Proven Sudoku
Hidden Triple
Also called Hidden Triplet, Concealed Triple.
New to this shorthand? How to read a sudoku grid explains r4c7, houses, candidates and the rest.
What it means
Three digits in a group can only go in the same three squares. Those squares are reserved for them, so clear every other digit out of those squares.
The exact rule, for stronger players
The rule, stated exactly: For a house H, if three digits are collectively confined to the same three cells of H, all other candidates may be eliminated from those three cells.
What it removes: Remove every candidate outside the three digits from the three cells.
Why it works: Three digits needing placement in H have only three available cells between them, so those cells are fully consumed by those digits.
Worked examples
These come from real Proven Sudoku boards. Nobody drew them by hand to make the pattern look neat. Each one is checked first, so the board is one you could really meet, the pattern is really there, and every digit it rules out is really wrong.
Learn these first
- Hidden PairTwo digits in one group can only go in the same two squares.
Related subsets
- Locked PairA pair that shares two groups at once, usually a row and a box.
- Locked TripleA triple that sits in two groups at once, usually a row and a box.
- Naked PairTwo squares in the same group both hold only the same two digits.
- Naked QuadFour squares in one group share the same four digits between them.
- Naked Subset (general form)Find some squares in one row, column or box.
How often does it come up?
Our rough estimate: uncommon, and frequently invisible without full pencil marks.