Same technique as Unique Pairs, but with three numbers in three cells.
In row C there are three cells with the numbers “2”, “5”, and “9”, therefore, they can be excluded from cells C4 and C7:
The same reasoning can be applied to a box, the numbers “4”, “5”, and “6” can be eliminated from cell A3 and C1. In this case, with three numbers in three cells, the solution for these cells will be among these three numbers:
Another example. A set of cells with a trio and a pair (containing two numbers from the trio). The numbers “5” and “7” can be eliminated from cells A5 and B5. Note that the three numbers (although it is a pair and a trio of candidates) will necessarily be the solution in these three cells:
In summary, if there are the same three numbers in three cells in a UNIT, they can be excluded from the other cells of that UNIT.
