PlaySudoku.us
Hard · Puzzle #492
4
1
9
3
7
1
7
6
3
8
9
5
1
2
5
1
2
6
7
1
9
8
2
6
9
3
"Knowledge is power." — Francis Bacon
"Knowledge is power." — Francis Bacon
The Swordfish technique extends X-Wing to three rows and three columns — rare but decisive on expert grids.
The Swordfish technique extends X-Wing to three rows and three columns — rare but decisive on expert grids.