Hidden Pair

If two cells in a group contain an identical pair of candidates and no other cells in that group
contain those two candidates, then other candidates in those two cells can be excluded.
In the example below, the candidates 7 and 8 are located in two highlighted
cells of a row, and therefore form a pair. All candidates except 7 and 8 can be excluded from these two
cells as one cell must be the 7 while the other must be the 8.


Hidden Triple

If three cells in a group contain an identical triple of candidates and no other cells in that group
contain those three candidates, then other candidates in those three cells can be excluded.
In the example below, the candidates 4, 5 and 9 are located in three highlighted
cells of a row, and therefore form a triple. We do not yet know the values of the cells,
but we do know that these cells must be a 4, a 5 or a 9.
All candidates except 4, 5 and 9 can be excluded from these three cells.
Hidden triples are very hard to spot, but fortunately they're rarely required
to solve a puzzle. Usually the Hidden Triple is not required, since the same effect is achieved by
using the Naked Pair or Naked Triple.


