LEVEL 9
Alternating Inference Chain
Strong and weak links across candidates form a logical implication chain.
How to find it
- Choose a candidate proposition.
- Alternate strong and weak implications across houses and cells.
- Use matching endpoints or a contradiction to justify the elimination.
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
Alternating Inference Chain training
Loading a mathematically verified puzzle state…