PlaySudoku.us
Hard · Puzzle #790
1
2
9
2
5
6
4
6
4
3
9
1
4
7
5
1
2
5
8
9
6
6
5
2
7
7
4
8
9
6
The hardest Sudoku puzzles require techniques equivalent to propositional logic — the same foundation used in computer proofs.
The hardest Sudoku puzzles require techniques equivalent to propositional logic — the same foundation used in computer proofs.
A Sudoku grid is a special case of a Latin square: a 9×9 grid where each symbol appears exactly once in each row and column.
A Sudoku grid is a special case of a Latin square: a 9×9 grid where each symbol appears exactly once in each row and column.