Sudoku HintHow it works
When two cells in the same row, column, or block contain the same two candidates, those candidates can be removed from other cells in that area.
For example, if two cells in a row only have candidates '3' and '7', then one must be '3' and the other '7'.
Therefore, '3' and '7' can be removed from all other cells in that row.
Example
1
2
3 7
4
3 7
6
8
9
Common mistakes
Both cells must have exactly the same two candidates. A pair such as {2,7} and {2,7,9} does not qualify. Do not erase the pair itself.
Practice · 2
Naked Pairs · Practice
Find two cells with the same two candidates, then select what can be removed elsewhere.
Two examples let you practise just one technique without solving a whole puzzle.