Naked Single
Only one candidate value remains for this cell — place it.
How it works
- 1The top row already holds 2, 3 and 4.
- 2A row holds each number from 1 to 4 exactly once, so the only number left for the first cell is 1.
- 3Nothing about the signs was needed — this is pure row bookkeeping, and it is the move that finishes most cells on most boards.
- Number this technique proves
- Cells read together — The connecting line shows which cells combine to make the deduction.
- Conclusion — The coloured candidate, or the final arrow when it lands outside the pattern, shows the result.