Expert technique · Technique Academy

W-Wing

A W-Wing is two cells that do not see each other but hold the same two candidates, X and Y, joined by a strong link on X: a unit where X has only two places, one seeing each cell. Y is the digit you can eliminate.

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

The reasoning

Why does the W-Wing work?

If one of the two cells is X, the link forces the other to be Y, and if it is not X then it is already Y. So one of them is always Y, and any cell seeing both loses Y.

A worked example

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

W-Wing worked exampleA sudoku board with pencil marks. The W-Wing uses R1C6, R1C5, R5C5, R5C7 and digit 8 (R1C6 and R5C7). The move strikes candidate 8 in R5C6.62591778343418743581529618189634527876125349344913676787852352784978169174556362834268479371345534281679
The move strikes candidate 8 in R5C6. Digit 8, R1C6 and R5C7.
  • Cells that form the pattern
  • Cells that lose a candidate
  • Struck digit: ruled out

Make it stick

How can you practise the W-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.

EasierXYZ-WingHarderFinned X-Wing