Discovered attack

A discovered attack in chess is placing an opponent's piece, often his king or queen, in jeopardy by moving a piece out of the line of attack in order to activate it. Then the opponent has to deal with the attack rather than with the piece that was moved to uncover the attack.

A discovered attack is most effective when there is a vulnerable king and an unprotected other significance piece.

An element of surprise is involved because typically the opponent does not see the attack until it is uncovered by moving the piece that was previously blocking. In blitz chess, discovered attacks can be particularly effective because an opponent has less time to spot the surprise.

Any piece can be the one moved to create a discovered attack, in contrast with skewers and pins which use only certain pieces. Typically this results in a gain of an undefended piece, or at least an improvement in position by the side doing the discovered attack.