Naked Singles Strategy
The most fundamental Sudoku solving technique - learn to identify cells that can only contain one number.
A naked single occurs when a cell can only contain one possible number. This happens when all other numbers (1-9) are already present in the same row, column, or 3×3 box, leaving only one valid option.
How to Identify Naked Singles
Look at any empty cell in the puzzle. Start with cells that seem to have fewer possibilities.
Examine which numbers are already present in the same row, column, and 3×3 box.
If 8 out of 9 numbers are eliminated, the remaining number is your naked single!
Place the number in the cell and look for new naked singles that this placement creates.
Interactive Example
Watch as we identify and fill naked singles step by step
Ready to Start
Click the play button or use the step controls to see this solving technique in action. Each step will be explained as we progress through the solution.
- • Start with rows, columns, or boxes that have the most numbers filled in
- • Look for cells in the intersection of nearly complete rows, columns, and boxes
- • After filling a naked single, always check if it creates new naked singles nearby
- • Practice identifying naked singles quickly - they're the foundation of all Sudoku solving