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

This Sudoku Puzzle has 51 steps and it is solved using Naked Single, Full House, Hidden Single, Naked Triple, Skyscraper, Bivalue Universal Grave + 1, Give Up techniques.

Try To Solve This Puzzle

## Solution Steps:

1. Row 4 / Column 7 → 5 (Naked Single)
2. Row 3 / Column 8 → 5 (Naked Single)
3. Row 3 / Column 9 → 9 (Naked Single)
4. Row 3 / Column 6 → 3 (Naked Single)
5. Row 3 / Column 5 → 8 (Naked Single)
6. Row 3 / Column 4 → 4 (Full House)
7. Row 4 / Column 6 → 6 (Naked Single)
8. Row 9 / Column 6 → 1 (Naked Single)
9. Row 2 / Column 6 → 5 (Naked Single)
10. Row 7 / Column 6 → 9 (Full House)
11. Row 9 / Column 7 → 6 (Naked Single)
12. Row 8 / Column 7 → 1 (Naked Single)
13. Row 5 / Column 7 → 9 (Full House)
14. Row 9 / Column 5 → 7 (Naked Single)
15. Row 5 / Column 1 → 6 (Naked Single)
16. Row 7 / Column 1 → 3 (Naked Single)
17. Row 4 / Column 1 → 4 (Naked Single)
18. Row 6 / Column 1 → 9 (Full House)
19. Row 1 / Column 4 → 9 (Hidden Single)
20. Row 6 / Column 5 → 3 (Hidden Single)
21. Row 6 / Column 2 → 2 (Naked Single)
22. Row 5 / Column 2 → 8 (Naked Single)
23. Row 4 / Column 2 → 3 (Naked Single)
24. Row 9 / Column 2 → 4 (Naked Single)
25. Row 8 / Column 2 → 6 (Naked Single)
26. Row 7 / Column 2 → 1 (Full House)
27. Row 8 / Column 5 → 5 (Naked Single)
28. Row 8 / Column 4 → 8 (Naked Single)
29. Row 7 / Column 4 → 6 (Full House)
30. Row 8 / Column 3 → 9 (Naked Single)
31. Row 8 / Column 8 → 3 (Naked Single)
32. Row 8 / Column 9 → 4 (Full House)
33. Row 7 / Column 9 → 5 (Hidden Single)
34. Naked Triple: 1,6,7 in r126c9 => r4c9<>7
35. Skyscraper: 1 in r1c5,r6c4 (connected by r16c9) => r2c4,r5c5<>1
36. Row 2 / Column 4 → 2 (Naked Single)
37. Row 5 / Column 5 → 2 (Naked Single)
38. Row 4 / Column 4 → 7 (Naked Single)
39. Bivalue Universal Grave + 1 => r2c9<>6, r2c9<>7
40. Row 2 / Column 9 → 1 (Naked Single)
41. Row 1 / Column 9 → 6 (Naked Single)
42. Row 2 / Column 8 → 7 (Full House)
43. Row 2 / Column 5 → 6 (Full House)
44. Row 1 / Column 5 → 1 (Full House)
45. Row 6 / Column 9 → 7 (Naked Single)
46. Row 5 / Column 8 → 1 (Naked Single)
47. Row 6 / Column 3 → 5 (Naked Single)
48. Row 5 / Column 3 → 7 (Full House)
49. Row 5 / Column 4 → 5 (Full House)
50. Row 6 / Column 4 → 1 (Full House)
51. Give Up: Don't know how to proceed!