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

This Sudoku Puzzle has 66 steps and it is solved using Naked Quadruple, Naked Single, Hidden Single, Locked Candidates Type 1 (Pointing), Hidden Pair, Full House techniques.

Try To Solve This Puzzle

## Solution Steps:

1. Naked Quadruple: 1,2,3,5 in r1289c2 => r467c2<>1, r4c2<>2, r4c2<>3, r7c2<>5
2. Row 7 / Column 2 → 9 (Naked Single)
3. Row 4 / Column 2 → 4 (Naked Single)
4. Row 6 / Column 2 → 4 (Naked Single)
5. Row 7 / Column 5 → 5 (Hidden Single)
6. Locked Candidates Type 1 (Pointing): 4 in b5 => r5c79<>4
7. Locked Candidates Type 1 (Pointing): 4 in b8 => r9c89<>4
8. Row 7 / Column 8 → 4 (Hidden Single)
9. Row 2 / Column 7 → 4 (Hidden Single)
10. Locked Candidates Type 1 (Pointing): 7 in b8 => r9c89<>7
11. Hidden Pair: 4,7 in r45c1 => r45c1<>1, r45c1<>2, r45c1<>3, r4c1<>9
12. Row 4 / Column 1 → 7 (Naked Single)
13. Row 5 / Column 1 → 7 (Naked Single)
14. Row 3 / Column 1 → 9 (Hidden Single)
15. Row 1 / Column 8 → 7 (Hidden Single)
16. Row 6 / Column 6 → 7 (Hidden Single)
17. Row 9 / Column 5 → 7 (Hidden Single)
18. Row 2 / Column 4 → 7 (Hidden Single)
19. Row 7 / Column 7 → 7 (Hidden Single)
20. Row 6 / Column 3 → 9 (Hidden Single)
21. Row 4 / Column 6 → 9 (Hidden Single)
22. Row 9 / Column 4 → 4 (Hidden Single)
23. Row 5 / Column 5 → 4 (Hidden Single)
24. Locked Candidates Type 1 (Pointing): 1 in b4 => r239c3<>1
25. Locked Candidates Type 1 (Pointing): 2 in b4 => r239c3<>2
26. Locked Candidates Type 1 (Pointing): 3 in b4 => r239c3<>3
27. Row 2 / Column 3 → 5 (Naked Single)
28. Row 3 / Column 3 → 6 (Naked Single)
29. Row 9 / Column 3 → 6 (Naked Single)
30. Row 7 / Column 1 → 1 (Naked Single)
31. Row 7 / Column 9 → 6 (Full House)
32. Row 6 / Column 9 → 1 (Naked Single)
33. Row 4 / Column 8 → 2 (Naked Single)
34. Row 5 / Column 9 → 2 (Naked Single)
35. Row 6 / Column 7 → 6 (Naked Single)
36. Row 5 / Column 7 → 5 (Naked Single)
37. Row 2 / Column 9 → 3 (Naked Single)
38. Row 8 / Column 9 → 3 (Naked Single)
39. Row 9 / Column 9 → 3 (Naked Single)
40. Row 4 / Column 7 → 5 (Naked Single)
41. Row 5 / Column 6 → 1 (Naked Single)
42. Row 8 / Column 2 → 2 (Naked Single)
43. Row 9 / Column 1 → 2 (Naked Single)
44. Row 2 / Column 6 → 2 (Naked Single)
45. Row 2 / Column 2 → 1 (Full House)
46. Row 1 / Column 1 → 3 (Full House)
47. Row 1 / Column 2 → 3 (Full House)
48. Row 5 / Column 3 → 3 (Naked Single)
49. Row 5 / Column 4 → 3 (Naked Single)
50. Row 9 / Column 6 → 8 (Naked Single)
51. Row 9 / Column 2 → 5 (Naked Single)
52. Row 4 / Column 3 → 1 (Naked Single)
53. Row 3 / Column 4 → 1 (Naked Single)
54. Row 4 / Column 4 → 6 (Naked Single)
55. Row 4 / Column 5 → 6 (Naked Single)
56. Row 8 / Column 6 → 6 (Naked Single)
57. Row 8 / Column 5 → 1 (Full House)
58. Row 1 / Column 6 → 5 (Full House)
59. Row 9 / Column 8 → 1 (Naked Single)
60. Row 3 / Column 8 → 8 (Full House)
61. Row 1 / Column 4 → 5 (Naked Single)
62. Row 1 / Column 5 → 8 (Naked Single)
63. Row 8 / Column 7 → 8 (Naked Single)
64. Row 3 / Column 5 → 3 (Naked Single)
65. Row 3 / Column 7 → 2 (Full House)
66. Row 1 / Column 7 → 1 (Full House)