Naked Pairs - Eliminate Candidates Efficiently

Naked pairs are often the first truly satisfying elimination pattern in sudoku. Two cells in the same unit contain exactly the same two candidates, such as {2, 8} and {2, 8}. Because those digits must occupy those two cells in some order, no other cell in that row, column, or box can keep 2 or 8 as candidates.

This technique becomes common in Challenging Sudoku and stays relevant far beyond that level. It rarely finishes a puzzle on its own, but it opens the grid by shrinking candidate sets until easier placements reappear.

How to Spot a Naked Pair

Scan one unit at a time and look for two cells that each contain exactly two candidates. If the pair of digits is identical in both cells, you found a naked pair. The important part is exclusivity: there must be two cells and exactly the same two candidates in both.

Once found, remove those two digits from every other cell in the unit. This elimination is the whole purpose of the technique.

How to Use Naked Pair Elimination

Imagine a row where two cells are {4, 7} and {4, 7}. A third cell in the same row currently shows {1, 4, 7}. Because 4 and 7 are already reserved for the naked pair, that third cell collapses to {1}. You just created a new naked single without guessing.

That is why good solvers keep rescanning after every pair elimination. Pairs are not the goal; they are the trigger for cleaner follow-up placements.

Naked Triples - The Extension

Naked triples work on the same principle with three cells and three shared digits. They are slightly harder to see, but if you understand naked pairs first, the jump feels natural. Before tackling that extension, make sure you also know Hidden Pairs.

Frequently Asked Questions

What is a naked pair in sudoku?

It is a pattern where two cells in one unit share exactly the same two candidates.

Why are naked pairs useful?

They remove candidates from other cells and often unlock easier placements.

What comes after naked pairs?

Hidden pairs and pointing pairs are the usual next techniques to learn.