X-Wing in Sudoku: How to Spot It
Learn the X-Wing Sudoku technique with a simple candidate pattern, clear elimination rule, and practice-focused explanation.
Visual example
X-Wing: four corners control two columns
Candidate 7 forms a rectangle in two rows, so 7 can be removed from the same columns outside the rectangle.
Quick answer
X-Wing
An X-Wing in Sudoku is a rectangle pattern for one candidate. If that candidate appears in the same two columns in two different rows, it must occupy opposite corners of the rectangle, so that candidate can be removed from other cells in those columns.
Recognition rules
How to spot it
- Choose one candidate number.
- Find two rows where that number appears in exactly the same two columns.
- Confirm the four candidate positions form a rectangle.
- Remove that candidate from other cells in those two columns.
What is an X-Wing?
An X-Wing is a rectangle formed by one candidate appearing in exactly two positions in each of two rows, and those positions line up in the same columns. The same logic also works with rows and columns reversed.
When to look for it
Look for X-Wings after simpler candidate eliminations are no longer moving the puzzle forward. Choose one number and scan rows or columns for matching two-position patterns.
Why the elimination works
If candidate 7 must be in one of two columns in row 2, and the same is true in row 8, then the two 7s lock into opposite corners of the rectangle. No other cell in those columns can be 7.
FAQ
What is an X-Wing in Sudoku?
An X-Wing is a rectangle pattern where one candidate appears in two matching positions across two rows or two columns.
How do you spot an X-Wing?
Pick one candidate and find two rows with that candidate in the same two columns, or two columns with that candidate in the same two rows.
What can you eliminate with X-Wing?
You eliminate that candidate from the other cells in the affected columns or rows outside the rectangle.
Is X-Wing an advanced Sudoku technique?
Yes. X-Wing is usually considered advanced because it requires scanning candidate positions across multiple rows or columns.
Practice this technique in Sudoku Coach
Read the pattern, then practice it step by step with guided hints that explain why the move works.
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