LEVEL 6

Swordfish

A candidate in three rows is restricted to the same three columns.

How to find it

  1. Choose one candidate and map it across rows.
  2. Find three rows covering only three shared columns.
  3. Remove the candidate from those columns outside the fish.

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

Swordfish 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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