Three digits confined to the same three cells in a unit; all other candidates in those cells are eliminated.
When three digits can only appear in the same three cells within a unit, all other candidates in those three cells can be eliminated. It's harder to spot than a Hidden Pair since the three cells may have many other candidates obscuring the pattern.
| 3 | 8 | 6 | 25 | 14 | 7 | 125 | 45 | 9 |
| 1 | 2 | 4 | 35 | 6 | 9 | 57 | 357 | 8 |
| 5 | 7 | 9 | 23 | 14 | 8 | 126 | 34 | 246 |
28 | 45 | 1 | 6 | 7 | 3 | 258 | 9 | 24 |
28 | 456 | 3 | 1 | 9 | 25 | 2568 | 458 | 7 |
| 9 | 56 | 7 | 4 | 8 | 25 | 3 | 1 | 26 |
| 4 | 3 | 8 | 7 | 2 | 1 | 9 | 6 | 5 |
| 6 | 1 | 2 | 9 | 5 | 4 | 78 | 78 | 3 |
| 7 | 9 | 5 | 8 | 3 | 6 | 4 | 2 | 1 |
This 9×9 puzzle is solver-verified to require this technique on its solution path.