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_2645
|
..1....9.6..1..8..58.9..1.6.5.6..2....6.9....1...7..6.86..4....2...6...3..58.....
|
471286395639154827582937146754618239326495718198372564863741952217569483945823671
|
Basic 9x9 Sudoku 2645
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 1 . . . . 9 .
6 . . 1 . . 8 . .
5 8 . 9 . . 1 . 6
. 5 . 6 . . 2 . .
. . 6 . 9 . . . .
1 . . . 7 . . 6 .
8 6 . . 4 . . . .
2 . . . 6 . . . 3
. . 5 8 . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
471286395639154827582937146754618239326495718198372564863741952217569483945823671 #1 Extreme (20746) bf
Hidden Single: r5c3=6
Hidden Single: r1c6=6
Hidden Single: r9c7=6
Hidden Single: r8c8=8
Hidden Single: r1c5=8
Hidden Single: r2c5=5
Brute Force: r5c8=1
Hidden Single: r7c8=5
Brute Force: r5c7=7
Naked Single: r7c7=9
Naked Single: r8c7=4
Continuous Nice Loop: 3/4/7/9 9= r4c1 =7= r4c3 -7- r8c3 -9- r9c1 =9= r4c1 =7 => r4c1<>3, r4c1<>4, r237c3<>7, r89c2<>9
Naked Single: r7c3=3
Swordfish: 3 r349 c568 => r2c68,r56c6<>3
Hidden Single: r2c2=3
Hidden Single: r5c1=3
Hidden Single: r2c3=9
Naked Single: r8c3=7
Naked Single: r8c2=1
Naked Single: r8c4=5
Full House: r8c6=9
Naked Single: r9c2=4
Full House: r9c1=9
Naked Single: r5c2=2
Naked Single: r4c1=7
Full House: r1c1=4
Naked Single: r1c2=7
Full House: r6c2=9
Full House: r3c3=2
Naked Single: r5c4=4
Naked Single: r3c5=3
Naked Single: r1c4=2
Naked Single: r4c5=1
Full House: r9c5=2
Naked Single: r1c9=5
Full House: r1c7=3
Full House: r6c7=5
Naked Single: r6c4=3
Full House: r7c4=7
Naked Single: r9c8=7
Naked Single: r5c9=8
Full House: r5c6=5
Naked Single: r4c6=8
Full House: r6c6=2
Naked Single: r7c6=1
Full House: r7c9=2
Full House: r9c9=1
Full House: r9c6=3
Naked Single: r3c8=4
Full House: r3c6=7
Full House: r2c6=4
Naked Single: r6c9=4
Full House: r6c3=8
Full House: r4c3=4
Naked Single: r2c8=2
Full House: r2c9=7
Full House: r4c8=3
Full House: r4c9=9
|
normal_sudoku_3590
|
.8.3..6.......8.2...1.5...75..........672...1.7..9.4....78..3.......2.5..9..4...8
|
289371645753468129461259837542186973936724581178593462627815394814932756395647218
|
Basic 9x9 Sudoku 3590
|
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 . . 6 . .
. . . . . 8 . 2 .
. . 1 . 5 . . . 7
5 . . . . . . . .
. . 6 7 2 . . . 1
. 7 . . 9 . 4 . .
. . 7 8 . . 3 . .
. . . . . 2 . 5 .
. 9 . . 4 . . . 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
289371645753468129461259837542186973936724581178593462627815394814932756395647218 #1 Extreme (12308) bf
Hidden Pair: 3,7 in r8c5,r9c6 => r8c5,r9c6<>1, r8c5,r9c6<>6, r9c6<>5
Brute Force: r5c5=2
Hidden Single: r3c4=2
Hidden Single: r4c5=8
Hidden Single: r8c5=3
Naked Single: r9c6=7
Hidden Single: r8c7=7
Hidden Single: r4c8=7
Skyscraper: 2 in r7c2,r9c7 (connected by r4c27) => r7c9,r9c13<>2
Hidden Single: r9c7=2
Naked Single: r4c7=9
Naked Single: r3c7=8
Naked Single: r5c7=5
Full House: r2c7=1
Hidden Single: r5c1=9
Hidden Single: r5c8=8
2-String Kite: 4 in r2c4,r5c2 (connected by r4c4,r5c6) => r2c2<>4
Discontinuous Nice Loop: 4/9 r1c9 =5= r1c3 =2= r1c1 -2- r7c1 =2= r7c2 =5= r2c2 -5- r2c9 =5= r1c9 => r1c9<>4, r1c9<>9
Naked Single: r1c9=5
Discontinuous Nice Loop: 3/6 r2c2 =5= r2c3 =9= r1c3 =2= r1c1 -2- r7c1 =2= r7c2 =5= r2c2 => r2c2<>3, r2c2<>6
Naked Single: r2c2=5
Hidden Single: r9c3=5
Hidden Single: r7c6=5
Hidden Single: r6c4=5
Hidden Single: r9c1=3
Hidden Single: r8c4=9
Locked Candidates Type 2 (Claiming): 1 in r8 => r7c12<>1
Naked Triple: 4,6,7 in r2c145 => r2c39<>4
Locked Candidates Type 1 (Pointing): 4 in b3 => r7c8<>4
Hidden Pair: 1,8 in r68c1 => r6c1<>2, r8c1<>4, r8c1<>6
2-String Kite: 3 in r2c3,r6c8 (connected by r2c9,r3c8) => r6c3<>3
Hidden Rectangle: 4/9 in r1c68,r3c68 => r3c6<>4
Continuous Nice Loop: 1/4/6 7= r1c1 =2= r1c3 =9= r2c3 -9- r2c9 =9= r7c9 =4= r8c9 =6= r8c2 =1= r8c1 -1- r6c1 =1= r6c6 -1- r1c6 =1= r1c5 =7= r1c1 =2 => r4c6<>1, r1c13,r8c2<>4, r7c9<>6
XY-Chain: 4 4- r7c9 -9- r2c9 -3- r2c3 -9- r1c3 -2- r6c3 -8- r8c3 -4 => r7c12,r8c9<>4
Naked Single: r8c9=6
Naked Single: r8c2=1
Naked Single: r9c8=1
Full House: r9c4=6
Full House: r7c5=1
Naked Single: r8c1=8
Full House: r8c3=4
Naked Single: r7c8=9
Full House: r7c9=4
Naked Single: r2c4=4
Full House: r4c4=1
Naked Single: r1c5=7
Full House: r2c5=6
Naked Single: r6c1=1
Naked Single: r1c8=4
Naked Single: r1c1=2
Naked Single: r2c1=7
Naked Single: r3c6=9
Full House: r1c6=1
Full House: r1c3=9
Naked Single: r3c8=3
Full House: r2c9=9
Full House: r2c3=3
Full House: r6c8=6
Naked Single: r7c1=6
Full House: r3c1=4
Full House: r7c2=2
Full House: r3c2=6
Naked Single: r4c3=2
Full House: r6c3=8
Naked Single: r6c6=3
Full House: r6c9=2
Full House: r4c9=3
Naked Single: r5c6=4
Full House: r4c6=6
Full House: r4c2=4
Full House: r5c2=3
|
normal_sudoku_527
|
..941....851...3....7..2..9.3....4.86........17..2.....1..3..2...8.5.......67..5.
|
269413785851796342347582169932165478685947213174328596516834927798251634423679851
|
Basic 9x9 Sudoku 527
|
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 1 . . . .
8 5 1 . . . 3 . .
. . 7 . . 2 . . 9
. 3 . . . . 4 . 8
6 . . . . . . . .
1 7 . . 2 . . . .
. 1 . . 3 . . 2 .
. . 8 . 5 . . . .
. . . 6 7 . . 5 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
269413785851796342347582169932165478685947213174328596516834927798251634423679851 #1 Unfair (778)
Hidden Single: r2c3=1
Hidden Single: r5c2=8
Hidden Single: r9c3=3
Hidden Single: r8c4=2
Hidden Single: r5c5=4
Hidden Single: r2c9=2
Hidden Single: r7c3=6
Hidden Single: r3c5=8
Hidden Single: r4c1=9
Naked Single: r4c5=6
Full House: r2c5=9
Naked Single: r2c4=7
Naked Single: r2c6=6
Full House: r2c8=4
Hidden Single: r6c3=4
Hidden Single: r5c7=2
Naked Single: r5c3=5
Full House: r4c3=2
Hidden Single: r7c1=5
Hidden Single: r1c8=8
Hidden Single: r8c1=7
Locked Candidates Type 1 (Pointing): 5 in b6 => r6c46<>5
Locked Candidates Type 1 (Pointing): 1 in b8 => r45c6<>1
Locked Candidates Type 2 (Claiming): 7 in c8 => r5c9<>7
XY-Chain: 6 6- r1c2 -2- r1c1 -3- r1c6 -5- r4c6 -7- r4c8 -1- r3c8 -6 => r1c79,r3c2<>6
Naked Single: r3c2=4
Naked Single: r3c1=3
Naked Single: r8c2=9
Naked Single: r1c1=2
Full House: r1c2=6
Full House: r9c2=2
Full House: r9c1=4
Naked Single: r3c4=5
Full House: r1c6=3
Naked Single: r9c9=1
Naked Single: r4c4=1
Naked Single: r5c9=3
Naked Single: r8c7=6
Naked Single: r4c8=7
Full House: r4c6=5
Naked Single: r5c4=9
Naked Single: r3c7=1
Full House: r3c8=6
Naked Single: r8c8=3
Naked Single: r8c9=4
Full House: r8c6=1
Naked Single: r5c6=7
Full House: r5c8=1
Full House: r6c8=9
Naked Single: r6c6=8
Full House: r6c4=3
Full House: r7c4=8
Naked Single: r7c9=7
Naked Single: r6c7=5
Full House: r6c9=6
Full House: r1c9=5
Full House: r1c7=7
Naked Single: r9c6=9
Full House: r7c6=4
Full House: r7c7=9
Full House: r9c7=8
|
normal_sudoku_6040
|
.....7.4..3..5.....4.2...7...7..6......52.31.51..78.92....8.76...6...2.127..1..58
|
182367549739854126645291873927136485468529317513478692351982764896745231274613958
|
Basic 9x9 Sudoku 6040
|
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 . 4 .
. 3 . . 5 . . . .
. 4 . 2 . . . 7 .
. . 7 . . 6 . . .
. . . 5 2 . 3 1 .
5 1 . . 7 8 . 9 2
. . . . 8 . 7 6 .
. . 6 . . . 2 . 1
2 7 . . 1 . . 5 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
182367549739854126645291873927136485468529317513478692351982764896745231274613958 #1 Hard (608)
Naked Single: r6c8=9
Naked Single: r4c8=8
Naked Single: r8c8=3
Full House: r2c8=2
Hidden Single: r2c1=7
Hidden Single: r5c9=7
Hidden Single: r6c7=6
Hidden Single: r4c2=2
Hidden Single: r7c6=2
Hidden Single: r8c4=7
Hidden Single: r4c4=1
Hidden Single: r9c4=6
Hidden Single: r1c3=2
Hidden Single: r8c6=5
Hidden Single: r2c9=6
Locked Candidates Type 1 (Pointing): 4 in b6 => r4c15<>4
Hidden Single: r8c5=4
Locked Candidates Type 2 (Claiming): 9 in r8 => r7c123,r9c3<>9
Naked Single: r7c2=5
Hidden Single: r3c3=5
Naked Pair: 3,4 in r69c3 => r57c3<>4, r7c3<>3
Naked Single: r7c3=1
Remote Pair: 3/4 r6c4 -4- r6c3 -3- r9c3 -4- r7c1 => r7c4<>3
Naked Single: r7c4=9
Full House: r9c6=3
Naked Single: r7c9=4
Full House: r7c1=3
Full House: r9c7=9
Full House: r9c3=4
Naked Single: r4c9=5
Full House: r4c7=4
Naked Single: r4c1=9
Full House: r4c5=3
Naked Single: r6c3=3
Full House: r6c4=4
Full House: r5c6=9
Naked Single: r5c3=8
Full House: r2c3=9
Naked Single: r8c1=8
Full House: r8c2=9
Naked Single: r2c4=8
Full House: r1c4=3
Naked Single: r3c6=1
Full House: r2c6=4
Full House: r2c7=1
Naked Single: r5c2=6
Full House: r1c2=8
Full House: r5c1=4
Naked Single: r1c9=9
Full House: r3c9=3
Naked Single: r3c1=6
Full House: r1c1=1
Naked Single: r3c7=8
Full House: r1c7=5
Full House: r1c5=6
Full House: r3c5=9
|
normal_sudoku_4848
|
..57..8....2.9....48.3....2.....93.5.5.43.92.6.....4....6.8..1..1.5..2.......7..3
|
165742839372896154489351762824619375751438926693275481236984517917563248548127693
|
Basic 9x9 Sudoku 4848
|
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 7 . . 8 . .
. . 2 . 9 . . . .
4 8 . 3 . . . . 2
. . . . . 9 3 . 5
. 5 . 4 3 . 9 2 .
6 . . . . . 4 . .
. . 6 . 8 . . 1 .
. 1 . 5 . . 2 . .
. . . . . 7 . . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
165742839372896154489351762824619375751438926693275481236984517917563248548127693 #1 Extreme (12206) bf
Brute Force: r5c7=9
Locked Candidates Type 1 (Pointing): 1 in b6 => r12c9<>1
Hidden Pair: 3,9 in r6c23 => r6c2<>2, r6c23<>7, r6c3<>1, r6c3<>8
Locked Candidates Type 1 (Pointing): 2 in b4 => r4c45<>2
Finned Franken Swordfish: 6 c47b6 r249 fr3c7 fr5c9 => r2c9<>6
Almost Locked Set XY-Wing: A=r1c1289 {13469}, B=r3c567 {1567}, C=r2c9 {47}, X,Y=4,7, Z=1 => r3c3<>1
Locked Candidates Type 1 (Pointing): 1 in b1 => r45c1<>1
Almost Locked Set XY-Wing: A=r6c23489 {123789}, B=r27c9 {479}, C=r7c4 {29}, X,Y=2,9, Z=7 => r5c9<>7
Locked Candidates Type 2 (Claiming): 7 in r5 => r4c123<>7
Finned X-Wing: 7 c27 r27 fr3c7 => r2c89<>7
Naked Single: r2c9=4
Naked Triple: 3,6,9 in r1c289 => r1c1<>3, r1c1<>9, r1c56<>6
Naked Single: r1c1=1
Locked Candidates Type 2 (Claiming): 9 in c1 => r79c2,r89c3<>9
Naked Pair: 2,4 in r49c2 => r7c2<>2, r7c2<>4
Hidden Single: r7c6=4
Naked Single: r1c6=2
Naked Single: r8c5=6
Naked Single: r1c5=4
Naked Single: r8c6=3
Hidden Single: r6c3=3
Naked Single: r6c2=9
Hidden Single: r3c3=9
Locked Candidates Type 1 (Pointing): 7 in b1 => r2c7<>7
Hidden Rectangle: 4/8 in r8c38,r9c38 => r8c8<>8
Sashimi X-Wing: 6 r35 c69 fr3c7 fr3c8 => r1c9<>6
Naked Single: r1c9=9
Naked Single: r7c9=7
Naked Single: r7c2=3
Naked Single: r7c7=5
Naked Single: r8c9=8
Naked Single: r1c2=6
Full House: r1c8=3
Naked Single: r9c7=6
Naked Single: r6c9=1
Full House: r5c9=6
Naked Single: r2c2=7
Full House: r2c1=3
Naked Single: r2c7=1
Full House: r3c7=7
Hidden Single: r9c1=5
Hidden Single: r4c4=6
Naked Single: r2c4=8
Naked Single: r6c4=2
Naked Single: r7c4=9
Full House: r7c1=2
Full House: r9c4=1
Full House: r9c5=2
Naked Single: r4c1=8
Naked Single: r9c2=4
Full House: r4c2=2
Naked Single: r4c8=7
Full House: r6c8=8
Naked Single: r5c1=7
Full House: r8c1=9
Naked Single: r8c3=7
Full House: r9c3=8
Full House: r9c8=9
Full House: r8c8=4
Naked Single: r4c5=1
Full House: r4c3=4
Full House: r5c3=1
Full House: r5c6=8
Naked Single: r6c6=5
Full House: r6c5=7
Full House: r3c5=5
Naked Single: r2c6=6
Full House: r2c8=5
Full House: r3c8=6
Full House: r3c6=1
|
normal_sudoku_1961
|
1.7......2...1.4.6.9......88.37..259....8......41..6......7............46328.5...
|
147658932258319476396427518813764259769582143524193687481976325975231864632845791
|
Basic 9x9 Sudoku 1961
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
1 . 7 . . . . . .
2 . . . 1 . 4 . 6
. 9 . . . . . . 8
8 . 3 7 . . 2 5 9
. . . . 8 . . . .
. . 4 1 . . 6 . .
. . . . 7 . . . .
. . . . . . . . 4
6 3 2 8 . 5 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
147658932258319476396427518813764259769582143524193687481976325975231864632845791 #1 Medium (448)
Naked Single: r4c1=8
Hidden Single: r4c2=1
Hidden Single: r6c8=8
Hidden Single: r5c8=4
Hidden Single: r3c1=3
Hidden Single: r9c5=4
Naked Single: r4c5=6
Full House: r4c6=4
Hidden Single: r7c1=4
Hidden Single: r1c2=4
Hidden Single: r3c4=4
Hidden Single: r5c2=6
Hidden Single: r3c3=6
Hidden Single: r1c6=8
Hidden Single: r6c2=2
Hidden Single: r1c4=6
Hidden Single: r8c2=7
Locked Candidates Type 1 (Pointing): 5 in b1 => r2c4<>5
Hidden Single: r5c4=5
Naked Single: r5c3=9
Naked Single: r5c1=7
Full House: r6c1=5
Full House: r8c1=9
Hidden Single: r5c6=2
Naked Single: r3c6=7
Hidden Single: r6c9=7
Naked Single: r9c9=1
Naked Single: r5c9=3
Full House: r5c7=1
Naked Single: r3c7=5
Naked Single: r1c9=2
Full House: r7c9=5
Naked Single: r3c5=2
Full House: r3c8=1
Naked Single: r7c2=8
Full House: r2c2=5
Full House: r2c3=8
Naked Single: r8c5=3
Naked Single: r7c3=1
Full House: r8c3=5
Naked Single: r6c5=9
Full House: r1c5=5
Full House: r6c6=3
Naked Single: r8c4=2
Naked Single: r8c7=8
Naked Single: r2c6=9
Full House: r2c4=3
Full House: r7c4=9
Full House: r2c8=7
Naked Single: r8c8=6
Full House: r8c6=1
Full House: r7c6=6
Naked Single: r7c7=3
Full House: r7c8=2
Naked Single: r9c8=9
Full House: r1c8=3
Full House: r1c7=9
Full House: r9c7=7
|
normal_sudoku_5254
|
.....63..53.789.2...2.....92...7..6...32.......4..5....48.1...6.9.8..1..12..47.8.
|
987426315531789624462531879259378461813264597674195238348912756796853142125647983
|
Basic 9x9 Sudoku 5254
|
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 3 . 7 8 9 . 2 .
. . 2 . . . . . 9
2 . . . 7 . . 6 .
. . 3 2 . . . . .
. . 4 . . 5 . . .
. 4 8 . 1 . . . 6
. 9 . 8 . . 1 . .
1 2 . . 4 7 . 8 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
987426315531789624462531879259378461813264597674195238348912756796853142125647983 #1 Medium (372)
Hidden Single: r2c2=3
Hidden Single: r1c5=2
Locked Pair: 2,3 in r78c6 => r34c6,r79c4,r8c5<>3
Hidden Single: r9c9=3
Hidden Single: r4c4=3
Hidden Single: r6c8=3
Hidden Single: r3c5=3
Hidden Single: r8c5=5
Naked Single: r7c4=9
Naked Single: r9c4=6
Naked Single: r6c4=1
Naked Single: r9c3=5
Full House: r9c7=9
Hidden Single: r5c8=9
Naked Single: r5c5=6
Full House: r6c5=9
Hidden Single: r3c6=1
Hidden Single: r4c3=9
Hidden Single: r1c1=9
Hidden Single: r1c8=1
Naked Single: r1c3=7
Naked Single: r2c9=4
Naked Single: r1c2=8
Naked Single: r8c3=6
Full House: r2c3=1
Full House: r2c7=6
Naked Single: r1c9=5
Full House: r1c4=4
Full House: r3c4=5
Naked Single: r3c2=6
Full House: r3c1=4
Naked Single: r3c8=7
Full House: r3c7=8
Naked Single: r6c2=7
Naked Single: r7c8=5
Full House: r8c8=4
Naked Single: r5c1=8
Naked Single: r6c7=2
Naked Single: r5c6=4
Full House: r4c6=8
Naked Single: r6c1=6
Full House: r6c9=8
Naked Single: r7c7=7
Full House: r8c9=2
Naked Single: r4c9=1
Full House: r5c9=7
Naked Single: r5c7=5
Full House: r4c7=4
Full House: r4c2=5
Full House: r5c2=1
Naked Single: r7c1=3
Full House: r7c6=2
Full House: r8c6=3
Full House: r8c1=7
|
normal_sudoku_4514
|
6.13...5.....261.3..7.1.6.......2...274..3...8531....6....9...55.826.3...4.....8.
|
621347859485926173937815624169452738274683591853179246312798465598264317746531982
|
Basic 9x9 Sudoku 4514
|
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 3 . . . 5 .
. . . . 2 6 1 . 3
. . 7 . 1 . 6 . .
. . . . . 2 . . .
2 7 4 . . 3 . . .
8 5 3 1 . . . . 6
. . . . 9 . . . 5
5 . 8 2 6 . 3 . .
. 4 . . . . . 8 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
621347859485926173937815624169452738274683591853179246312798465598264317746531982 #1 Extreme (4428)
Hidden Single: r5c1=2
Hidden Single: r2c3=5
Hidden Single: r5c4=6
Hidden Single: r9c5=3
Hidden Single: r4c8=3
Hidden Single: r9c3=6
Naked Single: r4c3=9
Full House: r7c3=2
Naked Single: r4c1=1
Full House: r4c2=6
Hidden Single: r7c8=6
Hidden Single: r6c6=9
Locked Candidates Type 2 (Claiming): 5 in c5 => r4c4<>5
Hidden Rectangle: 5/8 in r4c57,r5c57 => r4c7<>8
Sue de Coq: r8c89 - {1479} (r8c2 - {19}, r7c7 - {47}) => r9c79<>7, r8c6<>1
Discontinuous Nice Loop: 2 r1c7 -2- r1c2 =2= r3c2 =3= r3c1 -3- r7c1 -7- r9c1 -9- r9c7 -2- r1c7 => r1c7<>2
Discontinuous Nice Loop: 8 r1c2 -8- r2c2 =8= r2c4 -8- r7c4 =8= r7c6 =1= r7c2 =3= r3c2 =2= r1c2 => r1c2<>8
Discontinuous Nice Loop: 9 r2c2 -9- r8c2 -1- r7c2 =1= r7c6 =8= r7c4 -8- r2c4 =8= r2c2 => r2c2<>9
Naked Single: r2c2=8
Discontinuous Nice Loop: 4 r3c6 -4- r8c6 -7- r9c4 -5- r9c6 =5= r3c6 => r3c6<>4
Forcing Chain Contradiction in r8c8 => r3c8<>9
r3c8=9 r5c8<>9 r5c8=1 r8c8<>1
r3c8=9 r1c79<>9 r1c2=9 r8c2<>9 r9c1=9 r9c1<>7 r7c1=7 r7c7<>7 r7c7=4 r8c8<>4
r3c8=9 r3c4<>9 r2c4=9 r2c4<>7 r2c8=7 r8c8<>7
r3c8=9 r8c8<>9
Forcing Chain Contradiction in r1 => r1c9<>4
r1c9=4 r1c9<>2 r1c2=2 r1c2<>9
r1c9=4 r3c8<>4 r3c8=2 r6c8<>2 r6c7=2 r9c7<>2 r9c7=9 r1c7<>9
r1c9=4 r1c9<>9
Forcing Chain Verity => r6c7<>7
r1c5=4 r6c5<>4 r6c5=7 r6c7<>7
r1c6=4 r8c6<>4 r8c6=7 r8c89<>7 r7c7=7 r6c7<>7
r1c7=4 r7c7<>4 r7c7=7 r6c7<>7
Skyscraper: 7 in r2c4,r6c5 (connected by r26c8) => r1c5,r4c4<>7
XY-Chain: 9 9- r8c2 -1- r7c2 -3- r7c1 -7- r7c7 -4- r6c7 -2- r9c7 -9 => r8c89,r9c1<>9
Naked Single: r9c1=7
Naked Single: r7c1=3
Naked Single: r9c4=5
Naked Single: r7c2=1
Full House: r8c2=9
Naked Single: r9c6=1
Naked Single: r1c2=2
Full House: r3c2=3
Hidden Single: r3c6=5
Locked Candidates Type 2 (Claiming): 9 in r1 => r2c8,r3c9<>9
Hidden Single: r5c8=9
Hidden Single: r5c9=1
Hidden Single: r8c8=1
W-Wing: 4/7 in r2c8,r7c7 connected by 7 in r27c4 => r1c7<>4
Locked Candidates Type 2 (Claiming): 4 in r1 => r23c4<>4
2-String Kite: 4 in r4c4,r8c9 (connected by r7c4,r8c6) => r4c9<>4
W-Wing: 7/4 in r2c8,r7c7 connected by 4 in r38c9 => r1c7<>7
X-Wing: 7 r18 c69 => r4c9,r7c6<>7
Naked Single: r4c9=8
Naked Single: r4c4=4
Naked Single: r5c7=5
Full House: r5c5=8
Naked Single: r6c5=7
Full House: r4c5=5
Full House: r4c7=7
Full House: r1c5=4
Naked Single: r7c7=4
Naked Single: r6c7=2
Full House: r6c8=4
Naked Single: r7c6=8
Full House: r7c4=7
Full House: r8c6=4
Full House: r8c9=7
Full House: r1c6=7
Naked Single: r9c7=9
Full House: r1c7=8
Full House: r1c9=9
Full House: r9c9=2
Full House: r3c9=4
Naked Single: r2c8=7
Full House: r3c8=2
Naked Single: r2c4=9
Full House: r2c1=4
Full House: r3c1=9
Full House: r3c4=8
|
normal_sudoku_608
|
..2..154..54.7............32..548.6..4621.......6...5...9.....6.37......68.7294..
|
762381549354976812918452673293548167546217398871693254429135786137864925685729431
|
Basic 9x9 Sudoku 608
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 2 . . 1 5 4 .
