Discovered Attack
"Move one piece to unleash a hidden weapon behind it."
A discovered attack occurs when a piece moves and unmasks a second piece that delivers an attack. The piece that physically moves can also make a threat of its own, creating a double threat that is almost impossible to meet. The discovered check — where the king is attacked by the unmasked piece — is among the most powerful tactics in chess.
Key Ideas
- 1Two threats arise simultaneously: one from the moved piece and one from the unmasked piece
- 2A discovered check forces the opponent to deal with check first, giving your other piece free rein
- 3A 'double check' (where both pieces give check) can only be escaped by moving the king
- 4The 'battery' (two aligned pieces) must be set up before the discovery can be delivered
- 5The moving piece should create its own threat — check, capture, or decisive attack — not just step aside
How to Spot It
- ✓Look for pieces hiding behind other friendly pieces along ranks, files, or diagonals
- ✓Ask: if I move the blocking piece, what lines open up and what do they aim at?
- ✓Identify if the moving piece can simultaneously attack a second target
- ✓Realized knights are especially effective moving pieces — they can both reveal a bishop/rook battery and fork
How to Defend Against It
- ⚠Avoid placing your king on the same line as an enemy battery even if the line appears blocked
- ⚠Eliminate the front piece of a battery to defuse the potential discovery
- ⚠Keep track of all your opponent's hidden long-range piece alignments
- ⚠If facing a double check, the only legal response is to move the king — be sure the king has safe squares
Interactive Puzzles
Find the best move — drag or click a piece to play it out.
White to move
Move the knight to unleash the bishop — and fork the rook at the same time!
Frequently Asked Questions
What is a discovered attack in chess?
A discovered attack is when you move a piece to reveal an attack from a second piece hidden behind it. Both pieces can create threats simultaneously, making the tactic very difficult to defend.
What is a discovered check?
A discovered check is a discovered attack where the revealed piece gives check to the king. The moving piece is then free to create another threat since the opponent must first deal with the check.
What is a double check?
A double check is when both the moving piece and the revealed piece give check simultaneously. It is the most powerful form of discovered attack because the only legal response is to move the king — you cannot block or capture both checking pieces at once.
How do I create a discovered attack?
First, set up a 'battery' — two pieces aligned on the same rank, file, or diagonal with one blocking the other's line. Then look for a way to move the blocking piece with tempo (check, capture, or threat) to reveal the attack from behind.
Related Tactics
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