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

This Sudoku Puzzle has 69 steps and it is solved using Naked Single, Full House, Hidden Single, undefined, Finned Swordfish, Locked Candidates Type 1 (Pointing), AIC techniques.

Try To Solve This Puzzle

## Solution Steps:

1. Row 4 / Column 8 → 8 (Naked Single)
2. Row 6 / Column 8 → 4 (Naked Single)
3. Row 4 / Column 4 → 9 (Naked Single)
4. Row 5 / Column 9 → 3 (Naked Single)
5. Row 5 / Column 7 → 9 (Full House)
6. Row 4 / Column 1 → 3 (Hidden Single)
7. Row 6 / Column 4 → 5 (Hidden Single)
8. Row 3 / Column 7 → 1 (Hidden Single)
9. Row 5 / Column 5 → 4 (Hidden Single)
10. Row 3 / Column 3 → 3 (Hidden Single)
11. Row 3 / Column 4 → 8 (Naked Single)
12. Row 9 / Column 7 → 3 (Hidden Single)
13. Row 4 / Column 2 → 2 (Hidden Single)
14. Row 5 / Column 6 → 8 (Hidden Single)
15. Row 9 / Column 8 → 5 (Hidden Single)
16. Row 6 / Column 6 → 7 (Hidden Single)
17. Row 4 / Column 6 → 1 (Hidden Single)
18. Row 4 / Column 5 → 6 (Full House)
19. 2-String Kite: 7 in r1c5,r8c8 (connected by r1c9,r2c8) => r8c5<>7
20. Finned X-Wing: 4 r39 c19 fr9c2 => r78c1<>4
21. Finned Swordfish: 6 r157 c137 fr1c2 => r3c1<>6
22. X-Chain: 2 r1c3 =2= r7c3 -2- r7c9 =2= r8c8 -2- r2c8 =2= r2c5 => r1c5<>2
23. XY-Chain: 4 4- r2c2 -6- r2c6 -3- r8c6 -9- r3c6 -6- r3c8 -2- r3c9 -4 => r2c7,r3c1<>4
24. Row 2 / Column 2 → 4 (Hidden Single)
25. Row 3 / Column 9 → 4 (Hidden Single)
26. Row 9 / Column 1 → 4 (Hidden Single)
27. Locked Candidates Type 1 (Pointing): 6 in b1 => r1c7<>6
28. X-Wing: 2 c39 r17 => r17c1<>2
29. XY-Chain: 8 8- r1c7 -5- r2c7 -6- r2c6 -3- r8c6 -9- r8c5 -8 => r8c7<>8
30. AIC: 6 6- r2c6 -3- r2c4 -7- r2c8 =7= r8c8 -7- r9c9 -8- r9c2 =8= r8c2 -8- r8c5 -9- r8c6 =9= r3c6 =6= r3c8 -6 => r2c78,r3c6<>6
31. Row 2 / Column 7 → 5 (Naked Single)
32. Row 3 / Column 6 → 9 (Naked Single)
33. Row 1 / Column 7 → 8 (Naked Single)
34. Row 8 / Column 6 → 3 (Naked Single)
35. Row 2 / Column 6 → 6 (Full House)
36. Row 3 / Column 8 → 6 (Hidden Single)
37. Row 2 / Column 4 → 3 (Hidden Single)
38. Locked Candidates Type 1 (Pointing): 7 in b2 => r79c5<>7
39. AIC: 9 9- r8c5 -8- r8c2 =8= r9c2 -8- r9c9 -7- r9c3 -9 => r8c12,r9c5<>9
40. Row 8 / Column 5 → 9 (Hidden Single)
41. Row 8 / Column 2 → 8 (Hidden Single)
42. Row 1 / Column 2 → 6 (Hidden Single)
43. XY-Wing: 2/9/7 in r1c39,r9c3 => r9c9<>7
44. Row 9 / Column 9 → 8 (Naked Single)
45. Row 9 / Column 5 → 1 (Naked Single)
46. Row 7 / Column 5 → 8 (Naked Single)
47. Row 9 / Column 2 → 9 (Naked Single)
48. Row 6 / Column 2 → 1 (Full House)
49. Row 9 / Column 3 → 7 (Full House)
50. Row 6 / Column 1 → 9 (Full House)
51. Row 5 / Column 3 → 6 (Naked Single)
52. Row 5 / Column 1 → 7 (Full House)
53. Row 1 / Column 1 → 5 (Naked Single)
54. Row 7 / Column 3 → 2 (Naked Single)
55. Row 1 / Column 3 → 9 (Full House)
56. Row 3 / Column 1 → 2 (Full House)
57. Row 3 / Column 5 → 5 (Full House)
58. Row 1 / Column 5 → 7 (Naked Single)
59. Row 1 / Column 9 → 2 (Full House)
60. Row 7 / Column 9 → 7 (Full House)
61. Row 2 / Column 5 → 2 (Full House)
62. Row 2 / Column 8 → 7 (Full House)
63. Row 8 / Column 8 → 2 (Full House)
64. Row 8 / Column 1 → 6 (Naked Single)
65. Row 7 / Column 1 → 1 (Full House)
66. Row 7 / Column 4 → 4 (Naked Single)
67. Row 7 / Column 7 → 6 (Full House)
68. Row 8 / Column 7 → 4 (Full House)
69. Row 8 / Column 4 → 7 (Full House)