How to Use the Naked Pairs Strategy in Sudoku
What is a Naked Pair?
Unlike the “Naked Single” technique, we must spot two cells that have only two possible candidates in them, instead of just one.
To qualify as a Naked Pair, these two cells must meet two strict conditions:
- They must reside within the same unit (the same row, column, or 3×3 block).
- They must contain the exact same two candidates and absolutely no other numbers.
Can you spot the Naked Pair in this example? Take a look at the highlighted cells. We can see that two of them contain only two possible values: 7 and 8.
The Logic Behind the Elimination
The beauty of this strategy lies in logical certainty. This means that one of these cells contains 7 and the other one contains 8. Even if we don’t know yet which cell gets which number, we know with 100% certainty that those two spots are completely reserved for 7 and 8.
This also means that they can’t appear in any other cells within this unit.
Because the numbers 7 and 8 are locked into our pair, they are legally blocked from being placed anywhere else in that specific region. Therefore, you can safely perform the following action: erase the numbers 7 and 8 from the pencil notes of every other empty cell in that unit.
Step-by-Step Application
1. In a 3×3 Block
Scan a block to find two cells containing identical two-digit notes (eg., 7 and 8). Once found, look at all the other empty cells in that 3×3 square and delete any 7s or 8s written as candidates. This often exposes a Naked Single nearby!
2. In Rows and Columns
Naked Pairs can also be applied in a column or row. Look down a vertical column or across a horizontal row. If two cells on that line share the exact same pair of candidates, remove those two digits from all other notes along that entire line—even if those other cells are in different 3×3 blocks.
Why Naked Pairs Will Transform Your Gameplay
Mastering Naked Pairs changes how you look at Sudoku candidates. Instead of just looking for immediate answers, you begin to clean up the board by eliminating the noise. This strategy is the foundation for advanced tactics like Naked Triples, Naked Quads, and complex wing strategies.