X-Wing Technique

The X-Wing is an advanced elimination technique that uses four cells forming a rectangle. If a number appears in only two cells in two different rows, and those cells are in the same columns, you can eliminate that number from all other cells in those columns.

This pattern creates an "X" shape when you visualize the cell positions, hence the name. It's particularly powerful for solving medium to hard difficulty puzzles where basic techniques have been exhausted.