>1
Brute Force: r5c6=3
Forcing Net Contradiction in b6 => r4c9<>7
r4c9=7 r4c9<>1 r4c2=1 (r4c2<>2 r4c1=2 r1c1<>2 r1c6=2 r2c4<>2 r2c8=2 r2c8<>3) (r4c2<>2 r4c1=2 r4c1<>3) r6c2<>1 r6c9=1 r6c9<>4 r6c1=4 r6c1<>3 r1c1=3 r2c3<>3 r2c7=3 r4c7<>3
r4c9=7 (r4c9<>5) r4c9<>1 r4c2=1 r6c2<>1 r6c9=1 r6c9<>5 r3c9=5 (r2c8<>5) r3c8<>5 r4c8=5 r4c8<>3
r4c9=7 r4c9<>3
r4c9=7 r4c9<>1 r4c2=1 (r4c2<>2 r4c1=2 r1c1<>2 r1c6=2 r2c4<>2 r2c8=2 r2c8<>3) (r4c2<>2 r4c1=2 r4c1<>3) r6c2<>1 r6c9=1 r6c9<>4 r6c1=4 r6c1<>3 r1c1=3 r2c3<>3 r2c7=3 r6c7<>3
r4c9=7 r4c9<>1 r4c2=1 r6c2<>1 r6c9=1 r6c9<>3
Brute Force: r5c8=7
Hidden Single: r1c9=7
Hidden Single: r6c7=6
Locked Candidates Type 2 (Claiming): 6 in c3 => r8c12<>6
Hidden Rectangle: 1/8 in r4c29,r6c29 => r4c9<>8
Grouped Discontinuous Nice Loop: 3 r8c8 -3- r12c8 =3= r2c7 -3- r4c7 -8- r5c9 -4- r8c9 =4= r8c8 => r8c8<>3
Grouped Discontinuous Nice Loop: 8 r8c8 -8- r78c7 =8= r4c7 -8- r5c9 -4- r8c9 =4= r8c8 => r8c8<>8
Grouped Discontinuous Nice Loop: 3 r9c8 -3- r12c8 =3= r2c7 -3- r4c7 -8- r5c9 -4- r8c9 =4= r8c8 =6= r9c8 => r9c8<>3
Discontinuous Nice Loop: 8 r9c5 -8- r9c8 -6- r8c8 =6= r8c5 =3= r9c5 => r9c5<>8
Grouped Discontinuous Nice Loop: 7/8/9 r7c3 =6= r7c5 -6- r8c5 =6= r8c8 =4= r8c9 -4- r5c9 -8- r3c9 =8= r13c8 -8- r9c8 -6- r9c3 =6= r7c3 => r7c3<>7, r7c3<>8, r7c3<>9
Naked Single: r7c3=6
Hidden Pair: 3,6 in r89c5 => r8c5<>1, r8c5<>5, r8c5<>8, r89c5<>9
Hidden Single: r8c6=1
Hidden Single: r8c4=5
Sashimi Swordfish: 8 c347 r469 fr7c7 fr8c7 => r9c89<>8
Naked Single: r9c8=6
Naked Single: r8c8=4
Naked Single: r9c5=3
Naked Single: r8c5=6
Naked Single: r9c9=9
Hidden Single: r2c7=9
Naked Single: r2c4=2
Hidden Single: r4c4=9
Hidden Single: r9c6=2
Hidden Single: r1c3=9
Naked Single: r1c6=8
Naked Single: r1c5=1
Naked Single: r2c5=5
Full House: r3c6=9
Naked Single: r2c8=3
Full House: r2c3=1
Naked Single: r7c6=7
Full House: r6c6=5
Naked Single: r1c8=2
Full House: r1c1=3
Naked Single: r7c7=8
Full House: r7c5=9
Full House: r9c4=8
Full House: r6c4=7
Full House: r9c3=7
Naked Single: r4c7=3
Full House: r8c7=7
Full House: r8c9=3
Naked Single: r6c1=4
Naked Single: r8c1=9
Full House: r8c2=8
Naked Single: r4c3=8
Full House: r6c3=3
Naked Single: r5c1=6
Naked Single: r6c2=1
Full House: r6c9=8
Naked Single: r4c5=4
Full House: r5c5=8
Naked Single: r4c8=5
Full House: r3c8=8
Full House: r3c9=5
Naked Single: r3c1=2
Full House: r3c2=6
Full House: r4c1=7
Naked Single: r5c2=9
Full House: r4c2=2
Full House: r5c9=4
Full House: r4c9=1
|
normal_sudoku_1131
|
..2.9.5.......3.4....8....61.......5.4735..8..59...7..9...31.5..8..7.2....56....3
|
362194578871563942594827316138749625247356189659218734926431857483975261715682493
|
Basic 9x9 Sudoku 1131
|
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 . 5 . .
. . . . . 3 . 4 .
. . . 8 . . . . 6
1 . . . . . . . 5
. 4 7 3 5 . . 8 .
. 5 9 . . . 7 . .
9 . . . 3 1 . 5 .
. 8 . . 7 . 2 . .
. . 5 6 . . . . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
362194578871563942594827316138749625247356189659218734926431857483975261715682493 #1 Extreme (21826) bf
Brute Force: r5c4=3
Hidden Single: r7c5=3
Locked Candidates Type 1 (Pointing): 1 in b5 => r6c89<>1
Locked Candidates Type 1 (Pointing): 8 in b8 => r9c7<>8
2-String Kite: 3 in r3c7,r6c1 (connected by r4c7,r6c8) => r3c1<>3
Finned X-Wing: 3 c27 r34 fr1c2 => r3c3<>3
Forcing Chain Contradiction in r1 => r1c2<>1
r1c2=1 r9c2<>1 r8c3=1 r8c3<>3 r8c1=3 r1c1<>3
r1c2=1 r1c2<>3
r1c2=1 r9c2<>1 r8c3=1 r8c3<>3 r8c1=3 r6c1<>3 r6c8=3 r1c8<>3
Forcing Chain Contradiction in r8 => r3c7<>1
r3c7=1 r3c7<>3 r4c7=3 r4c3<>3 r8c3=3 r8c3<>1
r3c7=1 r3c3<>1 r3c3=4 r7c3<>4 r7c3=6 r7c78<>6 r8c8=6 r8c8<>1
r3c7=1 r5c7<>1 r5c9=1 r8c9<>1
Forcing Chain Contradiction in r8 => r4c8<>6
r4c8=6 r4c23<>6 r56c1=6 r8c1<>6
r4c8=6 r45c7<>6 r7c7=6 r7c7<>8 r2c7=8 r2c3<>8 r4c3=8 r4c3<>3 r8c3=3 r8c3<>6
r4c8=6 r8c8<>6
Forcing Net Verity => r3c7=3
r2c3=1 (r3c3<>1 r3c3=4 r7c3<>4 r7c3=6 r7c7<>6) (r2c7<>1) (r2c2<>1) r3c2<>1 r9c2=1 r9c7<>1 r5c7=1 r5c7<>6 r4c7=6 r4c7<>3 r3c7=3
r2c3=6 (r1c2<>6 r1c6=6 r5c6<>6) (r1c2<>6 r1c6=6 r5c6<>6) (r7c3<>6 r7c3=4 r8c1<>4) r2c3<>8 r4c3=8 r4c3<>3 r8c3=3 r8c1<>3 r8c1=6 r5c1<>6 r5c7=6 (r5c7<>1 r5c9=1 r5c9<>9) r5c1<>6 r5c1=2 r5c6<>2 r5c6=9 r4c4<>9 r8c4=9 r8c9<>9 r2c9=9 r3c7<>9 r3c7=3
r2c3=8 (r1c1<>8) r2c1<>8 r6c1=8 r6c1<>3 r6c8=3 r4c7<>3 r3c7=3
Almost Locked Set XZ-Rule: A=r1c8 {17}, B=r8c9,r9c78 {1479}, X=7, Z=1 => r8c8<>1
Discontinuous Nice Loop: 1 r1c9 -1- r8c9 =1= r8c3 =3= r4c3 =8= r2c3 -8- r1c1 =8= r1c9 => r1c9<>1
Forcing Chain Verity => r2c9<>1
r2c2=1 r2c9<>1
r3c2=1 r3c2<>9 r3c8=9 r3c8<>2 r2c9=2 r2c9<>1
r9c2=1 r9c8<>1 r13c8=1 r2c9<>1
Forcing Chain Contradiction in c7 => r4c3<>6
r4c3=6 r4c7<>6
r4c3=6 r4c3<>3 r8c3=3 r8c3<>1 r8c9=1 r5c9<>1 r5c7=1 r5c7<>6
r4c3=6 r4c3<>8 r2c3=8 r2c7<>8 r7c7=8 r7c7<>6
Forcing Chain Contradiction in r8c1 => r7c2<>6
r7c2=6 r78c3<>6 r2c3=6 r2c3<>8 r4c3=8 r4c3<>3 r8c3=3 r8c1<>3
r7c2=6 r7c3<>6 r7c3=4 r8c1<>4
r7c2=6 r8c1<>6
Forcing Chain Contradiction in r5 => r2c3<>6
r2c3=6 r12c2<>6 r4c2=6 r5c1<>6
r2c3=6 r2c5<>6 r1c6=6 r5c6<>6
r2c3=6 r2c3<>8 r4c3=8 r4c3<>3 r8c3=3 r8c3<>1 r8c9=1 r5c9<>1 r5c7=1 r5c7<>6
Locked Candidates Type 2 (Claiming): 6 in c3 => r8c1<>6
Discontinuous Nice Loop: 6 r6c8 -6- r8c8 =6= r8c3 =3= r8c1 -3- r6c1 =3= r6c8 => r6c8<>6
Locked Candidates Type 1 (Pointing): 6 in b6 => r7c7<>6
Hidden Pair: 5,6 in r78c8 => r7c8<>7, r8c8<>9
Grouped Discontinuous Nice Loop: 6 r4c5 -6- r4c7 =6= r5c7 =1= r5c9 -1- r8c9 =1= r8c3 =3= r4c3 =8= r6c1 =6= r6c56 -6- r4c5 => r4c5<>6
Grouped Discontinuous Nice Loop: 6 r4c6 -6- r4c7 =6= r5c7 =1= r5c9 -1- r8c9 =1= r8c3 =3= r4c3 =8= r6c1 =6= r6c56 -6- r4c6 => r4c6<>6
Forcing Chain Contradiction in r4c2 => r7c3=6
r7c3<>6 r7c8=6 r7c8<>5 r7c4=5 r7c4<>2 r7c2=2 r4c2<>2
r7c3<>6 r8c3=6 r8c3<>3 r4c3=3 r4c2<>3
r7c3<>6 r8c3=6 r8c3<>1 r8c9=1 r5c9<>1 r5c7=1 r5c7<>6 r4c7=6 r4c2<>6
Naked Single: r7c8=5
Naked Single: r8c8=6
Almost Locked Set XZ-Rule: A=r1c48 {147}, B=r7c24 {247}, X=4, Z=7 => r1c2<>7
Forcing Chain Contradiction in r4c8 => r2c4<>2
r2c4=2 r2c9<>2 r3c8=2 r4c8<>2
r2c4=2 r2c9<>2 r3c8=2 r6c8<>2 r6c8=3 r4c8<>3
r2c4=2 r2c4<>5 r8c4=5 r8c4<>9 r4c4=9 r4c8<>9
Discontinuous Nice Loop: 4 r6c4 -4- r6c9 -2- r2c9 =2= r2c5 =6= r6c5 =1= r6c4 => r6c4<>4
Discontinuous Nice Loop: 4 r6c5 -4- r6c9 -2- r2c9 =2= r2c5 =6= r6c5 => r6c5<>4
Forcing Chain Contradiction in r5c6 => r2c4<>1
r2c4=1 r6c4<>1 r6c4=2 r5c6<>2
r2c4=1 r2c3<>1 r2c3=8 r4c3<>8 r6c1=8 r6c1<>6 r6c56=6 r5c6<>6
r2c4=1 r2c4<>5 r8c4=5 r8c4<>9 r4c4=9 r5c6<>9
Forcing Chain Contradiction in r8 => r2c7<>1
r2c7=1 r2c3<>1 r2c3=8 r4c3<>8 r4c3=3 r8c3<>3 r8c1=3 r8c1<>4
r2c7=1 r5c7<>1 r5c9=1 r8c9<>1 r8c3=1 r8c3<>4
r2c7=1 r1c8<>1 r1c4=1 r6c4<>1 r6c4=2 r7c4<>2 r7c4=4 r8c4<>4
r2c7=1 r1c8<>1 r1c4=1 r6c4<>1 r6c4=2 r7c4<>2 r7c4=4 r8c6<>4
r2c7=1 r1c8<>1 r1c4=1 r6c4<>1 r6c4=2 r6c9<>2 r6c9=4 r8c9<>4
Locked Candidates Type 1 (Pointing): 1 in b3 => r9c8<>1
Discontinuous Nice Loop: 1 r3c2 -1- r2c3 -8- r2c7 -9- r2c2 =9= r3c2 => r3c2<>1
W-Wing: 9/7 in r3c2,r9c8 connected by 7 in r7c29 => r3c8<>9
Hidden Single: r3c2=9
Skyscraper: 9 in r8c4,r9c8 (connected by r4c48) => r8c9,r9c6<>9
Naked Triple: 2,4,8 in r7c4,r9c56 => r8c46<>4
Sue de Coq: r79c7 - {1489} (r2c7 - {89}, r8c9 - {14}) => r7c9<>4, r45c7<>9
Naked Pair: 7,8 in r17c9 => r2c9<>7, r2c9<>8
XY-Chain: 4 4- r6c9 -2- r2c9 -9- r2c7 -8- r7c7 -4 => r4c7,r8c9<>4
Naked Single: r4c7=6
Naked Single: r8c9=1
Naked Single: r5c7=1
Hidden Single: r6c9=4
Hidden Single: r9c2=1
Locked Candidates Type 1 (Pointing): 6 in b4 => r12c1<>6
Locked Candidates Type 2 (Claiming): 4 in r8 => r9c1<>4
Skyscraper: 7 in r1c9,r2c2 (connected by r7c29) => r1c1<>7
Finned X-Wing: 2 c24 r47 fr6c4 => r4c56<>2
Sue de Coq: r2c12 - {5678} (r2c4 - {57}, r1c12,r23c3 - {13468}) => r3c1<>4
XY-Chain: 8 8- r2c7 -9- r9c7 -4- r7c7 -8- r7c9 -7- r7c2 -2- r4c2 -3- r4c3 -8 => r2c3<>8
Naked Single: r2c3=1
Naked Single: r3c3=4
Naked Single: r8c3=3
Full House: r4c3=8
Naked Single: r8c1=4
Naked Single: r4c5=4
Hidden Rectangle: 2/8 in r6c56,r9c56 => r6c6<>2
XY-Chain: 3 3- r4c2 -2- r7c2 -7- r2c2 -6- r2c5 -2- r2c9 -9- r5c9 -2- r6c8 -3 => r4c8,r6c1<>3
Hidden Single: r4c2=3
Naked Single: r1c2=6
Naked Single: r2c2=7
Full House: r7c2=2
Full House: r9c1=7
Naked Single: r2c4=5
Naked Single: r3c1=5
Naked Single: r7c4=4
Naked Single: r9c8=9
Naked Single: r2c1=8
Full House: r1c1=3
Naked Single: r8c4=9
Full House: r8c6=5
Naked Single: r7c7=8
Full House: r7c9=7
Full House: r9c7=4
Full House: r2c7=9
Naked Single: r4c8=2
Naked Single: r1c9=8
Naked Single: r2c9=2
Full House: r5c9=9
Full House: r6c8=3
Full House: r2c5=6
Naked Single: r4c4=7
Full House: r4c6=9
Naked Single: r1c4=1
Full House: r6c4=2
Naked Single: r1c8=7
Full House: r1c6=4
Full House: r3c8=1
Naked Single: r3c5=2
Full House: r3c6=7
Naked Single: r5c6=6
Full House: r5c1=2
Full House: r6c1=6
Naked Single: r9c5=8
Full House: r6c5=1
Full House: r6c6=8
Full House: r9c6=2
|
normal_sudoku_2919
|
..61...7.2...6.4...8....9.6...3..6.7..35.6..4.6..1753.6...8...5..47.1.6...865..4.
|
946135872217968453385274916159342687873596124462817539621483795594721368738659241
|
Basic 9x9 Sudoku 2919
|
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 1 . . . 7 .
2 . . . 6 . 4 . .
. 8 . . . . 9 . 6
. . . 3 . . 6 . 7
. . 3 5 . 6 . . 4
. 6 . . 1 7 5 3 .
6 . . . 8 . . . 5
. . 4 7 . 1 . 6 .
