Discovered attacks: the piece that moves is not the piece that attacks

The tactic that wins the most material per occurrence, because the piece that moves gets a completely free move while the threat comes from somewhere else entirely.

• 120 positions in the course
• Difficulty 635–2291
• Section: Sharper Tactics
• 5 levels

What a discovered attack is

A discovered attack happens when you move one piece off a line, revealing an attack from a piece behind it. Two things now threaten at once -- whatever the moving piece does, and whatever the uncovered piece hits -- and the opponent has one move.

It is the most powerful of the double attacks precisely because the front piece is unconstrained. It can go anywhere, including somewhere it can be captured, because if the discovered threat is bigger the capture never happens. A discovered attack where the front piece delivers check is close to unanswerable.

How to spot it

• Look for your own pieces standing in front of your own rooks, bishops and queens. That is the whole precondition.
• Then ask what the back piece would be attacking if the front one vanished. If it is the king or the queen, you have a tactic.
• Give the front piece the most violent move available -- a capture, a check, a fork. It is getting a free move, so use it.
• Watch for enemy discovered attacks the same way: any piece of theirs sitting on a line with a bigger piece behind it is a piece that can move with tempo.

Three discovered attacks

Three positions from the 120 in this skill, easiest first. The highlighted squares are the move your opponent has just played. Work it out before you open the answer.

Defending against a discovery

You cannot really parry a discovered attack once it is available -- you have to not allow the alignment. Keep your king and queen off lines where an enemy piece is sitting in front of an enemy rook, bishop or queen, and treat every such stack as loaded.

If one is already on the board, the defences are narrow: capture the front piece before it moves, block the line permanently, or move the target off the line with tempo. Counting whether any of those exists is what you should be doing before you allow the stack, not after.

Questions people ask

Nearby patterns

Discovered Attacks sits in Sharper Tactics. The rest of that section:

• Double CheckTwo checks at once, king must move
• DeflectionDrag the defender away
• AttractionLure a piece to a bad square
• X-RayAttacking through a piece
• ClearanceGet out of your own way

Tell it apart from its neighbour

Discovered Attacks is confused with these more often than anything else, and the difference is usually one sentence long.

• Discovered attack vs double checkOne threat uncovered, or two at once