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

This Sudoku Puzzle has 78 steps and it is solved using Naked Single, Hidden Single, Locked Candidates Type 1 (Pointing), Locked Candidates Type 2 (Claiming), undefined, AIC, Discontinuous Nice Loop, Full House, Sue de Coq techniques.

Try To Solve This Puzzle

Solution Steps:

  1. Row 9 / Column 3 → 8 (Naked Single)
  2. Row 3 / Column 3 → 1 (Hidden Single)
  3. Row 9 / Column 9 → 1 (Hidden Single)
  4. Row 4 / Column 2 → 8 (Hidden Single)
  5. Row 3 / Column 1 → 7 (Hidden Single)
  6. Row 1 / Column 1 → 8 (Hidden Single)
  7. Row 4 / Column 8 → 3 (Hidden Single)
  8. Row 1 / Column 3 → 5 (Hidden Single)
  9. Row 1 / Column 8 → 4 (Naked Single)
  10. Row 4 / Column 5 → 1 (Hidden Single)
  11. Row 6 / Column 8 → 1 (Hidden Single)
  12. Row 2 / Column 8 → 5 (Hidden Single)
  13. Row 2 / Column 9 → 7 (Hidden Single)
  14. Locked Candidates Type 1 (Pointing): 4 in b1 => r68c2<>4
  15. Row 8 / Column 7 → 4 (Hidden Single)
  16. Locked Candidates Type 1 (Pointing): 2 in b3 => r3c45<>2
  17. Locked Candidates Type 1 (Pointing): 2 in b6 => r5c5<>2
  18. Locked Candidates Type 1 (Pointing): 7 in b6 => r7c7<>7
  19. Locked Candidates Type 1 (Pointing): 8 in b9 => r7c45<>8
  20. Locked Candidates Type 2 (Claiming): 2 in c8 => r7c79,r9c7<>2
  21. X-Wing: 6 c26 r68 => r6c45,r8c45<>6
  22. XY-Wing: 3/6/2 in r8c26,r9c1 => r9c56<>2
  23. Row 9 / Column 1 → 2 (Hidden Single)
  24. AIC: 3 3- r1c9 -9- r1c5 -6- r5c5 =6= r5c3 -6- r7c3 =6= r8c2 =3= r8c5 -3- r9c5 =3= r9c7 -3 => r1c7,r7c9<>3
  25. Row 1 / Column 9 → 3 (Hidden Single)
  26. 2-String Kite: 9 in r1c5,r7c9 (connected by r1c7,r3c9) => r7c5<>9
  27. Discontinuous Nice Loop: 9 r2c5 -9- r1c5 -6- r5c5 =6= r5c3 -6- r7c3 =6= r8c2 =3= r8c5 =8= r2c5 => r2c5<>9
  28. Discontinuous Nice Loop: 4 r5c5 -4- r4c6 -2- r8c6 -6- r6c6 =6= r5c5 => r5c5<>4
  29. Discontinuous Nice Loop: 5 r6c6 -5- r6c4 =5= r3c4 =6= r7c4 -6- r8c6 =6= r6c6 => r6c6<>5
  30. Row 9 / Column 6 → 5 (Hidden Single)
  31. X-Wing: 9 r19 c57 => r3c57,r6c5,r7c7<>9
  32. XY-Chain: 4 4- r5c9 -2- r5c7 -7- r6c7 -8- r7c7 -3- r7c1 -4 => r5c1<>4
  33. Row 5 / Column 1 → 5 (Naked Single)
  34. XY-Wing: 2/7/6 in r35c7,r5c5 => r3c5<>6
  35. XY-Chain: 4 4- r4c6 -2- r4c4 -7- r5c5 -6- r1c5 -9- r9c5 -3- r9c7 -9- r7c9 -8- r6c9 -4 => r6c56<>4
  36. Row 4 / Column 6 → 4 (Hidden Single)
  37. Row 4 / Column 3 → 7 (Naked Single)
  38. Row 4 / Column 4 → 2 (Full House)
  39. XY-Wing: 2/9/6 in r1c5,r28c6 => r7c5<>6
  40. Sue de Coq: r12c5 - {24689} (r356c5 - {4567}, r2c46 - {289}) => r3c4<>9, r78c5<>7
  41. Locked Candidates Type 1 (Pointing): 7 in b8 => r6c4<>7
  42. XY-Wing: 5/6/9 in r1c5,r36c4 => r2c4<>9
  43. Row 2 / Column 4 → 8 (Naked Single)
  44. Row 8 / Column 4 → 7 (Naked Single)
  45. Row 8 / Column 8 → 2 (Naked Single)
  46. Row 7 / Column 8 → 7 (Full House)
  47. Row 8 / Column 6 → 6 (Naked Single)
  48. Row 6 / Column 6 → 9 (Naked Single)
  49. Row 2 / Column 6 → 2 (Full House)
  50. Row 7 / Column 4 → 9 (Naked Single)
  51. Row 8 / Column 2 → 3 (Naked Single)
  52. Row 8 / Column 5 → 8 (Full House)
  53. Row 6 / Column 4 → 5 (Naked Single)
  54. Row 3 / Column 4 → 6 (Full House)
  55. Row 2 / Column 5 → 4 (Naked Single)
  56. Row 2 / Column 2 → 9 (Full House)
  57. Row 3 / Column 2 → 4 (Full House)
  58. Row 6 / Column 2 → 6 (Full House)
  59. Row 7 / Column 9 → 8 (Naked Single)
  60. Row 9 / Column 5 → 3 (Naked Single)
  61. Row 7 / Column 5 → 2 (Full House)
  62. Row 9 / Column 7 → 9 (Full House)
  63. Row 7 / Column 7 → 3 (Full House)
  64. Row 7 / Column 1 → 4 (Naked Single)
  65. Row 6 / Column 1 → 3 (Full House)
  66. Row 5 / Column 3 → 4 (Full House)
  67. Row 7 / Column 3 → 6 (Full House)
  68. Row 6 / Column 5 → 7 (Naked Single)
  69. Row 5 / Column 5 → 6 (Full House)
  70. Row 1 / Column 5 → 9 (Naked Single)
  71. Row 3 / Column 5 → 5 (Full House)
  72. Row 1 / Column 7 → 6 (Full House)
  73. Row 3 / Column 7 → 2 (Naked Single)
  74. Row 3 / Column 9 → 9 (Full House)
  75. Row 6 / Column 9 → 4 (Naked Single)
  76. Row 5 / Column 9 → 2 (Full House)
  77. Row 6 / Column 7 → 8 (Full House)
  78. Row 5 / Column 7 → 7 (Full House)
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