. . 8 6 5 . . 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
946135872217968453385274916159342687873596124462817539621483795594721368738659241 #1 Extreme (17922) bf
Hidden Single: r1c3=6
Hidden Single: r8c8=6
Hidden Single: r9c4=6
Finned X-Wing: 4 c25 r14 fr3c5 => r1c6<>4
Brute Force: r5c4=5
Sashimi X-Wing: 8 c48 r26 fr4c8 fr5c8 => r6c79<>8
Forcing Chain Contradiction in c8 => r6c1<>5
r6c1=5 r6c1<>4 r4c12=4 r4c5<>4 r13c5=4 r3c4<>4 r3c4=2 r3c8<>2
r6c1=5 r6c7<>5 r6c7=2 r4c8<>2
r6c1=5 r6c7<>5 r6c7=2 r5c8<>2
r6c1=5 r6c7<>5 r6c7=2 r6c9<>2 r6c9=9 r45c8<>9 r7c8=9 r7c8<>2
Forcing Chain Contradiction in r7c4 => r6c4<>2
r6c4=2 r7c4<>2
r6c4=2 r3c4<>2 r3c4=4 r7c4<>4
r6c4=2 r6c9<>2 r6c9=9 r45c8<>9 r7c8=9 r7c4<>9
Forcing Net Verity => r3c5=7
r5c2=2 (r5c8<>2) (r4c3<>2) r6c3<>2 r7c3=2 (r7c3<>9) (r7c8<>2) r7c4<>2 r3c4=2 r3c8<>2 r4c8=2 (r4c8<>9) r6c9<>2 r6c9=9 (r5c8<>9) (r6c3<>9) (r6c4<>9) r5c8<>9 r7c8=9 r7c4<>9 r2c4=9 r2c3<>9 r4c3=9 (r5c1<>9) r5c2<>9 r5c5=9 r5c5<>7 r3c5=7
r5c5=2 r5c5<>7 r3c5=7
r5c7=2 r6c9<>2 r6c9=9 (r5c8<>9) (r6c3<>9) (r6c4<>9) (r4c8<>9) r5c8<>9 r7c8=9 (r7c3<>9) r7c4<>9 r2c4=9 r2c3<>9 r4c3=9 (r5c1<>9) r5c2<>9 r5c5=9 r5c5<>7 r3c5=7
r5c8=2 (r5c8<>9) r6c9<>2 r6c9=9 (r6c3<>9) (r6c4<>9) (r4c8<>9) r5c8<>9 r7c8=9 (r7c3<>9) r7c4<>9 r2c4=9 r2c3<>9 r4c3=9 (r5c1<>9) r5c2<>9 r5c5=9 r5c5<>7 r3c5=7
Hidden Single: r6c6=7
Naked Triple: 2,5,9 in r6c379 => r6c14<>9
X-Wing: 4 c25 r14 => r14c1,r4c6<>4
2-String Kite: 3 in r3c1,r8c5 (connected by r1c5,r3c6) => r8c1<>3
Empty Rectangle: 3 in b3 (r18c5) => r8c9<>3
Empty Rectangle: 9 in b9 (r6c39) => r7c3<>9
Hidden Rectangle: 2/4 in r3c46,r7c46 => r7c6<>2
Discontinuous Nice Loop: 9 r1c5 -9- r2c4 -8- r6c4 -4- r4c5 =4= r1c5 => r1c5<>9
Grouped Discontinuous Nice Loop: 9 r2c3 -9- r2c4 =9= r7c4 -9- r7c8 =9= r45c8 -9- r6c9 =9= r6c3 -9- r2c3 => r2c3<>9
Locked Candidates Type 2 (Claiming): 9 in c3 => r4c12,r5c12<>9
Grouped Discontinuous Nice Loop: 2 r4c8 -2- r6c9 -9- r5c8 =9= r5c5 =2= r4c56 -2- r4c8 => r4c8<>2
Sashimi Swordfish: 2 c348 r357 fr4c3 fr6c3 => r5c2<>2
Sue de Coq: r5c78 - {1289} (r5c12 - {178}, r6c79 - {259}) => r4c8<>5, r4c8<>9
Hidden Single: r6c7=5
Discontinuous Nice Loop: 2 r4c5 -2- r5c5 -9- r5c8 =9= r7c8 -9- r7c4 =9= r2c4 =8= r6c4 =4= r4c5 => r4c5<>2
Grouped Discontinuous Nice Loop: 3 r1c2 -3- r1c79 =3= r2c9 =1= r23c8 -1- r4c8 -8- r4c6 =8= r6c4 =4= r6c1 -4- r3c1 =4= r1c2 => r1c2<>3
Grouped Discontinuous Nice Loop: 1 r2c3 -1- r2c9 =1= r9c9 -1- r79c7 =1= r5c7 -1- r5c2 -7- r2c2 =7= r2c3 => r2c3<>1
Almost Locked Set XZ-Rule: A=r1c579 {2348}, B=r3c3468 {12345}, X=4, Z=3 => r1c6<>3
Almost Locked Set XZ-Rule: A=r1c579 {2348}, B=r3c4 {24}, X=4, Z=2 => r1c6<>2
Almost Locked Set XZ-Rule: A=r1c579 {2348}, B=r4c56,r5c5 {2489}, X=4, Z=8 => r1c6<>8
Locked Candidates Type 1 (Pointing): 8 in b2 => r2c89<>8
Locked Candidates Type 2 (Claiming): 8 in c8 => r5c7<>8
XY-Chain: 8 8- r4c8 -1- r5c7 -2- r5c5 -9- r4c5 -4- r6c4 -8 => r4c6<>8
Hidden Single: r2c6=8
Naked Single: r2c4=9
Naked Single: r1c6=5
Hidden Single: r6c4=8
Naked Single: r6c1=4
Hidden Single: r4c5=4
Hidden Single: r1c2=4
Hidden Single: r1c1=9
Naked Single: r8c1=5
Naked Pair: 1,8 in r4c18 => r4c23<>1
Skyscraper: 9 in r7c8,r8c5 (connected by r5c58) => r7c6,r8c9<>9
Swordfish: 9 r578 c258 => r9c2<>9
2-String Kite: 3 in r2c9,r9c1 (connected by r2c2,r3c1) => r9c9<>3
Locked Candidates Type 1 (Pointing): 3 in b9 => r1c7<>3
Uniqueness Test 2: 2/4 in r3c46,r7c46 => r9c6<>3
Naked Pair: 2,9 in r49c6 => r3c6<>2
Skyscraper: 3 in r7c6,r9c1 (connected by r3c16) => r7c2<>3
Uniqueness Test 4: 1/8 in r4c18,r5c18 => r5c18<>1
Uniqueness Test 6: 2/8 in r1c79,r8c79 => r1c9,r8c7<>8
Hidden Single: r1c7=8
Hidden Single: r8c9=8
Empty Rectangle: 2 in b6 (r1c59) => r5c5<>2
Naked Single: r5c5=9
Full House: r4c6=2
Naked Single: r4c2=5
Naked Single: r9c6=9
Naked Single: r4c3=9
Naked Single: r6c3=2
Full House: r6c9=9
Hidden Single: r7c8=9
Hidden Single: r8c2=9
Locked Candidates Type 1 (Pointing): 3 in b7 => r9c7<>3
Remote Pair: 2/3 r1c9 -3- r1c5 -2- r8c5 -3- r8c7 => r9c9<>2
Naked Single: r9c9=1
Naked Single: r2c9=3
Full House: r1c9=2
Full House: r1c5=3
Full House: r8c5=2
Full House: r8c7=3
Naked Single: r3c6=4
Full House: r3c4=2
Full House: r7c4=4
Full House: r7c6=3
Hidden Single: r5c7=1
Naked Single: r4c8=8
Full House: r4c1=1
Full House: r5c8=2
Naked Single: r5c2=7
Full House: r5c1=8
Naked Single: r3c1=3
Full House: r9c1=7
Naked Single: r2c2=1
Naked Single: r7c3=1
Naked Single: r9c7=2
Full House: r7c7=7
Full House: r7c2=2
Full House: r9c2=3
Naked Single: r2c8=5
Full House: r2c3=7
Full House: r3c3=5
Full House: r3c8=1
|
normal_sudoku_2167
|
5.28..13..13.25..998..3.5.2..1.82.9.8..9732152...64...3.5...9.819...83....83....1
|
562849137413725869987631542731582694846973215259164783375416928194258376628397451
|
Basic 9x9 Sudoku 2167
|
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 8 . . 1 3 .
. 1 3 . 2 5 . . 9
9 8 . . 3 . 5 . 2
. . 1 . 8 2 . 9 .
8 . . 9 7 3 2 1 5
2 . . . 6 4 . . .
3 . 5 . . . 9 . 8
1 9 . . . 8 3 . .
. . 8 3 . . . . 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
562849137413725869987631542731582694846973215259164783375416928194258376628397451 #1 Extreme (21600) bf
Hidden Single: r2c2=1
Hidden Single: r3c1=9
Hidden Single: r1c4=8
Hidden Single: r9c3=8
Hidden Single: r2c3=3
Locked Candidates Type 1 (Pointing): 5 in b5 => r8c4<>5
Locked Candidates Type 2 (Claiming): 9 in c4 => r5c56<>9
Hidden Rectangle: 7/9 in r5c34,r6c34 => r5c4<>7
Hidden Rectangle: 7/8 in r2c78,r6c78 => r2c8<>7
Brute Force: r5c7=2
Almost Locked Set XY-Wing: A=r4c14679 {234567}, B=r1579c2 {23467}, C=r5c456,r6c4 {13579}, X,Y=3,5, Z=4,6,7 => r4c2<>4, r4c2<>6, r4c2<>7
Brute Force: r5c8=1
Naked Single: r5c4=9
Naked Single: r5c5=7
Naked Single: r5c6=3
Naked Single: r4c6=2
Naked Single: r4c4=5
Full House: r6c4=1
Naked Single: r4c2=3
Hidden Single: r7c5=1
Hidden Single: r6c3=9
Hidden Single: r6c2=5
Hidden Single: r3c6=1
Hidden Single: r6c9=3
Hidden Single: r4c1=7
Skyscraper: 7 in r1c9,r3c3 (connected by r8c39) => r1c2,r3c8<>7
Hidden Single: r3c3=7
Naked Pair: 4,6 in r8c3,r9c1 => r79c2<>4, r79c2<>6
X-Wing: 4 r37 c48 => r2c48,r8c48,r9c8<>4
2-String Kite: 7 in r2c4,r8c9 (connected by r1c9,r2c7) => r8c4<>7
Locked Candidates Type 2 (Claiming): 7 in r8 => r79c8,r9c7<>7
Naked Pair: 4,6 in r9c17 => r9c5<>4, r9c68<>6
Naked Pair: 4,6 in r49c7 => r2c7<>4, r2c7<>6
Hidden Single: r2c1=4
Full House: r1c2=6
Full House: r9c1=6
Naked Single: r5c2=4
Full House: r5c3=6
Full House: r8c3=4
Naked Single: r9c7=4
Naked Single: r8c5=5
Naked Single: r4c7=6
Full House: r4c9=4
Naked Single: r9c5=9
Full House: r1c5=4
Naked Single: r1c9=7
Full House: r1c6=9
Full House: r8c9=6
Naked Single: r9c6=7
Full House: r7c6=6
Naked Single: r3c4=6
Full House: r2c4=7
Full House: r3c8=4
Naked Single: r2c7=8
Full House: r2c8=6
Full House: r6c7=7
Full House: r6c8=8
Naked Single: r7c8=2
Naked Single: r8c4=2
Full House: r7c4=4
Full House: r7c2=7
Full House: r9c2=2
Full House: r8c8=7
Full House: r9c8=5
|
normal_sudoku_160
|
5231.4.698...3.1.2..1.......345.1.98.1...8...6583....1.75913..61..856...386427915
|
523184769869735142741692583234571698917268354658349271475913826192856437386427915
|
Basic 9x9 Sudoku 160
|
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 2 3 1 . 4 . 6 9
8 . . . 3 . 1 . 2
. . 1 . . . . . .
. 3 4 5 . 1 . 9 8
. 1 . . . 8 . . .
6 5 8 3 . . . . 1
. 7 5 9 1 3 . . 6
1 . . 8 5 6 . . .
3 8 6 4 2 7 9 1 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
523184769869735142741692583234571698917268354658349271475913826192856437386427915 #1 Extreme (3788)
Naked Single: r4c2=3
Naked Single: r1c6=4
Naked Single: r9c4=4
Full House: r8c5=5
Naked Single: r9c1=3
Naked Single: r9c9=5
Hidden Single: r1c4=1
Hidden Single: r5c2=1
Hidden Single: r9c8=1
Hidden Single: r1c3=3
Hidden Single: r7c3=5
Hidden Single: r6c2=5
Hidden Single: r6c3=8
Naked Single: r9c3=6
Full House: r9c2=8
Locked Candidates Type 1 (Pointing): 9 in b4 => r5c5<>9
2-String Kite: 2 in r4c7,r8c3 (connected by r4c1,r5c3) => r8c7<>2
2-String Kite: 4 in r2c8,r7c1 (connected by r2c2,r3c1) => r7c8<>4
Empty Rectangle: 7 in b5 (r1c57) => r5c7<>7
Finned X-Wing: 7 r16 c57 fr6c8 => r4c7<>7
X-Chain: 7 r1c7 =7= r1c5 -7- r4c5 =7= r4c1 -7- r3c1 =7= r2c3 => r2c8<>7
Discontinuous Nice Loop: 9 r3c2 -9- r2c3 -7- r2c4 -6- r2c2 =6= r3c2 => r3c2<>9
Discontinuous Nice Loop: 7 r3c7 -7- r1c7 =7= r1c5 -7- r4c5 -6- r4c7 =6= r5c7 =5= r3c7 => r3c7<>7
Discontinuous Nice Loop: 4 r5c8 -4- r5c5 =4= r6c5 =9= r6c6 -9- r2c6 -5- r2c8 -4- r5c8 => r5c8<>4
Grouped Discontinuous Nice Loop: 2 r5c1 -2- r4c1 =2= r4c7 =6= r5c7 =5= r5c8 -5- r2c8 =5= r2c6 =9= r2c23 -9- r3c1 =9= r5c1 => r5c1<>2
Discontinuous Nice Loop: 7 r5c5 -7- r4c5 =7= r4c1 =2= r5c3 -2- r5c4 =2= r6c6 =9= r6c5 =4= r5c5 => r5c5<>7
Discontinuous Nice Loop: 7 r6c5 -7- r4c5 =7= r4c1 =2= r5c3 -2- r5c4 =2= r6c6 =9= r6c5 => r6c5<>7
Locked Candidates Type 2 (Claiming): 7 in r6 => r5c89<>7
AIC: 2/7 7- r6c8 =7= r6c7 -7- r1c7 =7= r1c5 -7- r4c5 =7= r4c1 =2= r7c1 -2- r8c3 =2= r8c8 -2 => r6c8<>2, r8c8<>7
AIC: 7 7- r1c7 =7= r1c5 -7- r4c5 -6- r4c7 =6= r5c7 =5= r5c8 -5- r2c8 -4- r6c8 -7 => r3c8,r6c7<>7
Hidden Single: r6c8=7
W-Wing: 4/2 in r6c7,r7c1 connected by 2 in r4c17 => r7c7<>4
Hidden Single: r7c1=4
Naked Single: r8c2=9
Full House: r8c3=2
Hidden Single: r4c1=2
Naked Single: r4c7=6
Full House: r4c5=7
Naked Single: r1c5=8
Full House: r1c7=7
Hidden Single: r8c9=7
W-Wing: 6/4 in r3c2,r5c5 connected by 4 in r35c9 => r3c5<>6
Naked Single: r3c5=9
Naked Single: r2c6=5
Naked Single: r3c1=7
Full House: r5c1=9
Full House: r5c3=7
Full House: r2c3=9
Naked Single: r6c5=4
Full House: r5c5=6
Naked Single: r2c8=4
Naked Single: r3c6=2
Full House: r6c6=9
Full House: r6c7=2
Full House: r5c4=2
Naked Single: r2c2=6
Full House: r2c4=7
Full House: r3c4=6
Full House: r3c2=4
Naked Single: r3c9=3
Full House: r5c9=4
Naked Single: r8c8=3
Full House: r8c7=4
Naked Single: r7c7=8
Full House: r7c8=2
Naked Single: r5c8=5
Full House: r3c8=8
Full House: r3c7=5
Full House: r5c7=3
|
normal_sudoku_1933
|
.7.9813.2...37214.231564978.....7...7.3859....2..36.87.18.......9..1..23..2.....4
|
674981352859372146231564978186247539743859261925136487418623795597418623362795814
|
Basic 9x9 Sudoku 1933
|
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.
|
. 7 . 9 8 1 3 . 2
. . . 3 7 2 1 4 .
2 3 1 5 6 4 9 7 8
. . . . . 7 . . .
7 . 3 8 5 9 . . .
. 2 . . 3 6 . 8 7
. 1 8 . . . . . .
. 9 . . 1 . . 2 3
. . 2 . . . . . 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
674981352859372146231564978186247539743859261925136487418623795597418623362795814 #1 Easy (320)
Hidden Single: r3c2=3
Hidden Single: r2c5=7
Naked Single: r3c6=4
Naked Single: r3c5=6
Naked Single: r5c6=9
Naked Single: r1c4=9
Full House: r1c5=8
Naked Single: r3c3=1
Full House: r3c8=7
Hidden Single: r6c5=3
Naked Single: r4c6=7
Hidden Single: r1c9=2
Hidden Single: r9c3=2
Naked Single: r9c5=9
Hidden Single: r4c8=3
Hidden Single: r9c8=1
Naked Single: r5c8=6
Naked Single: r1c8=5
Full House: r2c9=6
Full House: r7c8=9
Naked Single: r5c2=4
Naked Single: r5c9=1
Full House: r5c7=2
Naked Single: r7c9=5
Full House: r4c9=9
Naked Single: r7c6=3
Hidden Single: r8c3=7
Hidden Single: r9c1=3
Hidden Single: r1c3=4
Full House: r1c1=6
Naked Single: r7c1=4
Naked Single: r7c5=2
Full House: r4c5=4
Naked Single: r8c1=5
Full House: r9c2=6
Naked Single: r4c7=5
Full House: r6c7=4
Naked Single: r6c4=1
Full House: r4c4=2
Naked Single: r8c6=8
Full House: r9c6=5
Naked Single: r9c4=7
Full House: r9c7=8
Naked Single: r4c2=8
Full House: r2c2=5
Naked Single: r4c3=6
Full House: r4c1=1
Naked Single: r6c1=9
Full House: r2c1=8
Full House: r2c3=9
Full House: r6c3=5
Naked Single: r8c7=6
Full House: r7c7=7
Full House: r7c4=6
Full House: r8c4=4
|
normal_sudoku_4539
|
..87...9..945..2..2....4..3.458.7....2..61...18..593......7.4.14....8.3..6......2
|
318726594794513268256984713645837129923461857187259346539672481472198635861345972
|
Basic 9x9 Sudoku 4539
|
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 . . . 9 .
