4
6
1
3
5
8
7
9
2
8
5
2
1
7
9
6
3
4
9
7
3
6
2
4
8
5
1
2
8
3
6
4
9
5
1
7
7
4
5
2
1
8
9
6
3
1
6
9
5
3
7
2
4
8
8
2
6
9
3
4
1
7
5
4
9
7
5
2
1
3
8
6
3
1
5
7
8
6
4
9
2

This Sudoku Puzzle has 78 steps and it is solved using Hidden Single, Locked Pair, Locked Candidates Type 1 (Pointing), Naked Single, Hidden Rectangle, AIC, Discontinuous Nice Loop, undefined, Full House, Hidden Triple, Uniqueness Test 3 techniques.

Naked Single Explanation
Hidden Single Explanation
Locked Candidates Explanation
Full House Explanation
Try To Solve This Puzzle

Solution Steps:

  1. Row 4 / Column 8 → 6 (Hidden Single)
  2. Row 6 / Column 9 → 8 (Hidden Single)
  3. Row 3 / Column 4 → 6 (Hidden Single)
  4. Row 5 / Column 8 → 3 (Hidden Single)
  5. Locked Pair: 4,7 in r13c1 => r1c23,r468c1<>7, r1c23,r78c1<>4
  6. Locked Candidates Type 1 (Pointing): 1 in b1 => r1c457<>1
  7. Locked Candidates Type 1 (Pointing): 1 in b3 => r5c9<>1
  8. Row 5 / Column 9 → 7 (Naked Single)
  9. Locked Candidates Type 1 (Pointing): 5 in b5 => r13c6<>5
  10. Locked Candidates Type 1 (Pointing): 7 in b5 => r12c4<>7
  11. Locked Candidates Type 1 (Pointing): 2 in b6 => r1c7<>2
  12. Locked Candidates Type 1 (Pointing): 4 in b8 => r12c4<>4
  13. Hidden Rectangle: 5/7 in r1c58,r3c58 => r1c5<>7
  14. AIC: 5 5- r4c1 -2- r8c1 =2= r8c5 -2- r5c5 -1- r3c5 =1= r3c9 =5= r7c9 -5- r9c8 =5= r9c3 -5 => r46c3,r7c1<>5
  15. Hidden Rectangle: 2/5 in r4c16,r6c16 => r6c6<>2
  16. Discontinuous Nice Loop: 4/7/9 r9c3 =5= r9c8 =8= r8c8 -8- r8c5 -2- r5c5 -1- r3c5 =1= r3c9 =5= r7c9 -5- r7c3 =5= r9c3 => r9c3<>4, r9c3<>7, r9c3<>9
  17. Row 9 / Column 3 → 5 (Naked Single)
  18. Row 7 / Column 9 → 5 (Hidden Single)
  19. Row 8 / Column 9 → 6 (Hidden Single)
  20. Locked Candidates Type 1 (Pointing): 9 in b7 => r8c78<>9
  21. Locked Candidates Type 1 (Pointing): 4 in b9 => r1c7<>4
  22. Discontinuous Nice Loop: 2 r1c5 -2- r8c5 -8- r8c8 -7- r3c8 -5- r3c5 =5= r1c5 => r1c5<>2
  23. Discontinuous Nice Loop: 9 r1c4 -9- r1c7 -7- r3c8 -5- r3c5 =5= r1c5 =8= r1c4 => r1c4<>9
  24. Discontinuous Nice Loop: 1 r2c5 -1- r5c5 -2- r8c5 -8- r8c8 -7- r2c8 =7= r2c5 => r2c5<>1
  25. XY-Wing: 2/8/7 in r28c5,r8c8 => r2c8<>7
  26. Row 2 / Column 5 → 7 (Hidden Single)
  27. AIC: 1/9 1- r2c4 =1= r3c5 -1- r5c5 -2- r8c5 =2= r8c1 =9= r8c3 -9- r5c3 =9= r5c4 -9 => r5c4<>1, r2c4<>9
  28. Locked Candidates Type 1 (Pointing): 9 in b2 => r6c6<>9
  29. W-Wing: 1/2 in r2c4,r5c5 connected by 2 in r7c4,r8c5 => r3c5,r46c4<>1
  30. Row 3 / Column 9 → 1 (Hidden Single)
  31. Row 2 / Column 9 → 4 (Full House)
  32. Row 5 / Column 5 → 1 (Hidden Single)
  33. Row 2 / Column 4 → 1 (Hidden Single)
  34. Row 8 / Column 5 → 2 (Hidden Single)
  35. Hidden Triple: 1,3,7 in r46c3,r6c2 => r6c2<>2, r6c3<>9
  36. XYZ-Wing: 2/4/6 in r57c2,r7c3 => r9c2<>4
  37. Row 9 / Column 2 → 7 (Naked Single)
  38. Row 6 / Column 2 → 1 (Naked Single)
  39. Row 1 / Column 2 → 6 (Naked Single)
  40. Row 6 / Column 7 → 2 (Naked Single)
  41. Row 4 / Column 7 → 1 (Full House)
  42. Row 1 / Column 3 → 1 (Naked Single)
  43. Row 7 / Column 3 → 6 (Hidden Single)
  44. Uniqueness Test 3: 3/7 in r4c34,r6c34 => r79c4<>8
  45. Row 7 / Column 4 → 4 (Naked Single)
  46. Row 7 / Column 2 → 2 (Naked Single)
  47. Row 5 / Column 2 → 4 (Full House)
  48. Row 7 / Column 1 → 8 (Full House)
  49. Row 9 / Column 4 → 3 (Naked Single)
  50. Row 9 / Column 5 → 8 (Full House)
  51. Row 5 / Column 3 → 9 (Naked Single)
  52. Row 5 / Column 4 → 2 (Full House)
  53. Row 8 / Column 1 → 9 (Naked Single)
  54. Row 8 / Column 3 → 4 (Full House)
  55. Row 1 / Column 5 → 5 (Naked Single)
  56. Row 3 / Column 5 → 3 (Full House)
  57. Row 9 / Column 8 → 9 (Naked Single)
  58. Row 9 / Column 7 → 4 (Full House)
  59. Row 6 / Column 1 → 5 (Naked Single)
  60. Row 1 / Column 4 → 8 (Naked Single)
  61. Row 4 / Column 4 → 7 (Naked Single)
  62. Row 6 / Column 4 → 9 (Full House)
  63. Row 8 / Column 7 → 7 (Naked Single)
  64. Row 1 / Column 7 → 9 (Full House)
  65. Row 8 / Column 8 → 8 (Full House)
  66. Row 3 / Column 6 → 4 (Naked Single)
  67. Row 2 / Column 8 → 2 (Naked Single)
  68. Row 2 / Column 6 → 9 (Full House)
  69. Row 1 / Column 6 → 2 (Full House)
  70. Row 4 / Column 1 → 2 (Naked Single)
  71. Row 6 / Column 6 → 3 (Naked Single)
  72. Row 4 / Column 6 → 5 (Full House)
  73. Row 4 / Column 3 → 3 (Full House)
  74. Row 6 / Column 3 → 7 (Full House)
  75. Row 3 / Column 1 → 7 (Naked Single)
  76. Row 1 / Column 1 → 4 (Full House)
  77. Row 1 / Column 8 → 7 (Full House)
  78. Row 3 / Column 8 → 5 (Full House)
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