PlaySudoku.us
Hard · Puzzle #100
7
9
3
5
9
6
9
7
3
8
5
9
7
4
3
5
8
2
1
6
4
2
8
4
9
1
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.
"The cosmos is within us. We are made of star-stuff." — Carl Sagan
"The cosmos is within us. We are made of star-stuff." — Carl Sagan