PlaySudoku.us
Expert · Puzzle #298
2
9
8
3
7
1
6
3
1
9
9
8
5
8
7
4
4
6
1
8
5
1
3
4
9
8
Donald Knuth's "Algorithm X" with dancing links solves exact cover problems — of which Sudoku is a special case.
Donald Knuth's "Algorithm X" with dancing links solves exact cover problems — of which Sudoku is a special case.
Before using pencil marks, see how far you can get with pure logic and mental candidate tracking.
Before using pencil marks, see how far you can get with pure logic and mental candidate tracking.