PlaySudoku.us
Expert · Puzzle #494
9
6
2
4
5
1
4
7
7
8
8
9
1
6
4
4
3
5
2
8
6
4
9
2
1
7
A Sudoku grid can be solved using only row and column logic, never needing box constraints — but it becomes exponentially harder.
A Sudoku grid can be solved using only row and column logic, never needing box constraints — but it becomes exponentially harder.
Use pencil marks to track candidates. Eliminating one candidate often triggers a chain reaction.
Use pencil marks to track candidates. Eliminating one candidate often triggers a chain reaction.