PlaySudoku.us
Hard · Puzzle #118
5
6
2
7
1
4
4
5
8
6
9
1
4
2
7
8
2
3
4
7
2
7
6
3
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.
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.