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
Nikoli, the Japanese puzzle company that popularized Sudoku, requires all their puzzles to be created by hand — no computers.
Nikoli, the Japanese puzzle company that popularized Sudoku, requires all their puzzles to be created by hand — no computers.
The pigeonhole principle explains why 8 clues are never enough to guarantee a unique Sudoku solution.
The pigeonhole principle explains why 8 clues are never enough to guarantee a unique Sudoku solution.