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

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

Try To Solve This Puzzle

## Solution Steps:

1. Row 4 / Column 4 → 1 (Hidden Single)
2. Row 6 / Column 4 → 7 (Hidden Single)
3. Locked Candidates Type 1 (Pointing): 5 in b3 => r4c8<>5
4. Locked Candidates Type 1 (Pointing): 5 in b4 => r78c3<>5
5. Locked Candidates Type 1 (Pointing): 6 in b4 => r79c3<>6
6. Locked Candidates Type 1 (Pointing): 6 in b5 => r1c5<>6
7. Locked Candidates Type 1 (Pointing): 9 in b8 => r13c4<>9
8. Naked Pair: 2,8 in r4c17 => r4c358<>2, r4c89<>8
9. Row 4 / Column 8 → 7 (Naked Single)
10. Row 4 / Column 9 → 5 (Naked Single)
11. Row 6 / Column 3 → 5 (Hidden Single)
12. Row 6 / Column 5 → 6 (Hidden Single)
13. Row 4 / Column 5 → 4 (Naked Single)
14. Row 4 / Column 3 → 6 (Naked Single)
15. Row 3 / Column 5 → 2 (Hidden Single)
16. Locked Candidates Type 1 (Pointing): 2 in b5 => r5c38<>2
17. Locked Candidates Type 1 (Pointing): 2 in b4 => r78c1<>2
18. Locked Candidates Type 1 (Pointing): 3 in b5 => r5c8<>3
19. Locked Candidates Type 1 (Pointing): 2 in b6 => r8c7<>2
20. Locked Candidates Type 2 (Claiming): 3 in c5 => r1c46,r23c6,r3c4<>3
21. Row 1 / Column 4 → 6 (Naked Single)
22. Row 3 / Column 4 → 5 (Naked Single)
23. Row 2 / Column 8 → 5 (Hidden Single)
24. Locked Candidates Type 2 (Claiming): 8 in c9 => r79c8<>8
25. Naked Triple: 1,3,9 in r2c157 => r2c36<>1, r2c3<>3, r2c3<>9
26. Naked Triple: 4,7,9 in r13c2,r2c3 => r2c1,r3c3<>9, r3c3<>7
27. Locked Candidates Type 1 (Pointing): 9 in b1 => r5789c2<>9
28. Hidden Pair: 5,6 in r7c26 => r7c2<>7, r7c2<>8, r7c6<>2, r7c6<>3
29. XY-Wing: 4/8/9 in r15c2,r5c8 => r1c8<>9
30. W-Wing: 1/3 in r1c8,r2c1 connected by 3 in r12c5 => r2c7<>1
31. Row 2 / Column 1 → 1 (Hidden Single)
32. Row 3 / Column 3 → 3 (Naked Single)
33. Sue de Coq: r7c123 - {2356789} (r7c48 - {239}, r89c2 - {5678}) => r8c3<>7, r7c9<>3, r7c9<>9
34. XY-Chain: 3 3- r2c7 -9- r2c5 -3- r1c5 -9- r1c2 -4- r5c2 -8- r5c8 -9- r6c9 -3 => r6c7<>3
35. Row 6 / Column 9 → 3 (Hidden Single)
36. Locked Candidates Type 2 (Claiming): 9 in c9 => r79c8,r8c7<>9
37. Naked Triple: 1,2,3 in r179c8 => r3c8<>1
38. W-Wing: 3/9 in r2c7,r8c1 connected by 9 in r6c17 => r8c7<>3
39. Row 8 / Column 7 → 1 (Naked Single)
40. Row 2 / Column 7 → 3 (Hidden Single)
41. Row 1 / Column 8 → 1 (Naked Single)
42. Row 2 / Column 5 → 9 (Naked Single)
43. Row 1 / Column 5 → 3 (Full House)
44. Row 1 / Column 6 → 4 (Naked Single)
45. Row 1 / Column 2 → 9 (Full House)
46. Row 2 / Column 6 → 7 (Naked Single)
47. Row 2 / Column 3 → 4 (Full House)
48. Row 3 / Column 2 → 7 (Full House)
49. Row 3 / Column 6 → 1 (Full House)
50. Row 5 / Column 3 → 9 (Naked Single)
51. Row 8 / Column 2 → 5 (Naked Single)
52. Row 5 / Column 8 → 8 (Naked Single)
53. Row 6 / Column 1 → 2 (Naked Single)
54. Row 6 / Column 7 → 9 (Full House)
55. Row 4 / Column 7 → 2 (Full House)
56. Row 4 / Column 1 → 8 (Full House)
57. Row 5 / Column 2 → 4 (Full House)
58. Row 3 / Column 7 → 8 (Full House)
59. Row 3 / Column 8 → 9 (Full House)
60. Row 8 / Column 3 → 2 (Naked Single)
61. Row 7 / Column 2 → 6 (Naked Single)
62. Row 9 / Column 2 → 8 (Full House)
63. Row 7 / Column 3 → 7 (Naked Single)
64. Row 9 / Column 3 → 1 (Full House)
65. Row 8 / Column 6 → 3 (Naked Single)
66. Row 7 / Column 6 → 5 (Naked Single)
67. Row 9 / Column 9 → 9 (Naked Single)
68. Row 7 / Column 9 → 8 (Naked Single)
69. Row 8 / Column 9 → 7 (Full House)
70. Row 8 / Column 1 → 9 (Full House)
71. Row 7 / Column 1 → 3 (Full House)
72. Row 5 / Column 6 → 2 (Naked Single)
73. Row 5 / Column 4 → 3 (Full House)
74. Row 9 / Column 6 → 6 (Full House)
75. Row 9 / Column 4 → 2 (Naked Single)
76. Row 7 / Column 4 → 9 (Full House)
77. Row 7 / Column 8 → 2 (Full House)
78. Row 9 / Column 8 → 3 (Full House)