Example of a Buried Triple
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Buried Triple: Three Squares in the same Row, Column, or Box that contain the same three Possibles - and the Possibles occur nowhere else in that same Row, Column, or Box.

In this example, the Buried Triple is the three Squares containing the Possibles 3, 4 and 8 (coloured black). These three Squares MUST contain 3, 4 or 8. Therefore they cannot contain any other Possibles. The 1, 6 and 9 outlined in orange are impossible solutions and can be removed.