PlaySudoku.us
Hard · Puzzle #369
7
9
1
3
4
7
8
2
9
9
8
6
3
1
1
5
6
2
4
3
6
1
5
7
1
6
2
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.