Sudoku FlowX-Wing vs Swordfish
X-Wing and Swordfish are the same idea at two sizes. How each pattern works, how to tell them apart, and what they let you remove.
Updated 2026-10-04
X-Wing
Find a digit that, in two different rows, can go in exactly two cells, with both rows using the same two columns. The digit must take one of the two cells in each row, so between them the rows fill the digit in both columns: remove it from every other cell of those two columns.
Swordfish
The same idea with three rows and three columns. In each of three rows, the digit can only go in some of the same three columns, two or three cells per row. Between them, the three rows use up the digit in all three columns, so remove it from the rest of those columns.
The difference at a glance
| X-Wing | Swordfish | |
|---|---|---|
| Rows in the pattern | 2 | 3 |
| Columns in the pattern | 2 | 3 |
| Candidates per row | Exactly 2 | 2 or 3 |
| Removes the digit from | The 2 columns, outside the 2 rows | The 3 columns, outside the 3 rows |
| Level in our app | Expert | Expert |
Rows or columns
Both patterns also work the other way round: take the columns as the base and remove the digit from the rows.
Learn each technique
Practice
Every Find the Mistake puzzle on this site has exactly one wrong digit, and you can play each board right on its page.
