LEVEL 3
Locked Candidates
Candidates confined to one line inside a box eliminate that digit elsewhere on the line.
How to find it
- Inspect one digit’s candidates within a 3×3 box.
- Find candidates that all share a row or column.
- Remove that digit from the rest of the same row or column outside the box.
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.
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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
Locked Candidates training
Loading a mathematically verified puzzle state…