A discovered attack is chess with two pieces moving at once — almost. You move one piece, and a bishop, rook or queen that was standing behind it suddenly attacks along the opened line. The moving piece is free to create a second threat of its own, and defending two threats born on the same move is often impossible. Solve the featured real-game puzzle below, then continue in the trainer at your own level.
The strongest version is the discovered check: the uncovered piece checks the king, so the moving piece can grab anything it likes — the opponent must answer the check first. Stronger still is the double check, where both pieces give check at once; the only legal reply is a king move, which makes double checks the engine behind many forced mates, including the classic smothered mate.
Look for your own batteries in the making: a line piece behind a friendly piece that can move with tempo. Ask what the front piece could attack, capture or threaten while the back piece does its work — the best discoveries make the front piece's move a threat in itself, so both halves of the move demand an answer. Run the same scan against your opponent's lined-up pieces and you will stop walking into them, which is worth as many points as landing your own.
In a discovered attack the uncovered piece attacks any target — often the queen. In a discovered check the uncovered piece attacks the king, which is far stronger: the check must be answered immediately, so the piece that moved is effectively free to capture or threaten anything for one move.
Because neither blocking nor capturing can answer two checks at once — the king must move. That single rule collapses the defender's options to a handful of squares, which is why so many forced mates run through a double check even when both checking pieces hang.
Watch for batteries: two pieces of the same army on one line, where moving the front one unmasks the back one. On your side, ask what the front piece could do with tempo. On the opponent's side, treat any piece standing in front of a bishop, rook or queen as a loaded spring — and keep your king and queen off that line.