LEVEL 2
Hidden Single
A digit has only one possible cell inside a row, column or box.
How to find it
- Choose one house and one missing digit.
- Check every empty cell in that house.
- Place the digit when only one cell can accept it.
Candidate-map demonstration
The violet cells mark the pattern and the gold cell marks the resulting placement or elimination. Treat this compact map as orientation; use the verified full puzzle below to practise the actual deduction.
••••
Common mistakes
- Using cells that do not share the required row, column, box or peer relationship.
- Removing a candidate before confirming every occurrence in the pattern.
- Confusing a possible pattern with a completed logical proof.
VERIFIED PRACTICE
Hidden Single training
Loading a mathematically verified puzzle state…