LEVEL 8
X-Chain
Alternating strong and weak links for one candidate prove an elimination.
How to find it
- Choose one digit and follow alternating inference links.
- End on two nodes that both imply the candidate.
- Remove the candidate from cells seeing both ends.
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
X-Chain training
Loading a mathematically verified puzzle state…