Hidden Pair Walkthrough

A Hidden Pair is two digits that appear in only the same two cells of a unit. Those cells must hold those two digits, so all other candidates can be stripped from them.

Sudoku board with pencil-mark candidates before applying the Hidden Pair technique
Before — candidates pencilled in. There is a Hidden Pair in Row 5.

There is a Hidden Pair in Row 5. Applying the Hidden Pair eliminates 4 candidates (struck out in red below; any solved cells shown in green).

The same Sudoku board after the Hidden Pair technique eliminates 4 candidates
After applying the Hidden Pair.