Sudoku solving technique · Beginner
Naked Single
A cell where only one digit can still go.
What is a Naked Single?
When a cell has only one possible candidate left, that must be the answer. All other numbers are already used in the same row, column, or block.
How to spot a Naked Single
Look at cells whose row, column and block are already nearly full, and rule out every digit that already appears there. Notes make it quicker: a cell with only one note left is a Naked Single, and that digit can be placed.
- Difficulty
- In Sudoku Pro, this technique belongs to the Beginner level.
- Learning path
- Technique 1 of 20 on the learning path
An example from the app
| Given 1 | Given 2 | Given 3 | Pattern (purple). Candidates 4 |
| Empty | Empty | Given 1 | Given 2 |
| Empty | Empty | Empty | Given 3 |
| Empty | Empty | Empty | Given 1 |
Small digits are candidates. Crossed-out digits can be removed in this step.
- Pattern (purple)