PlaySudoku.us
Expert · Puzzle #129
1
3
7
8
2
3
4
7
1
2
9
8
9
1
6
7
7
5
8
5
8
6
1
7
4
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.