1
7
5
3
8
1
2
2
1
3
8
3
2
4
9
1
8
6
4
1
5
6
2
5
8
9
4
6
2
4
9
When a row, column, and box all intersect, the intersection cell is the most constrained — always check it first.
When a row, column, and box all intersect, the intersection cell is the most constrained — always check it first.
"The pin is mightier than the sword." — Fred Reinfeld
"The pin is mightier than the sword." — Fred Reinfeld