. 9 4 5 . . 2 . .
2 . . . . 4 . . 3
. 4 5 8 . 7 . . .
. 2 . . 6 1 . . .
1 8 . . 5 9 3 . .
. . . . 7 . 4 . 1
4 . . . . 8 . 3 .
. 6 . . . . . . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
318726594794513268256984713645837129923461857187259346539672481472198635861345972 #1 Extreme (17102) bf
Brute Force: r5c6=1
Hidden Single: r6c5=5
Hidden Single: r4c6=7
Grouped Discontinuous Nice Loop: 5 r1c9 -5- r1c1 =5= r79c1 -5- r7c2 -3- r4c2 -4- r1c2 =4= r1c9 => r1c9<>5
Forcing Chain Contradiction in r1c7 => r9c5=4
r9c5<>4 r4c5=4 r4c5<>2 r4c8=2 r4c8<>1 r4c7=1 r1c7<>1
r9c5<>4 r4c5=4 r4c2<>4 r4c2=3 r7c2<>3 r7c2=5 r3c2<>5 r1c12=5 r1c7<>5
r9c5<>4 r4c5=4 r4c2<>4 r1c2=4 r1c9<>4 r1c9=6 r1c7<>6
XY-Wing: 2/3/4 in r4c25,r6c4 => r6c3<>4
2-String Kite: 4 in r1c9,r5c3 (connected by r1c2,r2c3) => r5c9<>4
Finned X-Wing: 4 r14 c29 fr4c8 => r6c9<>4
Naked Pair: 6,7 in r6c39 => r6c8<>6, r6c8<>7
Discontinuous Nice Loop: 6 r2c3 -6- r6c3 =6= r6c9 -6- r1c9 -4- r1c2 =4= r2c3 => r2c3<>6
Discontinuous Nice Loop: 9 r8c9 -9- r8c5 =9= r3c5 =8= r2c5 -8- r2c9 =8= r5c9 =5= r8c9 => r8c9<>9
Locked Candidates Type 1 (Pointing): 9 in b9 => r45c7<>9
Discontinuous Nice Loop: 5 r9c7 -5- r8c9 =5= r5c9 =8= r2c9 -8- r2c5 =8= r3c5 =9= r8c5 -9- r8c7 =9= r9c7 => r9c7<>5
Grouped Discontinuous Nice Loop: 8 r2c8 -8- r2c5 =8= r3c5 =9= r8c5 -9- r8c7 =9= r9c7 =8= r79c8 -8- r2c8 => r2c8<>8
Grouped Discontinuous Nice Loop: 8 r5c8 -8- r5c9 =8= r2c9 -8- r2c5 =8= r3c5 =9= r8c5 -9- r8c7 =9= r9c7 =8= r79c8 -8- r5c8 => r5c8<>8
Almost Locked Set XZ-Rule: A=r1347c2 {13457}, B=r36c3 {167}, X=1, Z=7 => r2c3<>7
Forcing Chain Contradiction in c1 => r1c9=4
r1c9<>4 r1c9=6 r1c1<>6
r1c9<>4 r1c2=4 r4c2<>4 r4c2=3 r4c5<>3 r12c5=3 r2c6<>3 r2c6=6 r2c1<>6
r1c9<>4 r1c9=6 r6c9<>6 r6c3=6 r4c1<>6
Hidden Single: r4c2=4
Hidden Single: r2c3=4
Empty Rectangle: 3 in b1 (r4c15) => r1c5<>3
AIC: 1 1- r2c8 =1= r2c5 =3= r4c5 =2= r4c8 =1= r4c7 -1 => r13c7,r4c8<>1
Hidden Single: r4c7=1
Grouped AIC: 5 5- r7c2 -3- r79c3 =3= r5c3 -3- r5c4 =3= r79c4 -3- r9c6 -5 => r7c6,r9c1<>5
Hidden Single: r9c6=5
Grouped Discontinuous Nice Loop: 6 r2c9 -6- r46c9 =6= r4c8 =2= r4c5 =3= r2c5 =8= r2c9 => r2c9<>6
Discontinuous Nice Loop: 6 r3c4 -6- r3c3 =6= r6c3 =7= r6c9 -7- r2c9 -8- r2c5 =8= r3c5 =9= r3c4 => r3c4<>6
Locked Candidates Type 1 (Pointing): 6 in b2 => r7c6<>6
Sue de Coq: r789c4 - {12369} (r3c4 - {19}, r7c6 - {23}) => r8c5<>2
Continuous Nice Loop: 3/5 3= r1c2 =1= r1c5 =2= r1c6 -2- r7c6 -3- r7c2 =3= r1c2 =1 => r7c134<>3, r1c2<>5
X-Wing: 3 c34 r59 => r59c1<>3
Naked Triple: 7,8,9 in r9c178 => r9c3<>7, r9c34<>9
XY-Chain: 9 9- r7c3 -2- r7c6 -3- r9c4 -1- r8c5 -9 => r7c4,r8c3<>9
Locked Candidates Type 1 (Pointing): 9 in b8 => r8c7<>9
Hidden Single: r9c7=9
Locked Candidates Type 1 (Pointing): 8 in b9 => r3c8<>8
2-String Kite: 7 in r3c2,r9c8 (connected by r8c2,r9c1) => r3c8<>7
W-Wing: 6/2 in r4c8,r7c4 connected by 2 in r6c48 => r7c8<>6
Hidden Single: r7c4=6
Uniqueness Test 6: 1/9 in r3c45,r8c45 => r3c5,r8c4<>9
Hidden Single: r3c4=9
Hidden Single: r8c5=9
Finned Swordfish: 6 r368 c379 fr3c8 => r1c7<>6
Naked Single: r1c7=5
Hidden Single: r7c1=5
Naked Single: r7c2=3
Naked Single: r7c8=8
Naked Single: r1c2=1
Naked Single: r7c6=2
Full House: r7c3=9
Naked Single: r9c3=1
Naked Single: r9c8=7
Naked Single: r1c5=2
Naked Single: r8c2=7
Full House: r3c2=5
Naked Single: r8c4=1
Full House: r9c4=3
Full House: r9c1=8
Full House: r8c3=2
Naked Single: r8c7=6
Full House: r8c9=5
Naked Single: r4c5=3
Naked Single: r5c4=4
Full House: r6c4=2
Naked Single: r5c8=5
Naked Single: r6c8=4
Hidden Single: r5c3=3
Hidden Single: r4c8=2
Skyscraper: 7 in r2c1,r6c3 (connected by r26c9) => r3c3,r5c1<>7
Naked Single: r3c3=6
Full House: r6c3=7
Full House: r6c9=6
Naked Single: r5c1=9
Full House: r4c1=6
Full House: r4c9=9
Naked Single: r1c1=3
Full House: r1c6=6
Full House: r2c1=7
Full House: r2c6=3
Naked Single: r3c8=1
Full House: r2c8=6
Naked Single: r2c9=8
Full House: r2c5=1
Full House: r3c5=8
Full House: r3c7=7
Full House: r5c9=7
Full House: r5c7=8
|
normal_sudoku_5678
|
.7.6...8......4....6.81.72..27.4.6.8...3.....9..52.17.7.246.91.19...5...6.3.9....
|
379652481218734596465819723527941638841376259936528174782463915194285367653197842
|
Basic 9x9 Sudoku 5678
|
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 . 6 . . . 8 .
. . . . . 4 . . .
. 6 . 8 1 . 7 2 .
. 2 7 . 4 . 6 . 8
. . . 3 . . . . .
9 . . 5 2 . 1 7 .
7 . 2 4 6 . 9 1 .
1 9 . . . 5 . . .
6 . 3 . 9 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
379652481218734596465819723527941638841376259936528174782463915194285367653197842 #1 Extreme (1966)
Hidden Single: r7c1=7
Naked Single: r7c4=4
Naked Single: r6c4=5
Locked Pair: 1,9 in r4c46 => r4c58,r5c56<>9, r5c6<>1
Naked Single: r4c5=4
Locked Candidates Type 1 (Pointing): 5 in b7 => r25c2<>5
2-String Kite: 3 in r2c2,r4c8 (connected by r4c1,r6c2) => r2c8<>3
Empty Rectangle: 8 in b5 (r7c26) => r5c2<>8
W-Wing: 5/3 in r2c7,r4c1 connected by 3 in r26c2 => r2c1<>5
XY-Wing: 3/5/4 in r49c8,r6c9 => r5c8,r89c9<>4
Locked Candidates Type 2 (Claiming): 4 in c8 => r89c7<>4
XYZ-Wing: 3/7/8 in r58c5,r7c6 => r9c5<>8
Uniqueness Test 3: 1/9 in r4c46,r9c46 => r9c5<>7
Naked Single: r9c5=9
W-Wing: 5/3 in r1c5,r7c9 connected by 3 in r7c6,r8c5 => r1c9<>5
Hidden Rectangle: 6/8 in r5c36,r6c36 => r5c3<>8
Finned X-Wing: 4 c17 r15 fr3c1 => r1c3<>4
Finned Swordfish: 3 r367 c269 fr3c1 => r2c2<>3
Hidden Single: r6c2=3
Naked Single: r4c1=5
Naked Single: r6c9=4
Naked Single: r4c8=3
Hidden Single: r1c7=4
Skyscraper: 8 in r6c3,r7c2 (connected by r67c6) => r8c3<>8
Naked Single: r8c3=4
Naked Single: r8c8=6
Hidden Single: r3c1=4
Naked Single: r5c1=8
Naked Single: r5c5=7
Naked Single: r6c3=6
Full House: r6c6=8
Naked Single: r5c6=6
Naked Single: r5c3=1
Full House: r5c2=4
Naked Single: r7c6=3
Naked Single: r3c6=9
Naked Single: r7c9=5
Full House: r7c2=8
Full House: r9c2=5
Full House: r2c2=1
Naked Single: r8c5=8
Naked Single: r1c6=2
Naked Single: r3c3=5
Full House: r3c9=3
Naked Single: r4c6=1
Full House: r4c4=9
Full House: r9c6=7
Naked Single: r9c8=4
Naked Single: r1c1=3
Full House: r2c1=2
Naked Single: r2c4=7
Naked Single: r1c3=9
Full House: r2c3=8
Naked Single: r2c7=5
Naked Single: r8c4=2
Full House: r9c4=1
Naked Single: r9c9=2
Full House: r9c7=8
Naked Single: r1c5=5
Full House: r1c9=1
Full House: r2c5=3
Naked Single: r2c8=9
Full House: r2c9=6
Full House: r5c8=5
Naked Single: r5c7=2
Full House: r8c7=3
Full House: r8c9=7
Full House: r5c9=9
|
normal_sudoku_6017
|
41..6.2..58.4.21762..15..34.526..4....4.15.298...24....2.5463..3.52...41.4...15.2
|
413967285589432176276158934752693418634815729891724653128546397365279841947381562
|
Basic 9x9 Sudoku 6017
|
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 1 . . 6 . 2 . .
5 8 . 4 . 2 1 7 6
2 . . 1 5 . . 3 4
. 5 2 6 . . 4 . .
. . 4 . 1 5 . 2 9
8 . . . 2 4 . . .
. 2 . 5 4 6 3 . .
3 . 5 2 . . . 4 1
. 4 . . . 1 5 . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
413967285589432176276158934752693418634815729891724653128546397365279841947381562 #1 Hard (1248)
Hidden Single: r2c7=1
Hidden Single: r5c8=2
Hidden Single: r3c1=2
Hidden Single: r3c4=1
Hidden Single: r8c4=2
Hidden Single: r3c9=4
Hidden Single: r1c1=4
Hidden Single: r8c8=4
Locked Candidates Type 1 (Pointing): 3 in b1 => r6c3<>3
Locked Candidates Type 1 (Pointing): 5 in b3 => r1c34<>5
Hidden Single: r7c4=5
Hidden Single: r2c1=5
Hidden Single: r8c3=5
Hidden Single: r3c5=5
Hidden Single: r8c9=1
Skyscraper: 8 in r3c6,r5c4 (connected by r35c7) => r1c4,r4c6<>8
Locked Candidates Type 1 (Pointing): 8 in b2 => r8c6<>8
Skyscraper: 8 in r5c4,r8c5 (connected by r58c7) => r4c5,r9c4<>8
Hidden Single: r5c4=8
Hidden Single: r5c2=3
Locked Pair: 6,7 in r56c7 => r6c8,r8c7<>6, r46c9,r8c7<>7
Hidden Single: r8c2=6
Hidden Single: r9c8=6
Hidden Single: r7c9=7
Hidden Single: r3c3=6
Hidden Single: r5c1=6
Full House: r5c7=7
Naked Single: r6c7=6
Locked Candidates Type 1 (Pointing): 7 in b7 => r9c45<>7
Skyscraper: 7 in r1c4,r3c2 (connected by r6c24) => r1c3,r3c6<>7
Hidden Single: r3c2=7
Full House: r6c2=9
Locked Candidates Type 1 (Pointing): 9 in b1 => r79c3<>9
Swordfish: 9 r348 c567 => r1c6,r29c5<>9
Naked Single: r2c5=3
Full House: r2c3=9
Full House: r1c3=3
Naked Single: r9c5=8
Naked Single: r9c3=7
Naked Single: r6c3=1
Full House: r4c1=7
Full House: r7c3=8
Naked Single: r9c1=9
Full House: r7c1=1
Full House: r7c8=9
Full House: r9c4=3
Full House: r8c7=8
Full House: r3c7=9
Full House: r3c6=8
Naked Single: r6c8=5
Naked Single: r4c5=9
Full House: r8c5=7
Full House: r8c6=9
Naked Single: r6c4=7
Full House: r6c9=3
Full House: r4c6=3
Full House: r1c6=7
Full House: r1c4=9
Naked Single: r1c8=8
Full House: r1c9=5
Full House: r4c9=8
Full House: r4c8=1
|
normal_sudoku_23
|
2.4.79.31...2.39.4.3.41.72.1.794.2.3....21.4742.63719.......4..84.1...7.6....4..2
|
264579831718263954539418726187945263396821547425637198972386415843152679651794382
|
Basic 9x9 Sudoku 23
|
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 . 4 . 7 9 . 3 1
. . . 2 . 3 9 . 4
. 3 . 4 1 . 7 2 .
1 . 7 9 4 . 2 . 3
. . . . 2 1 . 4 7
4 2 . 6 3 7 1 9 .
. . . . . . 4 . .
8 4 . 1 . . . 7 .
6 . . . . 4 . . 2
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
264579831718263954539418726187945263396821547425637198972386415843152679651794382 #1 Extreme (21578) bf
Hidden Single: r5c5=2
Hidden Single: r6c7=1
Hidden Single: r1c3=4
Hidden Single: r3c7=7
Hidden Single: r3c8=2
Hidden Single: r5c8=4
Hidden Single: r4c5=4
Hidden Single: r1c1=2
Hidden Single: r2c9=4
Hidden Single: r4c9=3
Brute Force: r6c5=3
Forcing Net Contradiction in c2 => r7c4<>6
r7c4=6 (r5c4<>6) (r8c5<>6 r2c5=6 r2c8<>6 r4c8=6 r5c7<>6) (r8c5<>6 r2c5=6 r3c6<>6) (r8c5<>6) (r8c6<>6) r7c4<>3 r9c4=3 r9c7<>3 r8c7=3 r8c7<>6 r8c9=6 r3c9<>6 r3c3=6 r5c3<>6 r5c2=6 r5c2<>9
r7c4=6 (r8c5<>6) (r8c6<>6) r7c4<>3 r9c4=3 r9c7<>3 r8c7=3 r8c7<>6 r8c9=6 r8c9<>9 r7c9=9 r7c2<>9
r7c4=6 r7c4<>3 r9c4=3 r9c4<>7 r9c2=7 r9c2<>9
Brute Force: r6c4=6
Hidden Single: r6c6=7
Naked Pair: 5,8 in r15c4 => r79c4<>5, r79c4<>8
Skyscraper: 6 in r1c7,r4c8 (connected by r14c2) => r2c8,r5c7<>6
Hidden Single: r4c8=6
Naked Pair: 5,8 in r4c2,r6c3 => r5c123<>5, r5c23<>8
Remote Pair: 5/8 r1c4 -8- r5c4 -5- r4c6 -8- r4c2 => r1c2<>5, r1c2<>8
Naked Single: r1c2=6
Naked Single: r5c2=9
Naked Single: r5c1=3
Naked Single: r5c3=6
Hidden Single: r8c7=6
Hidden Single: r3c9=6
Hidden Single: r2c5=6
Hidden Single: r8c3=3
Hidden Single: r9c7=3
Naked Single: r9c4=7
Naked Single: r7c4=3
Hidden Single: r7c6=6
Hidden Single: r8c6=2
Hidden Single: r7c3=2
Remote Pair: 5/8 r2c8 -8- r1c7 -5- r1c4 -8- r3c6 -5- r4c6 -8- r5c4 -5- r5c7 -8- r6c9 -5- r6c3 -8- r4c2 => r2c2,r3c3<>5, r2c2,r3c3<>8
Naked Single: r3c3=9
Naked Single: r3c1=5
Full House: r3c6=8
Full House: r1c4=5
Full House: r4c6=5
Full House: r1c7=8
Full House: r5c4=8
Full House: r4c2=8
Full House: r2c8=5
Full House: r5c7=5
Full House: r6c3=5
Full House: r6c9=8
Naked Single: r2c1=7
Full House: r7c1=9
Naked Single: r9c3=1
Full House: r2c3=8
Full House: r2c2=1
Naked Single: r7c9=5
Full House: r8c9=9
Full House: r8c5=5
Naked Single: r9c2=5
Full House: r7c2=7
Naked Single: r9c8=8
Full House: r7c8=1
Full House: r7c5=8
Full House: r9c5=9
|
normal_sudoku_3065
|
9..54....3..18.7.6..13.....4.3.91....18.3....29...8.3.1.98.4....3492..1.82..139.4
|
972546183345182796681379542463291875518437269297658431159864327734925618826713954
|
Basic 9x9 Sudoku 3065
|
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 4 . . . .
