PlaySudoku.us
Expert · Puzzle #233
2
7
4
9
1
5
3
1
3
6
2
2
6
8
9
4
7
3
5
1
6
4
7
2
Track your error rate, not just your time. Accuracy improves faster than speed when you measure it.
Track your error rate, not just your time. Accuracy improves faster than speed when you measure it.
When a box has only two empty cells, you know exactly which two digits fill them.
When a box has only two empty cells, you know exactly which two digits fill them.