In chess, a discovered attack is a move which reveals a threat to an opponent's piece when another piece is moved out of the threat's path. When the discovered attack is a check, the move is called, naturally, a discovered check. These tactics can be very effective, particularly if the piece being moved out of the way poses a seperate threat, as well. This sometimes results in a fork-like situation where the player being threatened will inevitably lose material.
Discovered attacks can cause check or capture with either piece (i.e. the piece being moved and the piece being revealed). These are the different names given for such types of discovered attacks (most are rather blunt titles):
- Discovered attack with check- The revealed piece threatens the opponent's, while the moved piece causes check.
- Discovered double check- Both the piece being moved away and the piece being revealed give check.
- Discovered attack with capture- A discovered attack in which the piece being moved captures another piece. These are extremely effective because they allow the moved piece to take another piece even if it is protected, as the opponent is preoccupied by their piece being threatened.
- Discovered check with capture- Same as previous discovered attack with capture, but the revealed piece gives check. These are generally more effective than the latter, because the other player must focus on the new threat rather than decide if they should take the moved piece or not.
- Discovered attack with mate threat- The piece being moved, rather than capturing or directly threatening another piece, moves to a square where it threatens to inflict checkmate on the next move.
These are the basic variations, though others can be made that are combinations of two or more, such as discovered attack with capture and mate threat, or discovered double check with capture (though they are a bit wordy).