Claiming Pair
Also known as Box-Line Reduction.
The mirror of a pointing pair. When a line confines a candidate to one box, the line 'claims' it, clearing it from the rest of that box.
In this row, candidate 9 only fits these two cells — both inside the same box.
How to spot it
- 1Scan a row or column for a candidate surviving in only two or three cells.
- 2Confirm those cells all sit inside one 3×3 box.
- 3Erase the candidate from every other cell of that box.
When to use
Alongside pointing pairs — together they unlock most hard puzzles.
Common mistake
Confusing the direction. Claiming goes line → box; pointing goes box → line.
Worked Example
Claiming pairs work the mirror direction from pointing pairs: instead of a box confining a candidate to a line, a line confines a candidate to a box. If a row's only two or three candidates for 9 all happen to sit inside one box, that box must supply its 9 from within that row.
That means the rest of the box — outside the row — can't hold a 9 either, so those candidates come off. It's easy to mix up the direction: claiming goes line → box, pointing goes box → line. Learning both together is what usually unlocks a hard puzzle.