. 5 4 . 7 . . . .
. . . . . . . . 3
2 . . 5 4 8 . 6 .
. 4 6 2 1 . . . .
. . . 6 . . . 5 .
. . 9 . . . . . 6
. 3 7 . . . . . .
6 8 . 7 2 9 4 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
762381549354976812918452673293548167546217398871693254429135786137864925685729431 #1 Easy (352)
Hidden Single: r5c3=6
Hidden Single: r7c2=2
Hidden Single: r6c5=9
Hidden Single: r6c9=4
Hidden Single: r9c8=3
Hidden Single: r5c1=5
Hidden Single: r9c3=5
Full House: r9c9=1
Hidden Single: r6c7=2
Hidden Single: r4c2=9
Naked Single: r4c9=7
Hidden Single: r8c9=5
Hidden Single: r4c7=1
Full House: r4c3=3
Hidden Single: r5c6=7
Full House: r6c6=3
Hidden Single: r8c8=2
Hidden Single: r2c9=2
Naked Single: r2c6=6
Naked Single: r8c6=4
Naked Single: r7c6=5
Full House: r3c6=2
Naked Single: r8c1=1
Full House: r7c1=4
Naked Single: r8c4=8
Naked Single: r7c5=3
Naked Single: r8c5=6
Full House: r8c7=9
Full House: r7c4=1
Naked Single: r1c5=8
Full House: r3c5=5
Naked Single: r2c7=8
Naked Single: r1c9=9
Full House: r5c9=8
Naked Single: r5c7=3
Full House: r5c8=9
Naked Single: r7c7=7
Full House: r3c7=6
Full House: r7c8=8
Naked Single: r1c4=3
Naked Single: r2c8=1
Full House: r3c8=7
Naked Single: r1c1=7
Full House: r1c2=6
Naked Single: r2c4=9
Full House: r2c1=3
Full House: r3c4=4
Naked Single: r3c2=1
Full House: r6c2=7
Naked Single: r6c1=8
Full House: r3c1=9
Full House: r3c3=8
Full House: r6c3=1
|
normal_sudoku_4983
|
.....5..4...39.5...7.4...3.183.....54.7...38..56....475....6..3.3.1...2.6.2..47.8
|
391625874864397512275481639183742965427569381956813247548276193739158426612934758
|
Basic 9x9 Sudoku 4983
|
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 . . 4
. . . 3 9 . 5 . .
. 7 . 4 . . . 3 .
1 8 3 . . . . . 5
4 . 7 . . . 3 8 .
. 5 6 . . . . 4 7
5 . . . . 6 . . 3
. 3 . 1 . . . 2 .
6 . 2 . . 4 7 . 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
391625874864397512275481639183742965427569381956813247548276193739158426612934758 #1 Unfair (1474)
Hidden Single: r5c3=7
Hidden Single: r3c3=5
Hidden Single: r1c1=3
Hidden Single: r8c5=5
Naked Single: r9c4=9
Naked Single: r9c5=3
Naked Single: r9c2=1
Full House: r9c8=5
Hidden Single: r8c1=7
Naked Single: r8c6=8
Hidden Single: r4c5=4
Hidden Single: r6c6=3
Hidden Single: r5c4=5
Hidden Single: r7c3=8
Hidden Single: r2c1=8
Swordfish: 6 r358 c579 => r1c57,r2c9,r4c7<>6
Empty Rectangle: 9 in b1 (r6c17) => r1c7<>9
W-Wing: 1/9 in r1c3,r7c8 connected by 9 in r7c2,r8c3 => r1c8<>1
W-Wing: 2/9 in r3c1,r4c7 connected by 9 in r6c17 => r3c7<>2
W-Wing: 2/9 in r4c7,r5c2 connected by 9 in r6c17 => r5c9<>2
Locked Candidates Type 1 (Pointing): 2 in b6 => r1c7<>2
XY-Wing: 2/9/1 in r1c3,r3c16 => r1c5<>1
Finned Swordfish: 2 r157 c245 fr5c6 => r46c4,r6c5<>2
Naked Single: r6c4=8
Naked Single: r6c5=1
Hidden Single: r5c9=1
Naked Single: r2c9=2
Hidden Single: r5c5=6
Naked Single: r4c4=7
Naked Single: r7c4=2
Full House: r1c4=6
Full House: r7c5=7
Hidden Single: r4c8=6
Hidden Single: r2c6=7
Naked Single: r2c8=1
Naked Single: r1c7=8
Naked Single: r2c3=4
Full House: r2c2=6
Naked Single: r7c8=9
Full House: r1c8=7
Naked Single: r1c5=2
Full House: r3c5=8
Full House: r3c6=1
Naked Single: r8c3=9
Full House: r7c2=4
Full House: r1c3=1
Full House: r1c2=9
Full House: r7c7=1
Full House: r3c1=2
Full House: r5c2=2
Full House: r6c1=9
Full House: r5c6=9
Full House: r6c7=2
Full House: r4c6=2
Full House: r4c7=9
Naked Single: r8c9=6
Full House: r3c9=9
Full House: r3c7=6
Full House: r8c7=4
|
normal_sudoku_4843
|
...1...6.9.5.....41.......221.8.745.4......2...6..41...2...169.59...2....3.4....5
|
342158967965723814187946532213897456479615328856234179724581693598362741631479285
|
Basic 9x9 Sudoku 4843
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . 1 . . . 6 .
9 . 5 . . . . . 4
1 . . . . . . . 2
2 1 . 8 . 7 4 5 .
4 . . . . . . 2 .
. . 6 . . 4 1 . .
. 2 . . . 1 6 9 .
5 9 . . . 2 . . .
. 3 . 4 . . . . 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
342158967965723814187946532213897456479615328856234179724581693598362741631479285 #1 Extreme (3212)
Hidden Single: r4c7=4
Hidden Single: r2c8=1
Hidden Single: r1c3=2
Hidden Single: r5c5=1
Hidden Single: r9c1=6
Hidden Single: r9c7=2
Hidden Single: r7c3=4
Hidden Single: r8c8=4
Hidden Single: r8c9=1
Hidden Single: r9c3=1
Skyscraper: 3 in r1c1,r3c8 (connected by r6c18) => r1c79,r3c3<>3
Hidden Single: r1c1=3
Naked Pair: 7,8 in r38c3 => r5c3<>7, r5c3<>8
Forcing Chain Contradiction in c8 => r3c5<>8
r3c5=8 r3c8<>8
r3c5=8 r3c3<>8 r8c3=8 r7c1<>8 r6c1=8 r6c8<>8
r3c5=8 r789c5<>8 r9c6=8 r9c8<>8
Forcing Chain Contradiction in r8c7 => r3c8<>7
r3c8=7 r3c8<>3 r23c7=3 r8c7<>3
r3c8=7 r3c3<>7 r8c3=7 r8c7<>7
r3c8=7 r9c8<>7 r9c8=8 r8c7<>8
Skyscraper: 7 in r7c1,r9c8 (connected by r6c18) => r7c9<>7
Grouped Discontinuous Nice Loop: 8 r8c5 -8- r8c3 -7- r8c7 =7= r9c8 =8= r9c56 -8- r8c5 => r8c5<>8
Almost Locked Set XY-Wing: A=r6c18 {378}, B=r123c2 {4678}, C=r3c38 {378}, X,Y=3,7, Z=8 => r6c2<>8
Forcing Chain Contradiction in r8c7 => r3c8=3
r3c8<>3 r23c7=3 r8c7<>3
r3c8<>3 r3c8=8 r9c8<>8 r9c8=7 r8c7<>7
r3c8<>3 r3c8=8 r3c3<>8 r8c3=8 r8c7<>8
Naked Pair: 7,8 in r6c18 => r6c29<>7, r6c9<>8
Naked Single: r6c2=5
Remote Pair: 8/7 r7c1 -7- r6c1 -8- r6c8 -7- r9c8 => r7c9<>8
Naked Single: r7c9=3
Naked Single: r6c9=9
Naked Single: r4c9=6
Hidden Single: r5c7=3
Naked Single: r5c3=9
Naked Single: r4c3=3
Full House: r4c5=9
Hidden Single: r2c6=3
Hidden Single: r3c4=9
Hidden Single: r9c6=9
Hidden Single: r1c7=9
Hidden Single: r3c7=5
Locked Candidates Type 1 (Pointing): 8 in b8 => r12c5<>8
Naked Pair: 7,8 in r8c37 => r8c45<>7
Remote Pair: 7/8 r2c7 -8- r1c9 -7- r5c9 -8- r5c2 -7- r6c1 -8- r6c8 -7- r9c8 -8- r9c5 => r2c25<>7, r2c2<>8
Naked Single: r2c2=6
Naked Single: r2c5=2
Naked Single: r2c4=7
Full House: r2c7=8
Full House: r1c9=7
Full House: r8c7=7
Full House: r5c9=8
Full House: r9c8=8
Full House: r6c8=7
Full House: r9c5=7
Naked Single: r6c5=3
Naked Single: r7c4=5
Naked Single: r8c3=8
Full House: r3c3=7
Full House: r7c1=7
Full House: r6c1=8
Full House: r5c2=7
Full House: r6c4=2
Full House: r7c5=8
Naked Single: r8c5=6
Full House: r8c4=3
Full House: r5c4=6
Full House: r5c6=5
Naked Single: r3c5=4
Full House: r1c5=5
Naked Single: r1c6=8
Full House: r1c2=4
Full House: r3c2=8
Full House: r3c6=6
|
normal_sudoku_4051
|
...34..6.............7.1...26....5.8.45.6.12.8.1....46..6.1......82.5.1..5....2.4
|
587342961914856372632791485263174598745968123891523746326419857478235619159687234
|
Basic 9x9 Sudoku 4051
|
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 4 . . 6 .
. . . . . . . . .
. . . 7 . 1 . . .
2 6 . . . . 5 . 8
. 4 5 . 6 . 1 2 .
8 . 1 . . . . 4 6
. . 6 . 1 . . . .
. . 8 2 . 5 . 1 .
. 5 . . . . 2 . 4
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
587342961914856372632791485263174598745968123891523746326419857478235619159687234 #1 Extreme (14512) bf
Hidden Single: r4c2=6
Hidden Single: r4c4=1
Hidden Single: r8c7=6
Hidden Single: r9c1=1
Hidden Single: r7c2=2
Hidden Single: r8c1=4
Hidden Single: r3c1=6
Hidden Single: r4c6=4
Hidden Single: r7c4=4
Brute Force: r4c8=9
Finned Franken Swordfish: 3 r48b6 c259 fr4c3 fr6c7 => r6c2<>3
W-Wing: 7/3 in r4c5,r5c9 connected by 3 in r4c3,r5c1 => r5c6<>7
Sashimi Swordfish: 7 r458 c259 fr4c3 fr5c1 => r6c2<>7
Naked Single: r6c2=9
Naked Single: r6c4=5
Naked Pair: 3,7 in r5c19 => r5c6<>3
Forcing Chain Contradiction in r3 => r1c9<>9
r1c9=9 r8c9<>9 r8c5=9 r9c456<>9 r9c3=9 r3c3<>9
r1c9=9 r8c9<>9 r8c5=9 r3c5<>9
r1c9=9 r3c7<>9
r1c9=9 r3c9<>9
Forcing Chain Contradiction in c1 => r2c9<>9
r2c9=9 r2c9<>1 r1c9=1 r1c9<>5 r1c1=5 r1c1<>9
r2c9=9 r2c1<>9
r2c9=9 r8c9<>9 r7c79=9 r7c1<>9
Forcing Chain Contradiction in r7c1 => r8c9<>3
r8c9=3 r5c9<>3 r5c1=3 r7c1<>3
r8c9=3 r8c2<>3 r8c2=7 r7c1<>7
r8c9=3 r8c9<>9 r7c79=9 r7c1<>9
Skyscraper: 3 in r4c3,r8c2 (connected by r48c5) => r9c3<>3
Grouped Discontinuous Nice Loop: 7 r1c1 -7- r5c1 -3- r7c1 =3= r8c2 =7= r12c2 -7- r1c1 => r1c1<>7
Grouped Discontinuous Nice Loop: 7 r2c1 -7- r5c1 -3- r7c1 =3= r8c2 =7= r12c2 -7- r2c1 => r2c1<>7
Turbot Fish: 7 r6c7 =7= r5c9 -7- r5c1 =7= r7c1 => r7c7<>7
Almost Locked Set XY-Wing: A=r6c7 {37}, B=r48c5 {379}, C=r58c9 {379}, X,Y=3,9, Z=7 => r6c5<>7
Forcing Chain Contradiction in r7c1 => r8c9=9
r8c9<>9 r8c9=7 r8c2<>7 r8c2=3 r7c1<>3
r8c9<>9 r8c9=7 r5c9<>7 r5c1=7 r7c1<>7
r8c9<>9 r7c79=9 r7c1<>9
Naked Pair: 3,7 in r48c5 => r69c5<>3, r9c5<>7
Naked Single: r6c5=2
Remote Pair: 7/3 r4c3 -3- r4c5 -7- r8c5 -3- r8c2 => r9c3<>7
Naked Single: r9c3=9
Naked Single: r9c5=8
Naked Single: r9c4=6
Hidden Single: r7c6=9
Naked Single: r5c6=8
Naked Single: r1c6=2
Naked Single: r5c4=9
Full House: r2c4=8
Naked Single: r1c3=7
Naked Single: r2c6=6
Naked Single: r4c3=3
Full House: r4c5=7
Full House: r5c1=7
Full House: r6c6=3
Full House: r5c9=3
Full House: r6c7=7
Full House: r9c6=7
Full House: r8c5=3
Full House: r9c8=3
Full House: r8c2=7
Full House: r7c1=3
Naked Single: r7c7=8
Naked Single: r1c7=9
Naked Single: r1c1=5
Full House: r2c1=9
Naked Single: r1c9=1
Full House: r1c2=8
Naked Single: r2c5=5
Full House: r3c5=9
Naked Single: r3c2=3
Full House: r2c2=1
Naked Single: r2c8=7
Naked Single: r3c7=4
Full House: r2c7=3
Naked Single: r2c9=2
Full House: r2c3=4
Full House: r3c3=2
Naked Single: r7c8=5
Full House: r3c8=8
Full House: r3c9=5
Full House: r7c9=7
|
normal_sudoku_1836
|
..5.6...82....7.639.......449.6.....1.....38.36.8759..5...1........9.......2.8...
|
745163298281947563936582174498631752157429386362875941574316829823794615619258437
|
Basic 9x9 Sudoku 1836
|
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 . 6 . . . 8
2 . . . . 7 . 6 3
9 . . . . . . . 4
4 9 . 6 . . . . .
1 . . . . . 3 8 .
3 6 . 8 7 5 9 . .
5 . . . 1 . . . .
. . . . 9 . . . .
. . . 2 . 8 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
745163298281947563936582174498631752157429386362875941574316829823794615619258437 #1 Easy (314)
Naked Single: r6c1=3
Naked Single: r1c1=7
Naked Single: r6c3=2
Naked Single: r9c1=6
Full House: r8c1=8
Naked Single: r5c3=7
Naked Single: r6c9=1
Full House: r6c8=4
Naked Single: r4c3=8
Full House: r5c2=5
Hidden Single: r3c3=6
Hidden Single: r5c9=6
Hidden Single: r1c8=9
Hidden Single: r4c6=1
Hidden Single: r2c4=9
Naked Single: r5c4=4
Naked Single: r5c5=2
Full House: r5c6=9
Full House: r4c5=3
Hidden Single: r7c7=8
Hidden Single: r7c6=6
Hidden Single: r8c7=6
Hidden Single: r9c7=4
Naked Single: r9c5=5
Naked Single: r3c5=8
Full House: r2c5=4
Naked Single: r2c3=1
Naked Single: r2c2=8
Full House: r2c7=5
Naked Single: r3c2=3
Full House: r1c2=4
Naked Single: r3c6=2
Naked Single: r1c6=3
Full House: r8c6=4
Naked Single: r1c4=1
Full House: r1c7=2
Full House: r3c4=5
Naked Single: r8c3=3
Naked Single: r4c7=7
Full House: r3c7=1
Full House: r3c8=7
Naked Single: r8c4=7
Full House: r7c4=3
Naked Single: r9c3=9
Full House: r7c3=4
Naked Single: r7c8=2
Naked Single: r9c9=7
Naked Single: r4c8=5
Full House: r4c9=2
Naked Single: r7c2=7
Full House: r7c9=9
Full House: r8c9=5
Naked Single: r9c2=1
Full House: r8c2=2
Full House: r8c8=1
Full House: r9c8=3
|
normal_sudoku_283
|
4.2........54.68.......15..9..5...2..57.....62.48.39.7.26..........8426...9.2..3.
|
472958613195436872683271594968547321357192486214863957826319745531784269749625138
|
Basic 9x9 Sudoku 283
|
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 . . . . . .
. . 5 4 . 6 8 . .
. . . . . 1 5 . .
9 . . 5 . . . 2 .
. 5 7 . . . . . 6
2 . 4 8 . 3 9 . 7
. 2 6 . . . . . .
. . . . 8 4 2 6 .
. . 9 . 2 . . 3 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
472958613195436872683271594968547321357192486214863957826319745531784269749625138 #1 Extreme (3002)
Naked Single: r6c6=3
Naked Single: r4c6=7
Naked Single: r9c6=5
Naked Single: r7c6=9
Naked Single: r1c6=8
Full House: r5c6=2
Hidden Single: r6c8=5
Hidden Single: r3c1=6
Hidden Single: r9c2=4
Hidden Single: r1c7=6
Hidden Single: r9c4=6
Hidden Single: r2c9=2
Hidden Single: r3c4=2
Hidden Single: r1c5=5
Hidden Single: r8c9=9
Hidden Single: r8c1=5
Hidden Single: r7c9=5
Locked Candidates Type 1 (Pointing): 3 in b3 => r4c9<>3
Locked Candidates Type 1 (Pointing): 7 in b3 => r7c8<>7
Locked Candidates Type 1 (Pointing): 8 in b7 => r5c1<>8
Hidden Single: r5c8=8
Hidden Single: r9c9=8
Hidden Single: r7c1=8
Locked Candidates Type 1 (Pointing): 3 in b7 => r8c4<>3
2-String Kite: 1 in r4c3,r9c7 (connected by r8c3,r9c1) => r4c7<>1
Uniqueness Test 4: 1/6 in r4c25,r6c25 => r4c25<>1
Hidden Rectangle: 3/8 in r3c23,r4c23 => r4c2<>3
Multi Colors 1: 1 (r1c9,r4c3,r5c7) / (r4c9,r8c3), (r9c1) / (r9c7) => r7c7,r8c2<>1
Discontinuous Nice Loop: 3 r3c2 -3- r3c9 -4- r4c9 -1- r4c3 =1= r8c3 =3= r8c2 -3- r3c2 => r3c2<>3
Discontinuous Nice Loop: 1 r7c4 -1- r7c8 -4- r3c8 =4= r3c9 =3= r1c9 -3- r1c4 =3= r7c4 => r7c4<>1
Skyscraper: 1 in r4c3,r5c4 (connected by r8c34) => r5c1<>1
Naked Single: r5c1=3
Hidden Single: r4c7=3
2-String Kite: 1 in r5c7,r7c5 (connected by r7c8,r9c7) => r5c5<>1
Turbot Fish: 1 r1c9 =1= r4c9 -1- r4c3 =1= r6c2 => r1c2<>1
Locked Candidates Type 1 (Pointing): 1 in b1 => r2c8<>1
XY-Chain: 9 9- r2c8 -7- r2c1 -1- r9c1 -7- r9c7 -1- r5c7 -4- r5c5 -9 => r2c5<>9
W-Wing: 3/7 in r2c5,r8c2 connected by 7 in r29c1 => r2c2<>3
Hidden Single: r2c5=3
Hidden Single: r7c4=3
2-String Kite: 7 in r3c5,r8c2 (connected by r7c5,r8c4) => r3c2<>7
W-Wing: 9/7 in r1c4,r2c8 connected by 7 in r3c58 => r1c8<>9
W-Wing: 1/7 in r1c8,r7c5 connected by 7 in r3c58 => r7c8<>1
Naked Single: r7c8=4
Naked Single: r7c7=7
Full House: r7c5=1
Full House: r9c7=1
Full House: r8c4=7
Full House: r5c7=4
Full House: r9c1=7
Full House: r4c9=1
Full House: r2c1=1
Naked Single: r6c5=6
Full House: r6c2=1
Naked Single: r1c4=9
Full House: r3c5=7
Full House: r5c4=1
Full House: r5c5=9
Full House: r4c5=4
Naked Single: r8c2=3
Full House: r8c3=1
Naked Single: r1c9=3
Full House: r3c9=4
Naked Single: r4c3=8
Full House: r3c3=3
Full House: r4c2=6
Naked Single: r3c8=9
Full House: r3c2=8
Naked Single: r1c2=7
Full House: r1c8=1
Full House: r2c8=7
Full House: r2c2=9
|
normal_sudoku_3910
|
..6.79.5.1.95.3...7..16...3....3......7...38...37...419.5.1.67..61......3.......5
|
436279158129583467758164923542831796617945382893726541985312674261457839374698215
|
Basic 9x9 Sudoku 3910
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 6 . 7 9 . 5 .
1 . 9 5 . 3 . . .
7 . . 1 6 . . . 3
. . . . 3 . . . .
. . 7 . . . 3 8 .
. . 3 7 . . . 4 1
9 . 5 . 1 . 6 7 .
. 6 1 . . . . . .
3 . . . . . . . 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
436279158129583467758164923542831796617945382893726541985312674261457839374698215 #1 Extreme (33130) bf
Hidden Single: r5c7=3
Hidden Single: r1c7=1
Hidden Single: r3c2=5
Hidden Single: r8c6=7
Hidden Single: r9c2=7
Hidden Single: r9c8=1
Hidden Single: r1c2=3
Hidden Single: r7c4=3
Hidden Single: r8c8=3
Hidden Single: r8c5=5
Brute Force: r5c2=1
Hidden Single: r4c6=1
Brute Force: r5c4=9
Hidden Single: r9c5=9
Forcing Net Contradiction in c2 => r4c4<>2
r4c4=2 (r5c5<>2) r6c5<>2 r2c5=2 r2c2<>2
r4c4=2 r4c2<>2
r4c4=2 (r4c8<>2) (r5c5<>2) r6c5<>2 r2c5=2 r2c8<>2 r2c8=6 r4c8<>6 r4c8=9 r6c7<>9 r6c2=9 r6c2<>2
r4c4=2 (r4c3<>2) (r4c8<>2) (r5c5<>2) r6c5<>2 r2c5=2 r2c8<>2 r3c8=2 r3c3<>2 r9c3=2 r7c2<>2
Forcing Net Contradiction in r8c7 => r4c7<>2
r4c7=2 (r4c7<>5 r4c1=5 r4c1<>6 r4c4=6 r4c4<>4 r5c5=4 r5c1<>4) (r4c7<>5 r4c1=5 r5c1<>5) (r4c7<>5 r4c1=5 r5c1<>5 r5c6=5 r5c6<>2) (r4c7<>5 r4c1=5 r4c1<>6 r4c4=6 r9c4<>6 r9c6=6 r9c6<>2) (r4c9<>2) (r5c9<>2) (r4c7<>7 r4c9=7 r4c9<>9 r8c9=9 r8c9<>2) (r4c8<>2) r5c9<>2 r5c9=6 (r2c9<>6 r2c8=6 r2c8<>2) r4c8<>6 r4c8=9 r3c8<>9 r3c8=2 (r3c6<>2) (r1c9<>2) r2c9<>2 r7c9=2 r7c6<>2 r6c6=2 r6c6<>6 r6c1=6 r5c1<>6 r5c1=2 (r8c1<>2 r8c4=2 r1c4<>2) r1c1<>2 r1c9=2 r3c8<>2 r4c8=2 r4c7<>2
Forcing Net Contradiction in r8c7 => r6c1<>2
r6c1=2 (r6c5<>2 r6c5=8 r4c4<>8) r6c1<>6 r6c6=6 (r6c6<>5) (r4c4<>6) r4c4<>6 r4c4=4 r5c5<>4 r5c5=2 r5c9<>2 r5c9=6 (r4c8<>6) r4c9<>6 r4c1=6 r4c1<>5 r4c7=5 r6c7<>5 r6c1=5 r6c1<>2
Brute Force: r5c1=6
Naked Single: r5c9=2
Naked Single: r5c5=4
Full House: r5c6=5
Hidden Single: r6c6=6
Naked Single: r4c4=8
Full House: r6c5=2
Full House: r2c5=8
Hidden Single: r9c4=6
Locked Candidates Type 1 (Pointing): 2 in b9 => r23c7<>2
Naked Pair: 4,8 in r17c9 => r28c9<>4, r8c9<>8
Naked Single: r8c9=9
Skyscraper: 8 in r1c9,r8c7 (connected by r18c1) => r3c7,r7c9<>8
Naked Single: r7c9=4
Naked Single: r1c9=8
Hidden Single: r3c3=8
X-Wing: 4 r18 c14 => r4c1<>4
Swordfish: 2 r237 c268 => r4c2,r9c6<>2
W-Wing: 2/4 in r1c1,r4c3 connected by 4 in r24c2 => r4c1<>2
Naked Single: r4c1=5
Naked Single: r6c1=8
Naked Single: r6c2=9
Full House: r6c7=5
Naked Single: r4c2=4
Full House: r4c3=2
Full House: r9c3=4
Naked Single: r2c2=2
Full House: r1c1=4
Full House: r8c1=2
Full House: r7c2=8
Full House: r1c4=2
Full House: r8c4=4
Full House: r8c7=8
Full House: r7c6=2
Full House: r9c6=8
Full House: r3c6=4
Full House: r9c7=2
Naked Single: r2c8=6
Naked Single: r3c7=9
Full House: r3c8=2
Full House: r4c8=9
Naked Single: r2c9=7
Full House: r2c7=4
Full House: r4c7=7
Full House: r4c9=6
|
normal_sudoku_5793
|
..3....92....3.8..94.2....7358...4...6.....8...9.8......2..9.348..47.92.......7..
|
183746592627935841945218367358162479461597283279384156712859634836471925594623718
|
Basic 9x9 Sudoku 5793
|
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
. . . . 3 . 8 . .
