A discovered attack occurs when a piece moves to reveal an attack by a second piece. If the attack is check, this is known as a discovered check. Discovered attacks can be a powerful method of winning material, as they potentially allow you to make two attacks simultanously - one with the piece you move, and another from the piece you uncovered. Here is an example of how this works in practice:
It works just as well if the piece moving away makes the threat that must be dealt with, leaving the uncovered piece free to capture. The next example shows a possibility that comes up frequently, so you should take care to look out for it in your own games.
There is another way you can win material with a discovered attack. Sometimes, an enemy piece might be too well protected to capture under normal circumstances, but if you can capture it with a discovered attack, your opponent has to spend a move dealing with the uncovered threat, allowing you to retreat your piece to safety again.
Sometimes both the piece that moves away, and the piece that is uncovered, give a check to the enemy king at the same time. This is called a double check, and it is powerful because the only way to escape from a double check is by moving the king - both attacking pieces cannot be blocked or captured at the same time. Here is an example of how deadly a double check can be:
The windmill (sometimes also known as the see-saw) is a tactical combination involving a series of checks and discovered checks, usually by a rook and bishop, which can win large amounts of material. A notable example of the windmill occurred in the game Torre-Repetto vs Lasker, Moscow 1925:
Now it's your turn to test your knowledge of discovered attacks.
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