Finned & Sashimi Fish

Understanding Basic Fish Patterns

In a basic fish, N base rows confine a digit's candidates to exactly N cover columns. The fundamental requirement is that every candidate falls strictly within the cover columns. Many near-fish fail this test by a single candidate. Finned fish rescue these situations.

What Is a Fin Cell?

A fin is an extra candidate outside the cover columns. It must share a block with at least one cover column. The extra candidates must all fall within a single block section.

How Finned Fish Eliminations Work

Case 1: Fin is false -- perfect fish, full eliminations apply. Case 2: Fin is true -- digit placed in fin cell, eliminated from its block. Cells eliminated in both cases: in a cover column, in the fin's block, not in a base row. This intersection defines the elimination zone.

Finned X-Wing, Swordfish, Jellyfish, and Squirmbag

Finned X-Wing: Level 7 (Very Hard) Finned Swordfish: Level 8 (Expert) Finned Jellyfish: Level 8 (Expert) Finned Squirmbag: Level 9 (Master)

What Makes Sashimi Fish Different

In sashimi fish, the fin row has NO candidates in the cover columns. The fin is the row's entire contribution. Without it, the fish would lose a base row. The elimination logic is identical to finned fish. The difference is in how you spot them: the fish looks incomplete, and you must recognize that a fin could complete the pattern.

Sashimi X-Wing, Swordfish, and Jellyfish

Sashimi X-Wing: Level 7 (Very Hard) Sashimi Swordfish: Level 9 (Master) Sashimi Jellyfish: Level 9 (Master)

How to Spot Finned and Sashimi Fish

1. Scan for near-complete fish. 2. Identify the fin (extra candidates outside cover columns, within a single block). 3. Check the block overlap with cover columns. 4. Find the elimination zone. 5. Consider the sashimi case. Tip: Start by looking for basic fish and notice when they fail by one candidate.

Difficulty Ratings and Practical Frequency

Finned X-Wing: Level 7, Occasional Sashimi X-Wing: Level 7, Rare Finned Swordfish: Level 8, Rare Finned Jellyfish: Level 8, Very rare Finned Squirmbag: Level 9, Extremely rare Sashimi Swordfish: Level 9, Extremely rare Sashimi Jellyfish: Level 9, Extremely rare

Summary

Finned and sashimi fish extend classic fish to handle imperfect alignments. The fin restricts eliminations to the intersection of the fin's block and the cover set. Sashimi fish allow a base row whose only contribution is the fin itself. These seven techniques bridge the gap between basic fish geometry and abstract chain-based techniques.