9 4 . 2 . . . . 7
3 5 8 . . . 4 . .
. 6 . . . . . 8 .
. . 9 . 8 . . . .
. . 2 . . 9 . 3 4
8 . . 4 7 . 9 2 .
. . . . . . 7 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
183746592627935841945218367358162479461597283279384156712859634836471925594623718 #1 Extreme (25348) bf
Hidden Single: r4c3=8
Hidden Single: r2c4=9
Hidden Single: r3c7=3
Hidden Single: r2c8=4
Hidden Single: r7c4=8
Hidden Single: r9c9=8
Hidden Single: r1c2=8
Hidden Single: r9c2=9
Hidden Single: r3c6=8
Hidden Single: r8c2=3
Locked Candidates Type 2 (Claiming): 2 in r4 => r5c56,r6c6<>2
Brute Force: r5c6=7
Hidden Single: r1c4=7
Hidden Single: r4c8=7
Hidden Single: r2c3=7
Hidden Rectangle: 1/7 in r6c12,r7c12 => r6c1<>1
Discontinuous Nice Loop: 1/2/5/6 r9c6 =3= r9c4 -3- r5c4 =3= r5c9 =9= r5c5 =4= r6c6 =3= r9c6 => r9c6<>1, r9c6<>2, r9c6<>5, r9c6<>6
Naked Single: r9c6=3
Hidden Single: r9c5=2
Hidden Single: r4c6=2
Grouped Discontinuous Nice Loop: 1 r5c4 -1- r4c45 =1= r4c9 =9= r5c9 =3= r5c4 => r5c4<>1
Hidden Rectangle: 3/5 in r5c49,r6c49 => r6c9<>5
Forcing Chain Contradiction in r8 => r6c6<>1
r6c6=1 r6c6<>4 r6c1=4 r5c3<>4 r5c3=1 r8c3<>1
r6c6=1 r8c6<>1
r6c6=1 r4c45<>1 r4c9=1 r8c9<>1
Forcing Net Verity => r1c5<>1
r6c1=4 (r5c3<>4 r5c3=1 r5c7<>1) (r6c1<>2) r6c1<>7 r6c2=7 (r7c2<>7 r7c2=1 r7c7<>1) r6c2<>2 r6c7=2 r6c7<>1 r1c7=1 r1c5<>1
r6c6=4 r1c6<>4 r1c5=4 r1c5<>1
Forcing Net Verity => r1c5<>5
r6c1=4 (r6c1<>7 r6c2=7 r7c2<>7 r7c1=7 r7c1<>5) (r5c1<>4) r5c3<>4 r5c3=1 (r5c7<>1) r5c1<>1 r5c1=2 r5c7<>2 r5c7=5 r7c7<>5 r7c5=5 r1c5<>5
r6c6=4 r1c6<>4 r1c5=4 r1c5<>5
Finned Franken Swordfish: 5 c48b2 r369 fr1c6 fr2c6 fr5c4 => r6c6<>5
Forcing Net Contradiction in c1 => r1c5=4
r1c5<>4 (r1c6=4 r1c6<>5) r5c5=4 (r5c1<>4) r5c3<>4 r5c3=1 (r5c7<>1) r5c1<>1 r5c1=2 r5c7<>2 r5c7=5 r1c7<>5 r1c1=5
r1c5<>4 r1c6=4 r6c6<>4 (r6c6=6 r6c4<>6 r9c4=6 r9c1<>6) r6c1=4 (r9c1<>4) r6c1<>7 r6c2=7 r7c2<>7 r7c2=1 r9c1<>1 r9c1=5
Hidden Single: r6c6=4
Hidden Rectangle: 1/4 in r5c13,r9c13 => r9c1<>1
Brute Force: r5c9=3
Naked Single: r5c4=5
Hidden Single: r6c4=3
Hidden Single: r5c5=9
Hidden Single: r4c9=9
Empty Rectangle: 5 in b1 (r37c5) => r7c1<>5
Finned Swordfish: 5 c169 r128 fr9c1 => r8c3<>5
Locked Candidates Type 1 (Pointing): 5 in b7 => r9c8<>5
Naked Pair: 1,6 in r9c48 => r9c13<>6, r9c3<>1
Empty Rectangle: 6 in b2 (r38c3) => r8c6<>6
Locked Candidates Type 2 (Claiming): 6 in c6 => r3c5<>6
Skyscraper: 6 in r3c8,r8c9 (connected by r38c3) => r2c9,r9c8<>6
Naked Single: r9c8=1
Naked Single: r9c4=6
Full House: r4c4=1
Full House: r4c5=6
Swordfish: 6 r127 c167 => r6c7<>6
Skyscraper: 1 in r3c5,r8c6 (connected by r38c3) => r12c6,r7c5<>1
Naked Single: r7c5=5
Full House: r3c5=1
Full House: r8c6=1
Naked Single: r7c7=6
Full House: r8c9=5
Full House: r8c3=6
Naked Single: r2c9=1
Full House: r6c9=6
Naked Single: r3c3=5
Full House: r3c8=6
Full House: r1c7=5
Full House: r6c8=5
Naked Single: r2c2=2
Naked Single: r9c3=4
Full House: r5c3=1
Full House: r9c1=5
Naked Single: r1c6=6
Full House: r1c1=1
Full House: r2c1=6
Full House: r2c6=5
Naked Single: r5c7=2
Full House: r5c1=4
Full House: r6c7=1
Naked Single: r6c2=7
Full House: r6c1=2
Full House: r7c1=7
Full House: r7c2=1
|
normal_sudoku_2081
|
.........478.9125.6...48..7...815.3........4.3.5.......37.....58.4..27..1...74..8
|
591237684478691253623548197746815932289763541315429876937186425864352719152974368
|
Basic 9x9 Sudoku 2081
|
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 7 8 . 9 1 2 5 .
6 . . . 4 8 . . 7
. . . 8 1 5 . 3 .
. . . . . . . 4 .
3 . 5 . . . . . .
. 3 7 . . . . . 5
8 . 4 . . 2 7 . .
1 . . . 7 4 . . 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
591237684478691253623548197746815932289763541315429876937186425864352719152974368 #1 Medium (522)
Naked Single: r2c2=7
Hidden Single: r5c7=5
Hidden Single: r4c2=4
Hidden Single: r6c8=7
Hidden Single: r1c1=5
Hidden Single: r7c5=8
Hidden Single: r6c4=4
Hidden Single: r7c7=4
Hidden Single: r1c9=4
Hidden Single: r4c1=7
Hidden Single: r5c2=8
Hidden Single: r1c8=8
Hidden Single: r6c7=8
Hidden Single: r8c5=5
Hidden Single: r3c4=5
Hidden Single: r9c2=5
Locked Candidates Type 1 (Pointing): 2 in b2 => r1c23<>2
Locked Candidates Type 1 (Pointing): 1 in b6 => r8c9<>1
Locked Candidates Type 1 (Pointing): 3 in b8 => r125c4<>3
Naked Single: r2c4=6
Full House: r2c9=3
Hidden Single: r1c7=6
Naked Single: r4c7=9
Naked Single: r3c7=1
Full House: r9c7=3
Full House: r3c8=9
Naked Single: r9c4=9
Naked Single: r3c2=2
Full House: r3c3=3
Naked Single: r7c4=1
Naked Single: r7c6=6
Full House: r8c4=3
Naked Single: r6c6=9
Naked Single: r7c8=2
Full House: r7c1=9
Full House: r5c1=2
Naked Single: r9c8=6
Full House: r8c8=1
Full House: r8c9=9
Full House: r8c2=6
Full House: r9c3=2
Naked Single: r4c3=6
Full House: r4c9=2
Naked Single: r5c4=7
Full House: r1c4=2
Naked Single: r6c2=1
Full House: r1c2=9
Full House: r5c3=9
Full House: r1c3=1
Naked Single: r5c6=3
Full House: r1c6=7
Full House: r1c5=3
Naked Single: r6c9=6
Full House: r5c9=1
Full House: r5c5=6
Full House: r6c5=2
|
normal_sudoku_918
|
.4...7...2....8.9...3..5......5...7..7..8...462...9.1.168.925....9.....8..2...9..
|
546927381217638495893145762384561279971283654625479813168392547439756128752814936
|
Basic 9x9 Sudoku 918
|
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 . . . 7 . . .
2 . . . . 8 . 9 .
. . 3 . . 5 . . .
. . . 5 . . . 7 .
. 7 . . 8 . . . 4
6 2 . . . 9 . 1 .
1 6 8 . 9 2 5 . .
. . 9 . . . . . 8
. . 2 . . . 9 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
546927381217638495893145762384561279971283654625479813168392547439756128752814936 #1 Medium (654)
Hidden Single: r9c3=2
Hidden Single: r6c7=8
Hidden Single: r9c4=8
Hidden Single: r5c1=9
Hidden Single: r4c9=9
Hidden Single: r2c3=7
Naked Single: r3c1=8
Naked Single: r1c1=5
Naked Single: r2c2=1
Naked Single: r1c3=6
Full House: r3c2=9
Hidden Single: r1c4=9
Hidden Single: r1c8=8
Hidden Single: r4c2=8
Hidden Single: r5c8=5
Naked Single: r5c3=1
Naked Single: r6c9=3
Naked Single: r4c3=4
Full House: r6c3=5
Full House: r4c1=3
Naked Single: r7c9=7
Hidden Single: r2c9=5
Hidden Single: r3c7=7
Locked Candidates Type 1 (Pointing): 3 in b3 => r8c7<>3
Locked Candidates Type 1 (Pointing): 2 in b6 => r18c7<>2
Hidden Single: r8c8=2
Locked Candidates Type 1 (Pointing): 6 in b6 => r28c7<>6
Locked Candidates Type 1 (Pointing): 6 in b3 => r3c45<>6
Locked Candidates Type 1 (Pointing): 6 in b9 => r9c56<>6
Locked Candidates Type 2 (Claiming): 4 in c6 => r78c4,r89c5<>4
Naked Single: r7c4=3
Full House: r7c8=4
Naked Single: r3c8=6
Full House: r9c8=3
Naked Single: r8c7=1
Full House: r9c9=6
Naked Single: r9c2=5
Full House: r8c2=3
Naked Single: r1c7=3
Naked Single: r2c7=4
Naked Single: r2c4=6
Full House: r2c5=3
Naked Single: r5c4=2
Naked Single: r8c4=7
Naked Single: r5c7=6
Full House: r4c7=2
Full House: r5c6=3
Naked Single: r6c4=4
Full House: r3c4=1
Full House: r6c5=7
Naked Single: r8c1=4
Full House: r9c1=7
Naked Single: r9c5=1
Full House: r9c6=4
Naked Single: r1c5=2
Full House: r1c9=1
Full House: r3c9=2
Full House: r3c5=4
Naked Single: r8c6=6
Full House: r4c6=1
Full House: r4c5=6
Full House: r8c5=5
|
normal_sudoku_5686
|
..2.14...13.82..4....3.7..237.1.2....8.4..2.......87..8..........7..3...4......95
|
762514983135829647948367152374192568681475239259638714893256471517943826426781395
|
Basic 9x9 Sudoku 5686
|
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 . 1 4 . . .
1 3 . 8 2 . . 4 .
. . . 3 . 7 . . 2
3 7 . 1 . 2 . . .
. 8 . 4 . . 2 . .
. . . . . 8 7 . .
8 . . . . . . . .
. . 7 . . 3 . . .
4 . . . . . . 9 5
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
762514983135829647948367152374192568681475239259638714893256471517943826426781395 #1 Extreme (15616) bf
Hidden Single: r4c6=2
Hidden Single: r5c5=7
Hidden Single: r3c3=8
Hidden Single: r2c9=7
Hidden Single: r1c1=7
Hidden Single: r9c4=7
Hidden Single: r6c5=3
Hidden Single: r3c2=4
Hidden Single: r7c8=7
Hidden Single: r9c2=2
Hidden Single: r8c8=2
Hidden Single: r6c1=2
Hidden Single: r7c4=2
Brute Force: r5c9=9
Hidden Single: r5c8=3
Hidden Single: r5c3=1
Forcing Net Verity => r1c2<>9
r3c1=5 (r3c1<>9 r8c1=9 r8c4<>9) (r1c2<>5) (r2c3<>5) r5c1<>5 r5c6=5 r2c6<>5 r2c7=5 (r1c7<>5) r1c8<>5 r1c4=5 r8c4<>5 r8c4=6 (r7c6<>6) r9c6<>6 r2c6=6 (r2c3<>6) r5c6<>6 r5c1=6 (r5c6<>6) r3c1<>6 r1c2=6 r1c2<>9
r3c1=6 (r3c1<>9 r8c1=9 r8c4<>9) (r1c2<>6) (r2c3<>6) r5c1<>6 r5c6=6 r2c6<>6 r2c7=6 (r1c7<>6) (r1c8<>6) r1c9<>6 r1c4=6 r8c4<>6 r8c4=5 r7c6<>5 r2c6=5 (r2c3<>5) r5c6<>5 r5c1=5 (r5c6<>5) r3c1<>5 r1c2=5 r1c2<>9
r3c1=9 r1c2<>9
Turbot Fish: 9 r3c1 =9= r2c3 -9- r4c3 =9= r4c5 => r3c5<>9
Forcing Chain Contradiction in r2c6 => r3c1<>5
r3c1=5 r5c1<>5 r5c6=5 r2c6<>5
r3c1=5 r3c5<>5 r3c5=6 r2c6<>6
r3c1=5 r3c1<>9 r2c3=9 r2c6<>9
Finned Franken Swordfish: 5 c14b1 r168 fr2c3 fr5c1 => r6c3<>5
Finned Franken Swordfish: 5 c16b1 r257 fr1c2 fr8c1 => r7c2<>5
Forcing Chain Contradiction in r2c6 => r3c1=9
r3c1<>9 r3c1=6 r3c5<>6 r3c5=5 r2c6<>5
r3c1<>9 r3c1=6 r5c1<>6 r5c6=6 r2c6<>6
r3c1<>9 r2c3=9 r2c6<>9
Finned Franken Swordfish: 6 c14b1 r168 fr2c3 fr5c1 => r6c3<>6
Forcing Chain Verity => r1c7<>5
r7c3=5 r2c3<>5 r1c2=5 r1c7<>5
r7c5=5 r3c5<>5 r3c78=5 r1c7<>5
r7c6=5 r7c6<>9 r2c6=9 r2c7<>9 r1c7=9 r1c7<>5
Forcing Chain Contradiction in r9 => r1c7<>6
r1c7=6 r1c2<>6 r2c3=6 r9c3<>6
r1c7=6 r3c78<>6 r3c5=6 r9c5<>6
r1c7=6 r1c7<>9 r1c4=9 r2c6<>9 r7c6=9 r7c6<>1 r9c6=1 r9c6<>6
r1c7=6 r9c7<>6
Forcing Chain Contradiction in c4 => r2c6<>5
r2c6=5 r2c6<>9 r1c4=9 r1c4<>6
r2c6=5 r5c6<>5 r5c6=6 r6c4<>6
r2c6=5 r5c6<>5 r5c6=6 r5c1<>6 r8c1=6 r8c4<>6
Skyscraper: 5 in r7c6,r8c1 (connected by r5c16) => r7c3,r8c45<>5
W-Wing: 6/5 in r1c2,r5c1 connected by 5 in r8c12 => r6c2<>6
W-Wing: 6/5 in r3c5,r5c6 connected by 5 in r7c56 => r2c6,r4c5<>6
Naked Single: r2c6=9
Hidden Single: r1c7=9
Hidden Single: r1c9=3
Hidden Single: r1c8=8
Turbot Fish: 6 r6c4 =6= r5c6 -6- r5c1 =6= r8c1 => r8c4<>6
Naked Single: r8c4=9
Hidden Single: r4c5=9
Remote Pair: 6/5 r2c7 -5- r2c3 -6- r1c2 -5- r1c4 -6- r6c4 -5- r5c6 -6- r5c1 -5- r8c1 => r4c3,r8c2<>5, r4c3,r78c2,r8c7<>6
Naked Single: r4c3=4
Naked Single: r8c2=1
Naked Single: r6c3=9
Naked Single: r7c2=9
Naked Single: r6c2=5
Full House: r1c2=6
Full House: r5c1=6
Full House: r1c4=5
Full House: r6c4=6
Full House: r2c3=5
Full House: r5c6=5
Full House: r8c1=5
Full House: r3c5=6
Full House: r2c7=6
Naked Single: r6c8=1
Full House: r6c9=4
Naked Single: r9c5=8
Naked Single: r3c8=5
Full House: r3c7=1
Full House: r4c8=6
Naked Single: r8c5=4
Full House: r7c5=5
Naked Single: r9c7=3
Naked Single: r4c9=8
Full House: r4c7=5
Naked Single: r8c7=8
Full House: r7c7=4
Full House: r8c9=6
Full House: r7c9=1
Naked Single: r9c3=6
Full House: r7c3=3
Full House: r7c6=6
Full House: r9c6=1
|
normal_sudoku_3316
|
.36..97.....2..5..2...3..9......18......94..716.3...4.3....2.7.9...13.5.615......
|
436159782897246513251738496749621835523894167168375249384562971972413658615987324
|
Basic 9x9 Sudoku 3316
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 3 6 . . 9 7 . .
. . . 2 . . 5 . .
2 . . . 3 . . 9 .
. . . . . 1 8 . .
. . . . 9 4 . . 7
1 6 . 3 . . . 4 .
3 . . . . 2 . 7 .
9 . . . 1 3 . 5 .
6 1 5 . . . . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
436159782897246513251738496749621835523894167168375249384562971972413658615987324 #1 Extreme (5192)
Hidden Single: r9c1=6
Locked Pair: 4,8 in r7c23 => r7c4579,r8c23<>4, r7c459,r8c23<>8
Locked Candidates Type 1 (Pointing): 2 in b7 => r8c79<>2
Locked Candidates Type 1 (Pointing): 7 in b7 => r8c4<>7
Locked Candidates Type 2 (Claiming): 6 in c6 => r2c5,r3c4<>6
Finned Swordfish: 5 r157 c145 fr5c2 => r4c1<>5
Discontinuous Nice Loop: 9 r9c7 -9- r9c4 =9= r7c4 =5= r7c5 =6= r4c5 =2= r6c5 -2- r6c7 -9- r9c7 => r9c7<>9
Grouped Discontinuous Nice Loop: 6 r4c9 -6- r45c8 =6= r2c8 -6- r2c6 =6= r3c6 =5= r6c6 -5- r6c9 =5= r4c9 => r4c9<>6
Almost Locked Set XZ-Rule: A=r5c123 {2358}, B=r35678c7 {123469}, X=3, Z=2 => r5c8<>2
Almost Locked Set XY-Wing: A=r4c123459 {2345679}, B=r35678c7 {123469}, C=r5c1234 {23568}, X,Y=3,6, Z=2 => r4c8<>2
Forcing Chain Contradiction in r6c9 => r1c4<>5
r1c4=5 r7c4<>5 r7c5=5 r7c5<>6 r4c5=6 r4c5<>2 r6c5=2 r6c9<>2
r1c4=5 r3c6<>5 r6c6=5 r6c9<>5
r1c4=5 r7c4<>5 r7c5=5 r7c5<>6 r4c5=6 r4c5<>2 r6c5=2 r6c7<>2 r6c7=9 r6c9<>9
Forcing Chain Contradiction in r5c4 => r3c4<>5
r3c4=5 r5c4<>5
r3c4=5 r7c4<>5 r7c5=5 r7c5<>6 r4c5=6 r5c4<>6
r3c4=5 r3c2<>5 r1c1=5 r5c1<>5 r5c1=8 r5c4<>8
Forcing Chain Contradiction in r4c9 => r7c4=5
r7c4<>5 r7c5=5 r7c5<>6 r4c5=6 r4c8<>6 r4c8=3 r5c7<>3 r9c7=3 r9c7<>2 r56c7=2 r4c9<>2
r7c4<>5 r7c5=5 r7c5<>6 r4c5=6 r4c8<>6 r4c8=3 r4c9<>3
r7c4<>5 r45c4=5 r6c56<>5 r6c9=5 r4c9<>5
r7c4<>5 r7c5=5 r7c5<>6 r4c5=6 r4c5<>2 r6c5=2 r6c7<>2 r6c7=9 r4c9<>9
Naked Single: r7c5=6
Hidden Single: r9c4=9
Locked Candidates Type 2 (Claiming): 5 in r5 => r4c2<>5
Skyscraper: 7 in r2c1,r3c4 (connected by r4c14) => r2c56,r3c23<>7
XY-Wing: 4/8/6 in r58c4,r8c7 => r5c7<>6
Locked Candidates Type 1 (Pointing): 6 in b6 => r2c8<>6
Sue de Coq: r6c56 - {2578} (r6c79 - {259}, r45c4 - {678}) => r4c5<>7, r6c3<>2, r6c3<>9
Locked Candidates Type 1 (Pointing): 9 in b4 => r4c9<>9
W-Wing: 8/7 in r6c3,r9c6 connected by 7 in r69c5 => r6c6<>8
W-Wing: 4/8 in r2c5,r7c3 connected by 8 in r6c35 => r2c3<>4
W-Wing: 4/8 in r2c5,r8c4 connected by 8 in r5c4,r6c5 => r13c4,r9c5<>4
Hidden Single: r8c4=4
Naked Single: r8c7=6
Naked Single: r8c9=8
XY-Wing: 7/8/4 in r4c1,r67c3 => r4c3<>4
Finned Swordfish: 8 r367 c235 fr3c4 fr3c6 => r12c5<>8
Naked Single: r2c5=4
Naked Single: r1c5=5
Naked Single: r4c5=2
Hidden Single: r5c1=5
Hidden Single: r3c2=5
Hidden Single: r6c6=5
Hidden Single: r4c9=5
Locked Candidates Type 1 (Pointing): 2 in b4 => r5c7<>2
Locked Candidates Type 2 (Claiming): 8 in c1 => r2c23,r3c3<>8
Locked Candidates Type 2 (Claiming): 8 in r3 => r1c4,r2c6<>8
Naked Single: r1c4=1
Naked Single: r2c6=6
Hidden Single: r3c9=6
XY-Wing: 2/8/7 in r58c2,r6c3 => r4c2,r8c3<>7
Naked Single: r8c3=2
Full House: r8c2=7
Naked Single: r2c2=9
Naked Single: r4c2=4
Naked Single: r4c1=7
Naked Single: r7c2=8
Full House: r5c2=2
Full House: r7c3=4
Naked Single: r2c1=8
Full House: r1c1=4
Naked Single: r4c4=6
Naked Single: r6c3=8
Naked Single: r3c3=1
Full House: r2c3=7
Naked Single: r1c9=2
Full House: r1c8=8
Naked Single: r4c8=3
Full House: r4c3=9
Full House: r5c3=3
Naked Single: r5c4=8
Full House: r6c5=7
Full House: r3c4=7
Full House: r9c5=8
Full House: r3c6=8
Full House: r3c7=4
Full House: r9c6=7
Naked Single: r6c9=9
Full House: r6c7=2
Naked Single: r2c8=1
Full House: r2c9=3
Naked Single: r5c7=1
Full House: r5c8=6
Full House: r9c8=2
Naked Single: r7c9=1
Full House: r9c9=4
Full House: r9c7=3
Full House: r7c7=9
|
normal_sudoku_1447
|
.67.2.14.2.4......13...67.2.4......1..671.2.4.2....37.....3......35.2......86...3
|
867325149294187635135946782748293561356718294921654378612439857483572916579861423
|
Basic 9x9 Sudoku 1447
|
01_file1
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 6 7 . 2 . 1 4 .
2 . 4 . . . . . .
1 3 . . . 6 7 . 2
. 4 . . . . . . 1
. . 6 7 1 . 2 . 4
. 2 . . . . 3 7 .
