PlaySudoku.us
Hard · Puzzle #316
4
8
3
6
6
7
9
5
2
4
3
7
6
8
3
3
8
2
5
1
2
5
1
6
1
6
9
1
8
2
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.