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

This Sudoku Puzzle has 66 steps and it is solved using Hidden Single, Locked Candidates Type 1 (Pointing), Locked Candidates Type 2 (Claiming), Naked Single, Full House, Uniqueness Test 1, Hidden Rectangle, Finned Swordfish 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 6 / Column 8 → 4 (Hidden Single)
  2. Row 9 / Column 3 → 1 (Hidden Single)
  3. Row 7 / Column 7 → 2 (Hidden Single)
  4. Row 2 / Column 8 → 2 (Hidden Single)
  5. Row 4 / Column 8 → 1 (Hidden Single)
  6. Locked Candidates Type 1 (Pointing): 2 in b1 => r56c3<>2
  7. Locked Candidates Type 1 (Pointing): 6 in b1 => r1c79<>6
  8. Locked Candidates Type 1 (Pointing): 7 in b3 => r89c7<>7
  9. Locked Candidates Type 1 (Pointing): 6 in b6 => r5c1356<>6
  10. Locked Candidates Type 1 (Pointing): 9 in b6 => r5c12356<>9
  11. Locked Candidates Type 2 (Claiming): 6 in c8 => r89c7,r9c9<>6
  12. Row 8 / Column 7 → 8 (Naked Single)
  13. Row 9 / Column 7 → 4 (Naked Single)
  14. Row 1 / Column 9 → 8 (Hidden Single)
  15. Row 9 / Column 4 → 8 (Hidden Single)
  16. Row 7 / Column 1 → 4 (Hidden Single)
  17. Row 3 / Column 1 → 9 (Naked Single)
  18. Row 3 / Column 3 → 2 (Naked Single)
  19. Row 3 / Column 9 → 4 (Naked Single)
  20. Row 2 / Column 2 → 4 (Hidden Single)
  21. Row 1 / Column 6 → 4 (Hidden Single)
  22. Row 7 / Column 3 → 8 (Hidden Single)
  23. Row 4 / Column 1 → 8 (Hidden Single)
  24. Row 6 / Column 6 → 8 (Hidden Single)
  25. Row 1 / Column 1 → 6 (Hidden Single)
  26. Row 1 / Column 3 → 3 (Full House)
  27. Row 5 / Column 3 → 5 (Naked Single)
  28. Row 8 / Column 3 → 9 (Naked Single)
  29. Row 6 / Column 3 → 6 (Full House)
  30. Row 9 / Column 5 → 9 (Hidden Single)
  31. Row 9 / Column 8 → 6 (Hidden Single)
  32. Row 8 / Column 8 → 7 (Full House)
  33. Row 4 / Column 5 → 6 (Hidden Single)
  34. Row 8 / Column 6 → 6 (Hidden Single)
  35. Uniqueness Test 1: 6/9 in r2c79,r5c79 => r2c7<>6, r2c7<>9
  36. Row 2 / Column 7 → 1 (Naked Single)
  37. Row 3 / Column 7 → 7 (Naked Single)
  38. Row 1 / Column 7 → 9 (Naked Single)
  39. Row 2 / Column 9 → 6 (Full House)
  40. Row 5 / Column 7 → 6 (Full House)
  41. Row 5 / Column 9 → 9 (Full House)
  42. Hidden Rectangle: 2/3 in r5c25,r6c25 => r5c2<>3
  43. Finned Swordfish: 3 r268 c246 fr6c5 => r5c6<>3
  44. Row 5 / Column 6 → 1 (Naked Single)
  45. Row 3 / Column 6 → 5 (Naked Single)
  46. Row 3 / Column 5 → 1 (Full House)
  47. Row 4 / Column 6 → 9 (Naked Single)
  48. Row 2 / Column 6 → 3 (Full House)
  49. Row 2 / Column 4 → 9 (Full House)
  50. Row 4 / Column 2 → 7 (Naked Single)
  51. Row 4 / Column 4 → 5 (Full House)
  52. Row 5 / Column 1 → 3 (Naked Single)
  53. Row 9 / Column 1 → 7 (Full House)
  54. Row 5 / Column 2 → 2 (Naked Single)
  55. Row 5 / Column 5 → 7 (Full House)
  56. Row 6 / Column 2 → 9 (Full House)
  57. Row 8 / Column 4 → 3 (Naked Single)
  58. Row 7 / Column 5 → 5 (Full House)
  59. Row 8 / Column 2 → 5 (Full House)
  60. Row 7 / Column 9 → 3 (Full House)
  61. Row 9 / Column 2 → 3 (Full House)
  62. Row 9 / Column 9 → 5 (Full House)
  63. Row 1 / Column 5 → 2 (Naked Single)
  64. Row 1 / Column 4 → 7 (Full House)
  65. Row 6 / Column 4 → 2 (Full House)
  66. Row 6 / Column 5 → 3 (Full House)
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