Expert technique · Technique Academy

Finned X-Wing

A finned X-Wing is an X-Wing with a spare candidate, the fin, tucked beside one corner in the same box. The pattern is not quite clean, yet it still earns eliminations.

Professor Cryptic, the owl who teaches in the app
Professor Cryptic is thinking

The reasoning

Why does the Finned X-Wing work?

Either the fin holds the digit, which sees those cells, or the X-Wing is genuine and claims the column. Either way, cells in the fin's box that share the corner's column must give the digit up.

A worked example

What does the Finned X-Wing look like on a real board?

Finned X-Wing worked exampleA sudoku board with pencil marks. The Finned X-Wing uses R3C6, R8C6, R3C7, R8C7, R8C9 and digit 1 (rows 3 and 8). The move strikes candidate 1 in R7C7.591263874387145149261962478918919354329175868593426347137716538483492391263845179127948671213512312751339129648
The move strikes candidate 1 in R7C7. Digit 1, rows 3 and 8.
  • Cells that form the pattern
  • Cells that lose a candidate
  • Struck digit: ruled out

Make it stick

How can you practise the Finned X-Wing?

The Technique Academy in Cryptic gives every technique its own lesson and 5 practice boards that need exactly this move.

Get it onGoogle PlayPlay Cryptic on the web

Further reading: HoDoKu's page on this family of techniques.

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