Naked Single Walkthrough

A Naked Single is a cell left with only one possible candidate once the digits already in its row, column, and 3x3 box are eliminated. That digit must go there.

Sudoku board with pencil-mark candidates before applying the Naked Single technique — Before — candidates pencilled in. There is a Naked Single in Row 2, Column 1.

There is a Naked Single in Row 2, Column 1. Applying the Naked Single eliminates 291 candidates and solves 5 cells (struck out in red below; any solved cells shown in green).

The same Sudoku board after the Naked Single technique eliminates 291 candidates and solves 5 cells — After applying the Naked Single.

Learn the Naked Single technique →Practice it on a real puzzle →