. . . . 3 . . . .
. . 3 5 . 2 . . .
. . . 8 6 . . . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
867325149294187635135946782748293561356718294921654378612439857483572916579861423 #1 Extreme (22234) bf
Hidden Single: r2c1=2
Hidden Single: r6c3=1
Hidden Single: r4c1=7
Hidden Single: r4c4=2
Hidden Single: r2c8=3
Hidden Single: r5c1=3
Hidden Single: r4c6=3
Hidden Single: r6c4=6
Hidden Single: r1c4=3
Brute Force: r6c6=4
Discontinuous Nice Loop: 9 r2c5 -9- r3c4 -4- r3c5 =4= r8c5 =7= r2c5 => r2c5<>9
Brute Force: r6c5=5
Skyscraper: 5 in r3c3,r5c2 (connected by r35c8) => r2c2,r4c3<>5
Hidden Single: r5c2=5
Naked Pair: 8,9 in r5c8,r6c9 => r4c78<>8, r4c78<>9
Finned Swordfish: 5 r349 c378 fr9c1 => r7c3<>5
Almost Locked Set XY-Wing: A=r9c12367 {124579}, B=r35c8 {589}, C=r347c3 {2589}, X,Y=2,5, Z=9 => r9c8<>9
Almost Locked Set Chain: 9- r3c45 {489} -8- r4c5 {89} -9- r5c6 {89} -8- r5c8 {89} -9 => r3c8<>9
XYZ-Wing: 5/8/9 in r16c9,r3c8 => r2c9<>8
Discontinuous Nice Loop: 9 r1c1 -9- r6c1 -8- r6c9 =8= r5c8 -8- r3c8 -5- r3c3 =5= r1c1 => r1c1<>9
Skyscraper: 9 in r1c9,r5c8 (connected by r15c6) => r6c9<>9
Naked Single: r6c9=8
Full House: r6c1=9
Full House: r4c3=8
Naked Single: r5c8=9
Full House: r5c6=8
Full House: r4c5=9
Hidden Single: r1c1=8
Naked Single: r2c2=9
Full House: r3c3=5
Naked Single: r2c4=1
Naked Single: r3c8=8
Naked Single: r3c5=4
Full House: r3c4=9
Full House: r7c4=4
Naked Single: r8c5=7
Full House: r2c5=8
Naked Single: r1c6=5
Full House: r1c9=9
Full House: r2c6=7
Naked Single: r8c9=6
Naked Single: r2c9=5
Full House: r2c7=6
Full House: r7c9=7
Naked Single: r8c1=4
Naked Single: r8c8=1
Naked Single: r4c7=5
Full House: r4c8=6
Naked Single: r9c1=5
Full House: r7c1=6
Naked Single: r8c2=8
Full House: r8c7=9
Naked Single: r9c8=2
Full House: r7c8=5
Naked Single: r7c2=1
Full House: r9c2=7
Naked Single: r7c7=8
Full House: r9c7=4
Naked Single: r9c3=9
Full House: r7c3=2
Full House: r7c6=9
Full House: r9c6=1
|
normal_sudoku_345
|
.9...631..5.9....2..81.....73..49.8...9.....381..6.97.94.6..73.5....41.6.....7...
|
297486315154973862368125497736549281429718653815362974942651738573894126681237549
|
Basic 9x9 Sudoku 345
|
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 . . . 6 3 1 .
. 5 . 9 . . . . 2
. . 8 1 . . . . .
7 3 . . 4 9 . 8 .
. . 9 . . . . . 3
8 1 . . 6 . 9 7 .
9 4 . 6 . . 7 3 .
5 . . . . 4 1 . 6
. . . . . 7 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
297486315154973862368125497736549281429718653815362974942651738573894126681237549 #1 Easy (274)
Hidden Single: r5c3=9
Hidden Single: r1c4=4
Naked Single: r1c1=2
Naked Single: r1c3=7
Naked Single: r3c2=6
Naked Single: r5c2=2
Naked Single: r9c2=8
Full House: r8c2=7
Hidden Single: r4c9=1
Hidden Single: r5c4=7
Hidden Single: r3c9=7
Hidden Single: r2c5=7
Hidden Single: r4c7=2
Naked Single: r4c4=5
Full House: r4c3=6
Naked Single: r5c1=4
Full House: r6c3=5
Naked Single: r3c1=3
Naked Single: r6c9=4
Naked Single: r2c1=1
Full House: r2c3=4
Full House: r9c1=6
Naked Single: r2c8=6
Naked Single: r2c7=8
Full House: r2c6=3
Naked Single: r5c8=5
Full House: r5c7=6
Naked Single: r1c9=5
Full House: r1c5=8
Naked Single: r6c6=2
Full House: r6c4=3
Naked Single: r3c7=4
Full House: r3c8=9
Full House: r9c7=5
Naked Single: r7c9=8
Full House: r9c9=9
Naked Single: r5c5=1
Full House: r5c6=8
Naked Single: r3c6=5
Full House: r3c5=2
Full House: r7c6=1
Naked Single: r9c4=2
Full House: r8c4=8
Naked Single: r8c8=2
Full House: r9c8=4
Naked Single: r7c5=5
Full House: r7c3=2
Naked Single: r9c5=3
Full House: r8c5=9
Full House: r8c3=3
Full House: r9c3=1
|
normal_sudoku_937
|
..2.1.......7.45.....82....5..4762....3.9.84......2.........46.1.6...3594.8.59..7
|
852913674319764582647825931581476293723591846964382715295137468176248359438659127
|
Basic 9x9 Sudoku 937
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 2 . 1 . . . .
. . . 7 . 4 5 . .
. . . 8 2 . . . .
5 . . 4 7 6 2 . .
. . 3 . 9 . 8 4 .
. . . . . 2 . . .
. . . . . . 4 6 .
1 . 6 . . . 3 5 9
4 . 8 . 5 9 . . 7
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
852913674319764582647825931581476293723591846964382715295137468176248359438659127 #1 Easy (282)
Naked Single: r8c7=3
Naked Single: r8c4=2
Naked Single: r9c7=1
Naked Single: r8c2=7
Naked Single: r9c8=2
Full House: r7c9=8
Naked Single: r8c6=8
Full House: r8c5=4
Naked Single: r9c2=3
Full House: r9c4=6
Naked Single: r7c5=3
Naked Single: r2c5=6
Full House: r6c5=8
Naked Single: r7c4=1
Full House: r7c6=7
Naked Single: r5c4=5
Naked Single: r5c6=1
Full House: r6c4=3
Full House: r1c4=9
Naked Single: r5c9=6
Naked Single: r5c2=2
Full House: r5c1=7
Hidden Single: r4c2=8
Hidden Single: r2c9=2
Hidden Single: r6c9=5
Hidden Single: r7c1=2
Hidden Single: r3c3=7
Hidden Single: r6c3=4
Hidden Single: r7c3=5
Full House: r7c2=9
Naked Single: r2c2=1
Naked Single: r2c3=9
Full House: r4c3=1
Naked Single: r6c2=6
Full House: r6c1=9
Naked Single: r4c9=3
Full House: r4c8=9
Naked Single: r6c7=7
Full House: r6c8=1
Naked Single: r1c9=4
Full House: r3c9=1
Naked Single: r1c7=6
Full House: r3c7=9
Naked Single: r3c8=3
Naked Single: r1c2=5
Full House: r3c2=4
Naked Single: r2c8=8
Full House: r1c8=7
Full House: r2c1=3
Naked Single: r3c1=6
Full House: r3c6=5
Full House: r1c6=3
Full House: r1c1=8
|
normal_sudoku_1916
|
..2.95.371...2....5.74.....3.......9.5...8.....1..36..816.5.423........6.2..3.87.
|
462895137198327564537416298384562719659178342271943685816759423743281956925634871
|
Basic 9x9 Sudoku 1916
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . 2 . 9 5 . 3 7
1 . . . 2 . . . .
5 . 7 4 . . . . .
3 . . . . . . . 9
. 5 . . . 8 . . .
. . 1 . . 3 6 . .
8 1 6 . 5 . 4 2 3
. . . . . . . . 6
. 2 . . 3 . 8 7 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
462895137198327564537416298384562719659178342271943685816759423743281956925634871 #1 Easy (332)
Naked Single: r7c9=3
Naked Single: r1c7=1
Hidden Single: r3c2=3
Hidden Single: r2c4=3
Hidden Single: r5c7=3
Hidden Single: r8c3=3
Hidden Single: r2c6=7
Naked Single: r7c6=9
Full House: r7c4=7
Hidden Single: r4c7=7
Hidden Single: r9c3=5
Naked Single: r9c9=1
Naked Single: r9c4=6
Naked Single: r1c4=8
Naked Single: r9c6=4
Full House: r9c1=9
Hidden Single: r3c7=2
Naked Single: r3c9=8
Hidden Single: r8c5=8
Hidden Single: r3c8=9
Naked Single: r2c7=5
Full House: r8c7=9
Full House: r8c8=5
Naked Single: r2c9=4
Full House: r2c8=6
Naked Single: r5c9=2
Full House: r6c9=5
Hidden Single: r4c4=5
Hidden Single: r6c1=2
Naked Single: r6c4=9
Naked Single: r5c4=1
Full House: r8c4=2
Full House: r8c6=1
Naked Single: r5c8=4
Naked Single: r3c6=6
Full House: r3c5=1
Full House: r4c6=2
Naked Single: r5c3=9
Naked Single: r6c8=8
Full House: r4c8=1
Naked Single: r2c3=8
Full House: r2c2=9
Full House: r4c3=4
Naked Single: r4c5=6
Full House: r4c2=8
Naked Single: r6c2=7
Full House: r5c1=6
Full House: r5c5=7
Full House: r6c5=4
Naked Single: r8c2=4
Full House: r1c2=6
Full House: r1c1=4
Full House: r8c1=7
|
normal_sudoku_1781
|
..8..1..7.7...491....7...4..8.9....421.4...59....32.......6.....9.8....18.....5..
|
948651237675324918123798645386975124217486359459132876731569482592843761864217593
|
Basic 9x9 Sudoku 1781
|
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 . . 7
. 7 . . . 4 9 1 .
. . . 7 . . . 4 .
. 8 . 9 . . . . 4
2 1 . 4 . . . 5 9
. . . . 3 2 . . .
. . . . 6 . . . .
. 9 . 8 . . . . 1
8 . . . . . 5 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
948651237675324918123798645386975124217486359459132876731569482592843761864217593 #1 Extreme (33388) bf
Locked Candidates Type 1 (Pointing): 8 in b5 => r5c78<>8
Forcing Net Verity => r3c6<>9
r6c1=7 (r6c1<>4) r6c1<>9 r6c3=9 r6c3<>4 r6c2=4 r1c2<>4 r1c1=4 r1c1<>9 r1c5=9 r3c6<>9
r6c3=7 r6c3<>9 r3c3=9 r3c6<>9
r6c7=7 r6c7<>1 r6c4=1 r4c5<>1 r9c5=1 r9c5<>9 r13c5=9 r3c6<>9
r6c8=7 r6c8<>8 r7c8=8 r7c8<>9 r7c6=9 r3c6<>9
Locked Candidates Type 1 (Pointing): 9 in b2 => r9c5<>9
Brute Force: r5c8=5
Forcing Chain Verity => r9c5<>7
r3c7=8 r3c6<>8 r5c6=8 r5c5<>8 r5c5=7 r9c5<>7
r6c7=8 r6c7<>1 r6c4=1 r4c5<>1 r9c5=1 r9c5<>7
r7c7=8 r7c7<>4 r8c7=4 r8c5<>4 r9c5=4 r9c5<>7
Forcing Net Contradiction in c2 => r4c8<>6
r4c8=6 (r4c8<>3) r4c8<>2 r4c7=2 (r1c7<>2) r4c7<>3 r5c7=3 r1c7<>3 r1c7=6 r1c2<>6
r4c8=6 (r4c6<>6) r6c9<>6 r6c9=8 r2c9<>8 r2c5=8 r5c5<>8 r5c6=8 r5c6<>6 r3c6=6 r3c2<>6
r4c8=6 (r4c8<>2 r4c7=2 r4c7<>3 r5c7=3 r5c3<>3) r6c9<>6 r6c9=8 r2c9<>8 r2c5=8 r5c5<>8 r5c5=7 r5c3<>7 r5c3=6 r6c2<>6
r4c8=6 (r6c9<>6) (r4c8<>3) r4c8<>2 r4c7=2 (r1c7<>2) r4c7<>3 r5c7=3 r1c7<>3 r1c7=6 (r2c9<>6) r3c9<>6 r9c9=6 r9c2<>6
Forcing Net Contradiction in r5c6 => r7c7<>3
r7c7=3 (r1c7<>3) (r4c7<>3) r5c7<>3 r5c3=3 (r5c3<>6) (r4c1<>3) r4c3<>3 r4c8=3 r4c8<>2 r4c7=2 r1c7<>2 r1c7=6 r5c7<>6 r5c6=6
r7c7=3 (r3c7<>3) (r1c7<>3) (r4c7<>3) r5c7<>3 r5c3=3 (r4c1<>3) r4c3<>3 r4c8=3 r4c8<>2 r4c7=2 (r3c7<>2) r1c7<>2 r1c7=6 r3c7<>6 r3c7=8 r3c6<>8 r5c6=8
Forcing Net Contradiction in r5c6 => r8c7<>3
r8c7=3 (r1c7<>3) (r4c7<>3) r5c7<>3 r5c3=3 (r5c3<>6) (r4c1<>3) r4c3<>3 r4c8=3 r4c8<>2 r4c7=2 r1c7<>2 r1c7=6 r5c7<>6 r5c6=6
r8c7=3 (r3c7<>3) (r1c7<>3) (r4c7<>3) r5c7<>3 r5c3=3 (r4c1<>3) r4c3<>3 r4c8=3 r4c8<>2 r4c7=2 (r3c7<>2) r1c7<>2 r1c7=6 r3c7<>6 r3c7=8 r3c6<>8 r5c6=8
Brute Force: r6c1=4
Hidden Single: r1c2=4
Hidden Single: r6c3=9
Locked Candidates Type 2 (Claiming): 7 in r6 => r4c78,r5c7<>7
Discontinuous Nice Loop: 2 r7c8 -2- r4c8 -3- r5c7 -6- r6c9 -8- r6c8 =8= r7c8 => r7c8<>2
Discontinuous Nice Loop: 8 r7c7 -8- r7c8 =8= r6c8 =7= r6c7 =1= r6c4 -1- r4c5 =1= r9c5 =4= r9c3 -4- r7c3 =4= r7c7 => r7c7<>8
Discontinuous Nice Loop: 3 r3c7 -3- r5c7 -6- r6c9 -8- r6c7 =8= r3c7 => r3c7<>3
Discontinuous Nice Loop: 7 r8c5 -7- r5c5 -8- r5c6 =8= r3c6 -8- r3c7 =8= r6c7 =1= r6c4 -1- r4c5 =1= r9c5 =4= r8c5 => r8c5<>7
Locked Candidates Type 1 (Pointing): 7 in b8 => r45c6<>7
Discontinuous Nice Loop: 2 r9c8 -2- r4c8 -3- r5c7 -6- r6c9 -8- r6c8 =8= r7c8 =9= r9c8 => r9c8<>2
Almost Locked Set XY-Wing: A=r9c249 {1236}, B=r148c8 {2367}, C=r6c2489 {15678}, X,Y=1,7, Z=3,6 => r9c8<>3, r9c8<>6
Hidden Rectangle: 7/9 in r7c68,r9c68 => r7c6<>7
Almost Locked Set XY-Wing: A=r1345c7 {12368}, B=r7c89,r8c78,r9c89 {2346789}, C=r123458c5 {1245789}, X,Y=1,4, Z=2 => r7c7<>2
Forcing Chain Contradiction in r8 => r3c5<>2
r3c5=2 r3c2<>2 r79c2=2 r8c3<>2
r3c5=2 r8c5<>2
r3c5=2 r1c45<>2 r1c78=2 r23c9<>2 r79c9=2 r8c7<>2
r3c5=2 r1c45<>2 r1c78=2 r23c9<>2 r79c9=2 r8c8<>2
Forcing Chain Verity => r2c5<>5
r1c5=2 r1c5<>9 r1c1=9 r1c1<>5 r1c45=5 r2c5<>5
r2c5=2 r2c5<>5
r8c5=2 r8c5<>4 r9c5=4 r9c5<>1 r4c5=1 r4c7<>1 r6c7=1 r6c7<>8 r3c7=8 r2c9<>8 r2c5=8 r2c5<>5
r9c5=2 r9c5<>1 r4c5=1 r4c7<>1 r6c7=1 r6c7<>8 r3c7=8 r2c9<>8 r2c5=8 r2c5<>5
Forcing Chain Contradiction in r3c5 => r3c6<>5
r3c6=5 r3c5<>5
r3c6=5 r3c9<>5 r2c9=5 r2c9<>8 r2c5=8 r3c5<>8
r3c6=5 r1c45<>5 r1c1=5 r1c1<>9 r1c5=9 r3c5<>9
Forcing Chain Contradiction in r8 => r3c7<>2
r3c7=2 r3c2<>2 r79c2=2 r8c3<>2
r3c7=2 r3c7<>8 r6c7=8 r6c7<>1 r6c4=1 r4c5<>1 r9c5=1 r9c5<>4 r8c5=4 r8c5<>2
r3c7=2 r8c7<>2
r3c7=2 r4c7<>2 r4c8=2 r8c8<>2
Forcing Chain Contradiction in r3c6 => r7c6<>3
r7c6=3 r3c6<>3
r7c6=3 r7c6<>9 r7c8=9 r7c8<>8 r7c9=8 r6c9<>8 r6c9=6 r6c4<>6 r12c4=6 r3c6<>6
r7c6=3 r7c6<>9 r7c8=9 r7c8<>8 r7c9=8 r2c9<>8 r2c5=8 r3c6<>8
Forcing Net Verity => r6c2=5
r7c4=3 (r1c4<>3) (r7c9<>3) (r7c2<>3) (r8c6<>3) r9c6<>3 r3c6=3 (r3c9<>3) r3c2<>3 r9c2=3 (r8c3<>3 r8c8=3 r1c8<>3) r9c9<>3 r2c9=3 r1c7<>3 r1c1=3 (r1c1<>5) r1c1<>9 r1c5=9 r1c5<>5 r1c4=5 r6c4<>5 r6c2=5
r8c6=3 (r8c6<>5) r8c6<>7 r9c6=7 r9c8<>7 r9c8=9 r7c8<>9 r7c6=9 r7c6<>5 r4c6=5 r6c4<>5 r6c2=5
r9c4=3 (r1c4<>3) (r9c9<>3) (r9c2<>3) (r8c6<>3) r9c6<>3 r3c6=3 (r3c9<>3) r3c2<>3 r7c2=3 r7c9<>3 r2c9=3 (r1c7<>3) r1c8<>3 r1c1=3 (r1c1<>5) r1c1<>9 r1c5=9 r1c5<>5 r1c4=5 r6c4<>5 r6c2=5
r9c6=3 (r9c6<>7 r8c6=7 r8c6<>5) r9c6<>9 r9c8=9 r7c8<>9 r7c6=9 r7c6<>5 r4c6=5 r6c4<>5 r6c2=5
Grouped Discontinuous Nice Loop: 6 r9c3 -6- r9c2 =6= r3c2 -6- r3c6 =6= r12c4 -6- r6c4 -1- r4c5 =1= r9c5 =4= r9c3 => r9c3<>6
Forcing Chain Contradiction in c6 => r3c3<>6
r3c3=6 r3c6<>6
r3c3=6 r5c3<>6 r4c13=6 r4c6<>6
r3c3=6 r3c7<>6 r3c7=8 r3c6<>8 r5c6=8 r5c6<>6
Forcing Chain Contradiction in c6 => r8c3<>6
r8c3=6 r9c2<>6 r3c2=6 r3c6<>6
r8c3=6 r5c3<>6 r4c13=6 r4c6<>6
r8c3=6 r9c2<>6 r3c2=6 r3c7<>6 r3c7=8 r3c6<>8 r5c6=8 r5c6<>6
Forcing Chain Verity => r8c8<>2
r8c1=6 r9c2<>6 r3c2=6 r3c6<>6 r12c4=6 r6c4<>6 r6c4=1 r6c7<>1 r4c7=1 r4c7<>2 r4c8=2 r8c8<>2
r8c7=6 r5c7<>6 r5c7=3 r4c8<>3 r4c8=2 r8c8<>2
r8c8=6 r8c8<>2
Forcing Net Verity => r1c1=9
r3c5=5 (r3c5<>8) (r4c5<>5 r4c6=5 r4c6<>6) (r2c4<>5) (r1c4<>5) r1c5<>5 r1c1=5 (r2c1<>5) r2c3<>5 r2c9=5 r2c9<>8 r2c5=8 r5c5<>8 r5c6=8 r5c6<>6 r3c6=6 (r3c9<>6) (r2c4<>6 r6c4=6 r6c9<>6) r3c2<>6 r9c2=6 r9c9<>6 r2c9=6 r2c9<>5 r3c9=5 r3c5<>5 r3c5=9 r1c5<>9 r1c1=9
r3c5=8 (r3c5<>5) r2c5<>8 r2c9=8 r6c9<>8 r6c9=6 r9c9<>6 r9c2=6 (r9c2<>3) r9c2<>3 r7c2=3 r7c4<>3 r9c4=3 (r9c9<>3) r9c6<>3 r3c6=3 (r3c9<>3) (r8c6<>3) (r1c4<>3) (r2c4<>3) (r3c2<>3) r3c2<>3 r7c2=3 r7c9<>3 r2c9=3 r2c9<>8 r2c5=8 r3c5<>8 r3c5=9 r1c5<>9 r1c1=9
r3c5=9 r1c5<>9 r1c1=9
Hidden Single: r3c5=9
Locked Candidates Type 2 (Claiming): 5 in r1 => r2c4<>5
Forcing Chain Contradiction in c9 => r4c7=1
r4c7<>1 r4c5=1 r6c4<>1 r6c4=6 r1c4<>6 r1c78=6 r2c9<>6
r4c7<>1 r4c5=1 r6c4<>1 r6c4=6 r1c4<>6 r1c78=6 r3c9<>6
r4c7<>1 r4c5=1 r6c4<>1 r6c4=6 r6c9<>6
r4c7<>1 r4c5=1 r6c4<>1 r6c4=6 r12c4<>6 r3c6=6 r3c2<>6 r9c2=6 r9c9<>6
Hidden Single: r9c5=1
Hidden Single: r6c4=1
Hidden Single: r4c8=2
Hidden Single: r9c3=4
Hidden Single: r8c5=4
Hidden Single: r5c7=3
Hidden Single: r7c7=4
Locked Candidates Type 1 (Pointing): 6 in b5 => r3c6<>6
Locked Candidates Type 1 (Pointing): 2 in b8 => r12c4<>2
Naked Triple: 2,3,6 in r9c249 => r9c6<>3
2-String Kite: 3 in r1c8,r8c6 (connected by r1c4,r3c6) => r8c8<>3
XY-Wing: 6/8/3 in r1c8,r3c67 => r1c4,r3c9<>3
Hidden Single: r1c8=3
W-Wing: 2/3 in r7c2,r9c4 connected by 3 in r79c9 => r7c4,r9c2<>2
Hidden Single: r9c4=2
XY-Wing: 3/8/6 in r2c4,r3c67 => r2c9<>6
Uniqueness Test 3: 7/9 in r7c68,r9c68 => r7c13<>3, r7c13<>5, r7c3<>2
Locked Pair: 1,7 in r7c13 => r7c8,r8c13<>7
Locked Candidates Type 1 (Pointing): 5 in b7 => r8c6<>5
Empty Rectangle: 3 in b7 (r38c6) => r3c2<>3
Locked Candidates Type 2 (Claiming): 3 in c2 => r8c13<>3
Hidden Single: r8c6=3
Naked Single: r3c6=8
Naked Single: r7c4=5
Naked Single: r2c5=2
Naked Single: r3c7=6
Naked Single: r5c6=6
Naked Single: r1c4=6
Full House: r2c4=3
Full House: r1c5=5
Full House: r1c7=2
Naked Single: r7c6=9
Full House: r9c6=7
Full House: r4c6=5
Naked Single: r3c2=2
Naked Single: r5c3=7
Full House: r5c5=8
Full House: r4c5=7
Naked Single: r3c9=5
Full House: r2c9=8
Naked Single: r8c7=7
Full House: r6c7=8
Naked Single: r7c8=8
Naked Single: r9c8=9
Naked Single: r7c2=3
Full House: r9c2=6
Full House: r9c9=3
Naked Single: r7c3=1
Naked Single: r6c9=6
Full House: r7c9=2
Full House: r8c8=6
Full House: r7c1=7
Full House: r6c8=7
Naked Single: r8c1=5
Full House: r8c3=2
Naked Single: r3c3=3
Full House: r3c1=1
Naked Single: r2c1=6
Full House: r2c3=5
Full House: r4c3=6
Full House: r4c1=3
|
normal_sudoku_520
|
.....2.7.4.5.......7..534.8.2.....946...1..2...9...1...961...42......8..1.32.6.5.
|
318492675465781239972653418821367594654819723739524186596178342247935861183246957
|
Basic 9x9 Sudoku 520
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . . 2 . 7 .
4 . 5 . . . . . .
. 7 . . 5 3 4 . 8
. 2 . . . . . 9 4
6 . . . 1 . . 2 .
. . 9 . . . 1 . .
