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Hidden Pair (and Triple)

When two digits can only appear in the same two cells within a unit - even though those cells have other candidates - the two digits form a hidden pair. All other candidates can be eliminated from those two cells.

Basic

How to read the grids

  • Given - clues from the starting puzzle
  • Subject - cells the technique focuses on
  • Eliminated - candidates this technique removes
  • Candidate - pencil marks shown for reference

How to spot it

For each unit, list which cells can hold each digit. If two digits have an identical pair of candidate cells, the cells form a hidden pair. Strip everything else from them. Hidden triples work the same with three digits sharing three cells.

The hidden pair {4,7} clears the two cells of every other candidate.

Worked example

In this row, only two cells can hold a 4 or a 7. Even if those cells also pencil 1, 2, 5, the only digits that can stay are 4 and 7.

Time to practice

Reading is half the work. Try a puzzle now and look for the techniques you just learned.