Swordfish

How It Works

Swordfish extends the X-Wing pattern to three rows and three columns. When a candidate appears in at most two cells per row across three rows, and those cells collectively span exactly three columns, the candidate can be eliminated from other cells in those three columns.

Step by Step

1. Find three rows where a candidate appears in only 2-3 cells each.
2. Check if all those cells fall within exactly three columns.
3. Eliminate that candidate from other cells in those three columns.