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

This Sudoku Puzzle has 69 steps and it is solved using Hidden Single, Naked Single, Full House, Locked Candidates Type 1 (Pointing), Locked Candidates Type 2 (Claiming), Naked Pair, Empty Rectangle, Sue de Coq, Continuous Nice Loop, undefined techniques.

Try To Solve This Puzzle

## Solution Steps:

1. Row 5 / Column 5 → 4 (Hidden Single)
2. Row 1 / Column 1 → 2 (Hidden Single)
3. Row 9 / Column 7 → 9 (Hidden Single)
4. Row 5 / Column 3 → 9 (Hidden Single)
5. Row 5 / Column 1 → 1 (Hidden Single)
6. Row 4 / Column 3 → 6 (Hidden Single)
7. Row 4 / Column 8 → 8 (Hidden Single)
8. Row 3 / Column 3 → 8 (Hidden Single)
9. Row 3 / Column 1 → 3 (Naked Single)
10. Row 3 / Column 9 → 6 (Naked Single)
11. Row 9 / Column 1 → 7 (Naked Single)
12. Row 3 / Column 7 → 4 (Naked Single)
13. Row 7 / Column 1 → 5 (Naked Single)
14. Row 6 / Column 1 → 8 (Full House)
15. Row 3 / Column 8 → 9 (Naked Single)
16. Row 3 / Column 5 → 1 (Full House)
17. Row 4 / Column 4 → 1 (Hidden Single)
18. Row 8 / Column 4 → 7 (Hidden Single)
19. Row 4 / Column 6 → 7 (Hidden Single)
20. Locked Candidates Type 1 (Pointing): 3 in b4 => r8c2<>3
21. Locked Candidates Type 1 (Pointing): 5 in b4 => r12c2<>5
22. Locked Candidates Type 1 (Pointing): 6 in b5 => r6c8<>6
23. Locked Candidates Type 2 (Claiming): 5 in r5 => r4c7<>5
24. Naked Pair: 2,3 in r26c8 => r7c8<>2, r78c8<>3
25. Empty Rectangle: 4 in b2 (r9c34) => r2c3<>4
26. Sue de Coq: r78c7 - {2367} (r4c7 - {23}, r78c8 - {467}) => r7c9<>7, r1c7<>3
27. Continuous Nice Loop: 4/5/6/7 6= r5c7 =5= r5c9 -5- r2c9 =5= r2c3 =1= r2c2 -1- r8c2 -4- r8c8 -6- r5c8 =6= r5c7 =5 => r8c6<>4, r1c9<>5, r7c8<>6, r5c7<>7
28. XY-Chain: 5 5- r4c5 -2- r4c7 -3- r8c7 -6- r5c7 -5- r5c9 -7- r1c9 -3- r2c8 -2- r6c8 -3- r6c2 -5 => r4c2,r6c56<>5
29. Row 4 / Column 2 → 3 (Naked Single)
30. Row 6 / Column 2 → 5 (Full House)
31. Row 4 / Column 7 → 2 (Naked Single)
32. Row 4 / Column 5 → 5 (Full House)
33. Row 6 / Column 8 → 3 (Naked Single)
34. Row 2 / Column 8 → 2 (Naked Single)
35. Row 8 / Column 6 → 5 (Hidden Single)
36. Locked Candidates Type 1 (Pointing): 3 in b3 => r789c9<>3
37. XY-Chain: 3 3- r1c9 -7- r1c7 -5- r5c7 -6- r5c8 -7- r7c8 -4- r7c6 -6- r6c6 -9- r2c6 -4- r2c4 -3 => r1c45,r2c9<>3
38. Row 2 / Column 9 → 5 (Naked Single)
39. Row 1 / Column 7 → 7 (Naked Single)
40. Row 1 / Column 9 → 3 (Full House)
41. Row 2 / Column 3 → 1 (Naked Single)
42. Row 5 / Column 9 → 7 (Naked Single)
43. Row 5 / Column 8 → 6 (Naked Single)
44. Row 5 / Column 7 → 5 (Full House)
45. Row 8 / Column 8 → 4 (Naked Single)
46. Row 7 / Column 8 → 7 (Full House)
47. Row 8 / Column 2 → 1 (Naked Single)
48. Row 8 / Column 9 → 8 (Naked Single)
49. Row 9 / Column 9 → 2 (Naked Single)
50. Row 7 / Column 9 → 1 (Full House)
51. Row 2 / Column 4 → 3 (Hidden Single)
52. Row 9 / Column 4 → 4 (Naked Single)
53. Row 1 / Column 4 → 6 (Naked Single)
54. Row 6 / Column 4 → 2 (Full House)
55. Row 7 / Column 6 → 6 (Naked Single)
56. Row 9 / Column 3 → 3 (Naked Single)
57. Row 7 / Column 3 → 4 (Full House)
58. Row 9 / Column 5 → 8 (Full House)
59. Row 1 / Column 3 → 5 (Full House)
60. Row 1 / Column 5 → 9 (Naked Single)
61. Row 1 / Column 2 → 4 (Full House)
62. Row 2 / Column 6 → 4 (Full House)
63. Row 6 / Column 6 → 9 (Full House)
64. Row 6 / Column 5 → 6 (Full House)
65. Row 2 / Column 2 → 9 (Full House)
66. Row 7 / Column 7 → 3 (Naked Single)
67. Row 7 / Column 5 → 2 (Full House)
68. Row 8 / Column 5 → 3 (Full House)
69. Row 8 / Column 7 → 6 (Full House)