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Naked Pair

A Naked Pair is two cells in the same unit that share the exact same two candidates, and nothing else. Between the two of them, those two digits are fully accounted for — you just don't know which cell gets which yet.

Why it works

If two cells in a unit can only be 3 or 5, then one of them is 3 and the other is 5 — in some order. That means no other cell in that same unit can be 3 or 5, since both digits are already spoken for. You can safely cross 3 and 5 out of every other cell's candidates in that unit.

Worked example

Tips

• Look for cells with exactly two candidates left, then check whether another cell in the same row, column, or box shares that identical pair.
• The elimination only applies within the shared unit — a Naked Pair in a box doesn't affect cells outside that box unless they also share the row or column.