Naked Pair
Two cells in the same unit holding exactly the same two candidates. Those digits belong to those cells, and can be removed everywhere else in the unit.
What it is
When two cells in one row, column or box each show exactly the same two candidates, those two digits must occupy those two cells in some order. Which goes where is unknown and does not matter: together they claim both digits, so no other cell in that unit can hold either of them. It is the first genuine elimination technique most solvers learn.
How to spot it
Scan units for cells with exactly two pencil marks, then look for a second cell in the same unit with the identical pair. The pair must match exactly — {3,9} and {3,9}, not {3,9} and {3,9,5}. Once found, delete both digits from every other cell in that unit.
Worked example
Step through the reasoning below. Each step adds one layer: first the position, then the pattern, then the candidates involved, and finally what can be eliminated.
Step 1 of 4: The starting position
- Pattern cells
- 6/2, 6/4
- Digits
- 3, 9
- Eliminations
- 6/5, 6/8
Press a marked square to point it out on the board above.
Why it matters
The naked pair rarely places a digit itself, but it removes candidates that block naked and hidden singles. On medium and hard puzzles it is often the move that reopens a stalled grid, and it is the foundation for triples, quads and the wing techniques.
Practise now
Solve a puzzle where this technique decides the game
Frequently asked questions
Must the two cells be next to each other?
No. They only need to share a unit — the same row, the same column or the same box. They can sit at opposite ends of a row.
What if a third cell has the same two candidates?
Then something has gone wrong: three cells cannot share two digits. Re-check your pencil marks, because one of them is almost certainly incorrect.
Does a naked pair let me place a digit?
Not directly. It removes candidates elsewhere, and those removals are what create the singles you can place.
Put it to use
Where you will meet it
Medium grids are where this move starts to matter: the obvious cells run out and the pattern takes over.
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