What is an X-Wing in Sudoku?
An X-Wing is four positions for one candidate aligned in two rows and the same two columns, or the column-first equivalent.
Pure Sudoku
Advanced technique
X-Wing locks one candidate into a rectangle.
If one candidate appears in exactly two matching columns across two rows, the four positions form a rectangle and clear that candidate from the rest of those columns.
- Level
- Advanced
- Pattern
- Two rows and two columns form four corners
- Outcome
- Logical progress
Focused example
Four candidate 5 positions form an X-Wing rectangle.
The highlighted cells show the exact scope of the pattern. Read the candidates before making an elimination.
How it works
Apply the pattern in four checks.
- Pick one candidate and find a row where it appears in exactly two cells.
- Find a second row where the candidate appears in the same two columns.
- Confirm the four candidates form the rectangle corners.
- Remove that candidate from other cells in the two columns.
Know the difference
Use the pattern only when every condition is true.
A pair operates inside one unit. X-Wing links two rows with two columns, so the elimination occurs outside the four corner cells.
After the move, re-scan the affected unit for singles before searching for another advanced pattern.
Common mistake
Protect the logic before erasing a candidate.
Each selected row must restrict the candidate to the same two columns. Extra candidate positions in either row break the X-Wing.
If any required condition is missing, leave the candidates in place and continue scanning.
Continue playing
Choose your next Sudoku route.
FAQ
Quick answers before you play.
What does X-Wing eliminate?
It removes the candidate from other cells in the two intersecting columns or rows.
Is X-Wing required on every hard puzzle?
No. Use it only when the exact four-corner restriction appears.
Practice loop
Find it on a live board.
Pause when the board slows down, check the candidate conditions, make one justified move, and scan again.