3 . . 1 8 . 7 . 6
. . 1 3 . . . . .
4 . 3 . 9 1 . . .
. 1 8 . 3 . . . .
2 9 . . . 8 . 3 .
1 . 9 8 . 4 . . .
. 3 4 9 2 . . 1 .
8 2 . . 1 3 9 . 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
972546183345182796681379542463291875518437269297658431159864327734925618826713954 #1 Extreme (11566)
Hidden Single: r4c6=1
Hidden Single: r8c3=4
Hidden Single: r9c6=3
Hidden Single: r4c3=3
Hidden Single: r7c3=9
Hidden Single: r5c5=3
Hidden Single: r2c1=3
Hidden Single: r8c4=9
Hidden Single: r7c4=8
Locked Candidates Type 1 (Pointing): 2 in b2 => r5c6<>2
Hidden Pair: 1,3 in r1c79 => r1c79<>2, r1c79<>8
Finned Swordfish: 5 r249 c238 fr4c7 fr4c9 => r5c8<>5
Forcing Net Verity => r3c2<>5
r7c7=5 (r7c7<>2) r7c7<>3 r7c9=3 r7c9<>2 r7c8=2 r1c8<>2 r1c8=8 (r3c7<>8) (r3c8<>8) r3c9<>8 r3c2=8 r3c2<>5
r7c8=5 (r2c8<>5) r9c8<>5 r9c3=5 r2c3<>5 r2c2=5 r3c2<>5
r7c9=5 (r7c9<>2) r7c9<>3 r7c7=3 r7c7<>2 r7c8=2 r1c8<>2 r1c8=8 (r3c7<>8) (r3c8<>8) r3c9<>8 r3c2=8 r3c2<>5
r8c7=5 (r8c1<>5) r8c6<>5 r5c6=5 r5c1<>5 r3c1=5 r3c2<>5
r8c9=5 (r8c1<>5) r8c6<>5 r5c6=5 r5c1<>5 r3c1=5 r3c2<>5
r9c8=5 r2c8<>5 r2c23=5 r3c2<>5
Forcing Net Verity => r3c2<>6
r3c5=6 r3c2<>6
r6c5=6 (r6c3<>6) (r4c4<>6) (r5c4<>6) r6c4<>6 r9c4=6 r9c3<>6 r1c3=6 r3c2<>6
r7c5=6 (r7c2<>6) (r3c5<>6 r3c5=7 r3c1<>7) (r3c5<>6 r3c5=7 r1c6<>7) (r3c5<>6 r3c5=7 r3c6<>7) r9c4<>6 r9c4=7 r8c6<>7 r5c6=7 r5c1<>7 r8c1=7 r7c2<>7 r7c2=5 (r2c2<>5) r9c3<>5 r9c8=5 r2c8<>5 r2c3=5 r2c3<>2 r1c3=2 r1c8<>2 r1c8=8 (r3c7<>8) (r3c8<>8) r3c9<>8 r3c2=8 r3c2<>6
Forcing Net Verity => r3c2<>7
r3c5=7 r3c2<>7
r6c5=7 (r6c3<>7) (r4c4<>7) (r5c4<>7) r6c4<>7 r9c4=7 r9c3<>7 r1c3=7 r3c2<>7
r7c5=7 (r7c2<>7) (r3c5<>7 r3c5=6 r3c1<>6) (r3c5<>7 r3c5=6 r1c6<>6) (r3c5<>7 r3c5=6 r3c6<>6) r9c4<>7 r9c4=6 r8c6<>6 r5c6=6 r5c1<>6 r8c1=6 (r8c7<>6 r8c7=8 r3c7<>8) r7c2<>6 r7c2=5 (r2c2<>5) r9c3<>5 r9c8=5 r2c8<>5 r2c3=5 r2c3<>2 r1c3=2 r1c8<>2 r1c8=8 (r3c8<>8) r3c9<>8 r3c2=8 r3c2<>7
Forcing Net Verity => r3c7<>8
r1c6=7 (r8c6<>7) (r3c5<>7) r3c6<>7 r3c1=7 r8c1<>7 r8c9=7 r8c9<>8 r8c7=8 r3c7<>8
r3c6=7 (r1c6<>7) r3c5<>7 r3c5=6 r1c6<>6 r1c6=2 r1c8<>2 r1c8=8 r3c7<>8
r5c6=7 (r5c6<>5 r8c6=5 r7c5<>5 r7c5=6 r7c2<>6) (r5c1<>7) (r1c6<>7) r3c6<>7 r3c5=7 r3c1<>7 r8c1=7 r7c2<>7 r7c2=5 r2c2<>5 r2c2=4 r3c2<>4 r3c2=8 r3c7<>8
r8c6=7 (r1c6<>7) (r3c6<>7 r3c5=7 r6c5<>7) r8c6<>5 r5c6=5 r6c5<>5 r6c5=6 (r6c3<>6) r6c4<>6 r9c4=6 (r4c4<>6) (r5c4<>6) r9c3<>6 r1c3=6 r1c6<>6 r1c6=2 r1c8<>2 r1c8=8 r3c7<>8
Forcing Net Contradiction in r1c8 => r3c8<>5
r3c8=5 (r2c8<>5) r9c8<>5 r9c3=5 r2c3<>5 r2c2=5 r2c2<>4 r2c8=4 (r3c7<>4) (r3c7<>4) r3c8<>4 r3c2=4 r3c2<>8 r1c2=8 r1c8<>8 r1c8=2 r3c7<>2 r3c7=5 r3c8<>5
Forcing Net Verity => r3c9<>8
r1c6=6 (r8c6<>6) (r3c5<>6) r3c6<>6 r3c1=6 r8c1<>6 r8c7=6 r8c7<>8 r8c9=8 r3c9<>8
r3c6=6 (r1c6<>6) r3c5<>6 r3c5=7 r1c6<>7 r1c6=2 r1c8<>2 r1c8=8 r3c9<>8
r5c6=6 (r5c6<>5 r8c6=5 r7c5<>5 r7c5=7 r7c2<>7) (r5c1<>6) (r1c6<>6) r3c6<>6 r3c5=6 r3c1<>6 r8c1=6 r7c2<>6 r7c2=5 r2c2<>5 r2c2=4 r3c2<>4 r3c2=8 r3c9<>8
r8c6=6 (r1c6<>6) (r9c4<>6 r9c4=7 r9c3<>7) (r3c6<>6 r3c5=6 r6c5<>6) r8c6<>5 r5c6=5 r6c5<>5 r6c5=7 r6c3<>7 r1c3=7 r1c6<>7 r1c6=2 r1c8<>2 r1c8=8 r3c9<>8
Locked Candidates Type 1 (Pointing): 8 in b3 => r4c8<>8
Forcing Net Verity => r4c8<>5
r7c7=5 (r9c8<>5 r9c3=5 r2c3<>5 r2c3=2 r2c8<>2) (r9c8<>5 r9c3=5 r2c3<>5 r2c3=2 r2c6<>2 r2c6=9 r2c8<>9) (r9c8<>5 r9c3=5 r2c3<>5 r2c3=2 r1c3<>2) (r7c7<>2) r7c7<>3 r7c9=3 r7c9<>2 r7c8=2 r1c8<>2 r1c6=2 r1c8<>2 r1c8=8 r3c8<>8 r3c2=8 r3c2<>4 r2c2=4 r2c8<>4 r2c8=5 r4c8<>5
r7c8=5 r4c8<>5
r7c9=5 (r9c8<>5 r9c3=5 r2c3<>5 r2c3=2 r2c8<>2) (r9c8<>5 r9c3=5 r2c3<>5 r2c3=2 r2c6<>2 r2c6=9 r2c8<>9) (r9c8<>5 r9c3=5 r2c3<>5 r2c3=2 r1c3<>2) (r7c9<>2) r7c9<>3 r7c7=3 r7c7<>2 r7c8=2 r1c8<>2 r1c6=2 r1c8<>2 r1c8=8 r3c8<>8 r3c2=8 r3c2<>4 r2c2=4 r2c8<>4 r2c8=5 r4c8<>5
r8c7=5 (r8c6<>5 r5c6=5 r6c5<>5) (r6c7<>5) r9c8<>5 r9c3=5 r6c3<>5 r6c9=5 r4c8<>5
r8c9=5 (r8c6<>5 r5c6=5 r6c5<>5) (r6c9<>5) r9c8<>5 r9c3=5 r6c3<>5 r6c7=5 r4c8<>5
r9c8=5 r4c8<>5
Forcing Net Verity => r5c4<>6
r7c5=6 (r6c5<>6) (r9c4<>6) (r8c6<>6) r9c4<>6 r9c4=7 r8c6<>7 r5c6=7 (r5c1<>7) r3c6<>7 r3c5=7 (r1c6<>7) (r1c6<>7) (r3c6<>7) r3c1<>7 r8c1=7 r8c1<>6 r8c7=6 (r6c7<>6) r9c8<>6 r9c3=6 r6c3<>6 r6c4=6 r5c4<>6
r8c6=6 (r8c1<>6) (r1c6<>6) r3c6<>6 r3c5=6 r3c1<>6 r5c1=6 r5c4<>6
r9c4=6 r5c4<>6
Forcing Net Verity => r5c4<>7
r7c5=7 (r6c5<>7) (r9c4<>7) (r8c6<>7) r9c4<>7 r9c4=6 r8c6<>6 r5c6=6 (r5c1<>6) r3c6<>6 r3c5=6 (r1c6<>6) (r1c6<>6) (r3c6<>6) r3c1<>6 r8c1=6 r8c1<>7 r8c9=7 (r6c9<>7) r9c8<>7 r9c3=7 r6c3<>7 r6c4=7 r5c4<>7
r8c6=7 (r8c1<>7) (r1c6<>7) r3c6<>7 r3c5=7 r3c1<>7 r5c1=7 r5c4<>7
r9c4=7 r5c4<>7
Forcing Net Verity => r5c7<>5
r5c6=5 r5c7<>5
r5c6=6 (r5c6<>5 r8c6=5 r7c5<>5 r6c5=5 r6c3<>5) (r5c6<>5 r8c6=5 r7c5<>5 r7c5=7 r7c2<>7) (r5c1<>6) (r1c6<>6) r3c6<>6 r3c5=6 r3c1<>6 r8c1=6 r7c2<>6 r7c2=5 r4c2<>5 r5c1=5 r5c7<>5
r5c6=7 (r5c6<>5 r8c6=5 r7c5<>5 r6c5=5 r6c3<>5) (r5c6<>5 r8c6=5 r7c5<>5 r7c5=6 r7c2<>6) (r5c1<>7) (r1c6<>7) r3c6<>7 r3c5=7 r3c1<>7 r8c1=7 r7c2<>7 r7c2=5 r4c2<>5 r5c1=5 r5c7<>5
Forcing Chain Verity => r7c9<>5
r5c1=5 r3c1<>5 r2c23=5 r2c8<>5 r79c8=5 r7c9<>5
r5c6=5 r8c6<>5 r7c5=5 r7c9<>5
r5c9=5 r7c9<>5
Forcing Net Verity => r5c9<>5
r5c6=5 r5c9<>5
r5c6=6 (r5c6<>5 r8c6=5 r7c5<>5 r6c5=5 r6c3<>5) (r5c6<>5 r8c6=5 r7c5<>5 r7c5=7 r7c2<>7) (r5c1<>6) (r1c6<>6) r3c6<>6 r3c5=6 r3c1<>6 r8c1=6 r7c2<>6 r7c2=5 r4c2<>5 r5c1=5 r5c9<>5
r5c6=7 (r5c6<>5 r8c6=5 r7c5<>5 r6c5=5 r6c3<>5) (r5c6<>5 r8c6=5 r7c5<>5 r7c5=6 r7c2<>6) (r5c1<>7) (r1c6<>7) r3c6<>7 r3c5=7 r3c1<>7 r8c1=7 r7c2<>7 r7c2=5 r4c2<>5 r5c1=5 r5c9<>5
Grouped Discontinuous Nice Loop: 5 r7c7 -5- r7c5 =5= r6c5 -5- r5c6 =5= r5c1 -5- r3c1 =5= r2c23 -5- r2c8 =5= r79c8 -5- r7c7 => r7c7<>5
Forcing Net Verity => r1c6<>2
r1c6=6 r1c6<>2
r3c6=6 (r8c6<>6) (r3c1<>6) r3c5<>6 r3c5=7 (r3c1<>7) (r6c5<>7) r3c1<>7 r3c1=5 (r2c3<>5) r5c1<>5 r5c6=5 r6c5<>5 r6c5=6 (r6c3<>6) r6c5<>5 r7c5=5 r8c6<>5 r8c6=7 r8c1<>7 r5c1=7 r6c3<>7 r6c3=5 r9c3<>5 r9c8=5 r2c8<>5 r2c2=5 r2c2<>4 r2c8=4 (r3c7<>4) r3c8<>4 r3c2=4 r3c2<>8 r3c8=8 r1c8<>8 r1c8=2 r1c6<>2
r5c6=6 (r3c6<>6 r3c5=6 r3c1<>6) r5c6<>5 r5c1=5 r3c1<>5 r3c1=7 (r1c2<>7) r1c3<>7 r1c6=7 r1c6<>2
r8c6=6 (r8c6<>5 r5c6=5 r6c5<>5 r7c5=5 r7c2<>5) (r8c6<>5 r5c6=5 r6c5<>5 r6c5=7 r6c3<>7) (r8c1<>6) (r1c6<>6) r3c6<>6 r3c5=6 r3c1<>6 r5c1=6 r6c3<>6 r6c3=5 r4c2<>5 r2c2=5 r2c2<>4 r2c8=4 (r3c7<>4) r3c8<>4 r3c2=4 r3c2<>8 r3c8=8 r1c8<>8 r1c8=2 r1c6<>2
Naked Pair: 6,7 in r1c6,r3c5 => r3c6<>6, r3c6<>7
Hidden Pair: 6,7 in r3c15 => r3c1<>5
Locked Candidates Type 1 (Pointing): 5 in b1 => r2c8<>5
Locked Candidates Type 2 (Claiming): 5 in c8 => r8c79<>5
Finned Franken Swordfish: 6 c34b2 r169 fr3c5 fr4c4 => r6c5<>6
W-Wing: 7/6 in r1c6,r9c4 connected by 6 in r37c5 => r8c6<>7
2-String Kite: 7 in r3c1,r5c6 (connected by r1c6,r3c5) => r5c1<>7
Sashimi Swordfish: 7 c346 r169 fr4c4 fr5c6 => r6c5<>7
Naked Single: r6c5=5
Hidden Single: r5c1=5
Hidden Single: r8c6=5
Naked Triple: 2,6,7 in r4c248 => r4c79<>2, r4c7<>6, r4c9<>7
Remote Pair: 6/7 r7c5 -7- r3c5 -6- r3c1 -7- r8c1 => r7c2<>6, r7c2<>7
Naked Single: r7c2=5
Naked Single: r2c2=4
Naked Single: r3c2=8
Hidden Single: r2c3=5
Hidden Single: r9c8=5
Hidden Single: r1c8=8
Hidden Single: r1c3=2
Remote Pair: 6/7 r4c2 -7- r1c2 -6- r1c6 -7- r5c6 => r4c4<>6, r4c4<>7
Naked Single: r4c4=2
Naked Single: r5c4=4
Hidden Single: r3c8=4
Hidden Single: r6c7=4
Hidden Single: r6c9=1
Naked Single: r1c9=3
Naked Single: r1c7=1
Hidden Single: r7c7=3
Remote Pair: 6/7 r4c8 -7- r4c2 -6- r1c2 -7- r1c6 -6- r3c5 -7- r7c5 => r7c8<>6, r7c8<>7
Naked Single: r7c8=2
Naked Single: r2c8=9
Full House: r2c6=2
Naked Single: r7c9=7
Full House: r7c5=6
Full House: r3c5=7
Full House: r9c4=7
Full House: r6c4=6
Full House: r9c3=6
Full House: r5c6=7
Full House: r6c3=7
Full House: r8c1=7
Full House: r3c1=6
Full House: r4c2=6
Full House: r1c2=7
Full House: r1c6=6
Full House: r3c6=9
Naked Single: r8c9=8
Full House: r8c7=6
Naked Single: r5c8=6
Full House: r4c8=7
Naked Single: r4c9=5
Full House: r4c7=8
Naked Single: r5c7=2
Full House: r3c7=5
Full House: r3c9=2
Full House: r5c9=9
|
normal_sudoku_3226
|
8.563....37..5468..64....355.73..84..43.78.5668.5413..43..25........35...5..1...3
|
815639274372154689964782135527396841143278956689541327431925768798463512256817493
|
Basic 9x9 Sudoku 3226
|
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 3 . . . .
