PlaySudoku.us
Hard · Puzzle #872
1
8
4
2
8
1
6
4
8
3
7
2
4
6
2
1
2
4
6
3
4
8
7
6
9
6
9
3
7
5
A hidden pair in a row is often invisible until you track each digit separately through that row.
A hidden pair in a row is often invisible until you track each digit separately through that row.
Set theory provides the formal foundation for Sudoku's rules: each digit must appear exactly once per set.
Set theory provides the formal foundation for Sudoku's rules: each digit must appear exactly once per set.