. 9 6 1 . . . 4 2
. . . . . . 8 . .
1 . 3 2 . 6 . 5 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
318492675465781239972653418821367594654819723739524186596178342247935861183246957 #1 Hard (536)
Naked Single: r9c8=5
Hidden Single: r2c6=1
Hidden Single: r2c7=2
Hidden Single: r6c8=8
Hidden Single: r4c3=1
Naked Single: r1c3=8
Naked Single: r3c3=2
Naked Single: r3c1=9
Naked Single: r1c1=3
Naked Single: r3c4=6
Full House: r3c8=1
Naked Single: r2c2=6
Full House: r1c2=1
Naked Single: r2c8=3
Full House: r8c8=6
Naked Single: r2c9=9
Naked Single: r9c9=7
Naked Single: r7c7=3
Naked Single: r9c7=9
Full House: r8c9=1
Hidden Single: r6c5=2
Hidden Single: r8c1=2
Hidden Single: r6c9=6
Naked Single: r1c9=5
Full House: r1c7=6
Full House: r5c9=3
Hidden Single: r4c5=6
Hidden Single: r6c2=3
Hidden Single: r4c4=3
Hidden Single: r8c5=3
Hidden Single: r1c5=9
Full House: r1c4=4
Hidden Single: r9c5=4
Full House: r9c2=8
Hidden Single: r6c6=4
Hidden Single: r4c1=8
Naked Pair: 5,7 in r4c6,r6c4 => r5c46<>5, r5c46<>7
Remote Pair: 5/7 r4c6 -7- r6c4 -5- r6c1 -7- r7c1 => r7c6<>5, r7c6<>7
Naked Single: r7c6=8
Naked Single: r5c6=9
Naked Single: r7c5=7
Full House: r2c5=8
Full House: r7c1=5
Full House: r2c4=7
Full House: r6c1=7
Full House: r6c4=5
Naked Single: r5c4=8
Full House: r4c6=7
Full House: r8c6=5
Full House: r8c4=9
Full House: r4c7=5
Full House: r5c7=7
Naked Single: r8c2=4
Full House: r5c2=5
Full House: r5c3=4
Full House: r8c3=7
|
normal_sudoku_4561
|
85.7..2..64...5..1.13............7....1.43..99...6..42....8..2..8...93.5...4..69.
|
859714236642935871713628954564192783271843569938567142195386427486279315327451698
|
Basic 9x9 Sudoku 4561
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
8 5 . 7 . . 2 . .
6 4 . . . 5 . . 1
. 1 3 . . . . . .
. . . . . . 7 . .
. . 1 . 4 3 . . 9
9 . . . 6 . . 4 2
. . . . 8 . . 2 .
. 8 . . . 9 3 . 5
. . . 4 . . 6 9 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
859714236642935871713628954564192783271843569938567142195386427486279315327451698 #1 Medium (466)
Naked Single: r1c1=8
Naked Single: r1c3=9
Hidden Single: r6c6=7
Naked Single: r6c2=3
Hidden Single: r7c2=9
Hidden Single: r9c9=8
Locked Candidates Type 1 (Pointing): 6 in b7 => r4c3<>6
Locked Candidates Type 1 (Pointing): 4 in b9 => r7c13<>4
Naked Triple: 1,2,6 in r79c6,r8c4 => r7c4,r89c5<>1, r7c4<>6, r89c5<>2
Naked Single: r8c5=7
Naked Single: r8c8=1
Naked Single: r7c7=4
Full House: r7c9=7
Hidden Single: r6c7=1
Hidden Single: r4c4=1
Hidden Single: r1c5=1
Hidden Single: r4c5=9
Naked Single: r3c5=2
Naked Single: r2c5=3
Full House: r9c5=5
Naked Single: r3c1=7
Full House: r2c3=2
Naked Single: r7c4=3
Naked Single: r9c3=7
Naked Single: r9c2=2
Naked Single: r4c2=6
Full House: r5c2=7
Naked Single: r8c1=4
Naked Single: r9c6=1
Full House: r9c1=3
Naked Single: r4c9=3
Naked Single: r8c3=6
Full House: r8c4=2
Full House: r7c6=6
Naked Single: r7c3=5
Full House: r7c1=1
Naked Single: r1c6=4
Naked Single: r6c3=8
Full House: r4c3=4
Full House: r6c4=5
Naked Single: r1c9=6
Full House: r1c8=3
Full House: r3c9=4
Naked Single: r3c6=8
Full House: r4c6=2
Full House: r5c4=8
Naked Single: r2c4=9
Full House: r3c4=6
Naked Single: r3c8=5
Full House: r3c7=9
Naked Single: r4c1=5
Full House: r4c8=8
Full House: r5c1=2
Naked Single: r5c7=5
Full House: r2c7=8
Full House: r5c8=6
Full House: r2c8=7
|
normal_sudoku_573
|
.6.8.49.....2....44....5.8.8....1.7.75..4..1...1.3...8...18..4.1..45...7.....7...
|
367814952985276134412395786896521473753648219241739568679182345128453697534967821
|
Basic 9x9 Sudoku 573
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. 6 . 8 . 4 9 . .
. . . 2 . . . . 4
4 . . . . 5 . 8 .
8 . . . . 1 . 7 .
7 5 . . 4 . . 1 .
. . 1 . 3 . . . 8
. . . 1 8 . . 4 .
1 . . 4 5 . . . 7
. . . . . 7 . . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
367814952985276134412395786896521473753648219241739568679182345128453697534967821 #1 Extreme (33484) bf
Hidden Single: r1c6=4
Hidden Single: r5c6=8
Hidden Single: r6c4=7
Hidden Single: r4c4=5
Brute Force: r5c7=2
Brute Force: r5c9=9
Naked Single: r5c4=6
Full House: r5c3=3
Forcing Chain Contradiction in r2c8 => r8c8<>6
r8c8=6 r8c8<>9 r9c8=9 r9c4<>9 r9c4=3 r3c4<>3 r2c6=3 r2c8<>3
r8c8=6 r6c8<>6 r6c8=5 r2c8<>5
r8c8=6 r2c8<>6
Forcing Net Contradiction in r9 => r1c9<>3
r1c9=3 r4c9<>3 r4c9=6 (r6c7<>6) r6c8<>6 r6c1=6 r9c1<>6
r1c9=3 (r3c9<>3) (r1c8<>3) r4c9<>3 r4c9=6 (r3c9<>6) r6c8<>6 r6c8=5 (r2c8<>5 r2c7=5 r2c7<>1) r1c8<>5 r1c8=2 r3c9<>2 r3c9=1 (r9c9<>1 r9c7=1 r9c7<>8) r1c9<>1 r1c5=1 r2c5<>1 r2c2=1 r2c2<>8 r2c3=8 r9c3<>8 r9c2=8 r9c2<>4 r9c3=4 r9c3<>6
r1c9=3 (r2c8<>3) r4c9<>3 r4c9=6 (r3c9<>6) r6c8<>6 r6c8=5 r2c8<>5 r2c8=6 r3c7<>6 r3c5=6 r9c5<>6
r1c9=3 (r1c9<>5) r4c9<>3 (r4c7=3 r7c7<>3) r4c9=6 r6c8<>6 r6c8=5 (r1c8<>5) r2c8<>5 r2c7=5 r7c7<>5 r7c7=6 r9c7<>6
r1c9=3 (r2c8<>3) r4c9<>3 r4c9=6 r6c8<>6 r6c8=5 r2c8<>5 r2c8=6 r9c8<>6
r1c9=3 r4c9<>3 r4c9=6 r9c9<>6
Forcing Net Verity => r2c1<>3
r2c6=3 r2c1<>3
r2c6=6 (r2c6<>3 r3c4=3 r9c4<>3 r9c4=9 r9c1<>9) (r2c8<>6) (r2c5<>6) r3c5<>6 r9c5=6 (r9c5<>2 r4c5=2 r6c6<>2 r6c6=9 r6c1<>9) (r9c1<>6) r9c8<>6 r6c8=6 r6c1<>6 r7c1=6 r7c1<>9 r2c1=9 r2c1<>3
r2c6=9 (r6c6<>9 r6c6=2 r4c5<>2 r9c5=2 r9c8<>2) r3c4<>9 r9c4=9 r9c8<>9 r8c8=9 r8c8<>2 r1c8=2 r1c8<>3 r1c1=3 r2c1<>3
Forcing Net Contradiction in r8c8 => r2c5<>9
r2c5=9 (r3c4<>9 r9c4=9 r8c6<>9 r6c6=9 r6c1<>9) (r3c4<>9 r9c4=9 r9c1<>9) (r9c5<>9) r4c5<>9 r4c5=2 r9c5<>2 r9c5=6 (r9c1<>6) (r9c8<>6) r8c6<>6 r2c6=6 (r7c6<>6) r2c8<>6 r6c8=6 r6c1<>6 r7c1=6 r7c1<>9 r2c1=9 r2c5<>9
Forcing Net Contradiction in c1 => r2c6<>9
r2c6=9 (r6c6<>9 r6c6=2 r4c5<>2 r9c5=2 r9c8<>2) r3c4<>9 r9c4=9 r9c8<>9 r8c8=9 r8c8<>2 r1c8=2 r1c1<>2
r2c6=9 r6c6<>9 r6c6=2 r6c1<>2
r2c6=9 (r6c6<>9 r6c6=2 r4c5<>2 r9c5=2 r9c9<>2) (r6c6<>9 r6c6=2 r4c5<>2 r9c5=2 r9c8<>2) r3c4<>9 r9c4=9 r9c8<>9 r8c8=9 r8c8<>2 r1c8=2 (r1c9<>2) r3c9<>2 r7c9=2 r7c1<>2
r2c6=9 r6c6<>9 r6c6=2 r4c5<>2 r9c5=2 r9c1<>2
Locked Candidates Type 1 (Pointing): 9 in b2 => r3c23<>9
Almost Locked Set XY-Wing: A=r3c3 {27}, B=r9c14589 {123569}, C=r1c1389 {12357}, X,Y=1,7, Z=2 => r9c3<>2
Almost Locked Set XY-Wing: A=r49c5 {269}, B=r26c8 {356}, C=r123c5,r2c6 {13679}, X,Y=3,9, Z=6 => r9c8<>6
Discontinuous Nice Loop: 3 r9c9 -3- r9c4 =3= r3c4 -3- r2c6 -6- r2c8 =6= r6c8 -6- r4c9 -3- r9c9 => r9c9<>3
Forcing Chain Contradiction in b3 => r4c3<>2
r4c3=2 r4c3<>6 r6c1=6 r6c8<>6 r6c8=5 r1c8<>5
r4c3=2 r3c3<>2 r3c3=7 r1c3<>7 r1c5=7 r1c5<>1 r1c9=1 r1c9<>5
r4c3=2 r3c3<>2 r3c3=7 r3c7<>7 r2c7=7 r2c7<>5
r4c3=2 r4c3<>6 r6c1=6 r6c8<>6 r6c8=5 r2c8<>5
Forcing Chain Contradiction in r8c3 => r7c2<>2
r7c2=2 r8c3<>2
r7c2=2 r46c2<>2 r6c1=2 r6c1<>6 r4c3=6 r8c3<>6
r7c2=2 r7c2<>7 r7c3=7 r1c3<>7 r1c5=7 r1c5<>1 r1c9=1 r9c9<>1 r9c7=1 r9c7<>8 r8c7=8 r8c3<>8
r7c2=2 r4c2<>2 r4c5=2 r4c5<>9 r6c6=9 r7c6<>9 r7c123=9 r8c3<>9
Forcing Chain Contradiction in r9c8 => r9c3<>9
r9c3=9 r7c123<>9 r7c6=9 r6c6<>9 r6c6=2 r4c5<>2 r9c5=2 r9c8<>2
r9c3=9 r9c4<>9 r9c4=3 r9c8<>3
r9c3=9 r9c3<>4 r9c2=4 r6c2<>4 r6c7=4 r6c7<>5 r6c8=5 r9c8<>5
r9c3=9 r9c8<>9
Forcing Chain Verity => r9c7<>3
r8c3=6 r4c3<>6 r6c1=6 r6c8<>6 r2c8=6 r2c6<>6 r2c6=3 r3c4<>3 r9c4=3 r9c7<>3
r8c6=6 r2c6<>6 r2c6=3 r3c4<>3 r9c4=3 r9c7<>3
r8c7=6 r8c7<>8 r9c7=8 r9c7<>3
Forcing Net Verity => r2c1=9
r3c2=3 r3c2<>1 r2c2=1 (r2c2<>9) r2c2<>8 r2c3=8 r2c3<>9 r2c1=9
r3c4=3 (r9c4<>3 r9c4=9 r8c6<>9 r6c6=9 r6c1<>9) (r9c4<>3 r9c4=9 r9c1<>9) r2c6<>3 r2c6=6 (r2c8<>6 r6c8=6 r6c1<>6) (r2c5<>6) r3c5<>6 r9c5=6 r9c1<>6 r7c1=6 r7c1<>9 r2c1=9
r3c7=3 (r3c7<>7 r2c7=7 r2c2<>7) (r1c8<>3 r1c1=3 r7c1<>3) (r7c7<>3) (r3c4<>3 r9c4=3 r7c6<>3) r4c7<>3 r4c9=3 r7c9<>3 r7c2=3 r7c2<>7 r3c2=7 r3c2<>1 r2c2=1 (r2c2<>9) r2c2<>8 r2c3=8 r2c3<>9 r2c1=9
r3c9=3 (r1c8<>3 r1c1=3 r7c1<>3) (r3c4<>3 r9c4=3 r7c6<>3) (r7c9<>3) r4c9<>3 (r4c9=6 r6c8<>6 r6c8=5 r1c8<>5 r1c8=2 r1c3<>2) r4c7=3 r7c7<>3 r7c2=3 r7c2<>7 r7c3=7 r1c3<>7 r1c3=5 r2c1<>5 r2c1=9
Empty Rectangle: 9 in b8 (r6c26) => r9c2<>9
Finned X-Wing: 9 r67 c26 fr7c3 => r8c2<>9
Forcing Chain Contradiction in r8c2 => r1c1<>2
r1c1=2 r6c1<>2 r46c2=2 r8c2<>2
r1c1=2 r1c1<>3 r79c1=3 r8c2<>3
r1c1=2 r3c3<>2 r3c3=7 r1c3<>7 r1c5=7 r1c5<>1 r1c9=1 r9c9<>1 r9c7=1 r9c7<>8 r8c7=8 r8c2<>8
Forcing Chain Contradiction in r8c3 => r2c2<>3
r2c2=3 r2c2<>1 r3c2=1 r3c2<>2 r13c3=2 r8c3<>2
r2c2=3 r2c6<>3 r2c6=6 r2c8<>6 r6c8=6 r6c1<>6 r4c3=6 r8c3<>6
r2c2=3 r2c2<>8 r2c3=8 r8c3<>8
r2c2=3 r2c6<>3 r3c4=3 r3c4<>9 r9c4=9 r9c8<>9 r8c8=9 r8c3<>9
Turbot Fish: 3 r1c1 =3= r3c2 -3- r3c4 =3= r9c4 => r9c1<>3
Forcing Chain Contradiction in r7 => r7c3<>2
r7c3=2 r7c3<>7 r7c2=7 r7c2<>9
r7c3=2 r7c3<>9
r7c3=2 r79c1<>2 r6c1=2 r6c6<>2 r6c6=9 r7c6<>9
Forcing Chain Contradiction in c8 => r7c9<>3
r7c9=3 r7c1<>3 r1c1=3 r1c8<>3
r7c9=3 r4c9<>3 r4c9=6 r6c8<>6 r2c8=6 r2c8<>3
r7c9=3 r8c8<>3
r7c9=3 r9c8<>3
Forcing Chain Verity => r7c7<>5
r7c1=3 r1c1<>3 r1c1=5 r1c9<>5 r79c9=5 r7c7<>5
r7c2=3 r7c2<>7 r7c3=7 r1c3<>7 r1c5=7 r1c5<>1 r1c9=1 r1c9<>5 r79c9=5 r7c7<>5
r7c6=3 r2c6<>3 r2c6=6 r2c8<>6 r6c8=6 r6c8<>5 r6c7=5 r7c7<>5
r7c7=3 r7c7<>5
Almost Locked Set XY-Wing: A=r4c235 {2469}, B=r9c145789 {1235689}, C=r478c7 {3468}, X,Y=4,8, Z=6 => r9c3<>6
Almost Locked Set XY-Wing: A=r9c145789 {1235689}, B=r123478c3 {2456789}, C=r478c7 {3468}, X,Y=4,8, Z=5 => r9c3<>5
Forcing Chain Contradiction in r7c9 => r1c1=3
r1c1<>3 r1c8=3 r1c8<>2 r89c8=2 r7c9<>2
r1c1<>3 r1c1=5 r9c1<>5 r7c13=5 r7c9<>5
r1c1<>3 r7c1=3 r7c7<>3 r7c7=6 r7c9<>6
Locked Candidates Type 1 (Pointing): 5 in b1 => r7c3<>5
AIC: 1 1- r1c9 =1= r1c5 =7= r1c3 =5= r2c3 =8= r2c2 =1= r3c2 -1 => r3c79<>1
Discontinuous Nice Loop: 7 r3c5 -7- r3c7 =7= r2c7 =1= r1c9 -1- r1c5 -7- r3c5 => r3c5<>7
Discontinuous Nice Loop: 8 r8c2 -8- r8c7 =8= r9c7 =1= r9c9 -1- r1c9 =1= r1c5 =7= r1c3 =5= r2c3 =8= r2c2 -8- r8c2 => r8c2<>8
Grouped AIC: 6 6- r7c7 -3- r89c8 =3= r2c8 -3- r2c6 -6- r23c5 =6= r9c5 -6 => r7c6,r9c79<>6
XYZ-Wing: 2/3/9 in r67c6,r9c4 => r8c6<>9
Sashimi Swordfish: 6 c168 r268 fr7c1 fr9c1 => r8c3<>6
Empty Rectangle: 6 in b9 (r47c3) => r4c7<>6
W-Wing: 3/6 in r2c6,r7c7 connected by 6 in r8c67 => r2c7,r7c6<>3
Naked Pair: 2,9 in r67c6 => r8c6<>2
2-String Kite: 3 in r2c8,r9c4 (connected by r2c6,r3c4) => r9c8<>3
X-Wing: 3 c68 r28 => r8c27<>3
Naked Single: r8c2=2
Hidden Single: r4c5=2
Full House: r6c6=9
Naked Single: r6c2=4
Naked Single: r7c6=2
Naked Single: r4c2=9
Naked Single: r4c3=6
Full House: r6c1=2
Naked Single: r4c9=3
Full House: r4c7=4
Hidden Single: r9c3=4
Hidden Single: r7c3=9
Naked Single: r8c3=8
Naked Single: r8c7=6
Naked Single: r9c2=3
Naked Single: r6c7=5
Full House: r6c8=6
Naked Single: r7c7=3
Naked Single: r7c9=5
Naked Single: r8c6=3
Full House: r8c8=9
Full House: r2c6=6
Naked Single: r7c2=7
Full House: r7c1=6
Full House: r9c1=5
Naked Single: r9c4=9
Full House: r3c4=3
Full House: r9c5=6
Naked Single: r3c7=7
Naked Single: r9c8=2
Naked Single: r3c2=1
Full House: r2c2=8
Naked Single: r2c7=1
Full House: r9c7=8
Full House: r9c9=1
Naked Single: r3c3=2
Naked Single: r1c8=5
Full House: r2c8=3
Naked Single: r3c5=9
Full House: r3c9=6
Full House: r1c9=2
Naked Single: r2c5=7
Full House: r1c5=1
Full House: r1c3=7
Full House: r2c3=5
|
normal_sudoku_3887
|
4..6....1..1..3.7.9.....3....974.8...1..69...74..3..9..5...7.8.2...5......7..4.3.
|
435678921861923574972415368629741853513869247748532196356197482284356719197284635
|
Basic 9x9 Sudoku 3887
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
4 . . 6 . . . . 1
. . 1 . . 3 . 7 .
9 . . . . . 3 . .
. . 9 7 4 . 8 . .
. 1 . . 6 9 . . .
7 4 . . 3 . . 9 .
. 5 . . . 7 . 8 .
2 . . . 5 . . . .
. . 7 . . 4 . 3 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
435678921861923574972415368629741853513869247748532196356197482284356719197284635 #1 Extreme (15904) bf
Brute Force: r5c5=6
Hidden Single: r8c6=6
Empty Rectangle: 6 in b4 (r34c8) => r3c3<>6
Discontinuous Nice Loop: 6 r6c7 -6- r6c3 =6= r7c3 =4= r8c3 -4- r8c8 -1- r4c8 =1= r6c7 => r6c7<>6
Forcing Net Contradiction in r7c7 => r4c6=1
r4c6<>1 r4c8=1 (r4c8<>6) r8c8<>1 r8c8=4 (r7c7<>4) r7c9<>4 r7c3=4 r7c3<>6 r6c3=6 (r4c1<>6) r4c2<>6 r4c9=6 r4c9<>3 r5c9=3 (r5c9<>4) r5c9<>7 r5c7=7 r5c7<>4 r5c8=4 r8c8<>4 r8c8=1 r4c8<>1 r4c6=1
Hidden Single: r8c8=1
Hidden Single: r6c7=1
Forcing Chain Contradiction in r2 => r6c9<>2
r6c9=2 r4c89<>2 r4c2=2 r2c2<>2
r6c9=2 r6c6<>2 r56c4=2 r2c4<>2
r6c9=2 r6c6<>2 r13c6=2 r2c5<>2
r6c9=2 r45c8<>2 r13c8=2 r2c7<>2
r6c9=2 r2c9<>2
XYZ-Wing: 2/5/6 in r14c8,r6c9 => r5c8<>5
Forcing Chain Contradiction in r2 => r3c8=6
r3c8<>6 r4c8=6 r6c9<>6 r6c9=5 r4c89<>5 r4c1=5 r2c1<>5
r3c8<>6 r4c8=6 r6c9<>6 r6c9=5 r6c6<>5 r56c4=5 r2c4<>5
r3c8<>6 r4c8=6 r4c8<>5 r13c8=5 r2c7<>5
r3c8<>6 r4c8=6 r4c8<>5 r13c8=5 r2c9<>5
Hidden Single: r5c8=4
Locked Candidates Type 1 (Pointing): 6 in b6 => r79c9<>6
Empty Rectangle: 2 in b4 (r14c8) => r1c3<>2
Continuous Nice Loop: 2/5/6/9 6= r9c7 =5= r9c9 -5- r6c9 -6- r6c3 =6= r7c3 -6- r7c7 =6= r9c7 =5 => r9c7<>2, r2345c9<>5, r7c1<>6, r9c7<>9
Discontinuous Nice Loop: 9 r2c9 -9- r1c7 =9= r1c5 =7= r3c5 =1= r3c4 =4= r3c9 =8= r2c9 => r2c9<>9
Locked Candidates Type 1 (Pointing): 9 in b3 => r78c7<>9
Continuous Nice Loop: 2/3/4 6= r4c9 =3= r5c9 =7= r5c7 -7- r8c7 -4- r8c3 =4= r7c3 =6= r6c3 -6- r6c9 =6= r4c9 =3 => r45c9<>2, r7c3<>3, r8c9<>4
Discontinuous Nice Loop: 3 r4c1 -3- r4c9 -6- r6c9 -5- r4c8 =5= r4c1 => r4c1<>3
Discontinuous Nice Loop: 3 r8c3 -3- r7c1 =3= r5c1 -3- r5c9 -7- r5c7 =7= r8c7 =4= r8c3 => r8c3<>3
Discontinuous Nice Loop: 9 r8c4 -9- r8c9 -7- r5c9 -3- r5c1 =3= r7c1 -3- r7c4 =3= r8c4 => r8c4<>9
Discontinuous Nice Loop: 6 r9c1 -6- r7c3 -4- r8c3 -8- r8c4 -3- r8c2 =3= r7c1 =1= r9c1 => r9c1<>6
Sue de Coq: r8c23 - {3489} (r8c79 - {479}, r79c1 - {138}) => r9c2<>8
Grouped Discontinuous Nice Loop: 5 r1c6 -5- r1c8 -2- r4c8 =2= r4c2 -2- r123c2 =2= r3c3 =5= r3c46 -5- r1c6 => r1c6<>5
Forcing Chain Contradiction in b8 => r3c6=5
r3c6<>5 r6c6=5 r6c6<>2 r56c4=2 r7c4<>2
r3c6<>5 r6c6=5 r6c9<>5 r9c9=5 r9c9<>2 r7c79=2 r7c5<>2
r3c6<>5 r6c6=5 r6c6<>2 r56c4=2 r9c4<>2
r3c6<>5 r6c6=5 r6c6<>8 r56c4=8 r89c4<>8 r9c5=8 r9c5<>2
Skyscraper: 5 in r2c7,r4c8 (connected by r24c1) => r1c8,r5c7<>5
Naked Single: r1c8=2
Full House: r4c8=5
Naked Single: r1c6=8
Full House: r6c6=2
Naked Single: r4c1=6
Naked Single: r6c9=6
Naked Single: r4c9=3
Full House: r4c2=2
Naked Single: r5c9=7
Full House: r5c7=2
Naked Single: r8c9=9
Hidden Single: r9c9=5
Naked Single: r9c7=6
Naked Single: r7c7=4
Naked Single: r9c2=9
Naked Single: r7c3=6
Naked Single: r7c9=2
Full House: r8c7=7
Hidden Single: r9c5=8
Naked Single: r8c4=3
Naked Single: r9c1=1
Full House: r9c4=2
Naked Single: r8c2=8
Full House: r8c3=4
Full House: r7c1=3
Naked Single: r2c2=6
Naked Single: r3c2=7
Full House: r1c2=3
Naked Single: r1c3=5
Naked Single: r1c7=9
Full House: r1c5=7
Full House: r2c7=5
Naked Single: r2c1=8
Full House: r3c3=2
Full House: r5c1=5
Naked Single: r6c3=8
Full House: r5c3=3
Full House: r5c4=8
Full House: r6c4=5
Naked Single: r2c9=4
Full House: r3c9=8
Naked Single: r3c5=1
Full House: r3c4=4
Naked Single: r2c4=9
Full House: r2c5=2
Full House: r7c5=9
Full House: r7c4=1
|
normal_sudoku_3146
|
..7...3.6..8.37..43..........9.61..2..297..31.7...38...91..8.23.8....1..7...2.9..
|
417582396928637514365419287539861742842975631176243859691758423284396175753124968
|
Basic 9x9 Sudoku 3146
|
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 . 6
. . 8 . 3 7 . . 4
3 . . . . . . . .
