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Naked Triples & Quads
Learn naked triples and quads: three or four cells in a unit sharing the same three or four candidates, letting you eliminate those digits everywhere else in the unit.
A naked triple is three cells in one unit whose candidates, taken together, use only three different digits: for example {1,4}, {4,7} and {1,7}, or {1,4,7} repeated. The key is the union. No cell needs to hold all three digits; what counts is the three between them.
Because those three cells must consume those three digits, none of them can appear anywhere else in the row, column or box, so you can erase all three from every other cell of the unit. A naked quad is the same idea with four cells sharing four candidates.
Triples are easy to miss because the candidates are spread differently across the cells. The trick is to look for any three cells whose combined notes never exceed three digits. Try it on the example: the highlighted cells never use more than three digits between them.
Practise the Naked triple
The best way to learn a technique is to use it. Play a puzzle at the level where it first appears, or drop a tricky board into the solver to watch it in action.
Frequently asked questions
What is a naked triple in Sudoku?
Three cells in the same row, column or box whose candidates together total just three digits. Those digits are locked to the three cells and can be removed from the rest of the unit.
Do all three cells need the same three candidates?
No. Each cell can show two or three of the digits — what matters is that the union across the three cells is exactly three digits. {1,4}, {4,7}, {1,7} is a valid naked triple.
How is a naked quad different?
A naked quad is the four-cell version: four cells whose candidates union to exactly four digits, which then leave the rest of the unit. Quads are rarer and harder to spot but follow the identical logic.
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