3 7 . . 5 4 6 8 .
. 6 4 . . . . 3 5
5 . 7 3 . . 8 4 .
. 4 3 . 7 8 . 5 6
6 8 . 5 4 1 3 . .
4 3 . . 2 5 . . .
. . . . . 3 5 . .
. 5 . . 1 . . . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
815639274372154689964782135527396841143278956689541327431925768798463512256817493 #1 Extreme (13462) bf
Hidden Single: r2c7=6
Hidden Single: r3c8=3
Hidden Single: r5c3=3
Hidden Single: r1c3=5
Hidden Single: r8c6=3
Hidden Single: r1c1=8
Finned Swordfish: 4 r159 c247 fr1c9 => r3c7<>4
Hidden Single: r3c3=4
Hidden Single: r5c2=4
Brute Force: r6c6=1
Hidden Single: r6c4=5
Hidden Single: r7c6=5
Hidden Single: r8c7=5
Hidden Single: r6c5=4
Finned X-Wing: 1 r14 c29 fr1c7 fr1c8 => r2c9<>1
Finned Franken Swordfish: 2 r26b5 c349 fr4c6 fr6c8 => r4c9<>2
W-Wing: 9/2 in r5c4,r6c3 connected by 2 in r4c26 => r5c1<>9
Sashimi Swordfish: 9 r256 c349 fr5c7 fr6c8 => r4c9<>9
Naked Single: r4c9=1
Hidden Single: r5c1=1
Finned Franken Swordfish: 9 c15b4 r348 fr6c3 fr9c1 => r8c3<>9
Forcing Chain Contradiction in r3 => r1c2<>2
r1c2=2 r3c1<>2
r1c2=2 r1c2<>1 r2c3=1 r2c4<>1 r3c4=1 r3c4<>2
r1c2=2 r4c2<>2 r4c6=2 r3c6<>2
r1c2=2 r4c2<>2 r4c6=2 r5c4<>2 r5c7=2 r3c7<>2
Multi Colors 1: 2 (r2c3) / (r3c1), (r4c2,r5c4) / (r4c6,r5c7,r6c3,r8c2) => r3c4<>2
W-Wing: 9/2 in r2c9,r5c7 connected by 2 in r25c4 => r13c7,r6c9<>9
AIC: 9 9- r1c2 -1- r2c3 =1= r2c4 =2= r5c4 =9= r5c7 -9- r6c8 =9= r6c3 -9 => r2c3,r4c2<>9
Naked Single: r4c2=2
Full House: r6c3=9
Hidden Single: r5c4=2
Full House: r5c7=9
Empty Rectangle: 9 in b3 (r18c2) => r8c9<>9
W-Wing: 9/1 in r2c4,r8c2 connected by 1 in r1c2,r2c3 => r8c4<>9
XY-Wing: 1/2/9 in r1c2,r2c39 => r1c89<>9
Hidden Single: r2c9=9
Naked Single: r2c4=1
Full House: r2c3=2
Naked Single: r3c1=9
Full House: r1c2=1
Full House: r8c2=9
Naked Single: r3c5=8
Naked Single: r3c4=7
Naked Single: r8c5=6
Full House: r4c5=9
Full House: r4c6=6
Naked Single: r3c6=2
Full House: r1c6=9
Full House: r3c7=1
Full House: r9c6=7
Naked Single: r7c7=7
Naked Single: r9c1=2
Full House: r8c1=7
Naked Single: r7c9=8
Naked Single: r9c7=4
Full House: r1c7=2
Naked Single: r7c4=9
Naked Single: r8c9=2
Naked Single: r1c8=7
Full House: r1c9=4
Full House: r6c9=7
Full House: r6c8=2
Naked Single: r9c4=8
Full House: r8c4=4
Naked Single: r8c8=1
Full House: r8c3=8
Naked Single: r9c3=6
Full House: r7c3=1
Full House: r7c8=6
Full House: r9c8=9
|
normal_sudoku_4982
|
.5.4269..69.5.84..4.8..7.659.6...5...3..5.6.4...6....3....61.29.6.2..35.2....5.46
|
357426981692518437418937265946183572831752694725649813584361729169274358273895146
|
Basic 9x9 Sudoku 4982
|
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 . 4 2 6 9 . .
6 9 . 5 . 8 4 . .
4 . 8 . . 7 . 6 5
9 . 6 . . . 5 . .
. 3 . . 5 . 6 . 4
. . . 6 . . . . 3
. . . . 6 1 . 2 9
. 6 . 2 . . 3 5 .
2 . . . . 5 . 4 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
357426981692518437418937265946183572831752694725649813584361729169274358273895146 #1 Extreme (11706) bf
Locked Candidates Type 1 (Pointing): 8 in b2 => r2c89<>8
Locked Candidates Type 2 (Claiming): 5 in r7 => r8c13,r9c3<>5
Almost Locked Set XZ-Rule: A=r125c3 {1237}, B=r79c2,r8c13,r9c3 {134789}, X=3, Z=7 => r7c3<>7
Brute Force: r5c7=6
Hidden Single: r7c5=6
Hidden Single: r9c9=6
Hidden Single: r9c6=5
Locked Candidates Type 1 (Pointing): 4 in b8 => r8c13<>4
Hidden Pair: 4,5 in r67c3 => r6c3<>1, r6c3<>2, r6c3<>7, r7c3<>3
Uniqueness Test 3: 4/5 in r6c13,r7c13 => r3c1<>1, r3c1<>3, r3c1<>6
Naked Single: r3c1=4
Hidden Single: r3c8=6
Hidden Single: r2c1=6
Hidden Single: r3c9=5
Hidden Single: r8c8=5
Locked Candidates Type 2 (Claiming): 3 in r3 => r2c56<>3
Naked Single: r2c6=8
Naked Single: r2c5=1
Hidden Single: r4c6=3
Skyscraper: 2 in r2c3,r4c2 (connected by r24c9) => r3c2,r5c3<>2
Naked Single: r3c2=1
Naked Single: r3c7=2
Naked Single: r2c9=7
Naked Single: r2c8=3
Full House: r2c3=2
Hidden Single: r5c6=2
Hidden Single: r4c9=2
Hidden Single: r6c2=2
Locked Candidates Type 1 (Pointing): 7 in b9 => r6c7<>7
Uniqueness Test 3: 3/9 in r3c45,r9c45 => r9c37<>7, r9c7<>8
Naked Single: r9c7=1
Naked Single: r6c7=8
Full House: r7c7=7
Full House: r8c9=8
Full House: r1c9=1
Full House: r1c8=8
Empty Rectangle: 7 in b8 (r49c2) => r4c5<>7
W-Wing: 9/3 in r3c4,r9c3 connected by 3 in r7c14 => r9c4<>9
W-Wing: 7/1 in r4c8,r5c3 connected by 1 in r6c18 => r4c2,r5c8<>7
Hidden Single: r9c2=7
Naked Single: r8c1=1
Naked Single: r8c3=9
Naked Single: r8c6=4
Full House: r6c6=9
Full House: r8c5=7
Naked Single: r9c3=3
Naked Single: r6c5=4
Naked Single: r1c3=7
Full House: r1c1=3
Naked Single: r9c4=8
Full House: r9c5=9
Full House: r7c4=3
Naked Single: r4c5=8
Full House: r3c5=3
Full House: r3c4=9
Naked Single: r6c3=5
Naked Single: r5c3=1
Full House: r7c3=4
Naked Single: r4c2=4
Full House: r7c2=8
Full House: r7c1=5
Naked Single: r6c1=7
Full House: r5c1=8
Full House: r6c8=1
Naked Single: r5c4=7
Full House: r5c8=9
Full House: r4c8=7
Full House: r4c4=1
|
normal_sudoku_2647
|
142.5...9398.6..5.576...1..289.74...6132..4..457.36...9.......7725.436818....5.4.
|
142357869398461752576892134289574316613289475457136298934618527725943681861725943
|
Basic 9x9 Sudoku 2647
|
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 2 . 5 . . . 9
3 9 8 . 6 . . 5 .
5 7 6 . . . 1 . .
2 8 9 . 7 4 . . .
6 1 3 2 . . 4 . .
4 5 7 . 3 6 . . .
9 . . . . . . . 7
7 2 5 . 4 3 6 8 1
8 . . . . 5 . 4 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
142357869398461752576892134289574316613289475457136298934618527725943681861725943 #1 Easy (238)
Naked Single: r1c2=4
Naked Single: r6c2=5
Naked Single: r1c1=1
Naked Single: r2c2=9
Naked Single: r6c3=7
Naked Single: r2c3=8
Full House: r3c1=5
Naked Single: r8c2=2
Naked Single: r5c1=6
Full House: r5c3=3
Naked Single: r8c3=5
Naked Single: r7c1=9
Full House: r8c1=7
Full House: r8c4=9
Naked Single: r9c3=1
Full House: r7c3=4
Naked Single: r9c5=2
Naked Single: r9c9=3
Naked Single: r7c8=2
Naked Single: r9c2=6
Full House: r7c2=3
Naked Single: r9c7=9
Full House: r7c7=5
Full House: r9c4=7
Naked Single: r3c8=3
Naked Single: r4c7=3
Hidden Single: r1c8=6
Naked Single: r4c8=1
Naked Single: r4c4=5
Full House: r4c9=6
Naked Single: r6c8=9
Full House: r5c8=7
Hidden Single: r5c9=5
Hidden Single: r7c5=1
Naked Single: r7c6=8
Full House: r7c4=6
Naked Single: r1c6=7
Naked Single: r5c6=9
Full House: r5c5=8
Full House: r3c5=9
Full House: r6c4=1
Naked Single: r1c7=8
Full House: r1c4=3
Naked Single: r3c6=2
Full House: r2c6=1
Naked Single: r2c4=4
Full House: r3c4=8
Full House: r3c9=4
Naked Single: r6c7=2
Full House: r2c7=7
Full House: r2c9=2
Full House: r6c9=8
|
normal_sudoku_2767
|
..7..62...62..8.73.9....16.571843629623..1.4.849562731.3.1..4.7.8..3..1.7........
|
457316298162498573398257164571843629623971845849562731936125487285734916714689352
|
Basic 9x9 Sudoku 2767
|
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.
|
. . 7 . . 6 2 . .
. 6 2 . . 8 . 7 3
. 9 . . . . 1 6 .
5 7 1 8 4 3 6 2 9
6 2 3 . . 1 . 4 .
8 4 9 5 6 2 7 3 1
. 3 . 1 . . 4 . 7
. 8 . . 3 . . 1 .
7 . . . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
457316298162498573398257164571843629623971845849562731936125487285734916714689352 #1 Easy (278)
Naked Single: r4c7=6
Naked Single: r4c8=2
Naked Single: r5c2=2
Naked Single: r4c5=4
Full House: r4c6=3
Naked Single: r6c1=8
Full House: r5c3=3
Naked Single: r6c7=7
Naked Single: r6c9=1
Naked Single: r6c6=2
Full House: r6c5=6
Hidden Single: r2c2=6
Hidden Single: r2c8=7
Hidden Single: r9c7=3
Hidden Single: r9c2=1
Full House: r1c2=5
Hidden Single: r3c3=8
Hidden Single: r7c3=6
Hidden Single: r5c7=8
Full House: r5c9=5
Naked Single: r3c9=4
Naked Single: r1c9=8
Naked Single: r3c1=3
Naked Single: r1c8=9
Full House: r2c7=5
Full House: r8c7=9
Naked Single: r1c5=1
Naked Single: r1c1=4
Full House: r1c4=3
Full House: r2c1=1
Naked Single: r2c5=9
Full House: r2c4=4
Naked Single: r8c1=2
Full House: r7c1=9
Naked Single: r5c5=7
Full House: r5c4=9
Naked Single: r8c9=6
Full House: r9c9=2
Naked Single: r7c6=5
Naked Single: r8c4=7
Naked Single: r9c4=6
Full House: r3c4=2
Naked Single: r3c6=7
Full House: r3c5=5
Naked Single: r7c8=8
Full House: r7c5=2
Full House: r9c5=8
Full House: r9c8=5
Naked Single: r8c6=4
Full House: r8c3=5
Full House: r9c3=4
Full House: r9c6=9
|
normal_sudoku_3740
|
9..725....4..1......5.34.2..5918.342.......5...3...6.8.7.49.1..198.6..3...4..12.9
|
931725864247618593685934721759186342816342957423579618572493186198267435364851279
|
Basic 9x9 Sudoku 3740
|
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 . . 7 2 5 . . .
. 4 . . 1 . . . .
. . 5 . 3 4 . 2 .
. 5 9 1 8 . 3 4 2
. . . . . . . 5 .
. . 3 . . . 6 . 8
. 7 . 4 9 . 1 . .
1 9 8 . 6 . . 3 .
. . 4 . . 1 2 . 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
931725864247618593685934721759186342816342957423579618572493186198267435364851279 #1 Hard (870)
Hidden Single: r3c6=4
Hidden Single: r8c2=9
Hidden Single: r8c1=1
Hidden Single: r4c4=1
Hidden Single: r2c5=1
Locked Candidates Type 1 (Pointing): 4 in b7 => r9c7<>4
Naked Triple: 2,5,7 in r8c46,r9c5 => r7c5,r9c4<>5, r7c6,r9c4<>2
Naked Single: r7c5=9
Locked Candidates Type 1 (Pointing): 2 in b8 => r8c7<>2
Hidden Single: r9c7=2
Locked Candidates Type 1 (Pointing): 8 in b9 => r12c8<>8
Locked Candidates Type 2 (Claiming): 2 in c2 => r5c13,r6c1<>2
Naked Pair: 1,6 in r1c38 => r1c29<>1, r1c29<>6
Hidden Triple: 2,3,5 in r279c1 => r279c1<>6, r2c1<>7, r2c1<>8, r9c1<>4
Hidden Single: r9c3=4
Skyscraper: 1 in r1c3,r6c2 (connected by r16c8) => r3c2,r5c3<>1
Hidden Single: r3c9=1
Naked Single: r1c8=6
Naked Single: r5c9=7
Naked Single: r1c3=1
Naked Single: r7c8=8
Naked Single: r5c3=6
Naked Single: r5c5=4
Naked Single: r5c7=9
Full House: r6c8=1
Naked Single: r7c6=3
Naked Single: r9c8=7
Full House: r2c8=9
Naked Single: r4c1=7
Full House: r4c6=6
Naked Single: r7c3=2
Full House: r2c3=7
Naked Single: r5c1=8
Naked Single: r6c2=2
Naked Single: r5c6=2
Naked Single: r9c4=8
Naked Single: r9c5=5
Full House: r6c5=7
Naked Single: r6c1=4
Full House: r5c2=1
Full House: r5c4=3
Naked Single: r2c6=8
Naked Single: r7c1=5
Full House: r7c9=6
Naked Single: r3c1=6
Naked Single: r8c6=7
Full House: r8c4=2
Full House: r6c6=9
Full House: r6c4=5
Naked Single: r2c4=6
Full House: r3c4=9
Naked Single: r9c1=3
Full House: r2c1=2
Full House: r9c2=6
Naked Single: r2c7=5
Full House: r2c9=3
Naked Single: r3c2=8
Full House: r1c2=3
Full House: r3c7=7
Naked Single: r8c7=4
Full House: r1c7=8
Full House: r1c9=4
Full House: r8c9=5
|
normal_sudoku_1227
|
...1.7........21.9143958627...86.91..1879..32...21..6...4.2..9.9...862.1....79.56
|
296147385587632149143958627372865914618794532459213768764521893935486271821379456
|
Basic 9x9 Sudoku 1227
|
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.
|
. . . 1 . 7 . . .
. . . . . 2 1 . 9
1 4 3 9 5 8 6 2 7
. . . 8 6 . 9 1 .
. 1 8 7 9 . . 3 2
. . . 2 1 . . 6 .
. . 4 . 2 . . 9 .
9 . . . 8 6 2 . 1
. . . . 7 9 . 5 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
296147385587632149143958627372865914618794532459213768764521893935486271821379456 #1 Easy (364)
Naked Single: r3c5=5
Naked Single: r3c7=6
Naked Single: r3c8=2
Naked Single: r3c1=1
Full House: r3c4=9
Hidden Single: r4c4=8
Hidden Single: r2c6=2
Hidden Single: r9c6=9
Hidden Single: r4c8=1
Hidden Single: r8c5=8
Hidden Single: r6c8=6
Hidden Single: r1c4=1
Hidden Single: r5c2=1
Hidden Single: r5c4=7
Hidden Single: r7c6=1
Hidden Single: r9c3=1
Hidden Single: r8c8=7
Naked Single: r8c3=5
Naked Single: r8c2=3
Full House: r8c4=4
Naked Single: r9c4=3
Full House: r7c4=5
Full House: r2c4=6
Naked Single: r2c3=7
Naked Single: r4c3=2
Naked Single: r6c3=9
Full House: r1c3=6
Hidden Single: r5c1=6
Hidden Single: r6c7=7
Naked Single: r6c2=5
Naked Single: r2c2=8
Naked Single: r4c2=7
Naked Single: r2c1=5
Naked Single: r2c8=4
Full House: r1c8=8
Full House: r2c5=3
Full House: r1c5=4
Naked Single: r9c2=2
Naked Single: r7c2=6
Full House: r1c2=9
Full House: r1c1=2
Naked Single: r9c1=8
Full House: r7c1=7
Full House: r9c7=4
Naked Single: r5c7=5
Full House: r5c6=4
Naked Single: r1c7=3
Full House: r1c9=5
Full House: r7c7=8
Full House: r7c9=3
Naked Single: r4c9=4
Full House: r6c9=8
Naked Single: r6c6=3
Full House: r4c6=5
Full House: r4c1=3
Full House: r6c1=4
|
normal_sudoku_6427
|
395..874.867..31..241...9....9.36..1..6.81.7..185..6..153.6.8..972......684..5.17
|
395128746867943152241657938729436581536281479418579623153762894972814365684395217
|
Basic 9x9 Sudoku 6427
|
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 . . 8 7 4 .
