Naked Single Sudoku Strategy

A naked single is the simplest logical move in Sudoku. A cell's pencil marks shrink to one remaining candidate, so that digit must be correct.

How to spot a naked single

Example: A cell can only be 4 or 9. You scan its row and see 9 already placed elsewhere in the row. Eliminate 9 — the cell must be 4.

Always check naked singles after every placement and after updating pencil marks.

Why it matters

Naked singles appear constantly in Easy and Medium puzzles. Missing them usually means pencil marks are out of date.

Practice

Play easy Sudoku and look for cells with a single remaining candidate after each move.