Reversi danger squares: X-squares and C-squares
The squares next to an empty corner are dangerous in Reversi. Learn the X-squares and C-squares, and how playing there hands over a corner. Winning ideas · lesson 2 of 4.
The lesson in words
The squares diagonally next to a corner are called X-squares (red). The edge squares beside a corner are C-squares (marked with dots).
While the corner is empty, playing on them often lets your opponent take the corner.
Watch: gold plays on the X-square, and black jumps straight into the corner.
Same position, your move.
Try it: Make any move that doesn’t give away a corner.
Stay off the squares next to an empty corner. Next: why flipping fewer discs is often better.