Hidden Singles Strategy
Learn to find numbers that can only be placed in one location within a row, column, or box.
A hidden single occurs when a specific digit can only be placed in one cell within a row, column, or 3×3 box, even though that cell might appear to have multiple possibilities. The digit is "hidden" among other candidates but has only one valid location.
How to Find Hidden Singles
Choose any digit from 1-9. You'll systematically check where this digit can be placed.
Look at a row, column, or 3×3 box. Check if your chosen digit is already present.
If the digit is missing, identify all empty cells where it could potentially go.
If only one cell can contain the digit, you've found a hidden single!
Interactive Example
Watch as we systematically find hidden singles by scanning units
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.
Naked Singles:
- • Focus on individual cells
- • Look for cells with only one possibility
- • Eliminate based on existing numbers
- • Usually easier to spot
Hidden Singles:
- • Focus on digits within units
- • Look for digits with only one location
- • Scan systematically by digit
- • Requires more systematic approach
- • Start with digits that appear frequently in the puzzle
- • Focus on units (rows/columns/boxes) that are nearly complete
- • Use pencil marks to track where each digit can go
- • Combine with naked singles for maximum efficiency
- • Practice scanning systematically - don't jump around randomly