Discovered attack in chess
Move one piece and a different piece behind it makes the threat. The piece that moved can make a threat of its own, so one move often creates two attacks.
A discovered attack happens when a piece moves out of the way of a friendly bishop, rook or queen, revealing that piece's attack on an enemy target.
Why it is so strong
The piece that moves is free to make a second threat of its own, so a discovered attack often creates two threats at once. In a fork one piece makes both threats; here they come from two different pieces, so they can be far apart on the board.
The strongest version is the discovered check. The opponent has to answer the check first, so the moving piece can capture a defended piece or stand on an attacked square, and you usually have time to move it to safety afterwards. A discovered check that also attacks the queen usually wins it, unless the answer to the check saves the queen too.
The moving piece can often be left en prise, because the opponent has a bigger threat to deal with first. That is a big part of why discovered attacks are hard to spot: your candidate move looks like it blunders a piece.
Recognizing the setup
Look for a "battery in waiting":
- One of your bishops, rooks or queens pointing at a valuable enemy piece or the king.
- One of your own pieces sitting in between.
- Then ask what the blocking piece could do if it moved: capture something, give check, attack the queen or threaten mate.
The double check
If the moving piece gives check as well as the piece it uncovers, two pieces check the king at once. No single capture or block can answer two checks, so the king must move. Some famous combinations turn on a double check, including Reti's win over Tartakower (Vienna 1910) and Edward Lasker's king hunt against Thomas (London 1912).
Practice the discovered attack
Reading about a pattern is not the same as spotting it under time pressure. The free chess puzzles trainer serves rated positions from real games and adjusts to your level as you solve. When you get one wrong, press Analyze once the puzzle is over to open it on the analysis board and see what you missed.
Related tactics
Double check
Two checks at the same time, and the king has to move. No other answer is legal.
Fork
One piece, two targets. On Lichess, more puzzles turn on the fork than on any other motif, over twice as many as on the pin. It is the first tactic worth mastering.
Skewer
A pin turned around: the valuable piece is in front, it must move, and the piece behind it falls.
Frequently asked questions
What is a discovered attack?
A move that takes a piece off the line of a friendly bishop, rook or queen, revealing that piece's attack. The piece that moved can make a threat of its own, so the result is often two threats at once.
What is the difference between a discovered attack and a discovered check?
A discovered check is a discovered attack where the revealed attack is on the king. It is more forcing, because the opponent has to answer the check and usually has no time to deal with the second threat.
Why is a double check so strong?
Two pieces give check at the same time, and a capture or a block can stop only one of them. A king move is the only legal reply, which makes double check the most forcing kind of check.