8 6 7 . . 3 1 . .
2 4 1 . . . 9 . .
. . 9 . 3 6 . . 1
. . 6 . 8 1 . 7 .
. 1 8 5 . . 6 . .
1 5 3 . 6 . 8 . .
9 7 2 . . . . . .
6 8 4 . . 5 . 1 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
395128746867943152241657938729436581536281479418579623153762894972814365684395217 #1 Easy (232)
Naked Single: r3c3=1
Naked Single: r1c1=3
Naked Single: r1c2=9
Hidden Single: r4c9=1
Hidden Single: r9c1=6
Naked Single: r8c3=2
Naked Single: r4c3=9
Full House: r5c3=6
Naked Single: r9c2=8
Naked Single: r3c2=4
Full House: r2c1=8
Naked Single: r8c2=7
Full House: r7c1=1
Naked Single: r3c6=7
Naked Single: r4c2=2
Full House: r5c2=3
Naked Single: r8c6=4
Naked Single: r3c4=6
Naked Single: r3c5=5
Naked Single: r8c5=1
Naked Single: r1c5=2
Naked Single: r1c4=1
Full House: r1c9=6
Naked Single: r9c5=9
Naked Single: r2c5=4
Full House: r2c4=9
Full House: r6c5=7
Naked Single: r7c6=2
Full House: r6c6=9
Naked Single: r4c4=4
Full House: r5c4=2
Naked Single: r6c1=4
Naked Single: r7c4=7
Naked Single: r7c8=9
Full House: r7c9=4
Naked Single: r9c4=3
Full House: r8c4=8
Full House: r9c7=2
Naked Single: r4c7=5
Naked Single: r5c1=5
Full House: r4c1=7
Full House: r4c8=8
Naked Single: r5c7=4
Full House: r5c9=9
Full House: r8c7=3
Naked Single: r3c8=3
Full House: r3c9=8
Naked Single: r8c9=5
Full House: r8c8=6
Naked Single: r6c8=2
Full House: r2c8=5
Full House: r2c9=2
Full House: r6c9=3
|
normal_sudoku_1328
|
75213.4.8...52...11.3.....5618.5.....9.7836123274615892...4..5....3......4....9.6
|
752136498984527361163894275618952743495783612327461589239648157576319824841275936
|
Basic 9x9 Sudoku 1328
|
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.
|
7 5 2 1 3 . 4 . 8
. . . 5 2 . . . 1
1 . 3 . . . . . 5
6 1 8 . 5 . . . .
. 9 . 7 8 3 6 1 2
3 2 7 4 6 1 5 8 9
2 . . . 4 . . 5 .
. . . 3 . . . . .
. 4 . . . . 9 . 6
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
752136498984527361163894275618952743495783612327461589239648157576319824841275936 #1 Unfair (1438)
Hidden Single: r1c3=2
Hidden Single: r1c4=1
Hidden Single: r4c2=1
Hidden Single: r6c7=5
Naked Single: r1c7=4
Hidden Single: r3c9=5
Hidden Single: r6c3=7
Hidden Single: r1c2=5
Hidden Single: r6c8=8
Naked Single: r6c5=6
Naked Single: r6c4=4
Full House: r6c1=3
Naked Single: r5c2=9
Naked Single: r5c5=8
Naked Single: r5c6=3
Hidden Single: r4c1=6
Hidden Single: r3c6=4
Hidden Single: r7c2=3
Naked Single: r7c9=7
Naked Single: r8c9=4
Full House: r4c9=3
Naked Single: r8c8=2
Naked Single: r4c7=7
Full House: r4c8=4
Naked Single: r9c8=3
Naked Single: r2c7=3
Naked Single: r3c7=2
Hidden Single: r8c2=7
Locked Candidates Type 1 (Pointing): 9 in b1 => r2c68<>9
Locked Candidates Type 1 (Pointing): 6 in b7 => r2c3<>6
Locked Candidates Type 1 (Pointing): 8 in b7 => r2c1<>8
XY-Chain: 9 9- r3c5 -7- r9c5 -1- r9c3 -5- r9c1 -8- r9c4 -2- r4c4 -9 => r3c4<>9
Naked Pair: 6,8 in r3c24 => r3c8<>6
XY-Chain: 2 2- r4c6 -9- r1c6 -6- r3c4 -8- r9c4 -2 => r4c4,r9c6<>2
Naked Single: r4c4=9
Full House: r4c6=2
Hidden Single: r9c4=2
XYZ-Wing: 6/8/9 in r17c6,r7c4 => r8c6<>6
Hidden Single: r8c3=6
W-Wing: 9/1 in r7c3,r8c5 connected by 1 in r9c35 => r7c6,r8c1<>9
Hidden Single: r7c3=9
Naked Single: r2c3=4
Naked Single: r2c1=9
Naked Single: r5c3=5
Full House: r5c1=4
Full House: r9c3=1
Naked Single: r9c5=7
Naked Single: r3c5=9
Full House: r8c5=1
Naked Single: r1c6=6
Full House: r1c8=9
Naked Single: r3c8=7
Full House: r2c8=6
Naked Single: r8c7=8
Full House: r7c7=1
Naked Single: r3c4=8
Full House: r2c6=7
Full House: r2c2=8
Full House: r3c2=6
Full House: r7c4=6
Full House: r7c6=8
Naked Single: r8c1=5
Full House: r8c6=9
Full House: r9c6=5
Full House: r9c1=8
|
normal_sudoku_3478
|
4..2...1..32.17....91.482.31..9...2.9264...3.35..62....493....2.13.2..4.2....43..
|
475239618832617495691548273184973526926485137357162984749351862513826749268794351
|
Basic 9x9 Sudoku 3478
|
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 . . 2 . . . 1 .
. 3 2 . 1 7 . . .
. 9 1 . 4 8 2 . 3
1 . . 9 . . . 2 .
9 2 6 4 . . . 3 .
3 5 . . 6 2 . . .
. 4 9 3 . . . . 2
. 1 3 . 2 . . 4 .
2 . . . . 4 3 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
475239618832617495691548273184973526926485137357162984749351862513826749268794351 #1 Extreme (4116)
Hidden Single: r3c3=1
Hidden Single: r7c9=2
Hidden Single: r7c2=4
Hidden Single: r5c8=3
Hidden Single: r8c3=3
Hidden Single: r2c2=3
Hidden Single: r2c3=2
Hidden Single: r5c2=2
Hidden Single: r6c6=2
Locked Pair: 5,6 in r23c4 => r1c56,r89c4<>5, r1c6,r89c4<>6
Locked Candidates Type 1 (Pointing): 9 in b2 => r1c279<>9
Hidden Single: r3c2=9
2-String Kite: 1 in r6c4,r7c7 (connected by r7c6,r9c4) => r6c7<>1
X-Wing: 1 r69 c49 => r5c9<>1
Empty Rectangle: 7 in b7 (r3c18) => r9c8<>7
Finned Swordfish: 6 r149 c279 fr9c8 => r78c7,r8c9<>6
Almost Locked Set XZ-Rule: A=r7c5,r89c4 {1578}, B=r79c8,r8c79,r9c9 {156789}, X=1, Z=5 => r7c7<>5
Forcing Net Verity => r9c4<>8
r9c8=5 (r3c8<>5) r9c3<>5 r1c3=5 (r2c1<>5) r3c1<>5 r3c4=5 r2c4<>5 r2c4=6 r2c1<>6 r2c1=8 r78c1<>8 r9c23=8 r9c4<>8
r9c8=6 (r3c8<>6) r9c2<>6 r1c2=6 (r2c1<>6) r3c1<>6 r3c4=6 r2c4<>6 r2c4=5 r2c1<>5 r2c1=8 r78c1<>8 r9c23=8 r9c4<>8
r9c8=8 r9c4<>8
r9c8=9 (r9c8<>6) (r8c7<>9) r8c9<>9 r8c6=9 r8c6<>6 r8c1=6 r9c2<>6 r9c9=6 r9c9<>1 r9c4=1 r9c4<>8
Forcing Chain Contradiction in r7 => r6c8<>7
r6c8=7 r3c8<>7 r3c1=7 r7c1<>7
r6c8=7 r6c4<>7 r89c4=7 r7c5<>7
r6c8=7 r3c8<>7 r3c1=7 r78c1<>7 r9c23=7 r9c4<>7 r9c4=1 r9c9<>1 r7c7=1 r7c7<>7
r6c8=7 r7c8<>7
Forcing Net Verity => r2c1=8
r2c1=5 (r2c1<>6) (r2c8<>5) (r1c3<>5 r9c3=5 r9c8<>5) r2c4<>5 (r2c4=6 r2c8<>6) r3c4=5 r3c8<>5 r7c8=5 (r7c8<>6) r7c8<>7 r3c8=7 (r3c8<>6) r3c8<>6 r9c8=6 r9c2<>6 r1c2=6 r3c1<>6 r3c4=6 r2c4<>6 r2c4=5 r2c1<>5 r2c1=8
r2c1=6 (r2c1<>5) (r2c4<>6 r2c4=5 r2c8<>5) (r7c1<>6) r8c1<>6 r8c6=6 r7c6<>6 r7c8=6 (r7c8<>5) r7c8<>7 r3c8=7 (r3c8<>5) r3c8<>5 r9c8=5 r9c3<>5 r1c3=5 r3c1<>5 r3c4=5 r2c4<>5 r2c4=6 r2c1<>6 r2c1=8
r2c1=8 r2c1=8
Locked Candidates Type 1 (Pointing): 8 in b7 => r9c589<>8
Skyscraper: 8 in r7c8,r8c4 (connected by r6c48) => r7c5,r8c79<>8
Hidden Single: r8c4=8
Sashimi X-Wing: 7 r38 c18 fr8c7 fr8c9 => r7c8<>7
Hidden Single: r3c8=7
Locked Candidates Type 2 (Claiming): 7 in c1 => r9c23<>7
Discontinuous Nice Loop: 5 r7c8 -5- r7c5 -7- r9c4 -1- r9c9 =1= r7c7 =8= r7c8 => r7c8<>5
Skyscraper: 5 in r1c3,r2c8 (connected by r9c38) => r1c79<>5
Hidden Single: r1c3=5
Naked Single: r3c1=6
Full House: r1c2=7
Full House: r3c4=5
Naked Single: r9c3=8
Naked Single: r4c2=8
Full House: r9c2=6
Naked Single: r2c4=6
Hidden Single: r8c6=6
Hidden Single: r5c5=8
Hidden Single: r7c8=6
Hidden Single: r1c6=9
Full House: r1c5=3
Hidden Single: r9c5=9
Naked Single: r9c8=5
Naked Single: r2c8=9
Full House: r6c8=8
Hidden Single: r7c7=8
Naked Single: r1c7=6
Full House: r1c9=8
Hidden Single: r4c6=3
Hidden Single: r8c1=5
Full House: r7c1=7
Naked Single: r7c5=5
Full House: r4c5=7
Full House: r7c6=1
Full House: r5c6=5
Full House: r6c4=1
Full House: r9c4=7
Full House: r9c9=1
Naked Single: r4c3=4
Full House: r6c3=7
Naked Single: r5c9=7
Full House: r5c7=1
Naked Single: r4c7=5
Full House: r4c9=6
Naked Single: r8c9=9
Full House: r8c7=7
Naked Single: r2c7=4
Full House: r2c9=5
Full House: r6c9=4
Full House: r6c7=9
|
normal_sudoku_998
|
.7..9...2..26.49..9......4...954827.7...364.....1..8...9...53.4..648..9...7....28
|
674391582812654937953827146369548271781236459425179863298765314136482795547913628
|
Basic 9x9 Sudoku 998
|
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 . . 9 . . . 2
. . 2 6 . 4 9 . .
9 . . . . . . 4 .
. . 9 5 4 8 2 7 .
7 . . . 3 6 4 . .
. . . 1 . . 8 . .
. 9 . . . 5 3 . 4
. . 6 4 8 . . 9 .
. . 7 . . . . 2 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
674391582812654937953827146369548271781236459425179863298765314136482795547913628 #1 Extreme (25140) bf
Almost Locked Set XY-Wing: A=r2c1258 {13578}, B=r134589c7 {1245679}, C=r6c123589 {2345679}, X,Y=7,9, Z=1,5 => r2c7<>1, r2c7<>5
Forcing Chain Contradiction in c6 => r7c2<>2
r7c2=2 r7c2<>9 r7c4=9 r7c4<>7 r3c4=7 r3c6<>7
r7c2=2 r7c2<>9 r7c4=9 r5c4<>9 r6c6=9 r6c6<>7
r7c2=2 r7c45<>2 r8c6=2 r8c6<>7
Brute Force: r5c5=3
Grouped Discontinuous Nice Loop: 3 r3c9 -3- r4c9 =3= r4c12 -3- r6c3 =3= r13c3 -3- r2c12 =3= r2c89 -3- r3c9 => r3c9<>3
Forcing Net Contradiction in r6c6 => r6c9<>5
r6c9=5 (r6c8<>5) r5c8<>5 r5c8=1 r7c8<>1 r7c8=6 r6c8<>6 r6c8=3 (r4c9<>3) r6c9<>3 r2c9=3 (r2c9<>7) r2c9<>9 r2c7=9 r2c7<>7 r2c5=7 r6c5<>7 r6c6=7
r6c9=5 r6c9<>9 r6c6=9
Forcing Net Verity => r7c2<>8
r1c4=3 r9c4<>3 r9c4=9 r7c4<>9 r7c2=9 r7c2<>8
r1c4=5 (r2c5<>5) r3c5<>5 r6c5=5 r6c5<>7 r6c6=7 r6c6<>9 r9c6=9 r7c4<>9 r7c2=9 r7c2<>8
r1c4=8 (r1c1<>8) (r1c8<>8 r2c8=8 r2c1<>8) (r1c6<>8) r3c6<>8 r4c6=8 r4c1<>8 r7c1=8 r7c2<>8
Brute Force: r5c7=4
Hidden Single: r7c9=4
Hidden Single: r4c7=2
Naked Single: r4c6=8
Naked Single: r4c4=5
Hidden Single: r2c7=9
Locked Candidates Type 1 (Pointing): 7 in b9 => r8c6<>7
XYZ-Wing: 1/3/9 in r19c6,r9c4 => r8c6<>3
Locked Candidates Type 1 (Pointing): 3 in b8 => r9c12<>3
AIC: 9 9- r7c2 =9= r7c4 =7= r7c5 -7- r6c5 =7= r6c6 =9= r9c6 -9 => r7c4,r9c2<>9
Hidden Single: r7c2=9
Hidden Pair: 3,9 in r9c46 => r9c6<>1
Discontinuous Nice Loop: 1 r1c3 -1- r1c6 -3- r9c6 -9- r9c4 =9= r5c4 =2= r5c2 =8= r5c3 -8- r7c3 -1- r1c3 => r1c3<>1
Discontinuous Nice Loop: 2 r8c2 -2- r8c6 -1- r1c6 -3- r9c6 -9- r9c4 =9= r5c4 =2= r5c2 -2- r8c2 => r8c2<>2
Locked Candidates Type 1 (Pointing): 2 in b7 => r6c1<>2
Continuous Nice Loop: 1/3/5/8 8= r5c2 =2= r5c4 =9= r9c4 =3= r9c6 -3- r1c6 -1- r8c6 -2- r8c1 =2= r7c1 =8= r7c3 -8- r5c3 =8= r5c2 =2 => r3c6,r5c2,r7c1<>1, r3c6<>3, r5c2<>5, r13c3<>8
AIC: 3 3- r1c4 -8- r3c4 =8= r3c2 -8- r5c2 -2- r5c4 -9- r9c4 -3- r9c6 =3= r1c6 -3 => r1c138,r3c4<>3
Locked Candidates Type 1 (Pointing): 3 in b3 => r2c12<>3
Continuous Nice Loop: 1/2/5/7/8 3= r2c8 =8= r1c8 -8- r1c4 -3- r1c6 -1- r8c6 -2- r3c6 -7- r2c5 =7= r2c9 =3= r2c8 =8 => r2c89<>1, r6c6<>2, r2c89<>5, r3c45<>7, r1c1<>8
Hidden Single: r7c4=7
W-Wing: 7/2 in r3c6,r6c5 connected by 2 in r35c4 => r2c5,r6c6<>7
Naked Single: r6c6=9
Naked Single: r5c4=2
Full House: r6c5=7
Naked Single: r9c6=3
Naked Single: r3c4=8
Naked Single: r5c2=8
Naked Single: r1c6=1
Naked Single: r9c4=9
Full House: r1c4=3
Naked Single: r2c5=5
Naked Single: r8c6=2
Full House: r3c6=7
Full House: r3c5=2
Naked Single: r2c2=1
Naked Single: r2c1=8
Naked Single: r2c8=3
Full House: r2c9=7
Naked Single: r7c1=2
Hidden Single: r5c9=9
Hidden Single: r6c2=2
Hidden Single: r1c8=8
Hidden Single: r7c3=8
Hidden Single: r8c7=7
Hidden Single: r9c2=4
Hidden Single: r5c3=1
Full House: r5c8=5
Naked Single: r6c8=6
Full House: r7c8=1
Full House: r7c5=6
Full House: r9c5=1
Naked Single: r6c9=3
Full House: r4c9=1
Naked Single: r8c9=5
Full House: r3c9=6
Full House: r9c7=6
Full House: r9c1=5
Naked Single: r8c2=3
Full House: r8c1=1
Naked Single: r1c7=5
Full House: r3c7=1
Naked Single: r6c1=4
Full House: r6c3=5
Naked Single: r3c2=5
Full House: r4c2=6
Full House: r3c3=3
Full House: r1c3=4
Full House: r1c1=6
Full House: r4c1=3
|
normal_sudoku_3825
|
..48..2.328...94....3.24.8.4972...3.1....7.....6...7..5....2..1....5.64..4.9...2.
|
914876253285139467673524189497215836132687594856493712568342971329751648741968325
|
Basic 9x9 Sudoku 3825
|
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 8 . . 2 . 3
2 8 . . . 9 4 . .
