Sudoku techniques · Hard
Hidden Pair in Sudoku
A Hidden Pair is two numbers whose candidates appear in only two cells of a row, column or box. Those two numbers must take those two cells, so every other candidate in them can be erased, which usually turns a cluttered pair of cells into a clean Naked Pair.
Why it works
Two numbers whose candidates together appear in only two cells of a row, column, or box claim those cells for themselves.
How to spot it
Count, do not look. For each number missing from a unit, note how many cells could still take it.
- Two numbers with a count of two, landing in the same two cells, is a Hidden Pair.
- The cells often carry four or five candidates, which is exactly why the pattern is hidden.
- The elimination happens inside the pair, not outside it: the opposite of a Naked Pair.
Builds on
Worked example
These are the app's own lesson boards. Step through them the same way a hint does.
- 1
In this row, 4, 8 appear as candidates only in these two cells.
- 2
These two cells must contain 4, 8 between them, so we can remove any other candidates from those cells.