Hidden Pair
Two digits appear as candidates in only the same two cells of a unit — strip those cells down to just those two digits.
How it works
- 1The whole top-right box is drawn. Digits 1 and 5 appear in only two of its cells, G1 and H2 — nowhere else in the box can hold either.
- 2Six cells here are still empty, so the four left over don't collapse into a Naked Pair or Triple; nothing before Hidden Pair touches G1 or H2.
- 3Those two cells must take 1 and 5 between them, so every other candidate goes — G1 loses its 8, H2 loses its 7.
- Cells that establish the pattern
- Candidate ruled out