In the same way we have extended Naked Pairs to Naked Triples, we can extend Hidden Pairs to Hidden Triples.
The rule stays the same: if a total of three
candidates are only seen in exactly three cells within a **house** (row, column or square),
then we know that these three candidates will be in the cells. We do not know in which order, but we can eliminate
all other candidates in these three cells.

Let us consider the following example. Column **6** has a Hidden Triple formed by the cells
**A6**, **B6** and **C6**. The candidates triple **{3, 4, 7}** is contained in
all three cells and nowhere else in the column. Hence, the triple will surely be the values in
these three cells in some order. What we know for sure is that the other
candidates are not possible for these three cells and we can eliminate them.

Load in Solver

Similarly to Naked Triples, the three candidates, which form the triple, should not necessarily be
present in all 3 cells. More generally we are interested in a group of 3 cells which contain a total of
three candidates and the candidates are not seen anywhere else.

Load in Solver

In the same way we have formed Naked Triples, we can find Hidden Pairs for any such combination of two or three candidates per cell. We are only concerned with the total number of candidates, which should be three, among the three cells.