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

This Sudoku Puzzle has 71 steps and it is solved using Naked Single, Hidden Single, Full House, Locked Candidates Type 1 (Pointing), Skyscraper, undefined, Uniqueness Test 4, Sue de Coq, Empty Rectangle, AIC, Naked Pair techniques.

Try To Solve This Puzzle

Solution Steps:

  1. Row 5 / Column 5 → 9 (Naked Single)
  2. Row 5 / Column 4 → 2 (Hidden Single)
  3. Row 5 / Column 6 → 6 (Naked Single)
  4. Row 7 / Column 8 → 2 (Hidden Single)
  5. Row 8 / Column 5 → 5 (Hidden Single)
  6. Row 7 / Column 6 → 9 (Hidden Single)
  7. Row 6 / Column 4 → 4 (Hidden Single)
  8. Row 7 / Column 4 → 8 (Hidden Single)
  9. Row 6 / Column 2 → 7 (Hidden Single)
  10. Row 8 / Column 4 → 1 (Hidden Single)
  11. Row 3 / Column 4 → 3 (Naked Single)
  12. Row 9 / Column 4 → 7 (Full House)
  13. Row 8 / Column 6 → 3 (Full House)
  14. Row 4 / Column 6 → 7 (Naked Single)
  15. Row 4 / Column 5 → 3 (Full House)
  16. Locked Candidates Type 1 (Pointing): 7 in b9 => r2c9<>7
  17. Skyscraper: 8 in r3c2,r5c1 (connected by r35c9) => r12c1,r4c2<>8
  18. Skyscraper: 3 in r1c3,r2c9 (connected by r7c39) => r1c78,r2c1<>3
  19. W-Wing: 6/5 in r6c1,r9c2 connected by 5 in r2c12 => r4c2,r9c1<>6
  20. XY-Wing: 1/5/6 in r35c3,r6c1 => r1c1,r4c3<>6
  21. Uniqueness Test 4: 1/7 in r1c58,r2c58 => r12c8<>1
  22. Sue de Coq: r1c123 - {12368} (r1c6 - {28}, r3c3 - {16}) => r2c12,r3c2<>1, r3c2<>6, r1c7<>8
  23. Empty Rectangle: 1 in b6 (r3c38) => r4c3<>1
  24. Row 4 / Column 3 → 2 (Naked Single)
  25. Row 8 / Column 2 → 2 (Hidden Single)
  26. Locked Candidates Type 1 (Pointing): 4 in b7 => r7c79<>4
  27. AIC: 1/7 7- r1c5 =7= r1c8 =4= r1c7 -4- r8c7 =4= r8c9 -4- r5c9 -8- r4c7 =8= r2c7 =1= r2c5 -1 => r1c5<>1, r2c5<>7
  28. Row 1 / Column 5 → 7 (Naked Single)
  29. Row 2 / Column 5 → 1 (Full House)
  30. Row 2 / Column 8 → 7 (Hidden Single)
  31. AIC: 5 5- r2c1 -2- r2c6 -8- r2c7 =8= r4c7 =1= r1c7 -1- r3c8 =1= r3c3 -1- r5c3 -5 => r56c1<>5
  32. Row 6 / Column 1 → 6 (Naked Single)
  33. Row 5 / Column 3 → 5 (Hidden Single)
  34. Naked Pair: 3,5 in r67c7 => r29c7<>3, r9c7<>5
  35. Row 2 / Column 9 → 3 (Hidden Single)
  36. Row 7 / Column 9 → 7 (Naked Single)
  37. Row 8 / Column 3 → 7 (Hidden Single)
  38. Row 9 / Column 2 → 6 (Hidden Single)
  39. Row 9 / Column 7 → 9 (Naked Single)
  40. Row 2 / Column 7 → 8 (Naked Single)
  41. Row 2 / Column 6 → 2 (Naked Single)
  42. Row 1 / Column 6 → 8 (Full House)
  43. Row 2 / Column 1 → 5 (Naked Single)
  44. Row 2 / Column 2 → 9 (Full House)
  45. Row 1 / Column 2 → 1 (Naked Single)
  46. Row 9 / Column 1 → 3 (Naked Single)
  47. Row 9 / Column 8 → 5 (Full House)
  48. Row 3 / Column 2 → 8 (Naked Single)
  49. Row 3 / Column 3 → 6 (Naked Single)
  50. Row 4 / Column 2 → 4 (Naked Single)
  51. Row 7 / Column 2 → 5 (Full House)
  52. Row 1 / Column 1 → 2 (Naked Single)
  53. Row 1 / Column 3 → 3 (Full House)
  54. Row 7 / Column 3 → 1 (Full House)
  55. Row 7 / Column 1 → 4 (Full House)
  56. Row 7 / Column 7 → 3 (Full House)
  57. Row 6 / Column 8 → 3 (Naked Single)
  58. Row 6 / Column 7 → 5 (Full House)
  59. Row 3 / Column 9 → 9 (Naked Single)
  60. Row 3 / Column 8 → 1 (Full House)
  61. Row 5 / Column 8 → 4 (Naked Single)
  62. Row 1 / Column 8 → 6 (Naked Single)
  63. Row 1 / Column 7 → 4 (Full House)
  64. Row 4 / Column 8 → 9 (Full House)
  65. Row 5 / Column 9 → 8 (Naked Single)
  66. Row 5 / Column 1 → 1 (Full House)
  67. Row 4 / Column 1 → 8 (Full House)
  68. Row 8 / Column 7 → 6 (Naked Single)
  69. Row 4 / Column 7 → 1 (Full House)
  70. Row 4 / Column 9 → 6 (Full House)
  71. Row 8 / Column 9 → 4 (Full House)
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