Volodymyr Sakhan  ·  April 9, 2026  ·  Updated May 4, 2026

The naked pairs technique (also called obvious pairs) is one of the first intermediate strategies you need when basic solving methods no longer make progress. It works by spotting two cells in the same unit that share exactly the same pair of candidates — and using that fact to clear those numbers from every other cell in that unit.

To use naked pairs you need to have pencil marks active, so every empty cell shows its possible candidates. Once you have that, naked pairs are straightforward to spot and apply.

What Is a Naked Pair in Sudoku?

A naked pair is two cells within the same row, column, or box that each contain exactly the same two candidate digits — and no others. Because one of those two digits must go into each cell, the pair "uses up" both values. Neither digit can appear anywhere else in the shared unit.

The name comes from the candidates being fully exposed: both cells show only those two numbers, with nothing else hidden behind them. This is what distinguishes a naked pair from a hidden pair, where the same two cells share a pair of candidates but also carry additional candidates alongside them.

When to Use Naked Pairs

Naked pairs appear in medium and hard puzzles, typically once all hidden singles and naked singles have been placed. Look for them when:

• You have pencil marks filled in and no single cell can be resolved directly.
• You notice two cells in the same unit each showing exactly two candidates.
• Those two candidate sets are identical — the same pair of digits in both cells.

Step-by-Step Example

Naked pairs work the same way in a box, a row, or a column. Here are all three cases with a concrete board position for each.

Naked Pair in a Box

In the diagram below, cells D9 and F7 (highlighted green) each contain only the candidates {7, 9}. Cell F9 (highlighted orange) currently holds the candidates {2, 7, 9}.

1. Write pencil marks for every empty cell in the bottom-right box (columns G–I, rows 7–9).
2. Spot that D9 = {7, 9} and F7 = {7, 9} — they are identical two-candidate cells.
3. Conclude: one of D9 or F7 must hold 7, and the other must hold 9. No third cell can use either digit within this box.
4. Eliminate 7 and 9 from every other empty cell in the box.
5. F9 shrinks from {2, 7, 9} to {2} — two fewer candidates, making further deductions easier.
6. Check whether any remaining cell in the box now has only one candidate — that would be a naked single you can place immediately.

When two cells in a box share the same two-candidate set, lock those numbers into that pair and clear them from every other cell in the box.

Naked Pair in a Row

The same logic applies across a row. Here, cells B6 and F6 (green) both contain only {1, 7}. Cells E6, G6, H6, and I6 (orange) each carry a 1 or a 7 among their candidates and must have them removed.

1. Scan row 6 for cells with exactly two candidates.
2. Find B6 = {1, 7} and F6 = {1, 7} — the same pair in two different cells.
3. Since B6 and F6 must together account for both 1 and 7, no other cell in row 6 can contain either digit.
4. Eliminate 1 and 7 from E6, G6, H6, I6, and any other cells in row 6 that carry them.
5. I6 goes from {4, 7, 9} to {4} — a naked single that can be placed immediately.

A naked pair in a row clears both candidates from every other cell in that row, and often creates naked singles as a direct result.

Naked Pair in a Column

Columns work identically. In the diagram below, cells B1 and B4 (green) each contain only {3, 4}. Cells B2 and B9 (orange) have {3, 4, 9} and {3, 4, 8, 9} respectively and will lose both 3 and 4 once the pair is identified.

1. Scan column B for cells with exactly two candidates.
2. Find B1 = {3, 4} and B4 = {3, 4}.
3. One of these cells holds 3 and the other holds 4 — both values are spoken for within column B.
4. Eliminate 3 and 4 from every other empty cell in column B.
5. B2 reduces from {3, 4, 9} to {9} — another naked single, ready to place.

The rule is the same in every unit: find the matching two-candidate pair, then sweep both digits from everything else in that row, column, or box.

Practice Naked Pairs Online

Naked pairs appear regularly in medium puzzles, and even more often in hard ones. The best way to get comfortable with the pattern is to play with pencil marks turned on and actively scan each unit whenever you get stuck. Try a medium sudoku and look for matching two-candidate cells in every row, column, and box.

Once naked pairs feel natural, you are ready for the next step: naked triples follow the same principle with three cells instead of two, and hidden pairs are the mirror image — two candidates that only appear in two cells of a unit, even though those cells have other candidates too. You can find all techniques in our complete sudoku solving guide.