Swordfish
AdvancedUsed at: Master
An advanced extension of X-Wing to three rows and three columns. For experienced players.
Swordfish — Explained
Swordfish extends X-Wing to a 3×3 grid. When a digit appears in three rows confined to only three columns, eliminations can be made in those columns.
When to Use
Expert to master-level puzzles where X-Wing can't finish the job.
Common Mistakes
Mistaking incomplete patterns for Swordfish. Each row's candidates must fit within three columns.
Tips
Master X-Wing first. Swordfish is the 3×3 version of X-Wing's 2×2 pattern.
Swordfish Steps
1
Find a digit in 3 rows
Find a digit in three rows, with candidates in only three columns total.
2
Confirm pattern
Each row must have candidates in at most three columns.
3
Eliminate
In those three columns, eliminate from rows other than the three.