. . 9 . 6 1 . . 2
. . 2 9 7 . . 3 1
. 7 . . . 3 8 . .
. 9 1 . . 8 . 2 3
. 8 . . . . 1 . .
7 . . . 2 . 9 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
417582396928637514365419287539861742842975631176243859691758423284396175753124968 #1 Hard (1508)
Hidden Single: r1c7=3
Hidden Single: r4c2=3
Hidden Single: r6c1=1
Hidden Single: r4c4=8
Hidden Single: r5c1=8
Hidden Single: r6c4=2
Hidden Single: r8c1=2
Hidden Single: r9c4=1
Hidden Single: r9c3=3
Hidden Single: r8c4=3
Hidden Single: r7c4=7
Locked Candidates Type 1 (Pointing): 6 in b8 => r3c6<>6
Locked Candidates Type 2 (Claiming): 4 in c4 => r1c56,r3c56<>4
Locked Candidates Type 2 (Claiming): 5 in c4 => r1c56,r3c56<>5
Locked Pair: 2,9 in r13c6 => r13c5,r8c6<>9
Hidden Single: r8c5=9
Skyscraper: 6 in r5c2,r7c1 (connected by r57c7) => r9c2<>6
Swordfish: 6 r689 c368 => r3c3<>6
Empty Rectangle: 4 in b9 (r67c5) => r6c8<>4
W-Wing: 5/4 in r4c1,r5c6 connected by 4 in r6c35 => r5c2<>5
2-String Kite: 5 in r5c7,r7c5 (connected by r5c6,r6c5) => r7c7<>5
Turbot Fish: 5 r6c3 =5= r4c1 -5- r7c1 =5= r7c5 => r6c5<>5
Naked Single: r6c5=4
Full House: r5c6=5
Naked Single: r7c5=5
Naked Pair: 4,6 in r57c7 => r4c7<>4
Remote Pair: 4/6 r5c2 -6- r5c7 -4- r7c7 -6- r7c1 => r4c1,r9c2<>4
Naked Single: r4c1=5
Naked Single: r9c2=5
Naked Single: r4c7=7
Full House: r4c8=4
Naked Single: r6c3=6
Full House: r5c2=4
Full House: r5c7=6
Naked Single: r9c9=8
Naked Single: r8c3=4
Full House: r3c3=5
Full House: r7c1=6
Full House: r7c7=4
Naked Single: r9c8=6
Full House: r9c6=4
Full House: r8c6=6
Naked Single: r3c7=2
Full House: r2c7=5
Naked Single: r2c1=9
Full House: r1c1=4
Naked Single: r3c6=9
Full House: r1c6=2
Naked Single: r2c4=6
Naked Single: r2c8=1
Full House: r2c2=2
Naked Single: r1c4=5
Full House: r3c4=4
Naked Single: r3c9=7
Naked Single: r1c2=1
Full House: r3c2=6
Naked Single: r3c8=8
Full House: r1c8=9
Full House: r1c5=8
Full House: r3c5=1
Naked Single: r8c9=5
Full House: r6c9=9
Full House: r6c8=5
Full House: r8c8=7
|
normal_sudoku_6626
|
3....6..8..67.8139..1..367.2.........542..7...9.....5......24.....6....7..2547.61
|
379416528546728139821953674218375946654289713793164852167832495435691287982547361
|
Basic 9x9 Sudoku 6626
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
3 . . . . 6 . . 8
. . 6 7 . 8 1 3 9
. . 1 . . 3 6 7 .
2 . . . . . . . .
. 5 4 2 . . 7 . .
. 9 . . . . . 5 .
. . . . . 2 4 . .
. . . 6 . . . . 7
. . 2 5 4 7 . 6 1
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
379416528546728139821953674218375946654289713793164852167832495435691287982547361 #1 Unfair (958)
Hidden Single: r2c8=3
Hidden Single: r4c6=5
Hidden Single: r6c6=4
Locked Candidates Type 2 (Claiming): 4 in r2 => r13c2,r3c1<>4
Empty Rectangle: 3 in b8 (r5c59) => r7c9<>3
Naked Single: r7c9=5
Hidden Single: r1c7=5
Hidden Single: r8c3=5
Locked Candidates Type 1 (Pointing): 3 in b9 => r46c7<>3
Finned Swordfish: 1 r167 c145 fr7c2 => r8c1<>1
Hidden Triple: 1,6,7 in r567c1 => r567c1<>8, r7c1<>9
Empty Rectangle: 8 in b8 (r5c58) => r7c8<>8
Naked Single: r7c8=9
Hidden Single: r4c7=9
Hidden Single: r1c3=9
Hidden Single: r9c1=9
Hidden Single: r3c4=9
Hidden Single: r1c2=7
Hidden Single: r3c9=4
Full House: r1c8=2
Naked Single: r1c5=1
Full House: r1c4=4
Naked Single: r8c8=8
Naked Single: r5c8=1
Full House: r4c8=4
Naked Single: r8c1=4
Naked Single: r9c7=3
Full House: r8c7=2
Full House: r9c2=8
Full House: r6c7=8
Naked Single: r5c1=6
Naked Single: r5c6=9
Full House: r8c6=1
Naked Single: r2c1=5
Naked Single: r3c2=2
Naked Single: r5c9=3
Full House: r5c5=8
Naked Single: r8c2=3
Full House: r8c5=9
Naked Single: r2c5=2
Full House: r2c2=4
Full House: r3c1=8
Full House: r3c5=5
Naked Single: r4c9=6
Full House: r6c9=2
Naked Single: r7c5=3
Full House: r7c4=8
Naked Single: r4c2=1
Full House: r7c2=6
Naked Single: r7c3=7
Full House: r7c1=1
Full House: r6c1=7
Naked Single: r4c5=7
Full House: r6c5=6
Naked Single: r4c4=3
Full House: r4c3=8
Full House: r6c3=3
Full House: r6c4=1
|
normal_sudoku_1497
|
1.59..3...42...961............7.163..1.5....97...6..15..1..7.......9.5......53.7.
|
185946327342875961967312854459721638216538749738469215521687493673194582894253176
|
Basic 9x9 Sudoku 1497
|
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 . 5 9 . . 3 . .
. 4 2 . . . 9 6 1
. . . . . . . . .
. . . 7 . 1 6 3 .
. 1 . 5 . . . . 9
7 . . . 6 . . 1 5
. . 1 . . 7 . . .
. . . . 9 . 5 . .
. . . . 5 3 . 7 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
185946327342875961967312854459721638216538749738469215521687493673194582894253176 #1 Extreme (14236) bf
Hidden Single: r5c2=1
Hidden Single: r2c5=7
Hidden Single: r6c6=9
Hidden Single: r3c8=5
Hidden Single: r8c4=1
Hidden Single: r9c7=1
Hidden Single: r2c6=5
Hidden Single: r3c5=1
Hidden Single: r5c7=7
Hidden Single: r7c8=9
Hidden Single: r5c5=3
Brute Force: r5c8=4
Finned Franken Swordfish: 2 c58b6 r147 fr6c7 fr8c8 => r7c7<>2
W-Wing: 8/2 in r1c8,r4c9 connected by 2 in r36c7 => r13c9<>8
Sashimi Swordfish: 8 c589 r147 fr8c8 fr8c9 fr9c9 => r7c7<>8
Naked Single: r7c7=4
Naked Pair: 2,8 in r1c8,r3c7 => r13c9<>2
Turbot Fish: 4 r6c3 =4= r6c4 -4- r9c4 =4= r8c6 => r8c3<>4
Forcing Chain Verity => r4c5<>8
r1c5=2 r1c5<>4 r4c5=4 r4c5<>8
r1c6=2 r5c6<>2 r5c6=8 r4c5<>8
r1c8=2 r1c8<>8 r8c8=8 r789c9<>8 r4c9=8 r4c5<>8
Skyscraper: 8 in r7c5,r8c8 (connected by r1c58) => r7c9,r8c6<>8
2-String Kite: 8 in r2c1,r7c5 (connected by r1c5,r2c4) => r7c1<>8
Turbot Fish: 8 r3c7 =8= r6c7 -8- r6c4 =8= r5c6 => r3c6<>8
2-String Kite: 8 in r2c1,r5c6 (connected by r1c6,r2c4) => r5c1<>8
Discontinuous Nice Loop: 6 r3c3 -6- r5c3 -8- r5c6 =8= r1c6 =6= r1c2 -6- r3c3 => r3c3<>6
Discontinuous Nice Loop: 2 r6c2 -2- r6c7 -8- r6c4 =8= r5c6 =2= r5c1 -2- r6c2 => r6c2<>2
Almost Locked Set XZ-Rule: A=r1c58 {248}, B=r4c5,r5c6 {248}, X=4, Z=8 => r1c6<>8
Hidden Single: r5c6=8
Naked Single: r5c3=6
Full House: r5c1=2
Finned X-Wing: 2 c68 r18 fr3c6 => r1c5<>2
XY-Chain: 8 8- r2c1 -3- r2c4 -8- r1c5 -4- r4c5 -2- r4c9 -8- r6c7 -2- r3c7 -8 => r3c123<>8
Turbot Fish: 8 r2c1 =8= r1c2 -8- r1c8 =8= r8c8 => r8c1<>8
Sashimi Swordfish: 8 r236 c147 fr6c2 fr6c3 => r4c1<>8
XY-Chain: 8 8- r1c5 -4- r4c5 -2- r4c9 -8- r6c7 -2- r3c7 -8 => r1c8,r3c4<>8
Naked Single: r1c8=2
Full House: r8c8=8
Naked Single: r3c7=8
Full House: r6c7=2
Full House: r4c9=8
Naked Single: r6c4=4
Full House: r4c5=2
Naked Single: r7c5=8
Full House: r1c5=4
Naked Single: r1c6=6
Naked Single: r1c9=7
Full House: r1c2=8
Full House: r3c9=4
Naked Single: r3c6=2
Full House: r8c6=4
Naked Single: r2c1=3
Full House: r2c4=8
Full House: r3c4=3
Naked Single: r6c2=3
Full House: r6c3=8
Naked Single: r8c1=6
Naked Single: r3c1=9
Naked Single: r7c1=5
Naked Single: r3c3=7
Full House: r3c2=6
Naked Single: r4c1=4
Full House: r9c1=8
Naked Single: r7c2=2
Naked Single: r8c3=3
Naked Single: r4c3=9
Full House: r4c2=5
Full House: r9c3=4
Naked Single: r7c4=6
Full House: r7c9=3
Full House: r9c4=2
Naked Single: r8c2=7
Full House: r9c2=9
Full House: r8c9=2
Full House: r9c9=6
|
normal_sudoku_243
|
..74.....2....5....6......982.6.39.59...5.3....5...21..89.36..1..3..4....5.17..3.
|
597461823248395167361827549824613975916752384735948216489236751173584692652179438
|
Basic 9x9 Sudoku 243
|
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 4 . . . . .
2 . . . . 5 . . .
. 6 . . . . . . 9
8 2 . 6 . 3 9 . 5
9 . . . 5 . 3 . .
. . 5 . . . 2 1 .
. 8 9 . 3 6 . . 1
. . 3 . . 4 . . .
. 5 . 1 7 . . 3 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
597461823248395167361827549824613975916752384735948216489236751173584692652179438 #1 Extreme (2522)
Hidden Single: r4c6=3
Hidden Single: r9c3=2
Hidden Single: r9c6=9
Hidden Single: r8c8=9
Hidden Single: r4c8=7
Hidden Single: r5c3=6
Hidden Single: r6c9=6
Locked Candidates Type 1 (Pointing): 4 in b6 => r5c2<>4
Locked Candidates Type 1 (Pointing): 8 in b6 => r5c46<>8
Locked Candidates Type 1 (Pointing): 4 in b7 => r36c1<>4
Locked Candidates Type 1 (Pointing): 8 in b8 => r8c79<>8
Locked Candidates Type 1 (Pointing): 6 in b9 => r12c7<>6
Naked Pair: 1,7 in r58c2 => r12c2<>1, r6c2<>7
Naked Pair: 4,8 in r59c9 => r12c9<>8, r2c9<>4
W-Wing: 2/7 in r5c4,r8c9 connected by 7 in r58c2 => r8c4<>2
Finned X-Wing: 2 c59 r18 fr3c5 => r1c6<>2
XYZ-Wing: 1/2/8 in r1c6,r38c5 => r12c5<>8
Sue de Coq: r56c6 - {1278} (r1c6 - {18}, r5c4 - {27}) => r6c4<>7, r3c6<>1, r3c6<>8
XY-Chain: 7 7- r8c2 -1- r5c2 -7- r5c4 -2- r7c4 -5- r8c4 -8- r8c5 -2- r8c9 -7 => r8c17<>7
XY-Chain: 3 3- r1c9 -2- r8c9 -7- r8c2 -1- r5c2 -7- r6c1 -3 => r1c1<>3
Naked Triple: 1,5,8 in r1c167 => r1c5<>1, r1c8<>5, r1c8<>8
XY-Wing: 1/6/5 in r18c1,r8c7 => r1c7<>5
Hidden Single: r1c1=5
Empty Rectangle: 1 in b1 (r4c35) => r3c5<>1
Naked Pair: 2,8 in r38c5 => r1c5<>2, r6c5<>8
Locked Candidates Type 1 (Pointing): 2 in b2 => r3c8<>2
XY-Wing: 3/4/9 in r16c2,r6c5 => r1c5<>9
Naked Single: r1c5=6
Naked Single: r1c8=2
Naked Single: r1c9=3
Naked Single: r1c2=9
Naked Single: r2c9=7
Naked Single: r8c9=2
Naked Single: r8c5=8
Naked Single: r3c5=2
Naked Single: r8c4=5
Full House: r7c4=2
Naked Single: r3c6=7
Naked Single: r8c7=6
Naked Single: r5c4=7
Naked Single: r6c6=8
Naked Single: r8c1=1
Full House: r8c2=7
Naked Single: r5c2=1
Naked Single: r1c6=1
Full House: r5c6=2
Full House: r1c7=8
Naked Single: r6c4=9
Naked Single: r3c1=3
Naked Single: r7c1=4
Full House: r9c1=6
Full House: r6c1=7
Naked Single: r4c3=4
Full House: r4c5=1
Full House: r6c5=4
Full House: r2c5=9
Full House: r6c2=3
Full House: r2c2=4
Naked Single: r9c7=4
Full House: r9c9=8
Full House: r5c9=4
Full House: r5c8=8
Naked Single: r3c4=8
Full House: r2c4=3
Naked Single: r7c8=5
Full House: r7c7=7
Naked Single: r2c7=1
Full House: r3c7=5
Naked Single: r2c8=6
Full House: r3c8=4
Full House: r3c3=1
Full House: r2c3=8
|
normal_sudoku_1905
|
.4.5....285.....61..6.18.5..3..7.2..98...3..5....86...41......8.6.3....95......1.
|
147569832852734961396218457631975284984123675725486193413697528268351749579842316
|
Basic 9x9 Sudoku 1905
|
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 . 5 . . . . 2
8 5 . . . . . 6 1
. . 6 . 1 8 . 5 .
. 3 . . 7 . 2 . .
9 8 . . . 3 . . 5
. . . . 8 6 . . .
4 1 . . . . . . 8
. 6 . 3 . . . . 9
5 . . . . . . 1 .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
147569832852734961396218457631975284984123675725486193413697528268351749579842316 #1 Easy (356)
Naked Single: r4c2=3
Hidden Single: r1c5=6
Hidden Single: r5c7=6
Naked Single: r4c9=4
Naked Single: r5c8=7
Naked Single: r6c9=3
Naked Single: r3c9=7
Full House: r9c9=6
Naked Single: r6c8=9
Naked Single: r4c8=8
Full House: r6c7=1
Naked Single: r1c8=3
Naked Single: r7c8=2
Full House: r8c8=4
Hidden Single: r4c6=5
Naked Single: r4c3=1
Naked Single: r4c1=6
Full House: r4c4=9
Hidden Single: r1c7=8
Hidden Single: r8c3=8
Hidden Single: r9c4=8
Hidden Single: r6c3=5
Hidden Single: r8c6=1
Hidden Single: r2c5=3
Hidden Single: r7c4=6
Hidden Single: r3c1=3
Hidden Single: r1c1=1
Hidden Single: r5c4=1
Hidden Single: r6c4=4
Full House: r5c5=2
Full House: r5c3=4
Naked Single: r3c4=2
Full House: r2c4=7
Naked Single: r8c5=5
Naked Single: r3c2=9
Full House: r3c7=4
Full House: r2c7=9
Naked Single: r1c6=9
Full House: r1c3=7
Full House: r2c3=2
Full House: r2c6=4
Naked Single: r7c5=9
Full House: r9c5=4
Naked Single: r8c7=7
Full House: r8c1=2
Full House: r6c1=7
Full House: r6c2=2
Full House: r9c2=7
Naked Single: r7c6=7
Full House: r9c6=2
Naked Single: r7c3=3
Full House: r7c7=5
Full House: r9c7=3
Full House: r9c3=9
|
normal_sudoku_1295
|
.....8...62.14....7......8.43..9....1......278.2.....6....8.9.....75.2..59....6..
|
913528764628147539745963182437296815169835427852471396271684953386759241594312678
|
Basic 9x9 Sudoku 1295
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . . 8 . . .
6 2 . 1 4 . . . .
7 . . . . . . 8 .
4 3 . . 9 . . . .
1 . . . . . . 2 7
8 . 2 . . . . . 6
. . . . 8 . 9 . .
. . . 7 5 . 2 . .
5 9 . . . . 6 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
913528764628147539745963182437296815169835427852471396271684953386759241594312678 #1 Easy (412)
Naked Single: r4c1=4
Naked Single: r8c1=3
Naked Single: r1c1=9
Full House: r7c1=2
Hidden Single: r2c3=8
Hidden Single: r6c8=9
Hidden Single: r5c3=9
Hidden Single: r8c6=9
Hidden Single: r8c2=8
Hidden Single: r1c8=6
Hidden Single: r3c4=9
Hidden Single: r9c9=8
Hidden Single: r2c9=9
Hidden Single: r8c3=6
Hidden Single: r5c2=6
Naked Single: r5c5=3
Hidden Single: r3c5=6
Hidden Single: r6c7=3
Hidden Single: r5c7=4
Naked Single: r5c6=5
Full House: r5c4=8
Naked Single: r6c4=4
Hidden Single: r4c7=8
Hidden Single: r1c4=5
Hidden Single: r6c2=5
Full House: r4c3=7
Hidden Single: r3c3=5
Naked Single: r3c7=1
Naked Single: r1c7=7
Full House: r2c7=5
Naked Single: r3c2=4
Naked Single: r1c5=2
Naked Single: r2c8=3
Full House: r2c6=7
Full House: r3c6=3
Full House: r3c9=2
Full House: r1c9=4
Naked Single: r1c2=1
Full House: r1c3=3
Full House: r7c2=7
Naked Single: r9c5=1
Full House: r6c5=7
Full House: r6c6=1
Naked Single: r8c9=1
Full House: r8c8=4
Naked Single: r9c3=4
Full House: r7c3=1
Naked Single: r4c9=5
Full House: r4c8=1
Full House: r7c9=3
Naked Single: r7c8=5
Full House: r9c8=7
Naked Single: r9c6=2
Full House: r9c4=3
Naked Single: r7c4=6
Full House: r4c4=2
Full House: r4c6=6
Full House: r7c6=4
|
normal_sudoku_6094
|
8...9...61.64.79...9.....7......2..1.8..467....2..8....6...4.535..3......4..1.6..
|
837291546126457938495683172654972381389146725712538469961724853578369214243815697
|
Basic 9x9 Sudoku 6094
|
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
1 . 6 4 . 7 9 . .
. 9 . . . . . 7 .
. . . . . 2 . . 1
. 8 . . 4 6 7 . .
. . 2 . . 8 . . .
. 6 . . . 4 . 5 3
5 . . 3 . . . . .
. 4 . . 1 . 6 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
837291546126457938495683172654972381389146725712538469961724853578369214243815697 #1 Extreme (14366) bf
Brute Force: r5c6=6
Naked Single: r8c6=9
Naked Single: r9c6=5
Hidden Single: r3c4=6
Hidden Single: r8c5=6
Locked Candidates Type 1 (Pointing): 8 in b2 => r7c5<>8
Locked Candidates Type 1 (Pointing): 1 in b5 => r1c4<>1
Locked Candidates Type 1 (Pointing): 3 in b5 => r23c5<>3
Locked Candidates Type 1 (Pointing): 9 in b9 => r9c13<>9
Sashimi X-Wing: 3 r25 c28 fr5c1 fr5c3 => r46c2<>3
Locked Candidates Type 2 (Claiming): 3 in c2 => r13c3,r3c1<>3
Hidden Pair: 1,3 in r3c67 => r3c7<>2, r3c7<>4, r3c7<>5, r3c7<>8
Uniqueness Test 1: 1/3 in r1c67,r3c67 => r1c7<>1, r1c7<>3
Almost Locked Set XZ-Rule: A=r3579c1 {23479}, B=r13c3 {457}, X=4, Z=7 => r789c3<>7
Hidden Rectangle: 5/7 in r1c23,r4c23 => r1c3<>5
Forcing Chain Contradiction in r5 => r1c2<>2
r1c2=2 r3c1<>2 r3c1=4 r3c3<>4 r3c3=5 r5c3<>5
r1c2=2 r1c4<>2 r1c4=5 r5c4<>5
r1c2=2 r1c4<>2 r1c4=5 r1c7<>5 r46c7=5 r5c9<>5
Discontinuous Nice Loop: 5/9 r5c4 =1= r5c3 -1- r7c3 =1= r7c7 -1- r3c7 -3- r2c8 =3= r2c2 =2= r8c2 =1= r6c2 -1- r6c4 =1= r5c4 => r5c4<>5, r5c4<>9
Naked Single: r5c4=1
Hidden Single: r6c2=1
Avoidable Rectangle Type 1: 1/6 in r3c46,r5c46 => r3c6<>1
Naked Single: r3c6=3
Full House: r1c6=1
Naked Single: r3c7=1
Hidden Single: r8c8=1
Naked Single: r8c3=8
Naked Single: r9c3=3
Hidden Single: r7c3=1
Hidden Single: r7c1=9
Naked Single: r5c1=3
Locked Candidates Type 1 (Pointing): 3 in b3 => r46c8<>3
Locked Candidates Type 2 (Claiming): 7 in r7 => r9c4<>7
Discontinuous Nice Loop: 7 r4c1 -7- r9c1 -2- r9c4 -8- r7c4 =8= r7c7 -8- r4c7 =8= r4c8 =6= r4c1 => r4c1<>7
Hidden Rectangle: 4/6 in r4c18,r6c18 => r6c8<>4
Discontinuous Nice Loop: 5 r1c2 -5- r1c4 -2- r9c4 -8- r7c4 =8= r7c7 -8- r4c7 =8= r4c8 =4= r1c8 =3= r1c2 => r1c2<>5
2-String Kite: 5 in r2c2,r5c9 (connected by r4c2,r5c3) => r2c9<>5
Hidden Rectangle: 2/8 in r2c59,r3c59 => r3c5<>2
2-String Kite: 2 in r3c9,r8c2 (connected by r2c2,r3c1) => r8c9<>2
W-Wing: 8/2 in r2c9,r7c7 connected by 2 in r27c5 => r9c9<>8
Locked Candidates Type 2 (Claiming): 8 in c9 => r2c8<>8
Finned Swordfish: 2 c257 r278 fr1c7 => r2c89<>2
Naked Single: r2c8=3
Naked Single: r2c9=8
Hidden Single: r1c2=3
Hidden Single: r3c5=8
Hidden Single: r1c3=7
Locked Candidates Type 1 (Pointing): 4 in b1 => r3c9<>4
X-Wing: 5 r35 c39 => r4c3,r6c9<>5
Turbot Fish: 5 r1c4 =5= r2c5 -5- r2c2 =5= r4c2 => r4c4<>5
W-Wing: 4/9 in r4c3,r6c9 connected by 9 in r46c4 => r4c78,r6c1<>4
Hidden Single: r1c8=4
Swordfish: 2 c189 r359 => r9c4<>2
Naked Single: r9c4=8
Hidden Single: r7c7=8
Hidden Single: r4c8=8
Hidden Single: r4c1=6
Naked Single: r6c1=7
Naked Single: r4c2=5
Naked Single: r9c1=2
Full House: r3c1=4
Full House: r8c2=7
Full House: r2c2=2
Full House: r3c3=5
Full House: r2c5=5
Full House: r3c9=2
Full House: r1c4=2
Full House: r1c7=5
Naked Single: r4c7=3
Naked Single: r5c3=9
Full House: r4c3=4
Naked Single: r9c8=9
Full House: r9c9=7
Naked Single: r8c9=4
Full House: r8c7=2
Full House: r6c7=4
Naked Single: r6c5=3
Naked Single: r7c4=7
Full House: r7c5=2
Full House: r4c5=7
Full House: r4c4=9
Full House: r6c4=5
Naked Single: r5c8=2
Full House: r5c9=5
Full House: r6c8=6
Full House: r6c9=9
|
normal_sudoku_4715
|
.3...4..9476....3...1...4..7.9......36..1...4.2...9.5.6..2...98.9.86.1...1..4.3..
|
532674819476198532981325467759436281368512974124789653643251798297863145815947326
|
Basic 9x9 Sudoku 4715
|
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 . . . 4 . . 9
4 7 6 . . . . 3 .
