Genius Academy / Level 8

LEVEL 8

X-Chain

Alternating strong and weak links for one candidate prove an elimination.

How to find it

  1. Choose one digit and follow alternating inference links.
  2. End on two nodes that both imply the candidate.
  3. Remove the candidate from cells seeing both ends.

Logical demonstration

The violet cells represent the pattern; the gold cell represents the resulting placement or elimination. Verify every highlighted candidate belongs to the required houses before acting.

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.

GUIDED PRACTICE · EXERCISE 1 OF 3

X-Chain training

Identify the logically justified next action. Violet cells form the pattern and the gold cell is the proposed result.

Which action is justified?

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