. . 3 . 2 4 . 8 .
4 9 7 2 . . . 3 .
1 . . . . 7 . . .
. . 6 . . . 7 . .
5 . . . . 2 . . 1
. . . . 5 . 6 4 .
. 4 . 9 . . . 2 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
914876253285139467673524189497215836132687594856493712568342971329751648741968325 #1 Extreme (11682)
Hidden Single: r3c5=2
Hidden Single: r4c3=7
Hidden Single: r1c3=4
Locked Candidates Type 1 (Pointing): 9 in b1 => r8c1<>9
Hidden Pair: 2,4 in r56c9 => r56c9<>5, r5c9<>6, r56c9<>8, r56c9<>9
Finned Franken Swordfish: 5 r14b4 c268 fr4c7 fr4c9 fr5c3 => r5c8<>5
Forcing Chain Contradiction in r9c9 => r2c9<>5
r2c9=5 r9c9<>5
r2c9=5 r2c3<>5 r2c3=1 r9c3<>1 r9c3=8 r7c3<>8 r7c3=9 r7c8<>9 r7c8=7 r9c9<>7
r2c9=5 r2c3<>5 r2c3=1 r9c3<>1 r9c3=8 r9c9<>8
Forcing Chain Verity => r5c4<>5
r1c8=5 r1c6<>5 r23c4=5 r5c4<>5
r2c8=5 r2c3<>5 r5c3=5 r5c4<>5
r6c8=5 r6c2<>5 r5c23=5 r5c4<>5
Forcing Chain Contradiction in c5 => r7c5<>7
r7c5=7 r7c8<>7 r7c8=9 r7c3<>9 r8c3=9 r8c3<>2 r5c3=2 r5c9<>2 r5c9=4 r5c5<>4
r7c5=7 r7c8<>7 r7c8=9 r6c8<>9 r6c5=9 r6c5<>4
r7c5=7 r7c5<>4
Forcing Net Contradiction in r7c7 => r1c1<>7
r1c1=7 (r1c1<>6) r1c1<>9 r1c8=9 (r7c8<>9 r7c8=7 r7c2<>7) (r3c7<>9) r3c9<>9 r3c1=9 r3c1<>6 r9c1=6 (r9c6<>6) r7c2<>6 r7c2=3 (r8c1<>3 r8c1=8 r6c1<>8) (r7c7<>3 r9c7=3 r9c6<>3) (r8c1<>3) r9c1<>3 r6c1=3 r6c1<>8 r5c3=8 r9c3<>8 r9c3=1 r9c6<>1 r9c6=8 r6c6<>8 r6c5=8 r6c5<>9 r6c8=9 r1c8<>9 r1c1=9 r1c1<>7
Forcing Net Verity => r1c8<>6
r1c8=5 r1c8<>6
r2c8=5 r2c3<>5 (r2c3=1 r9c3<>1 r9c3=8 r9c9<>8) r5c3=5 (r5c7<>5) r5c3<>2 r8c3=2 r8c3<>9 r8c9=9 r8c9<>8 r4c9=8 r5c7<>8 r5c7=9 r5c8<>9 r5c8=6 r1c8<>6
r6c8=5 (r6c8<>1) (r1c8<>5) (r4c7<>5) r4c9<>5 r4c6=5 r1c6<>5 r1c2=5 r2c3<>5 r2c3=1 r2c8<>1 r1c8=1 r1c8<>6
Forcing Net Verity => r1c8<>7
r1c8=5 r1c8<>7
r2c8=5 r2c3<>5 r2c3=1 r9c3<>1 r9c3=8 r7c3<>8 r7c3=9 r7c8<>9 r7c8=7 r1c8<>7
r6c8=5 (r6c8<>1) (r1c8<>5) (r4c7<>5) r4c9<>5 r4c6=5 r1c6<>5 r1c2=5 r2c3<>5 r2c3=1 r2c8<>1 r1c8=1 r1c8<>7
Forcing Chain Contradiction in r9 => r8c2<>7
r8c2=7 r9c1<>7
r8c2=7 r1c2<>7 r1c5=7 r9c5<>7
r8c2=7 r8c2<>2 r8c3=2 r8c3<>9 r8c9=9 r7c8<>9 r7c8=7 r9c9<>7
Sue de Coq: r89c1 - {3678} (r13c1 - {679}, r789c3,r8c2 - {12389}) => r7c2<>3
Forcing Chain Contradiction in c4 => r2c5<>6
r2c5=6 r2c4<>6
r2c5=6 r3c4<>6
r2c5=6 r2c8<>6 r5c8=6 r5c4<>6
r2c5=6 r2c9<>6 r2c9=7 r2c8<>7 r7c8=7 r7c2<>7 r7c2=6 r7c4<>6
Forcing Chain Contradiction in r7 => r6c5<>8
r6c5=8 r6c1<>8 r5c3=8 r7c3<>8
r6c5=8 r7c5<>8
r6c5=8 r6c1<>8 r6c1=3 r6c6<>3 r89c6=3 r7c45<>3 r7c7=3 r7c7<>8
Forcing Chain Contradiction in c5 => r7c5<>6
r7c5=6 r7c2<>6 r7c2=7 r7c8<>7 r7c8=9 r7c3<>9 r8c3=9 r8c3<>2 r5c3=2 r5c9<>2 r5c9=4 r5c5<>4
r7c5=6 r7c2<>6 r7c2=7 r7c8<>7 r7c8=9 r6c8<>9 r6c5=9 r6c5<>4
r7c5=6 r7c5<>4
Empty Rectangle: 6 in b2 (r7c24) => r1c2<>6
Forcing Chain Contradiction in c4 => r6c5=9
r6c5<>9 r6c8=9 r1c8<>9 r1c1=9 r1c1<>6 r1c56=6 r2c4<>6
r6c5<>9 r6c8=9 r1c8<>9 r1c1=9 r1c1<>6 r1c56=6 r3c4<>6
r6c5<>9 r6c8=9 r5c8<>9 r5c8=6 r5c4<>6
r6c5<>9 r6c8=9 r7c8<>9 r7c8=7 r7c2<>7 r7c2=6 r7c4<>6
Forcing Chain Contradiction in r1 => r2c8<>1
r2c8=1 r2c3<>1 r2c3=5 r1c2<>5
r2c8=1 r6c8<>1 r6c8=5 r6c4<>5 r23c4=5 r1c6<>5
r2c8=1 r6c8<>1 r6c8=5 r1c8<>5
Forcing Chain Contradiction in c4 => r1c5<>1
r1c5=1 r2c4<>1
r1c5=1 r3c4<>1
r1c5=1 r1c8<>1 r6c8=1 r6c4<>1
r1c5=1 r2c45<>1 r2c3=1 r9c3<>1 r8c23=1 r8c4<>1
Almost Locked Set XY-Wing: A=r1c15 {679}, B=r2c89 {567}, C=r16c8 {159}, X,Y=5,9, Z=7 => r2c45<>7
Locked Candidates Type 2 (Claiming): 7 in r2 => r3c9<>7
Almost Locked Set XY-Wing: A=r1c2568 {15679}, B=r2c345 {1356}, C=r257c8 {5679}, X,Y=5,9, Z=6 => r3c4<>6
Forcing Chain Contradiction in c4 => r1c6<>1
r1c6=1 r2c4<>1
r1c6=1 r3c4<>1
r1c6=1 r1c8<>1 r6c8=1 r6c4<>1
r1c6=1 r2c45<>1 r2c3=1 r9c3<>1 r8c23=1 r8c4<>1
W-Wing: 5/1 in r2c3,r6c8 connected by 1 in r1c28 => r2c8<>5
Locked Pair: 6,7 in r2c89 => r2c4,r3c9<>6
Locked Candidates Type 1 (Pointing): 6 in b2 => r1c1<>6
Naked Single: r1c1=9
Empty Rectangle: 5 in b2 (r16c8) => r6c4<>5
Locked Candidates Type 1 (Pointing): 5 in b5 => r1c6<>5
Naked Single: r1c6=6
Naked Single: r1c5=7
Naked Pair: 1,5 in r1c2,r2c3 => r3c2<>1, r3c2<>5
2-String Kite: 1 in r3c4,r6c8 (connected by r1c8,r3c7) => r6c4<>1
Continuous Nice Loop: 1/5/8 5= r5c3 =2= r8c3 =9= r8c9 -9- r3c9 -5- r3c4 =5= r2c4 -5- r2c3 =5= r5c3 =2 => r8c3<>1, r3c7<>5, r58c3<>8
Hidden Single: r6c1=8
Locked Candidates Type 1 (Pointing): 3 in b4 => r8c2<>3
Finned Swordfish: 1 r168 c268 fr8c4 => r9c6<>1
AIC: 4 4- r5c9 -2- r5c3 =2= r8c3 =9= r8c9 -9- r7c8 -7- r7c2 -6- r7c4 =6= r9c5 =1= r9c3 -1- r8c2 -2- r6c2 =2= r6c9 =4= r6c4 -4 => r5c45,r6c9<>4
Naked Single: r6c9=2
Naked Single: r5c9=4
Hidden Single: r7c5=4
Hidden Single: r6c4=4
Continuous Nice Loop: 3/6/7 7= r9c1 =6= r9c5 -6- r4c5 =6= r4c9 -6- r2c9 -7- r9c9 =7= r9c1 =6 => r9c1<>3, r5c5<>6, r8c9<>7
Hidden Single: r8c1=3
Hidden Single: r8c4=7
Locked Candidates Type 2 (Claiming): 1 in c4 => r2c5<>1
Naked Single: r2c5=3
Naked Single: r5c5=8
Swordfish: 1 r168 c268 => r4c6<>1
Naked Single: r4c6=5
X-Wing: 5 r16 c28 => r5c2<>5
W-Wing: 9/5 in r3c9,r5c7 connected by 5 in r9c79 => r3c7<>9
Naked Single: r3c7=1
Naked Single: r1c8=5
Full House: r1c2=1
Naked Single: r3c4=5
Full House: r2c4=1
Naked Single: r4c7=8
Naked Single: r3c9=9
Naked Single: r6c8=1
Naked Single: r2c3=5
Naked Single: r8c2=2
Naked Single: r4c9=6
Full House: r4c5=1
Full House: r9c5=6
Naked Single: r8c9=8
Naked Single: r6c6=3
Full House: r5c4=6
Full House: r7c4=3
Full House: r6c2=5
Naked Single: r5c3=2
Full House: r5c2=3
Naked Single: r8c3=9
Full House: r8c6=1
Full House: r9c6=8
Naked Single: r2c9=7
Full House: r2c8=6
Full House: r9c9=5
Naked Single: r5c8=9
Full House: r5c7=5
Full House: r7c8=7
Naked Single: r9c1=7
Full House: r3c1=6
Full House: r3c2=7
Full House: r7c2=6
Naked Single: r7c7=9
Full House: r7c3=8
Full House: r9c3=1
Full House: r9c7=3
|
normal_sudoku_1580
|
63..5......9..73..7..3....49...3.24..84129..6..2.45..8..75....3.9..738..8.3.1....
|
638254719419867325725391684956738241384129576172645938247586193591473862863912457
|
Basic 9x9 Sudoku 1580
|
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 . . 5 . . . .
. . 9 . . 7 3 . .
7 . . 3 . . . . 4
9 . . . 3 . 2 4 .
. 8 4 1 2 9 . . 6
. . 2 . 4 5 . . 8
. . 7 5 . . . . 3
. 9 . . 7 3 8 . .
8 . 3 . 1 . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
638254719419867325725391684956738241384129576172645938247586193591473862863912457 #1 Extreme (37806) bf
Turbot Fish: 3 r6c8 =3= r6c1 -3- r7c1 =3= r9c3 => r9c8<>3
Brute Force: r5c5=2
Hidden Single: r4c5=3
Hidden Single: r8c5=7
Locked Candidates Type 1 (Pointing): 3 in b6 => r7c8<>3
W-Wing: 6/8 in r2c5,r4c6 connected by 8 in r7c56 => r3c6<>6
AIC: 9 9- r3c5 =9= r7c5 =8= r7c6 -8- r5c6 -9 => r13c6<>9
Forcing Net Contradiction in r7c7 => r7c9<>1
r7c9=1 (r7c9<>9) r7c9<>3 r7c1=3 r9c3<>3 r9c9=3 (r9c9<>7) r9c9<>9 r1c9=9 r1c9<>7 r4c9=7 (r5c8<>7 r5c2=7 r5c2<>8) r4c4<>7 r6c4=7 r6c4<>9 r5c6=9 r5c6<>8 r5c3=8 r5c3<>3 r9c3=3 r7c1<>3 r7c9=3 r7c9<>1
Forcing Net Contradiction in r7c7 => r7c9<>2
r7c9=2 (r7c9<>9) r7c9<>3 r7c1=3 r9c3<>3 r9c9=3 (r9c9<>7) r9c9<>9 r1c9=9 r1c9<>7 r4c9=7 (r5c8<>7 r5c2=7 r5c2<>8) r4c4<>7 r6c4=7 r6c4<>9 r5c6=9 r5c6<>8 r5c3=8 r5c3<>3 r9c3=3 r7c1<>3 r7c9=3 r7c9<>2
Brute Force: r5c6=9
Locked Candidates Type 1 (Pointing): 8 in b5 => r4c23<>8
Finned X-Wing: 9 c49 r19 fr7c9 => r9c78<>9
Forcing Chain Contradiction in c9 => r1c7<>9
r1c7=9 r1c9<>9
r1c7=9 r6c7<>9 r6c8=9 r6c8<>3 r6c1=3 r7c1<>3 r7c9=3 r7c9<>9
r1c7=9 r1c4<>9 r9c4=9 r9c9<>9
Forcing Net Contradiction in c9 => r3c6<>8
r3c6=8 r3c6<>1 r1c6=1 r1c7<>1 r1c7=7 r1c9<>7
r3c6=8 (r4c6<>8 r4c6=6 r4c3<>6) (r4c6<>8 r4c6=6 r4c4<>6) (r4c6<>8 r4c6=6 r6c4<>6) (r3c5<>8) r2c5<>8 r2c5=6 (r2c4<>6) r3c5<>6 r3c5=9 r1c4<>9 r9c4=9 r9c4<>6 r8c4=6 r8c3<>6 r9c3=6 r9c3<>3 r5c3=3 r5c3<>8 r5c2=8 r5c2<>7 r5c78=7 r4c9<>7
r3c6=8 (r4c6<>8 r4c6=6 r4c3<>6) (r4c6<>8 r4c6=6 r4c4<>6) (r4c6<>8 r4c6=6 r6c4<>6) (r3c5<>8) r2c5<>8 r2c5=6 (r2c4<>6) r3c5<>6 r3c5=9 r1c4<>9 r9c4=9 r9c4<>6 r8c4=6 r8c3<>6 r9c3=6 r9c3<>3 r9c9=3 r9c9<>7
Forcing Net Verity => r9c4<>2
r7c5=9 (r7c5<>6) (r7c5<>8 r7c6=8 r7c6<>6) (r7c5<>8 r7c6=8 r4c6<>8 r4c6=6 r9c6<>6) (r7c5<>8 r7c6=8 r4c6<>8 r4c6=6 r4c3<>6) r7c9<>9 r7c9=3 r9c9<>3 r9c3=3 r9c3<>6 r8c3=6 r8c4<>6 r9c4=6 r9c4<>2
r9c4=9 r9c4<>2
Forcing Net Contradiction in r9c3 => r9c4<>4
r9c4=4 r9c4<>9 r9c9=9 r9c9<>3 r9c3=3
r9c4=4 (r8c4<>4) (r9c4<>9 r1c4=9 r1c4<>2) (r7c6<>4) r9c6<>4 r1c6=4 (r1c6<>2) r1c6<>1 r3c6=1 r3c6<>2 r2c4=2 r8c4<>2 r8c4=6 (r8c3<>6) r6c4<>6 r6c2=6 r4c3<>6 r9c3=6
Brute Force: r5c3=4
Hidden Single: r4c8=4
Hidden Single: r9c3=3
Hidden Single: r5c2=8
Hidden Single: r7c9=3
Locked Candidates Type 1 (Pointing): 4 in b1 => r2c4<>4
Locked Candidates Type 2 (Claiming): 7 in r5 => r4c9,r6c78<>7
Naked Triple: 1,3,9 in r6c178 => r6c2<>1
Naked Triple: 1,2,5 in r248c9 => r1c9<>1, r19c9<>2, r9c9<>5
X-Wing: 9 c49 r19 => r1c8<>9
2-String Kite: 6 in r6c4,r8c3 (connected by r4c3,r6c2) => r8c4<>6
XY-Wing: 1/7/9 in r1c79,r6c7 => r3c7<>9
XY-Wing: 5/7/1 in r15c7,r4c9 => r2c9,r6c7<>1
Naked Single: r6c7=9
2-String Kite: 1 in r6c1,r8c9 (connected by r4c9,r6c8) => r8c1<>1
Uniqueness Test 4: 6/7 in r4c24,r6c24 => r4c24<>6
Finned Swordfish: 1 r267 c128 fr7c7 => r8c8<>1
Sue de Coq: r12c4 - {24689} (r8c4 - {24}, r23c5 - {689}) => r1c6<>8
Discontinuous Nice Loop: 1 r1c3 -1- r1c7 -7- r5c7 -5- r4c9 -1- r8c9 =1= r8c3 -1- r1c3 => r1c3<>1
Naked Single: r1c3=8
Naked Triple: 1,2,5 in r3c236 => r3c78<>1, r3c78<>5, r3c8<>2
Naked Single: r3c7=6
Locked Candidates Type 1 (Pointing): 5 in b3 => r2c12<>5
Skyscraper: 5 in r8c1,r9c7 (connected by r5c17) => r8c89,r9c2<>5
W-Wing: 1/5 in r3c3,r4c9 connected by 5 in r34c2 => r4c3<>1
Skyscraper: 1 in r4c2,r8c3 (connected by r48c9) => r7c2<>1
W-Wing: 5/1 in r3c3,r4c9 connected by 1 in r8c39 => r4c3<>5
Naked Single: r4c3=6
Naked Single: r4c6=8
Naked Single: r6c2=7
Naked Single: r4c4=7
Full House: r6c4=6
Naked Single: r9c4=9
Naked Single: r9c9=7
Naked Single: r1c9=9
Naked Single: r3c8=8
Naked Single: r3c5=9
Hidden Single: r8c8=6
Hidden Single: r2c4=8
Naked Single: r2c5=6
Full House: r7c5=8
Hidden Single: r7c8=9
Skyscraper: 2 in r1c4,r2c9 (connected by r8c49) => r1c8<>2
Locked Pair: 1,7 in r1c78 => r1c6,r2c8<>1
Hidden Single: r3c6=1
Naked Single: r3c3=5
Full House: r3c2=2
Full House: r8c3=1
Naked Single: r8c9=2
Naked Single: r2c9=5
Full House: r4c9=1
Full House: r4c2=5
Naked Single: r8c4=4
Full House: r1c4=2
Full House: r8c1=5
Full House: r1c6=4
Naked Single: r9c8=5
Naked Single: r2c8=2
Naked Single: r6c8=3
Full House: r6c1=1
Full House: r5c1=3
Naked Single: r9c7=4
Full House: r7c7=1
Naked Single: r5c8=7
Full House: r1c8=1
Full House: r1c7=7
Full House: r5c7=5
Naked Single: r2c1=4
Full House: r2c2=1
Full House: r7c1=2
Naked Single: r9c2=6
Full House: r7c2=4
Full House: r7c6=6
Full House: r9c6=2
|
normal_sudoku_232
|
.7.1.5642..267.1581..82.37932.56.79..954..82....7....1..9346.87.4.25.9.....9.....
