Box Brain Sudoku
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Hard · technique 14 of 18
Hidden Triple
Three digits can only go in the same three cells of a house.
This example comes from a Thermo puzzle, but the technique works in every mode.
How it works
Those cells must hold those three digits, so their other candidates can go.
A worked example
Hidden Triple: in column 1, 1, 7 and 8 can only go in rows 1, 4 and 6, so other candidates are removed from those cells.
- The area to look at
- The cells that make the pattern
- Candidates it rules out
A real position from a puzzle in the app. Small digits are the candidates the step looks at; coloured digits are already solved.
Practise it in Box Brain Sudoku
The app teaches Hidden Triple on this same board, then hands you puzzles that need it. When you are stuck mid-game, a hint first points you to the right area, then names the technique and shows the move.