Pointing Triples
A gang of three cells shooting in one direction.
Pointing Triples extends the logic of Pointing Pairs from two cells to three. It occurs when a digit appears as a candidate in exactly three cells within a 3×3 box, and all three cells fall on the same row or column. Because the digit must appear somewhere within that box, and every cell that could hold it sits on the same line, the digit is locked into that row or column no matter which cell gets it. That lock lets you eliminate the digit from every other cell on that row or column outside the box, the same way a pointing pair does.
How It Works
- Choose a digit and find a 3×3 box where it appears as a candidate in exactly three cells.
- Confirm all three cells share the same row (or column).
- The digit must appear somewhere in those three cells — and since they all lie in the same line, the digit cannot appear in any other cell in that row (or column) outside the box.
- Eliminate the candidate from all other cells in that row (or column).
Example
Below board presents an example of a pointing triple on digit 3, confined to a single column within a box.
Three cells, one column, one box. Digit 3 can only land in column 8 within this box, so wherever it ends up, column 8 gets its 3 from here. Any other cell in column 8 — above or below the box — loses 3 as a candidate.
On Evil Boards
Pointing triples are rarer than pointing pairs — a box has to leave a digit exactly three candidates, all lined up in one row or column. But they are easier to spot once you know to look. Do not skip them: an evil board rarely resolves without squeezing every elimination out of pointing triples. When the three candidates don't line up, the box may still hold an obvious triple or a hidden triple instead.