Intermediate

Hidden Pair

When two numbers can only fit in the same two cells.

Explanation

In one row, column, or box, if two digits can appear only in the same two cells, those cells must contain the pair. Other candidates in the pair cells can be removed.

Hidden Pair example Sudoku board 5 3 7 6 1 9 5 9 8 6 8 6 3 4 8 3 1 7 2 6 6 2 8 4 1 9 5 8 7 9
An example board where Hidden Pair applies

Practice tip

Scan one unit at a time and track where each digit can still go.

Example steps

  1. Choose a unit and mark the possible cells for each digit.
  2. Find two digits that share exactly two possible cells.
  3. Keep those two digits in the pair cells and remove all other notes there.

Try this technique on a real puzzle.

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