Squirmbag

Squirmbag (or Sixfish) is a five-row, five-column fish pattern. It's extremely rare and only appears in very difficult puzzles.

Technique

1. Find five rows where a candidate is restricted to the same five columns.
2. Each row must have the candidate in 2-5 cells within these columns.
3. Eliminate the candidate from other cells in those five columns.

Tips

• Squirmbags are extremely rare in hand-solvable puzzles.
• If you find yourself looking for Squirmbags, the puzzle is very difficult.
• Computer solvers are typically needed to reliably find these.