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

This Sudoku Puzzle has 72 steps and it is solved using Hidden Single, Locked Pair, Naked Single, Locked Candidates Type 1 (Pointing), Locked Candidates Type 2 (Claiming), undefined, Empty Rectangle, Uniqueness Test 3, Naked Pair, AIC, Skyscraper, Full House techniques.

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

Solution Steps:

  1. Row 1 / Column 5 → 5 (Hidden Single)
  2. Row 4 / Column 2 → 5 (Hidden Single)
  3. Row 9 / Column 9 → 5 (Hidden Single)
  4. Row 2 / Column 3 → 5 (Hidden Single)
  5. Locked Pair: 4,9 in r3c23 => r1c13,r3c179<>4, r1c13,r2c2,r3c1579<>9
  6. Row 2 / Column 2 → 2 (Naked Single)
  7. Row 1 / Column 3 → 3 (Naked Single)
  8. Row 1 / Column 9 → 4 (Hidden Single)
  9. Row 3 / Column 9 → 1 (Hidden Single)
  10. Locked Candidates Type 1 (Pointing): 9 in b2 => r456c6<>9
  11. Locked Candidates Type 1 (Pointing): 2 in b8 => r456c5<>2
  12. Locked Candidates Type 2 (Claiming): 6 in c9 => r4c8,r5c7<>6
  13. 2-String Kite: 7 in r6c8,r7c5 (connected by r7c7,r8c8) => r6c5<>7
  14. Empty Rectangle: 8 in b8 (r3c57) => r8c7<>8
  15. Uniqueness Test 3: 4/9 in r3c23,r8c23 => r8c78<>7, r8c8<>3, r8c8<>8
  16. Row 6 / Column 8 → 7 (Hidden Single)
  17. Row 7 / Column 7 → 7 (Hidden Single)
  18. Row 6 / Column 4 → 2 (Hidden Single)
  19. Naked Pair: 6,8 in r24c4 => r1c4<>6, r8c4<>8
  20. XYZ-Wing: 6/8/9 in r28c8,r3c7 => r1c8<>6
  21. AIC: 8 8- r3c5 =8= r3c7 -8- r9c7 -4- r9c1 =4= r4c1 =2= r4c8 -2- r1c8 -9- r8c8 -6- r2c8 =6= r2c4 =8= r4c4 -8 => r2c4,r45c5<>8
  22. Row 2 / Column 4 → 6 (Naked Single)
  23. Row 4 / Column 4 → 8 (Naked Single)
  24. Row 8 / Column 8 → 6 (Hidden Single)
  25. Skyscraper: 8 in r8c6,r9c8 (connected by r2c68) => r9c5<>8
  26. AIC: 3 3- r4c6 -4- r4c1 =4= r9c1 -4- r9c7 =4= r8c7 =9= r7c9 -9- r6c9 -3 => r4c89,r6c56<>3
  27. Row 9 / Column 8 → 3 (Hidden Single)
  28. Row 2 / Column 8 → 8 (Hidden Single)
  29. Row 2 / Column 6 → 9 (Full House)
  30. Row 3 / Column 7 → 6 (Naked Single)
  31. Row 3 / Column 1 → 7 (Naked Single)
  32. Row 1 / Column 1 → 6 (Naked Single)
  33. Row 3 / Column 5 → 8 (Naked Single)
  34. Row 8 / Column 6 → 8 (Hidden Single)
  35. Locked Candidates Type 1 (Pointing): 3 in b8 => r45c5<>3
  36. Naked Pair: 6,9 in r4c59 => r4c18<>9
  37. Row 4 / Column 8 → 2 (Naked Single)
  38. Row 1 / Column 8 → 9 (Full House)
  39. Row 1 / Column 7 → 2 (Full House)
  40. Skyscraper: 9 in r7c1,r8c7 (connected by r5c17) => r7c9,r8c23<>9
  41. Row 7 / Column 9 → 8 (Naked Single)
  42. Row 9 / Column 7 → 4 (Naked Single)
  43. Row 8 / Column 7 → 9 (Full House)
  44. Row 5 / Column 7 → 8 (Full House)
  45. Row 9 / Column 1 → 2 (Naked Single)
  46. Row 7 / Column 3 → 9 (Naked Single)
  47. Row 9 / Column 5 → 1 (Naked Single)
  48. Row 9 / Column 3 → 8 (Full House)
  49. Row 3 / Column 3 → 4 (Naked Single)
  50. Row 3 / Column 2 → 9 (Full House)
  51. Row 7 / Column 1 → 3 (Naked Single)
  52. Row 7 / Column 5 → 2 (Full House)
  53. Row 6 / Column 5 → 9 (Naked Single)
  54. Row 8 / Column 4 → 7 (Naked Single)
  55. Row 1 / Column 4 → 1 (Full House)
  56. Row 8 / Column 5 → 3 (Full House)
  57. Row 1 / Column 6 → 7 (Full House)
  58. Row 8 / Column 3 → 1 (Naked Single)
  59. Row 5 / Column 3 → 2 (Full House)
  60. Row 8 / Column 2 → 4 (Full House)
  61. Row 4 / Column 1 → 4 (Naked Single)
  62. Row 5 / Column 1 → 9 (Full House)
  63. Row 4 / Column 5 → 6 (Naked Single)
  64. Row 5 / Column 5 → 7 (Full House)
  65. Row 6 / Column 9 → 3 (Naked Single)
  66. Row 4 / Column 6 → 3 (Naked Single)
  67. Row 4 / Column 9 → 9 (Full House)
  68. Row 5 / Column 9 → 6 (Full House)
  69. Row 6 / Column 2 → 1 (Naked Single)
  70. Row 5 / Column 2 → 3 (Full House)
  71. Row 5 / Column 6 → 1 (Full House)
  72. Row 6 / Column 6 → 4 (Full House)
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