Naked Pair in Sudoku: How to Spot It
Learn how Naked Pairs work in Sudoku, when to look for them, and how to remove candidates safely.
Guided example
See the Naked Pair on this board
Read this as one teaching unit: first identify the active unit, then the marked pattern cells, then the candidates removed or maintained.
Quick answer
A Naked Pair in Sudoku is a pattern where two cells in the same unit contain exactly the same two candidates. Those two numbers must occupy those two cells, so the same candidates can be removed from other cells in that row, column, or box.
How to spot it
Follow the board in order
- 1 Choose one row, column, or box and look only inside that unit.
- 2 Find two cells that contain the exact same two candidates.
- 3 Confirm both cells are in the same unit and contain no extra candidates.
- 4 Remove those two candidates from every other cell in that unit.
What is a Naked Pair?
A Naked Pair happens when two cells in the same row, column, or box contain the exact same two candidates. Those two numbers must occupy those two cells, so they can be removed from the other cells in that unit.
When to look for it
Look for Naked Pairs after basic singles are no longer obvious and you have written candidates. They are most useful when a row, column, or box has several cells with two or three remaining candidates.
Example walkthrough
This walkthrough uses a real expert app puzzle tagged Naked Pair. The two blue cells, r4c9 and r6c7, both contain exactly 8 and 9 inside the same box. Those two cells must take 8 and 9 in some order, so the other cell in that box, r4c7, cannot keep 8 or 9.
Why the elimination works
If two cells in one unit can only be {2, 7}, then one of those cells must be 2 and the other must be 7. No other cell in that same row, column, or box can use 2 or 7.
Naked Pair vs. Hidden Pair
A Naked Pair is visible because the two cells contain only the pair numbers.
A Hidden Pair may be buried inside cells with extra candidates. You find it by tracking where two numbers can appear, then remove the extra candidates from those two cells.
Common mistake
Do not remove the pair numbers from the pair cells themselves. A Naked Pair removes those candidates only from the other cells in the same row, column, or box.
FAQ
What is a Naked Pair in Sudoku?
A Naked Pair is two cells in one row, column, or box that contain the exact same two candidates.
How do you spot a Naked Pair?
Look for two cells in the same unit with identical two-candidate lists, such as {2, 7} and {2, 7}.
What can you eliminate with a Naked Pair?
You can remove the two paired candidates from every other cell in that same row, column, or box.
What is the difference between Naked Pair and Hidden Pair?
A Naked Pair is visible because the two cells contain only the pair. A Hidden Pair is hidden among extra candidates and must be uncovered by looking at where two numbers can go.
In this lesson
- Board example: see the pattern first.
- Walkthrough: connect each highlight to the rule.
- FAQ: check edge cases after the move is clear.
Practice this technique in Sudoku Coach
Read the pattern, then practice it step by step with guided hints that explain why the move works.
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