A pin is an attack along a line — a rank, file or diagonal — where an enemy piece is stuck in front of a more valuable piece behind it. If the front piece moves, the piece behind it is lost. When the piece behind is the king, the pin is absolute: the front piece legally cannot move at all. When it is a queen or rook, the pin is relative: the piece could move, but doing so loses material, so it usually stays frozen.
Only the long-range pieces can pin: bishops, rooks and queens. A pinned piece is a poor defender, which is the real point of most pins — you pin a knight that guards a square, then take what it was guarding, or pile more attackers onto the pinned piece until its defenders are outnumbered.
How to spot it
- An enemy piece standing on the same line as its king, queen or rook, with your bishop, rook or queen able to reach that line.
- A piece that defends something important while a more valuable piece sits behind it — pin the defender and the guarded target drops.
- Your own pieces lined up in front of your king: one line piece aiming down that line freezes the front one.
Using it — and stopping it
Build pins by putting a line piece on the same line as two enemy pieces, the cheaper one in front. Then increase the pressure: attack the pinned piece with a pawn or a smaller piece, because it cannot run away. To escape a pin, break the line (step the back piece off it), block the line, drive the pinning piece away, or give the pinned piece a useful job to do while it still can.
Common mistakes
- Assuming a pinned piece still defends everything it attacks. A pinned defender often defends nothing — count it as absent and re-check your captures.
- Breaking a relative pin without counting the cost: moving the pinned piece is legal, and sometimes losing the exchange behind it is still your best option.
- Pinning a piece and then doing nothing with it. A pin is a promise, not a result — add attackers before your opponent untangles.
When you see two enemy pieces on one line, you are one move away from freezing one of them. Try it on the board below.