PlaySudoku.us
Hard · Puzzle #253
1
4
8
3
2
8
5
4
7
6
9
8
3
4
3
2
4
9
6
3
5
3
2
5
9
6
7
1
5
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.