Naked single or hidden single? The beginner-friendly difference
Both methods prove one placement. The difference is where you look. For a naked single, inspect one cell. For a hidden single, follow one digit across a row, column, or 3×3 box.
One visible proof
One cell with one candidate is a naked single. One digit with one possible cell in a row, column, or 3×3 box is a hidden single.
- Naked single: inspect one cellOnly one candidate remains in that cell.
- Hidden single: follow one digitSeveral cells have notes, but only one cell in the row lists 7.
- Use the matching checkAsk “what fits in this cell?” for a naked single and “where can this digit go?” for a hidden single.
✓ Only the outlined cell in row 4 lists candidate 7. That cell may list another candidate too, but 7 has nowhere else to go in the row.
Use this reasoning on a fresh grid.
The interactive lesson shows one example, then lets you make the next check.
Practice hidden singles free →No account needed. Your progress stays on this device.