When a digit in a row or column is confined to one box, it can be eliminated from the rest of that box.
The reverse of Pointing Pairs. When a digit in a row or column can only appear within a single box, it can be eliminated from all other cells in that box (those not in the shared row/column).
Since the digit must be in that row/column within the box, it cannot appear elsewhere in the box.
| 8 | 2 | 9 | 4 | 3 | 1 | 5 | 6 | 7 |
| 1 | 3 | 46 | 5 | 69 | 7 | 2 | 8 | 49 |
| 5 | 46 | 7 | 2 | 8 | 69 | 1 | 3 | 49 |
| 2 | 7 | 1 | 368 | 4 | 36 | 9 | 5 | 68 |
| 6 | 8 | 5 | 9 | 1 | 2 | 7 | 4 | 3 |
| 4 | 9 | 3 | 68 | 7 | 5 | 68 | 1 | 2 |
| 3 | 46 | 2 | 1 | 69 | 4689 | 68 | 7 | 5 |
| 7 | 5 | 8 | 36 | 2 | 36 | 4 | 9 | 1 |
| 9 | 1 | 46 | 7 | 5 | 468 | 3 | 2 | 68 |
This 9×9 puzzle is solver-verified to require this technique on its solution path.