Discovered Attack: Unmasking a Hidden Threat

Two pieces are involved. The back piece, a bishop, rook or queen, is aimed down a line at a target. The front piece blocks that line. When the front piece moves, the line opens and the back piece attacks without having moved at all.

The power comes from the front piece being free to do something useful on its own. It can capture, give check, or attack a second target. The opponent now faces two threats from one move, and usually can only answer one.

When the uncovered attack is on the king, it is a discovered check. This is the most dangerous version, because the check must be answered and the moving piece gets a free move: it can go almost anywhere, even to a square where it can be captured, as long as its own threat is big enough.

Look for your own lines first. Any time one of your pieces stands between your bishop, rook or queen and an enemy piece, you have a loaded gun. Ask what happens if the blocking piece moves with a threat of its own, ideally a check or a capture.

Defenders miss discovered attacks because nothing seems to be attacking the target. The queen on the other side of the board looks harmless while a piece of its own blocks the line. When your opponent has a bishop or rook aimed at your king or queen through one of their own pieces, treat that line as already open.

The most common mistake is moving the front piece to a quiet square. The discovered threat is only half the tactic; the moving piece has to create a second problem, or the opponent just steps out of the way of the first one.

The other mistake is ignoring what the opponent can do with check. If the front piece moves and gives up its defensive duties, an enemy check can sometimes defuse everything. The discovered attacks you miss in your own games are the ones worth drilling.