Solving techniques
Naked triple
A naked triple extends the naked pair idea to three cells. The cells do not each need all three digits, which is what makes them hard to spot.
A naked triple is three cells in a row, column or box whose candidates together contain only three different digits. Those digits must go in those three cells, so they can be removed from every other cell of the unit.
The logic
If three cells use only the digits 2, 3 and 8 between them, the three digits fill the three cells. The rest of the unit cannot hold them. The cells may look like (2 3), (2 8) and (2 3 8): not every cell has all three.
How to find a naked triple
- Choose a unit and write notes.
- Select cells with two or three candidates.
- Look for three of them whose candidates combined are only three digits.
- Remove those three digits from the other cells of the unit.
Common mistakes
- Requiring each cell to have all three candidates. They do not have to.
- Counting a cell with four candidates. It cannot be part of a naked triple.
- Forgetting that the cells could be part of two units. Check both.
Related
Start with naked pairs. The opposite view, working from digits, is the hidden triple. Triples are the mark of Hard puzzles.
Frequently asked questions
What is a naked triple?
Three cells in a unit that together contain only three different candidates.
Does every cell need all three digits?
No. Each cell needs two or three of them.
What do you remove?
The three digits from every other cell of the unit.