| sudoku online hard | 0.55 | 0.4 | 9401 | 18 | 81 |
| sudoku online hard level | 1.05 | 0.3 | 6754 | 24 | 14 |
| sudoku online hard 247 | 1.25 | 0.7 | 610 | 22 | 17 |
| sudoku online hard billions | 0.81 | 0.9 | 4874 | 27 | 60 |
| sudoku online hard print | 0.36 | 0.4 | 6683 | 24 | 93 |
| online free sudoku hard | 0.59 | 0.4 | 8875 | 23 | 17 |
| sudoku online killer hard | 0.68 | 0.5 | 5692 | 25 | 72 |
| hardest sudoku puzzle online | 0.12 | 0.6 | 6608 | 28 | 93 |
| sudoku medium hard level | 1.14 | 1 | 3413 | 24 | 2 |
| sudoku online very hard | 1.04 | 0.7 | 2776 | 23 | 64 |
| hard level sudoku printable | 0.69 | 0.8 | 5909 | 27 | 38 |
| sudoku online easy to hard | 1.64 | 0.3 | 4195 | 26 | 12 |
| sudoku puzzles hard level | 1 | 0.6 | 1805 | 25 | 84 |
| tips for sudoku hard level | 0.96 | 0.9 | 1984 | 26 | 76 |
| sudoku online free hard | 0.29 | 0.6 | 934 | 23 | 93 |
| hardest level of sudoku | 0.13 | 0.2 | 6166 | 23 | 67 |
| sudoku game online hard | 1.34 | 0.4 | 6920 | 23 | 46 |
| free online sudoku very hard | 0.84 | 0.8 | 2005 | 28 | 19 |
| play sudoku online hard | 0.76 | 0.5 | 8740 | 23 | 16 |
| sudoku most difficult level | 1.02 | 0.7 | 9142 | 27 | 81 |
| sudoku free very hard | 0.2 | 0.2 | 3135 | 21 | 10 |
| sudoku hardest online daily | 0.66 | 0.4 | 6634 | 27 | 43 |
| sudoku game very hard | 1.48 | 0.8 | 4368 | 21 | 8 |
