Empty Rectangle

A digit boxed into one row and column, plus a conjugate pair.

Learn the Empty Rectangle Sudoku technique: a digit confined to one row and column of a box, with a conjugate pair, makes an elimination.

How to use it

1. Find the empty rectangle. In a box, find a digit whose candidates all lie in one row and one column of the box — an L with a corner cell.
2. Find a conjugate pair. Find a line crossing the corner’s row or column where the digit appears exactly twice, one end on that row or column.
3. Eliminate at the intersection. Remove the digit where the conjugate pair’s far end lines up with the rectangle’s other arm.