GridWits

Finned X-Wing / Finned Swordfish

Extreme Used by Smart Hint

An almost-fish pattern with one or more extra "fin" candidates confined to a single box — eliminations still hold, just narrowed to that box.

A 1 B 2 C 3 D 4 E 5 F 6 G 7 H 8 I 9 4 7 4 6 4 9 3 4

How it works

  1. Digit 4's candidates in row 1 fall in columns B and E — a normal X-Wing shape — except row 2 also carries an extra 4 at E2, the "fin," confined to the same box as E1.
  2. Either the fin at E2 is 4 (then the box already accounts for column E's 4, so nothing elsewhere in that box's rows can be 4), or it isn't (then the plain X-Wing applies as usual) — both cases agree D2 can be eliminated, since it shares the fin's box and lies in a cover column.
  3. Sashimi Finned Fish are the same idea with a base corner left empty instead of carrying an extra candidate.

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