PlaySudoku.us
Hard · Puzzle #857
5
3
2
7
5
2
2
3
9
8
5
8
1
4
6
8
7
5
5
9
1
2
8
2
3
1
6
2
Before using pencil marks, see how far you can get on a hard puzzle with pure mental tracking.
Before using pencil marks, see how far you can get on a hard puzzle with pure mental tracking.
"A theory that is not refutable by any conceivable event is non-scientific." — Karl Popper
"A theory that is not refutable by any conceivable event is non-scientific." — Karl Popper