Naked Triple
Three cells in a unit that between them use only three candidates. Those three digits are reserved for those cells.
What it is
Three cells form a naked triple when the union of their candidates contains exactly three digits. Crucially, not every cell needs all three: {1,4}, {4,7} and {1,7} is a valid triple, as is {1,4,7} with {1,4} and {4,7}. What matters is that three cells share three digits in total, so those digits are used up there and can be removed from the rest of the unit.
How to spot it
Look for units with several two- and three-candidate cells. Take three of them and combine their candidates. If the union has exactly three distinct digits, you have a triple. The partial forms are the ones people miss, so check combinations rather than looking for three identical cells.
Worked example
Step through the reasoning below. Each step adds one layer: first the position, then the pattern, then the candidates involved, and finally what can be eliminated.
Step 1 of 4: The starting position
- Pattern cells
- 7/3, 7/5, 7/9
- Digits
- 1, 4, 7
- Eliminations
- 7/7
Press a marked square to point it out on the board above.
Why it matters
Triples appear frequently on hard puzzles and often unlock a unit that pairs alone cannot. They also train the counting habit that quads and hidden subsets require.
Practise now
Solve a puzzle where this technique decides the game
Frequently asked questions
Do all three cells need all three candidates?
No, and this is the point most solvers get wrong. {1,4}, {4,7} and {1,7} is a perfectly valid triple. Only the union of the three cells must be exactly three digits.
How do I spot triples efficiently?
Focus on units containing three or more cells with two or three candidates, then test combinations. Cells with four or more candidates cannot be part of a triple.
Put it to use
Where you will meet it
Medium grids are where this move starts to matter: the obvious cells run out and the pattern takes over.
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