Tactics: Skewer (X-ray)

A skewer (x-ray) 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

• Only pieces that can move an indefinite number of squares in a horizontal, vertical, or diagonal line such as bishops, rooks and queens, can skewer opposing pieces. Kings, knights, and pawns cannot skewer.

The purpose of a successful Skewer is to:

1. Gain a material advantage.

Below are several diagrams of 
situations involving the skewer tactic.

A green colored box represents the attacking piece(s)
A blue colored box represents the path of attack
A red colored box represents the target(s) of the attack

Diagram 1

 Bishop skewer against a queen and a rook