|
978135642432679158156824379321568794795413826684792531519346287847251963263987415
|
Basic 9x9 Sudoku 232
|
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 . 1 . 5 6 4 2
. . 2 6 7 . 1 5 8
1 . . 8 2 . 3 7 9
3 2 . 5 6 . 7 9 .
. 9 5 4 . . 8 2 .
. . . 7 . . . . 1
. . 9 3 4 6 . 8 7
. 4 . 2 5 . 9 . .
. . . 9 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
978135642432679158156824379321568794795413826684792531519346287847251963263987415 #1 Easy (204)
Naked Single: r5c7=8
Naked Single: r1c8=4
Naked Single: r3c4=8
Naked Single: r7c4=3
Naked Single: r2c7=1
Naked Single: r2c9=8
Full House: r3c8=7
Naked Single: r4c8=9
Naked Single: r3c5=2
Naked Single: r4c4=5
Full House: r6c4=7
Naked Single: r8c7=9
Naked Single: r2c2=3
Naked Single: r3c6=4
Naked Single: r4c9=4
Naked Single: r1c3=8
Naked Single: r2c6=9
Full House: r1c5=3
Full House: r1c1=9
Full House: r2c1=4
Naked Single: r3c3=6
Full House: r3c2=5
Naked Single: r6c7=5
Naked Single: r4c3=1
Full House: r4c6=8
Naked Single: r5c5=1
Naked Single: r6c3=4
Naked Single: r7c2=1
Naked Single: r7c7=2
Full House: r7c1=5
Full House: r9c7=4
Naked Single: r6c5=9
Full House: r9c5=8
Naked Single: r5c6=3
Full House: r6c6=2
Naked Single: r9c2=6
Full House: r6c2=8
Naked Single: r5c9=6
Full House: r5c1=7
Full House: r6c1=6
Full House: r6c8=3
Naked Single: r8c9=3
Full House: r9c9=5
Naked Single: r8c1=8
Full House: r9c1=2
Naked Single: r9c8=1
Full House: r8c8=6
Naked Single: r8c3=7
Full House: r8c6=1
Full House: r9c6=7
Full House: r9c3=3
|
normal_sudoku_614
|
.......14..471.59.5...942.7135.4..797861394524.2..7......47.92.24....7.1..9.21.45
|
927358614364712598518694237135246879786139452492587163851473926243965781679821345
|
Basic 9x9 Sudoku 614
|
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 4
. . 4 7 1 . 5 9 .
5 . . . 9 4 2 . 7
1 3 5 . 4 . . 7 9
7 8 6 1 3 9 4 5 2
4 . 2 . . 7 . . .
. . . 4 7 . 9 2 .
2 4 . . . . 7 . 1
. . 9 . 2 1 . 4 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
927358614364712598518694237135246879786139452492587163851473926243965781679821345 #1 Extreme (32680) bf
Hidden Single: r5c9=2
Hidden Single: r6c1=4
Hidden Single: r7c4=4
Hidden Single: r9c8=4
Hidden Single: r2c3=4
Hidden Single: r3c9=7
Hidden Single: r8c1=2
Hidden Single: r7c5=7
Locked Candidates Type 1 (Pointing): 3 in b6 => r6c45<>3
Almost Locked Set XY-Wing: A=r1c234567 {2356789}, B=r2479c1 {13678}, C=r23679c2 {125679}, X,Y=7,9, Z=3,6,8 => r1c1<>3, r1c1<>6, r1c1<>8
Brute Force: r5c4=1
Brute Force: r5c5=3
Brute Force: r5c3=6
Naked Single: r4c1=1
Naked Single: r5c6=9
Full House: r5c1=7
Naked Single: r4c3=5
Full House: r6c2=9
Naked Single: r1c1=9
Hidden Single: r1c3=7
Hidden Single: r6c7=1
Hidden Single: r8c4=9
Hidden Single: r9c2=7
Hidden Single: r7c2=5
Hidden Single: r7c3=1
Hidden Single: r3c2=1
Locked Candidates Type 1 (Pointing): 6 in b7 => r2c1<>6
Empty Rectangle: 3 in b8 (r19c7) => r1c6<>3
Sashimi X-Wing: 6 r38 c48 fr8c5 fr8c6 => r9c4<>6
Finned Swordfish: 8 c358 r368 fr1c5 => r3c4<>8
Sashimi Swordfish: 3 c347 r139 fr8c3 => r9c1<>3
X-Wing: 3 r19 c47 => r3c4<>3
Naked Single: r3c4=6
X-Wing: 6 c58 r68 => r6c9,r8c6<>6
W-Wing: 8/3 in r2c1,r9c4 connected by 3 in r1c4,r2c6 => r9c1<>8
Naked Single: r9c1=6
Empty Rectangle: 8 in b6 (r9c47) => r6c4<>8
Naked Single: r6c4=5
Hidden Rectangle: 5/8 in r1c56,r8c56 => r8c6<>8
Finned Swordfish: 8 r149 c467 fr1c5 => r2c6<>8
Locked Candidates Type 1 (Pointing): 8 in b2 => r1c7<>8
W-Wing: 3/8 in r6c9,r7c1 connected by 8 in r2c19 => r7c9<>3
W-Wing: 8/6 in r4c7,r7c9 connected by 6 in r47c6 => r6c9,r9c7<>8
Naked Single: r6c9=3
Naked Single: r9c7=3
Full House: r9c4=8
Naked Single: r1c7=6
Full House: r4c7=8
Full House: r6c8=6
Full House: r6c5=8
Naked Single: r4c4=2
Full House: r1c4=3
Full House: r4c6=6
Naked Single: r1c2=2
Full House: r2c2=6
Naked Single: r2c9=8
Full House: r3c8=3
Full House: r8c8=8
Full House: r7c9=6
Full House: r3c3=8
Full House: r2c1=3
Full House: r2c6=2
Full House: r8c3=3
Full House: r7c1=8
Full House: r7c6=3
Naked Single: r1c5=5
Full House: r1c6=8
Full House: r8c6=5
Full House: r8c5=6
|
normal_sudoku_3543
|
..23....6....7.8...1..9.37..532..48926985413784.93..6.5....9..3...5..6....6.23...
|
472381956935672814618495372753216489269854137841937265584169723327548691196723548
|
Basic 9x9 Sudoku 3543
|
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 3 . . . . 6
. . . . 7 . 8 . .
. 1 . . 9 . 3 7 .
. 5 3 2 . . 4 8 9
2 6 9 8 5 4 1 3 7
8 4 . 9 3 . . 6 .
5 . . . . 9 . . 3
. . . 5 . . 6 . .
. . 6 . 2 3 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
472381956935672814618495372753216489269854137841937265584169723327548691196723548 #1 Extreme (21180) bf
Almost Locked Set XY-Wing: A=r3c13469 {234568}, B=r1479c7 {24579}, C=r8c135689 {1234789}, X,Y=2,3, Z=4,5 => r3c7<>4, r3c7<>5
Brute Force: r5c5=5
Hidden Single: r5c8=3
Hidden Single: r6c5=3
Hidden Single: r3c7=3
Hidden Rectangle: 7/9 in r5c34,r6c34 => r6c4<>7
Brute Force: r5c4=8
Naked Single: r5c9=7
Naked Single: r5c3=9
Full House: r5c2=6
Hidden Single: r4c8=8
Hidden Single: r6c4=9
Hidden Single: r4c7=4
Hidden Single: r6c8=6
Hidden Single: r4c2=5
Locked Candidates Type 1 (Pointing): 7 in b5 => r8c6<>7
Locked Candidates Type 2 (Claiming): 7 in r8 => r7c23,r9c12<>7
Naked Pair: 4,6 in r3c14 => r3c39<>4, r3c6<>6
Naked Pair: 2,5 in r36c9 => r28c9<>2, r29c9<>5
Naked Triple: 1,4,8 in r8c569 => r8c138<>1, r8c138<>4, r8c23<>8
Naked Single: r8c3=7
Naked Single: r6c3=1
Full House: r4c1=7
Naked Single: r6c6=7
Hidden Single: r1c2=7
Hidden Single: r9c1=1
Hidden Single: r3c3=8
Naked Single: r7c3=4
Full House: r2c3=5
Skyscraper: 1 in r7c4,r8c9 (connected by r2c49) => r7c8,r8c56<>1
Naked Single: r7c8=2
Naked Single: r8c6=8
Naked Single: r7c2=8
Naked Single: r7c7=7
Naked Single: r8c8=9
Naked Single: r8c5=4
Naked Single: r9c2=9
Naked Single: r8c1=3
Full House: r8c2=2
Full House: r8c9=1
Full House: r2c2=3
Naked Single: r9c7=5
Naked Single: r9c4=7
Naked Single: r2c9=4
Naked Single: r1c7=9
Full House: r6c7=2
Full House: r6c9=5
Naked Single: r9c8=4
Full House: r9c9=8
Full House: r3c9=2
Naked Single: r2c8=1
Full House: r1c8=5
Naked Single: r1c1=4
Naked Single: r3c6=5
Naked Single: r2c4=6
Naked Single: r1c6=1
Full House: r1c5=8
Naked Single: r3c1=6
Full House: r2c1=9
Full House: r2c6=2
Full House: r3c4=4
Full House: r7c4=1
Full House: r4c6=6
Full House: r7c5=6
Full House: r4c5=1
|
normal_sudoku_3510
|
.7...6.2.........5..1.8......4....5..8..2.39.9.36.8.414.2.37..9....625...3.8...7.
|
578416923346279815291583467764391258185724396923658741452137689817962534639845172
|
Basic 9x9 Sudoku 3510
|
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 . . . 6 . 2 .
. . . . . . . . 5
. . 1 . 8 . . . .
. . 4 . . . . 5 .
. 8 . . 2 . 3 9 .
9 . 3 6 . 8 . 4 1
4 . 2 . 3 7 . . 9
. . . . 6 2 5 . .
. 3 . 8 . . . 7 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
578416923346279815291583467764391258185724396923658741452137689817962534639845172 #1 Extreme (3402)
Hidden Single: r6c3=3
Locked Candidates Type 1 (Pointing): 8 in b7 => r8c89<>8
Hidden Pair: 7,8 in r8c13 => r8c1<>1, r8c3<>9
Skyscraper: 5 in r6c5,r7c4 (connected by r67c2) => r5c4,r9c5<>5
Finned Swordfish: 5 r159 c136 fr1c4 fr1c5 => r3c6<>5
Finned Swordfish: 5 r167 c245 fr1c1 fr1c3 => r3c2<>5
Skyscraper: 5 in r3c1,r7c2 (connected by r37c4) => r9c1<>5
Discontinuous Nice Loop: 6 r3c9 -6- r3c8 -3- r8c8 =3= r8c9 =4= r8c4 -4- r5c4 =4= r5c6 =5= r6c5 =7= r6c7 -7- r5c9 -6- r3c9 => r3c9<>6
Discontinuous Nice Loop: 1 r5c4 -1- r7c4 -5- r9c6 =5= r5c6 =4= r5c4 => r5c4<>1
AIC: 6 6- r5c9 -7- r6c7 =7= r6c5 =5= r5c6 =1= r5c1 -1- r9c1 -6 => r5c1,r9c9<>6
Locked Candidates Type 2 (Claiming): 6 in c9 => r4c7<>6
Discontinuous Nice Loop: 6 r3c1 -6- r3c8 -3- r8c8 =3= r8c9 =4= r8c4 -4- r5c4 =4= r5c6 =1= r5c1 -1- r9c1 -6- r3c1 => r3c1<>6
Discontinuous Nice Loop: 6 r7c2 -6- r9c1 -1- r5c1 =1= r5c6 =5= r9c6 -5- r9c3 =5= r7c2 => r7c2<>6
Locked Candidates Type 1 (Pointing): 6 in b7 => r9c7<>6
Naked Pair: 1,5 in r7c24 => r7c78<>1
AIC: 1 1- r7c4 -5- r9c6 =5= r5c6 =4= r5c4 -4- r8c4 =4= r8c9 =3= r8c8 =1= r9c7 -1 => r9c56<>1
Locked Candidates Type 1 (Pointing): 1 in b8 => r124c4<>1
Sashimi Swordfish: 1 r159 c157 fr5c6 => r4c5<>1
Locked Candidates Type 1 (Pointing): 1 in b5 => r2c6<>1
XY-Wing: 7/9/4 in r49c5,r5c4 => r8c4<>4
Hidden Single: r8c9=4
Naked Single: r9c9=2
Naked Single: r9c7=1
Naked Single: r8c8=3
Naked Single: r9c1=6
Naked Single: r3c8=6
Naked Single: r7c8=8
Full House: r2c8=1
Full House: r7c7=6
Hidden Single: r1c5=1
Hidden Single: r6c5=5
Naked Single: r6c2=2
Full House: r6c7=7
Naked Single: r5c9=6
Naked Single: r4c9=8
Full House: r4c7=2
Naked Single: r1c9=3
Full House: r3c9=7
Hidden Single: r9c6=5
Naked Single: r7c4=1
Full House: r7c2=5
Naked Single: r9c3=9
Full House: r9c5=4
Full House: r8c4=9
Naked Single: r8c2=1
Naked Single: r4c2=6
Hidden Single: r2c3=6
Hidden Single: r1c7=9
Naked Single: r3c7=4
Full House: r2c7=8
Naked Single: r3c2=9
Full House: r2c2=4
Naked Single: r3c6=3
Naked Single: r2c6=9
Naked Single: r2c5=7
Full House: r4c5=9
Naked Single: r4c6=1
Full House: r5c6=4
Naked Single: r2c4=2
Full House: r2c1=3
Naked Single: r4c1=7
Full House: r4c4=3
Full House: r5c4=7
Naked Single: r3c4=5
Full House: r1c4=4
Full House: r3c1=2
Naked Single: r5c3=5
Full House: r5c1=1
Naked Single: r8c1=8
Full House: r1c1=5
Full House: r1c3=8
Full House: r8c3=7
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.