4
1
6
3
2
7
7
9
8
3
8
7
5
1
1
5
4
6
7
9
5
2
5
3
8
Time 00:00
Mistakes 0
Ready
Hard Sudoku #140
Advanced patterns: X-Wings, triples and tighter candidate logic.
| Difficulty | Hard |
| Clues given | 25 of 81 |
| Technique score | 186.3 |
| Rated techniques | 7 |
Techniques this puzzle needs
Where to start
The first move on this board is a Naked Single: Row 1, column 8 already sees all eight other digits in its row, column and box, so it can only be 9.
Progress is saved in this browser automatically. Use the keyboard: arrows to move, 1–9 to fill, N for notes, H for a hint.