. . 1 . . . 4 . .
7 . 9 . . . . . .
3 6 . . 1 . . . 4
. 2 . . . 9 . 5 .
6 . . 2 . . . 9 8
. 9 . 8 6 . 1 . .
. 1 . . 4 . 3 . .
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
532674819476198532981325467759436281368512974124789653643251798297863145815947326 #1 Extreme (2362)
Hidden Single: r2c1=4
Hidden Single: r5c7=9
Hidden Single: r6c1=1
Hidden Single: r7c6=1
Hidden Single: r8c8=4
Hidden Single: r9c4=9
Hidden Single: r3c1=9
Hidden Single: r2c5=9
Locked Candidates Type 1 (Pointing): 2 in b1 => r1c578<>2
Skyscraper: 2 in r2c7,r3c5 (connected by r4c57) => r2c6,r3c89<>2
Discontinuous Nice Loop: 8 r3c5 -8- r2c6 =8= r2c7 =2= r4c7 -2- r4c5 =2= r3c5 => r3c5<>8
Discontinuous Nice Loop: 8 r5c6 -8- r2c6 =8= r2c7 =2= r4c7 -2- r5c8 =2= r5c6 => r5c6<>8
2-String Kite: 8 in r3c2,r5c8 (connected by r4c2,r5c3) => r3c8<>8
Grouped Discontinuous Nice Loop: 5 r1c4 -5- r2c6 -8- r3c6 =8= r3c2 =5= r1c13 -5- r1c4 => r1c4<>5
Grouped Discontinuous Nice Loop: 5 r1c5 -5- r2c6 -8- r3c6 =8= r3c2 =5= r1c13 -5- r1c5 => r1c5<>5
XY-Wing: 5/8/7 in r1c5,r29c6 => r3c6,r7c5<>7
Locked Candidates Type 1 (Pointing): 7 in b8 => r5c6<>7
Sashimi Swordfish: 5 c257 r347 fr1c7 fr2c7 => r3c9<>5
Locked Pair: 6,7 in r3c89 => r1c78,r3c46<>6, r1c78,r3c45<>7
Hidden Single: r4c6=6
Hidden Single: r1c4=6
Hidden Single: r6c7=6
Hidden Single: r1c8=1
Hidden Single: r2c4=1
Hidden Single: r1c5=7
Hidden Single: r7c7=7
Hidden Single: r4c9=1
Hidden Single: r6c9=3
Naked Single: r6c5=8
Naked Single: r6c3=4
Full House: r6c4=7
Naked Single: r5c4=5
Naked Single: r3c4=3
Full House: r4c4=4
Naked Single: r5c3=8
Full House: r4c2=5
Naked Single: r5c6=2
Full House: r4c5=3
Full House: r5c8=7
Naked Single: r3c2=8
Full House: r7c2=4
Naked Single: r7c5=5
Full House: r3c5=2
Full House: r7c3=3
Naked Single: r3c8=6
Naked Single: r3c6=5
Full House: r3c9=7
Full House: r2c6=8
Naked Single: r9c6=7
Full House: r8c6=3
Naked Single: r9c8=2
Full House: r4c8=8
Full House: r4c7=2
Naked Single: r8c9=5
Full House: r9c9=6
Full House: r2c9=2
Full House: r2c7=5
Full House: r1c7=8
Naked Single: r9c3=5
Full House: r9c1=8
Naked Single: r8c1=2
Full House: r1c1=5
Full House: r1c3=2
Full House: r8c3=7
|
normal_sudoku_2737
|
18......44....8....2.....6..18..23..3.9....7.2.4..3.51....3.......95...2..12.46.3
|
187629534436578129925341867518792346369415278274863951692137485843956712751284693
|
Basic 9x9 Sudoku 2737
|
puzzles1_unbiased
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
1 8 . . . . . . 4
4 . . . . 8 . . .
. 2 . . . . . 6 .
. 1 8 . . 2 3 . .
3 . 9 . . . . 7 .
2 . 4 . . 3 . 5 1
. . . . 3 . . . .
. . . 9 5 . . . 2
. . 1 2 . 4 6 . 3
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
187629534436578129925341867518792346369415278274863951692137485843956712751284693 #1 Extreme (3516)
Hidden Single: r6c1=2
Hidden Single: r5c7=2
Hidden Single: r7c3=2
Hidden Single: r4c8=4
Locked Triple: 1,8,9 in r789c8 => r12c8,r7c79<>9, r2c8,r78c7<>1, r7c79,r8c7<>8
Locked Candidates Type 1 (Pointing): 9 in b5 => r123c5<>9
Locked Candidates Type 1 (Pointing): 5 in b9 => r7c12<>5
Locked Candidates Type 2 (Claiming): 5 in c3 => r2c2,r3c1<>5
Hidden Rectangle: 4/7 in r7c27,r8c27 => r7c2<>7
Discontinuous Nice Loop: 6 r4c4 -6- r4c9 =6= r5c9 -6- r5c2 -5- r4c1 =5= r4c4 => r4c4<>6
Grouped Discontinuous Nice Loop: 6 r1c6 -6- r78c6 =6= r7c4 =8= r9c5 =7= r9c12 -7- r8c3 =7= r123c3 -7- r3c1 -9- r3c6 =9= r1c6 => r1c6<>6
Almost Locked Set XZ-Rule: A=r4c4 {57}, B=r578c6 {1567}, X=5, Z=7 => r7c4<>7
Almost Locked Set XZ-Rule: A=r5c269 {1568}, B=r78c6,r9c5 {1678}, X=1, Z=8 => r5c5<>8
Grouped Discontinuous Nice Loop: 5/7 r1c6 =9= r1c7 -9- r6c7 -8- r6c5 =8= r9c5 =7= r9c12 -7- r8c3 =7= r123c3 -7- r3c1 -9- r3c6 =9= r1c6 => r1c6<>5, r1c6<>7
Naked Single: r1c6=9
Naked Triple: 4,5,7 in r178c7 => r23c7<>5, r23c7<>7
Grouped Discontinuous Nice Loop: 1 r2c4 -1- r2c7 -9- r6c7 -8- r5c9 =8= r5c4 =4= r5c5 =1= r23c5 -1- r2c4 => r2c4<>1
Grouped Discontinuous Nice Loop: 7 r2c2 -7- r6c2 -6- r5c2 -5- r5c6 =5= r3c6 =7= r78c6 -7- r9c5 =7= r9c12 -7- r8c3 =7= r123c3 -7- r2c2 => r2c2<>7
Grouped Discontinuous Nice Loop: 7 r3c1 -7- r3c6 =7= r78c6 -7- r9c5 =7= r9c12 -7- r8c3 =7= r123c3 -7- r3c1 => r3c1<>7
Naked Single: r3c1=9
Locked Candidates Type 1 (Pointing): 7 in b1 => r8c3<>7
Discontinuous Nice Loop: 5/7 r2c9 =9= r2c7 -9- r6c7 -8- r6c5 =8= r9c5 -8- r9c8 -9- r9c2 =9= r7c2 =4= r8c2 =3= r8c3 -3- r3c3 =3= r3c4 =4= r5c4 =8= r5c9 =6= r4c9 =9= r2c9 => r2c9<>5, r2c9<>7
Naked Single: r2c9=9
Naked Single: r2c7=1
Naked Single: r4c9=6
Naked Single: r3c7=8
Naked Single: r5c9=8
Full House: r6c7=9
Hidden Single: r4c5=9
Locked Candidates Type 1 (Pointing): 6 in b4 => r278c2<>6
Naked Single: r2c2=3
Naked Single: r2c8=2
Naked Single: r1c8=3
Hidden Single: r3c4=3
Hidden Single: r8c3=3
Hidden Single: r1c5=2
Hidden Single: r3c5=4
Hidden Single: r5c4=4
Hidden Single: r3c6=1
Hidden Single: r5c5=1
Hidden Single: r7c4=1
Hidden Single: r8c8=1
Hidden Single: r5c6=5
Full House: r5c2=6
Naked Single: r4c4=7
Full House: r4c1=5
Full House: r6c2=7
Naked Single: r8c2=4
Naked Single: r7c2=9
Full House: r9c2=5
Naked Single: r8c7=7
Naked Single: r7c8=8
Full House: r9c8=9
Naked Single: r1c7=5
Full House: r3c9=7
Full House: r7c9=5
Full House: r7c7=4
Full House: r3c3=5
Naked Single: r8c6=6
Full House: r7c6=7
Full House: r8c1=8
Full House: r7c1=6
Full House: r9c5=8
Full House: r9c1=7
Naked Single: r1c4=6
Full House: r1c3=7
Full House: r2c3=6
Naked Single: r6c5=6
Full House: r2c5=7
Full House: r2c4=5
Full House: r6c4=8
|
normal_sudoku_5828
|
5...4......6..5..1.1.2.........1.9...61..3..7..37...2..87.5..9..3.4.....6....7..8
|
579341682326985471418276539752814963961523847843769125187652394235498716694137258
|
Basic 9x9 Sudoku 5828
|
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 . . . .
. . 6 . . 5 . . 1
. 1 . 2 . . . . .
. . . . 1 . 9 . .
. 6 1 . . 3 . . 7
. . 3 7 . . . 2 .
. 8 7 . 5 . . 9 .
. 3 . 4 . . . . .
6 . . . . 7 . . 8
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
579341682326985471418276539752814963961523847843769125187652394235498716694137258 #1 Extreme (39394) bf
Brute Force: r5c3=1
Hidden Single: r6c7=1
Grouped Discontinuous Nice Loop: 4 r9c8 -4- r7c79 =4= r7c1 =1= r8c1 -1- r8c8 =1= r9c8 => r9c8<>4
Forcing Chain Contradiction in c6 => r8c1<>9
r8c1=9 r89c3<>9 r13c3=9 r2c12<>9 r2c45=9 r1c6<>9
r8c1=9 r89c3<>9 r13c3=9 r2c12<>9 r2c45=9 r3c6<>9
r8c1=9 r5c1<>9 r5c45=9 r6c6<>9
r8c1=9 r8c6<>9
Forcing Net Verity => r1c9<>3
r7c1=1 r8c1<>1 r8c1=2 (r8c9<>2) (r8c6<>2) r5c1<>2 r5c5=2 r4c6<>2 r7c6=2 r7c9<>2 r1c9=2 r1c9<>3
r7c1=2 (r7c9<>2) (r7c6<>2) r5c1<>2 r5c5=2 r4c6<>2 r8c6=2 r8c9<>2 r1c9=2 r1c9<>3
r7c1=4 (r3c1<>4) (r2c1<>4) (r5c1<>4) (r9c2<>4) r9c3<>4 r9c7=4 (r3c7<>4) (r2c7<>4) r5c7<>4 r5c8=4 (r3c8<>4) r2c8<>4 r2c2=4 r3c3<>4 r3c9=4 r3c9<>9 r1c9=9 r1c9<>3
Forcing Net Verity => r1c9<>6
r7c1=1 r8c1<>1 r8c1=2 (r8c9<>2) (r8c6<>2) r5c1<>2 r5c5=2 r4c6<>2 r7c6=2 r7c9<>2 r1c9=2 r1c9<>6
r7c1=2 (r7c9<>2) (r7c6<>2) r5c1<>2 r5c5=2 r4c6<>2 r8c6=2 r8c9<>2 r1c9=2 r1c9<>6
r7c1=4 (r3c1<>4) (r2c1<>4) (r5c1<>4) (r9c2<>4) r9c3<>4 r9c7=4 (r3c7<>4) (r2c7<>4) r5c7<>4 r5c8=4 (r3c8<>4) r2c8<>4 r2c2=4 r3c3<>4 r3c9=4 r3c9<>9 r1c9=9 r1c9<>6
Forcing Net Verity => r2c1<>8
r7c1=1 r8c1<>1 r8c1=2 (r4c1<>2) (r2c1<>2) (r9c2<>2) (r9c3<>2) r5c1<>2 r5c5=2 (r4c6<>2) r9c5<>2 r9c7=2 r2c7<>2 r2c2=2 r4c2<>2 r4c3=2 r4c3<>8 r456c1=8 r2c1<>8
r7c1=2 (r4c1<>2) (r2c1<>2) (r9c2<>2) (r9c3<>2) r5c1<>2 r5c5=2 (r4c6<>2) r9c5<>2 r9c7=2 r2c7<>2 r2c2=2 r4c2<>2 r4c3=2 r4c3<>8 r456c1=8 r2c1<>8
r7c1=4 (r9c3<>4) (r2c1<>4) (r5c1<>4) (r9c2<>4) r9c3<>4 r9c7=4 (r2c7<>4) r5c7<>4 r5c8=4 r2c8<>4 r2c2=4 r3c3<>4 r4c3=4 r4c3<>8 r456c1=8 r2c1<>8
Forcing Net Verity => r2c2<>7
r7c1=1 r8c1<>1 r8c1=2 (r2c1<>2) (r9c2<>2) (r9c3<>2) r5c1<>2 r5c5=2 r9c5<>2 r9c7=2 r2c7<>2 r2c2=2 r2c2<>7
r7c1=2 (r2c1<>2) (r9c2<>2) (r9c3<>2) r5c1<>2 r5c5=2 r9c5<>2 r9c7=2 r2c7<>2 r2c2=2 r2c2<>7
r7c1=4 (r2c1<>4) (r5c1<>4) (r9c2<>4) r9c3<>4 r9c7=4 (r2c7<>4) r5c7<>4 r5c8=4 r2c8<>4 r2c2=4 r2c2<>7
Forcing Net Verity => r2c2<>9
r7c1=1 r8c1<>1 r8c1=2 (r2c1<>2) (r9c2<>2) (r9c3<>2) r5c1<>2 r5c5=2 r9c5<>2 r9c7=2 r2c7<>2 r2c2=2 r2c2<>9
r7c1=2 (r2c1<>2) (r9c2<>2) (r9c3<>2) r5c1<>2 r5c5=2 r9c5<>2 r9c7=2 r2c7<>2 r2c2=2 r2c2<>9
r7c1=4 (r2c1<>4) (r5c1<>4) (r9c2<>4) r9c3<>4 r9c7=4 (r2c7<>4) r5c7<>4 r5c8=4 r2c8<>4 r2c2=4 r2c2<>9
Forcing Chain Contradiction in r5 => r3c5<>9
r3c5=9 r2c45<>9 r2c1=9 r5c1<>9
r3c5=9 r2c45<>9 r2c1=9 r56c1<>9 r6c2=9 r6c2<>5 r6c9=5 r5c78<>5 r5c4=5 r5c4<>9
r3c5=9 r5c5<>9
Forcing Net Verity => r1c4<>9
r5c1=9 r2c1<>9 r2c45=9 r1c4<>9
r5c4=9 r1c4<>9
r5c5=9 r5c5<>2 r5c1=2 (r5c1<>4) (r7c1<>2) r8c1<>2 r8c1=1 r7c1<>1 r7c1=4 (r3c1<>4) (r2c1<>4) (r9c2<>4) r9c3<>4 r9c7=4 (r3c7<>4) (r2c7<>4) r5c7<>4 r5c8=4 (r3c8<>4) r2c8<>4 r2c2=4 r3c3<>4 r3c9=4 r3c9<>9 r1c9=9 r1c4<>9
Forcing Net Verity => r1c6<>9
r6c2=9 (r5c1<>9) r6c2<>5 r6c9=5 (r5c7<>5) r5c8<>5 r5c4=5 r5c4<>9 r5c5=9 r5c5<>2 r5c1=2 (r5c1<>4) (r7c1<>2) r8c1<>2 r8c1=1 r7c1<>1 r7c1=4 (r3c1<>4) (r2c1<>4) (r9c2<>4) r9c3<>4 r9c7=4 (r3c7<>4) (r2c7<>4) r5c7<>4 r5c8=4 (r3c8<>4) r2c8<>4 r2c2=4 r3c3<>4 r3c9=4 r3c9<>9 r1c9=9 r1c6<>9
r6c2<>9 r56c1=9 r2c1<>9 r2c45=9 r1c6<>9
Forcing Net Verity => r3c1<>8
r7c1=1 r8c1<>1 r8c1=2 (r4c1<>2) (r2c1<>2) (r9c2<>2) (r9c3<>2) r5c1<>2 r5c5=2 (r4c6<>2) r9c5<>2 r9c7=2 r2c7<>2 r2c2=2 r4c2<>2 r4c3=2 r4c3<>8 r456c1=8 r3c1<>8
r7c1=2 (r4c1<>2) (r2c1<>2) (r9c2<>2) (r9c3<>2) r5c1<>2 r5c5=2 (r4c6<>2) r9c5<>2 r9c7=2 r2c7<>2 r2c2=2 r4c2<>2 r4c3=2 r4c3<>8 r456c1=8 r3c1<>8
r7c1=4 (r9c3<>4) (r2c1<>4) (r5c1<>4) (r9c2<>4) r9c3<>4 r9c7=4 (r2c7<>4) r5c7<>4 r5c8=4 r2c8<>4 r2c2=4 r3c3<>4 r4c3=4 r4c3<>8 r456c1=8 r3c1<>8
Locked Candidates Type 1 (Pointing): 8 in b1 => r4c3<>8
Forcing Net Contradiction in r9 => r3c1<>9
r3c1=9 (r3c1<>3 r2c1=3 r2c1<>4) (r5c1<>9) (r5c1<>9) r6c1<>9 r6c2=9 (r6c6<>9 r8c6=9 r9c5<>9 r9c3=9 r9c3<>4) r6c2<>5 r6c9=5 (r5c7<>5) r5c8<>5 r5c4=5 r5c4<>9 r5c5=9 r5c5<>2 r5c1=2 (r5c1<>4) (r7c1<>2) r8c1<>2 r8c1=1 r7c1<>1 r7c1=4 (r9c2<>4) r9c3<>4 r9c7=4 (r2c7<>4) r5c7<>4 r5c8=4 r2c8<>4 r2c2=4 r3c3<>4 r4c3=4 r4c3<>5 r46c2=5 r9c2<>5
r3c1=9 (r3c6<>9) (r5c1<>9) r6c1<>9 r6c2=9 (r9c2<>9) r6c6<>9 r8c6=9 (r9c4<>9) r9c5<>9 r9c3=9 r9c3<>5
r3c1=9 (r5c1<>9) (r5c1<>9) r6c1<>9 r6c2=9 r6c2<>5 r6c9=5 (r5c7<>5) r5c8<>5 r5c4=5 r5c4<>9 r5c5=9 r5c5<>2 r5c1=2 (r7c1<>2) r8c1<>2 r8c1=1 r7c1<>1 r7c1=4 (r9c2<>4) r9c3<>4 r9c7=4 r9c7<>5
r3c1=9 (r5c1<>9) (r5c1<>9) r6c1<>9 r6c2=9 r6c2<>5 r6c9=5 (r5c7<>5) r5c8<>5 r5c4=5 r5c4<>9 r5c5=9 r5c5<>2 r5c1=2 r8c1<>2 r8c1=1 r8c8<>1 r9c8=1 r9c8<>5
Forcing Net Contradiction in r5c7 => r3c9<>3
r3c9=3 (r1c8<>3 r1c4=3 r9c4<>3) (r1c8<>3 r1c4=3 r2c5<>3 r2c1=3 r2c1<>9) r3c9<>9 r1c9=9 (r1c2<>9) r1c3<>9 r3c3=9 (r8c3<>9) r9c3<>9 r9c2=9 (r9c2<>2) r9c4<>9 r9c4=1 (r7c4<>1) r7c6<>1 r7c1=1 r8c1<>1 r8c1=2 (r9c3<>2) r5c1<>2 r5c5=2 r9c5<>2 r9c7=2 (r7c9<>2) r8c9<>2 r1c9=2 r1c9<>9 r3c9=9 r3c9<>3
Forcing Net Verity => r3c9<>5
r7c1=1 r8c1<>1 r8c1=2 (r9c2<>2) (r9c3<>2) r5c1<>2 r5c5=2 (r4c6<>2 r7c6=2 r7c9<>2) r9c5<>2 r9c7=2 r8c9<>2 r1c9=2 r1c9<>9 r3c9=9 r3c9<>5
r7c1=2 (r7c9<>2) (r7c6<>2) r5c1<>2 r5c5=2 r4c6<>2 r8c6=2 r8c9<>2 r1c9=2 r1c9<>9 r3c9=9 r3c9<>5
r7c1=4 (r3c1<>4) (r2c1<>4) (r5c1<>4) (r9c2<>4) r9c3<>4 r9c7=4 (r3c7<>4) (r2c7<>4) r5c7<>4 r5c8=4 (r3c8<>4) r2c8<>4 r2c2=4 r3c3<>4 r3c9=4 r3c9<>5
Forcing Net Verity => r3c9<>6
r7c1=1 r8c1<>1 r8c1=2 (r9c2<>2) (r9c3<>2) r5c1<>2 r5c5=2 (r4c6<>2 r7c6=2 r7c9<>2) r9c5<>2 r9c7=2 r8c9<>2 r1c9=2 r1c9<>9 r3c9=9 r3c9<>6
r7c1=2 (r7c9<>2) (r7c6<>2) r5c1<>2 r5c5=2 r4c6<>2 r8c6=2 r8c9<>2 r1c9=2 r1c9<>9 r3c9=9 r3c9<>6
r7c1=4 (r3c1<>4) (r2c1<>4) (r5c1<>4) (r9c2<>4) r9c3<>4 r9c7=4 (r3c7<>4) (r2c7<>4) r5c7<>4 r5c8=4 (r3c8<>4) r2c8<>4 r2c2=4 r3c3<>4 r3c9=4 r3c9<>6
Forcing Net Verity => r4c3<>5
r7c1=1 r8c1<>1 r8c1=2 (r4c1<>2) (r2c1<>2) (r9c2<>2) (r9c3<>2) r5c1<>2 r5c5=2 (r4c6<>2) r9c5<>2 r9c7=2 r2c7<>2 r2c2=2 r4c2<>2 r4c3=2 r4c3<>5
r7c1=2 (r4c1<>2) (r2c1<>2) (r9c2<>2) (r9c3<>2) r5c1<>2 r5c5=2 (r4c6<>2) r9c5<>2 r9c7=2 r2c7<>2 r2c2=2 r4c2<>2 r4c3=2 r4c3<>5
r7c1=4 (r9c3<>4) (r2c1<>4) (r5c1<>4) (r9c2<>4) r9c3<>4 r9c7=4 (r2c7<>4) r5c7<>4 r5c8=4 r2c8<>4 r2c2=4 r3c3<>4 r4c3=4 r4c3<>5
Locked Candidates Type 1 (Pointing): 5 in b4 => r9c2<>5
Forcing Net Verity => r1c7<>2
r2c1=2 (r4c1<>2) (r7c1<>2) r8c1<>2 r8c1=1 r7c1<>1 r7c1=4 r9c3<>4 (r9c7=4 r9c7<>5 r9c3=5 r9c3<>2) r4c3=4 r4c3<>2 r4c2=2 (r9c2<>2) (r9c2<>2) r2c2<>2 r2c2=4 (r3c3<>4) r9c2<>4 r9c2=9 (r9c4<>9) r9c5<>9 r9c5=3 r9c4<>3 r9c4=1 (r7c4<>1) r7c6<>1 r7c1=1 r8c1<>1 r8c1=2 r5c1<>2 r5c5=2 (r9c5<>2) (r4c6<>2) r9c5<>2 r9c7=2 r1c7<>2
r4c1=2 (r2c1<>2) (r4c3<>2 r4c3=4 r4c2<>4) (r4c3<>2 r4c3=4 r6c2<>4) (r7c1<>2) r8c1<>2 r8c1=1 r7c1<>1 r7c1=4 r9c2<>4 r2c2=4 r2c2<>2 r2c7=2 r1c7<>2
r5c1=2 (r2c1<>2) (r4c3<>2 r4c3=4 r4c2<>4) (r4c3<>2 r4c3=4 r6c2<>4) (r7c1<>2) r8c1<>2 r8c1=1 r7c1<>1 r7c1=4 r9c2<>4 r2c2=4 r2c2<>2 r2c7=2 r1c7<>2
r7c1=2 (r9c2<>2) (r9c3<>2) r5c1<>2 r5c5=2 r9c5<>2 r9c7=2 r1c7<>2
r8c1=2 (r9c2<>2) (r9c3<>2) r5c1<>2 r5c5=2 r9c5<>2 r9c7=2 r1c7<>2
Forcing Net Contradiction in c1 => r2c1<>2
