What Is a Discovered Check in Chess?

Definition

A discovered check is the most forcing version of a discovered attack: the revealed bishop, rook or queen delivers check to the enemy king. Because a check must be answered immediately, the piece that moved away can go almost anywhere — capturing material, or landing on a square that would normally be suicidal — and the opponent has no time to punish it. A double check, where both the moving piece and the revealed piece give check, forces the king to move, since no single capture or block can stop two attackers.

Example

A white knight on e5 sits between a bishop on b2 and Black's king on h8. The knight captures on f7 — the bishop now checks along the long diagonal, and Black must deal with the check rather than recapture the knight.

How to spot it

• Find your line pieces that point at the enemy king but are blocked by your own piece.
• Any legal move of that blocking piece delivers check — so pick the most damaging one.
• If the moving piece also checks, it is a double check and the king is forced to move.
• Watch for enemy discovered checks whenever your king shares a line with an enemy slider.

The mistake most players make

Trying to block or capture out of a double check. Against a double check the only legal answer is a king move — nothing else can address two checking pieces at once.

Related terms

• Discovered attack — A discovered attack is when moving one piece unveils an attack from a long-range piece behind it.
• Windmill — A windmill is a repeating cycle of discovered checks that harvests material with each turn of the wheel.
• Smothered mate — A smothered mate is checkmate by a knight against a king completely surrounded by its own pieces.
• Check — Check is a direct attack on the king that must be answered immediately.