High Quality Content by WIKIPEDIA articles! In chess, a skewer (or X-ray attack) is an attack upon two pieces in a line and is similar to a pin. In fact, a skewer is sometimes described as a "reverse pin"; the difference is that in a skewer, the more valuable piece is in front of the piece of lesser or equal value. The opponent is compelled to move the more valuable piece to avoid its capture, thereby exposing the less valuable piece which can then be captured (see chess piece relative value). The long-range pieces (queen, rook, and bishop) can skewer.