r2c1=2 (r2c2<>2 r2c2=4 r6c2<>4) (r7c1<>2) r8c1<>2 r8c1=1 r7c1<>1 r7c1=4 (r9c3<>4 r9c7=4 r5c7<>4) r6c1<>4 r6c9=4 r5c8<>4 r5c1=4
r2c1=2 (r7c1<>2) r8c1<>2 r8c1=1 r7c1<>1 r7c1=4
Forcing Chain Contradiction in r9 => r4c2<>2
r4c2=2 r9c2<>2
r4c2=2 r45c1<>2 r78c1=2 r9c3<>2
r4c2=2 r4c6<>2 r5c5=2 r9c5<>2
r4c2=2 r2c2<>2 r2c7=2 r9c7<>2
Forcing Net Contradiction in r8 => r4c2<>4
r4c2=4 (r4c3<>4 r4c3=2 r8c3<>2) (r9c2<>4) r2c2<>4 r2c2=2 r9c2<>2 r9c2=9 r8c3<>9 r8c3=5
r4c2=4 (r4c2<>5 r6c2=5 r6c9<>5 r6c9=6 r8c9<>6) r2c2<>4 r2c2=2 (r1c2<>2) r1c3<>2 r1c9=2 r8c9<>2 r8c9=5
Forcing Net Verity => r1c7<>8
r1c3=2 (r4c3<>2 r4c3=4 r9c3<>4 r9c7=4 r5c7<>4) (r1c9<>2 r1c9=9 r1c2<>9) (r1c2<>2) r2c2<>2 r9c2=2 r9c2<>9 r6c2=9 r6c2<>5 r6c9=5 r5c7<>5 r5c7=8 r1c7<>8
r1c3=8 r1c7<>8
r1c3=9 (r1c3<>8 r3c3=8 r3c6<>8 r3c6=6 r3c7<>6) (r9c3<>9) (r1c3<>8 r3c3=8 r3c3<>4) r1c9<>9 r1c9=2 (r1c2<>2 r1c2=7 r4c2<>7 r4c2=5 r6c2<>5 r6c9=5 r8c9<>5) r2c7<>2 r2c2=2 r2c2<>4 r6c2=4 r4c3<>4 (r4c3=2 r9c3<>2) (r4c3=2 r5c1<>2 r5c5=2 r9c5<>2) r9c3=4 (r9c3<>5) r9c3<>5 r8c3=5 r8c3<>9 r9c2=9 (r9c2<>4) r9c2<>2 r9c7=2 r9c7<>5 r9c8=5 r9c8<>1 r8c8=1 (r8c8<>7 r8c7=7 r8c7<>6) r8c1<>1 r8c1=2 r8c9<>2 r8c9=6 r7c7<>6 r1c7=6 r1c7<>8
Forcing Net Verity => r1c6<>8
r1c3=2 (r2c2<>2 r9c2=2 r9c5<>2) (r4c3<>2 r4c3=4 r5c1<>4) (r2c2<>2 r9c2=2 r9c2<>9 r6c2=9 r5c1<>9) (r2c2<>2 r2c7=2 r2c7<>8) r1c3<>8 r3c3=8 r3c7<>8 r5c7=8 r5c1<>8 r5c1=2 r5c5<>2 r8c5=2 r8c5<>8 r8c6=8 r1c6<>8
r1c3=8 r1c6<>8
r1c3=9 (r9c3<>9) (r1c3<>8 r3c3=8 r3c3<>4) r1c9<>9 r1c9=2 r2c7<>2 r2c2=2 r2c2<>4 r6c2=4 r4c3<>4 (r4c3=2 r9c3<>2) (r4c3=2 r5c1<>2 r5c5=2 r9c5<>2) r9c3=4 (r9c3<>5) r9c3<>5 r8c3=5 r8c3<>9 r9c2=9 (r9c2<>4) r9c2<>2 r9c7=2 r9c7<>5 r9c8=5 r9c8<>1 r9c4=1 r1c4<>1 r1c6=1 r1c6<>8
Forcing Net Contradiction in r9 => r2c7<>7
r2c7=7 (r1c8<>7 r1c2=7 r4c2<>7 r4c2=5 r6c2<>5) (r1c8<>7 r1c2=7 r1c2<>9) (r1c8<>7 r1c2=7 r1c2<>2) r2c7<>2 r2c2=2 r1c3<>2 r1c9=2 r1c9<>9 r1c3=9 (r8c3<>9) r9c3<>9 r9c2=9 (r9c4<>9) (r9c5<>9) r6c2<>9 r6c2=4 r4c3<>4 r4c3=2 r5c1<>2 r5c5=2 r9c5<>2 r9c5=3 r9c4<>3 r9c4=1
r2c7=7 r8c7<>7 r8c8=7 r8c8<>1 r9c8=1
Forcing Net Contradiction in r9c4 => r3c7<>4
r3c7=4 (r3c3<>4) (r3c3<>4) r3c9<>4 r3c9=9 r3c3<>9 r3c3=8 (r3c6<>8 r3c6=6 r1c6<>6 r1c6=1 r7c6<>1 r7c6=2 r9c5<>2) r1c3<>8 r1c3=9 (r9c3<>9) r1c9<>9 r1c9=2 (r1c3<>2) r2c7<>2 r2c2=2 r2c2<>4 r6c2=4 r4c3<>4 r9c3=4 (r9c3<>5) (r9c3<>2) r9c3<>5 r8c3=5 r8c3<>9 r9c2=9 (r9c2<>4) r9c2<>2 r9c7=2 r9c7<>5 r9c8=5 r3c8<>5 r3c7=5 r3c7<>4
Forcing Net Contradiction in r9 => r4c8<>4
r4c8=4 (r4c3<>4 r4c3=2 r8c3<>2) (r4c8<>6) r4c8<>3 r4c9=3 (r4c9<>5) r4c9<>6 r6c9=6 r6c9<>5 r8c9=5 r8c3<>5 r8c3=9 r9c2<>9
r4c8=4 (r4c3<>4 r4c3=2 r8c3<>2) (r4c8<>6) r4c8<>3 r4c9=3 (r4c9<>5) r4c9<>6 r6c9=6 r6c9<>5 r8c9=5 r8c3<>5 r8c3=9 r9c3<>9
r4c8=4 (r5c8<>4 r5c1=4 r5c1<>9) r4c3<>4 r4c3=2 r5c1<>2 r5c5=2 r5c5<>9 r5c4=9 r9c4<>9
r4c8=4 (r4c6<>4 r6c6=4 r6c6<>9) (r5c8<>4 r5c1=4 r5c1<>9) r4c3<>4 r4c3=2 r5c1<>2 r5c5=2 r5c5<>9 r5c4=9 (r2c4<>9) (r6c5<>9) r5c4<>5 r4c4=5 r4c2<>5 r6c2=5 r6c2<>9 r6c1=9 r2c1<>9 r2c5=9 r9c5<>9
Forcing Net Contradiction in r5c4 => r4c9<>4
r4c9=4 (r4c3<>4 r4c3=2 r8c3<>2) (r3c9<>4 r3c9=9 r3c6<>9) r4c6<>4 r6c6=4 r6c6<>9 r8c6=9 r8c3<>9 r8c3=5 r8c9<>5 r46c9=5 r5c78<>5 r5c4=5
r4c9=4 (r5c8<>4 r5c1=4 r5c1<>9) r4c3<>4 r4c3=2 r5c1<>2 r5c5=2 r5c5<>9 r5c4=9
Forcing Net Contradiction in r5c4 => r2c7<>3
r2c7=3 (r1c8<>3 r1c4=3 r7c4<>3 r7c9=3 r7c9<>4) r2c7<>2 r2c2=2 (r1c2<>2) r1c3<>2 r1c9=2 r1c9<>9 r3c9=9 (r3c6<>9) r3c9<>4 r6c9=4 (r5c8<>4 r5c1=4 r4c3<>4 r4c3=2 r8c3<>2) (r5c8<>4 r5c1=4 r5c1<>9) r6c9<>5 r6c2=5 r6c2<>9 r6c1=9 r6c6<>9 r8c6=9 r8c3<>9 r8c3=5 r8c9<>5 r46c9=5 r5c78<>5 r5c4=5
r2c7=3 (r1c8<>3 r1c4=3 r7c4<>3 r7c9=3 r7c9<>4) r2c7<>2 r2c2=2 (r1c2<>2) r1c3<>2 r1c9=2 r1c9<>9 r3c9=9 r3c9<>4 r6c9=4 (r5c7<>4) r5c8<>4 r5c1=4 (r5c1<>9) r5c1<>2 r5c5=2 r5c5<>9 r5c4=9
Forcing Net Contradiction in r4c4 => r2c1<>4
r2c1=4 (r2c1<>7) r2c1<>3 r3c1=3 r3c1<>7 r4c1=7 r4c2<>7 r4c2=5 r4c4<>5
r2c1=4 (r2c1<>7) r2c1<>3 r3c1=3 r3c1<>7 r4c1=7 r4c2<>7 r4c2=5 r6c2<>5 r6c9=5 r6c9<>6 r4c89=6 r4c4<>6
r2c1=4 (r2c2<>4 r2c2=2 r2c7<>2 r2c7=8 r1c8<>8) (r2c2<>4 r2c2=2 r1c3<>2 r1c9=2 r1c9<>9) (r2c1<>7) r2c1<>3 r3c1=3 r3c1<>7 r4c1=7 r4c2<>7 r1c2=7 r1c2<>9 r1c3=9 r1c3<>8 r1c4=8 r4c4<>8
Sue de Coq: r2c78 - {23478} (r2c145 - {3789}, r13c9 - {249}) => r3c8<>4
Forcing Net Contradiction in r5c4 => r5c1<>4
r5c1=4 (r4c3<>4 r4c3=2 r8c3<>2) (r5c8<>4 r2c8=4 r3c9<>4 r3c9=9 r3c6<>9) (r5c1<>9) r5c1<>2 r5c5=2 r5c5<>9 r5c4=9 r6c6<>9 r8c6=9 r8c3<>9 r8c3=5 r8c9<>5 r46c9=5 r5c78<>5 r5c4=5
r5c1=4 (r5c1<>9) r5c1<>2 r5c5=2 r5c5<>9 r5c4=9
Locked Candidates Type 2 (Claiming): 4 in r5 => r6c9<>4
Forcing Net Verity => r1c4<>8
r1c3=2 (r1c3<>8 r3c3=8 r3c7<>8 r5c7=8 r5c7<>5) (r4c3<>2 r4c3=4 r6c1<>4) (r1c9<>2 r1c9=9 r1c2<>9) (r1c2<>2) r2c2<>2 r9c2=2 r9c2<>9 r6c2=9 (r6c5<>9) r6c1<>9 r6c1=8 r6c5<>8 r6c5=6 (r4c4<>6) r6c9<>6 r6c9=5 r5c8<>5 r5c4=5 r4c4<>5 r4c4=8 r1c4<>8
r1c3=8 r1c4<>8
r1c3=9 (r9c3<>9 r9c2=9 r9c4<>9) (r9c3<>9 r9c2=9 r9c2<>4) r1c9<>9 (r3c9=9 r3c9<>4 r7c9=4 r9c7<>4 r9c3=4 r9c3<>5 r8c3=5 r8c3<>9 r9c2=9 r9c5<>9 r9c5=3 r7c4<>3) (r3c9=9 r3c9<>4 r7c9=4 r9c7<>4 r9c3=4 r9c3<>5 r8c3=5 r8c3<>9 r9c2=9 r9c2<>2 r9c7=2 r9c7<>5 r9c8=5 r9c8<>1 r9c4=1 r9c4<>3) r1c9=2 r2c7<>2 r2c2=2 r2c2<>4 r6c2=4 r6c2<>5 r6c9=5 r5c8<>5 r5c4=5 (r5c7<>5) r5c4<>9 r2c4=9 r2c4<>3 r1c4=3 r1c4<>8
Forcing Net Contradiction in c4 => r3c7<>3
r3c7=3 (r3c1<>3) (r7c7<>3) (r1c7<>3) r1c8<>3 r1c4=3 r7c4<>3 r7c9=3 r7c9<>4 r3c9=4 r3c1<>4 r3c1=7 (r3c5<>7 r2c5=7 r2c5<>9) r3c1<>3 r2c1=3 r2c1<>9 r2c4=9
r3c7=3 (r3c7<>5 r3c8=5 r9c8<>5) (r3c5<>3) (r1c7<>3) r1c8<>3 r1c4=3 (r9c4<>3) r2c5<>3 r9c5=3 r9c8<>3 r9c8=1 r9c4<>1 r9c4=9
Forcing Net Verity => r4c6<>8
r6c5=6 (r4c4<>6) r6c9<>6 r6c9=5 (r5c7<>5) r5c8<>5 r5c4=5 r4c4<>5 r4c4=8 r4c6<>8
r6c5=8 r4c6<>8
r6c5=9 (r2c5<>9) (r5c4<>9) r5c5<>9 r5c1=9 r2c1<>9 r2c4=9 r2c4<>8 r45c4=8 r4c6<>8
Forcing Net Verity => r3c7<>7
r6c2=4 (r2c2<>4 r2c2=2 r9c2<>2 r9c2=9 r8c3<>9 r8c3=5 r8c7<>5) (r2c2<>4 r2c2=2 r1c3<>2 r1c9=2 r8c9<>2 r8c9=6 r8c7<>6) (r2c2<>4 r2c2=2 r9c2<>2) r4c3<>4 r4c3=2 (r9c3<>2) r5c1<>2 r5c5=2 r9c5<>2 r9c7=2 r8c7<>2 r8c7=7 r3c7<>7
r6c2=5 r4c2<>5 r4c2=7 r1c2<>7 r1c78=7 r3c7<>7
r6c2=9 (r1c2<>9) r6c2<>5 r4c2=5 r4c2<>7 r1c2=7 (r1c2<>2) r1c2<>2 r1c3=2 (r1c3<>8 r1c8=8 r2c8<>8) (r1c3<>8 r1c8=8 r4c8<>8) (r4c3<>2 r4c3=4 r6c1<>4) r2c2<>2 r9c2=2 r9c2<>9 r6c2=9 (r1c2<>9) r6c1<>9 (r2c1=9 r1c3<>9 r1c9=9 r1c9<>2 r2c7=2 r2c7<>8) (r2c1=9 r1c3<>9 r1c9=9 r1c9<>2) r6c1=8 r4c1<>8 r4c4=8 r2c4<>8 r2c5=8 r2c5<>7 r3c5=7 r3c7<>7
Forcing Chain Verity => r8c7<>5
r4c9=5 r4c9<>3 r4c8=3 r123c8<>3 r1c7=3 r1c7<>7 r8c7=7 r8c7<>5
r6c9=5 r6c2<>5 r4c2=5 r4c2<>7 r1c2=7 r1c7<>7 r8c7=7 r8c7<>5
r8c9=5 r8c7<>5
Forcing Net Verity => r3c8<>7
r6c2=4 r2c2<>4 r2c2=2 (r9c2<>2 r9c2=9 r1c2<>9) (r1c2<>2) r1c3<>2 r1c9=2 r1c9<>9 (r3c9=9 r3c6<>9) r1c3=9 (r2c1<>9 r2c1=3 r3c1<>3) r1c3<>8 r3c3=8 r3c6<>8 r3c6=6 r1c6<>6 r1c6=1 r1c4<>1 r1c4=3 (r1c4<>6) r3c5<>3 r3c8=3 r3c8<>7
r6c2=5 r4c2<>5 r4c2=7 r1c2<>7 r1c78=7 r3c8<>7
r6c2=9 (r1c2<>9) r6c2<>5 r4c2=5 r4c2<>7 r1c2=7 (r1c2<>2) r1c2<>2 r1c3=2 (r1c3<>8 r1c8=8 r2c8<>8) (r1c3<>8 r1c8=8 r4c8<>8) (r4c3<>2 r4c3=4 r6c1<>4) r2c2<>2 r9c2=2 r9c2<>9 r6c2=9 (r1c2<>9) r6c1<>9 (r2c1=9 r1c3<>9 r1c9=9 r1c9<>2 r2c7=2 r2c7<>8) (r2c1=9 r1c3<>9 r1c9=9 r1c9<>2) r6c1=8 r4c1<>8 r4c4=8 r2c4<>8 r2c5=8 r2c5<>7 r3c5=7 r3c8<>7
Forcing Net Contradiction in r8 => r1c3<>2
r1c3=2 (r2c2<>2 r9c2=2 r9c5<>2) (r2c2<>2 r9c2=2 r9c2<>9 r6c2=9 r5c1<>9) (r2c2<>2 r2c7=2 r2c7<>8) r1c3<>8 r1c8=8 r3c7<>8 r5c7=8 r5c1<>8 r5c1=2 r5c5<>2 r8c5=2
r1c3=2 (r1c3<>8 r1c8=8 r1c8<>3) (r1c2<>2) r2c2<>2 r9c2=2 r8c1<>2 r8c1=1 r8c8<>1 r9c8=1 r9c8<>3 r4c8=3 r4c9<>3 r7c9=3 (r7c9<>2) r7c9<>4 r3c9=4 r3c9<>9 r1c9=9 (r1c2<>9 r1c2=7 r3c1<>7 r3c1=3 r3c8<>3) (r1c2<>9 r1c2=7 r1c7<>7 r8c7=7 r8c8<>7 r2c8=7 r2c8<>3) r1c9<>2 r8c9=2
Locked Candidates Type 1 (Pointing): 2 in b1 => r9c2<>2
Discontinuous Nice Loop: 6 r4c9 -6- r6c9 -5- r6c2 =5= r4c2 =7= r1c2 =2= r1c9 =9= r3c9 =4= r7c9 =3= r4c9 => r4c9<>6
Discontinuous Nice Loop: 6 r7c9 -6- r6c9 -5- r6c2 =5= r4c2 =7= r1c2 =2= r1c9 =9= r3c9 =4= r7c9 => r7c9<>6
Grouped Discontinuous Nice Loop: 9 r3c6 -9- r3c9 -4- r2c78 =4= r2c2 -4- r9c2 -9- r6c2 =9= r56c1 -9- r2c1 =9= r2c45 -9- r3c6 => r3c6<>9
Locked Candidates Type 1 (Pointing): 9 in b2 => r2c1<>9
Locked Candidates Type 2 (Claiming): 9 in c1 => r6c2<>9
Hidden Rectangle: 3/7 in r2c15,r3c15 => r3c5<>3
AIC: 2/8 2- r5c5 =2= r5c1 =9= r6c1 -9- r6c6 =9= r8c6 =8= r8c5 -8 => r8c5<>2, r5c5<>8
Grouped AIC: 2/9 9- r5c1 =9= r6c1 =8= r6c56 -8- r45c4 =8= r2c4 =9= r2c5 -9- r5c5 -2 => r5c1<>2, r5c5<>9
Naked Single: r5c5=2
Sue de Coq: r9c23 - {2459} (r9c458 - {1359}, r78c1 - {124}) => r8c3<>2, r9c7<>3, r9c7<>5
Sue de Coq: r78c9 - {23456} (r46c9 - {356}, r9c7 - {24}) => r78c7<>2, r7c7<>4
Naked Triple: 3,6,7 in r178c7 => r3c7<>6
AIC: 9 9- r1c2 =9= r9c2 -9- r8c3 -5- r9c3 =5= r9c8 =1= r8c8 -1- r8c1 =1= r7c1 =4= r7c9 -4- r3c9 -9 => r1c9,r3c3<>9
Naked Single: r1c9=2
Hidden Single: r3c9=9
Hidden Single: r2c2=2
Hidden Single: r9c7=2
Hidden Single: r7c9=4
Hidden Single: r4c3=2
Hidden Single: r4c9=3
Uniqueness Test 3: 1/2 in r7c16,r8c16 => r1c6<>6
Naked Single: r1c6=1
Hidden Rectangle: 4/8 in r2c78,r5c78 => r5c8<>8
XY-Chain: 5 5- r8c3 -9- r9c2 -4- r6c2 -5- r6c9 -6- r8c9 -5 => r8c8<>5
XY-Chain: 9 9- r8c3 -5- r8c9 -6- r6c9 -5- r6c2 -4- r9c2 -9 => r9c3<>9
XY-Chain: 6 6- r3c6 -8- r3c3 -4- r9c3 -5- r8c3 -9- r9c2 -4- r6c2 -5- r6c9 -6 => r6c6<>6
AIC: 9 9- r5c1 -8- r5c7 =8= r4c8 -8- r1c8 =8= r1c3 =9= r8c3 -9- r8c6 =9= r6c6 -9 => r5c4,r6c1<>9
Hidden Single: r5c1=9
Hidden Rectangle: 3/9 in r2c45,r9c45 => r2c4<>3
AIC: 4 4- r4c6 =4= r6c6 =9= r8c6 -9- r8c3 =9= r9c2 =4= r6c2 -4 => r4c1,r6c6<>4
Hidden Single: r4c6=4
Empty Rectangle: 6 in b2 (r4c48) => r3c8<>6
Locked Candidates Type 1 (Pointing): 6 in b3 => r1c4<>6
Naked Single: r1c4=3
Hidden Single: r7c7=3
Hidden Single: r9c5=3
Locked Candidates Type 1 (Pointing): 6 in b9 => r8c56<>6
Hidden Rectangle: 8/9 in r6c56,r8c56 => r6c6<>8
Naked Single: r6c6=9
W-Wing: 9/8 in r2c4,r8c5 connected by 8 in r38c6 => r2c5,r9c4<>9
Naked Single: r9c4=1
Naked Single: r7c4=6
Naked Single: r9c8=5
Naked Single: r7c6=2
Full House: r7c1=1
Naked Single: r5c8=4
Naked Single: r8c9=6
Full House: r6c9=5
Naked Single: r9c3=4
Full House: r9c2=9
Naked Single: r8c6=8
Full House: r3c6=6
Full House: r8c5=9
Naked Single: r8c1=2
Full House: r8c3=5
Naked Single: r8c7=7
Full House: r8c8=1
Naked Single: r5c7=8
Full House: r4c8=6
Full House: r5c4=5
Naked Single: r6c2=4
Naked Single: r3c3=8
Full House: r1c3=9
Naked Single: r1c2=7
Full House: r4c2=5
Naked Single: r1c7=6
Full House: r1c8=8
Naked Single: r2c7=4
Full House: r3c7=5
Naked Single: r4c4=8
Full House: r2c4=9
Full House: r4c1=7
Full House: r6c1=8
Full House: r6c5=6
Naked Single: r3c5=7
Full House: r2c5=8
Naked Single: r3c8=3
Full House: r2c8=7
Full House: r2c1=3
Full House: r3c1=4
|
normal_sudoku_5091
|
.....2..8.2...879..5..7..6...3..19..2..4...3..9..2...6..17.5...46....5.7.7..8...9
|
739612458126548793854973261643851972217496835598327146981765324462139587375284619
|
Basic 9x9 Sudoku 5091
|
puzzles4_forum_hardest_1905
|
Each row, column, and 3×3 subgrid must contain all digits from 1 to 9 exactly once. Digits cannot be repeated within any row, column, or 3×3 subgrid.
|
. . . . . 2 . . 8
. 2 . . . 8 7 9 .
. 5 . . 7 . . 6 .
. . 3 . . 1 9 . .
2 . . 4 . . . 3 .
. 9 . . 2 . . . 6
. . 1 7 . 5 . . .
4 6 . . . . 5 . 7
. 7 . . 8 . . . 9
| 9
| 9
|
None
|
Complete the sudoku board based on the rules and visual elements.
|
sudoku
|
sudoku_annotation
|
hard
|
739612458126548793854973261643851972217496835598327146981765324462139587375284619 #1 Hard (636)
Hidden Single: r7c4=7
Locked Candidates Type 2 (Claiming): 2 in r7 => r89c8,r9c7<>2
Locked Candidates Type 2 (Claiming): 3 in r8 => r7c5,r9c46<>3
Naked Pair: 1,8 in r5c27 => r5c3<>8, r5c9<>1
Naked Single: r5c9=5
Hidden Single: r1c8=5
Locked Candidates Type 2 (Claiming): 1 in c9 => r13c7<>1
2-String Kite: 3 in r1c2,r9c7 (connected by r7c2,r9c1) => r1c7<>3
Naked Single: r1c7=4
Hidden Single: r4c2=4
Naked Single: r4c9=2
Hidden Single: r7c9=4
Naked Single: r9c8=1
Naked Single: r8c8=8
Naked Single: r4c8=7
Naked Single: r7c8=2
Full House: r6c8=4
Hidden Single: r3c7=2
Hidden Single: r2c5=4
Naked Single: r2c3=6
Naked Single: r5c3=7
Naked Single: r1c3=9
Naked Single: r8c3=2
Naked Single: r9c3=5
Naked Single: r6c3=8
Full House: r3c3=4
Naked Single: r9c1=3
Naked Single: r5c2=1
Naked Single: r6c7=1
Full House: r5c7=8
Naked Single: r2c1=1
Naked Single: r7c2=8
Full House: r1c2=3
Full House: r7c1=9
Naked Single: r9c7=6
Full House: r7c7=3
Full House: r7c5=6
Naked Single: r6c1=5
Full House: r4c1=6
Naked Single: r1c1=7
Full House: r3c1=8
Naked Single: r2c9=3
Full House: r2c4=5
Full House: r3c9=1
Naked Single: r9c4=2
Full House: r9c6=4
Naked Single: r1c5=1
Full House: r1c4=6
Naked Single: r4c5=5
Full House: r4c4=8
Naked Single: r5c5=9
Full House: r5c6=6
Full House: r8c5=3
Naked Single: r6c4=3
Full House: r6c6=7
Naked Single: r8c6=9
Full House: r3c6=3
Full House: r3c4=9
Full House: r8c4=1
|
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