June 3, 2026 · 5 min read

Naked Pairs in Sudoku

A naked pair is two cells in the same row, column, or box that contain exactly the same two candidates — and nothing else. Because those two digits must occupy those two cells between them, they can be eliminated from every other cell in the unit. It's the first real candidate-elimination technique, and the gateway to solving hard puzzles.

Naked pairs need pencil marks. Once you've filled in candidates and scanning has stalled, this is one of the first patterns to look for. It rarely places a digit by itself, but the candidates it clears away almost always expose a hidden single somewhere nearby.

How a naked pair works

• the unit in focus
• the pattern
• a placement
• an elimination

In this box, two cells both hold exactly {3, 7} (amber). We don't know yet which is the 3 and which is the 7 — but we know that between them they will use up both digits. That means no other cell in the box can be a 3 or a 7. So those candidates are struck from every other cell in the box (red). In the cell that had {3, 4}, the 3 disappears and it becomes a plain 4 — a placement, handed to you for free.

The pair doesn't have to be solved to be useful. Its power comes entirely from the fact that two cells are reserved for two digits, locking those digits out of the rest of the unit.

What counts as a naked pair

Three conditions must all hold. The two cells must share the same unit — a row, a column, or a box. They must contain exactly two candidates each, no more. And those two candidates must be identical in both cells. {3, 7} and {3, 7} qualify; {3, 7} and {3, 8} do not, and neither does {3, 7} paired with {3, 7, 9}.

If the two cells happen to share more than one unit — say they're in the same row and the same box — then you can eliminate the pair's digits from both units at once. Those overlap cases are where naked pairs cascade fastest.

Finding them at the table

Scan for cells that have exactly two pencil marks — bivalue cells. Whenever you find one, glance along its row, down its column, and around its box for a twin with the identical pair. Pairs are easiest to catch right after you finish pencil-marking, while the candidate counts are fresh in your mind.

A naked pair is the mirror image of a hidden pair. The naked version is obvious in the cells but you act on the rest of the unit; the hidden version is disguised among other candidates but you act on the pair cells themselves. Learn both together — they often appear in the same puzzle.

Next steps

Once naked pairs feel natural, the extension to naked triples is straightforward: three cells, three shared candidates, same elimination logic. And the hidden pair teaches you to spot the pattern even when it's buried.