Hidden Pair sudoku technique

A hidden pair hides in plain sight: two digits that can only be placed in the same two cells of a unit. Those cells may show four or five pencil marks each, which is exactly why players miss it — but since the two digits must occupy the two cells between them, every other candidate written there is dead weight and can be erased.

How to find a hidden pair

1. For a stuck unit, check each missing digit and note which cells could take it.
2. When two digits share the same two possible cells, you have the pair.
3. Delete all other candidates from those two cells, leaving only the pair.
4. The cleaned-up cells frequently collapse into naked singles or feed a pointing pair.

The pattern on the grid

Worked example

The cells r1c4, r1c5 form a hidden pair on {3, 8}. Those digits are consumed inside the set however they distribute, so the shared unit sweeps them out everywhere else: r1c4 loses 56, r1c5 loses 25. Check the pencil marks in the diagram — every elimination is verifiable by eye.

When it fails

Confirm both digits are genuinely limited to the same two cells; a third possible home for either digit breaks the pair. This is where sloppy pencil marks hurt most — a missing mark fakes a pair that isn't there.

Puzzles that need it

These grids come from rated games on this site — our solver confirmed that hidden pair was part of the shortest solving path for each one.

Every string is the standard 81-character format (0 = empty) — paste it into any solver to verify the rating and the solving path yourself. Want to try one under the clock? Play a free puzzle — no account needed — or create an account to train specific difficulty tiers.

Related techniques

• Naked Pair
• Hidden Single
• XY-Wing

All solving techniques