Expert technique

X-Wing: How to Spot It and What to Rule Out

Also written X Wing or XWing.

Pick one color. Find two rows where it can only go in the same two columns. Those four cells form a rectangle, and the color can be removed from the rest of both columns.

A board with nothing left to place

BEFORE

No cell shows a single color, and no color has only one place left. Nothing can be placed. When a board is this crowded, look at one color at a time.

Look at one color

This is the same board with only the Orange dots showing. Nothing has been erased. Thirteen cells can still take Orange.

Two rows that match

Two rows each have only two cells for Orange, and they are in the same two columns. These four cells make a rectangle. Orange goes in two opposite corners.

Both columns are taken

Either way, each of those two columns gets its Orange from the rectangle. So no other cell in those columns can be Orange. Remove Orange from the rest of both columns.

Place what is left

AFTER

Look at the bottom row. Orange could go in two cells, and one of them just lost it. Only one cell is left, so place Orange there.

Cells being readColor tints match the color being followed

Key Insight

An X Wing almost never places a bubble by itself. It removes a color from other cells, and the answer shows up nearby. Pick a color, find the rows where it fits only two cells, and look for two rows that use the same two columns. It works the same with rows and columns swapped.

Related Techniques

SwordfishThe same pattern with three rows and three columns. It is harder to spot, but the reasoning is the same.

If you’re stuck on a puzzle, see what to try next, in order.