How to solve a naked triple in Sudoku
A naked triple is three cells in a unit that between them hold only three candidates, which can be removed from the rest of the unit.
How it works
Three cells in a unit can hold just the digits 2, 5 and 9 between them, even if no single cell lists all three. Together they must use up those three digits.
So 2, 5 and 9 can be removed from every other cell in the unit.
How to spot it
Look for cells in one unit with two or three candidates each, drawn from a set of just three digits.
A worked example
This is a step from a real puzzle, a moment where the next move needs a naked triple.
Struck-through digits are the ones that can be removed.
R2C9, R6C9, R9C9 can only hold 1, 4, 8 (a naked triple), so those digits can't go anywhere else in column 9. Remove them from R1C9, R3C9, R5C9.
Where it fits in Rocksled Sudoku
Puzzles that need a naked triple are never rated below Very Hard. Each step of this kind adds 28 points to a puzzle’s difficulty score. When you ask for a hint that needs it, the game names the technique and shows the cells involved. See how to play for the rest of the controls.