The Pin
A pin is a piece stuck in front of a more valuable one. The clearest way to understand it is not to read about it - it is to pick up the pinned piece and be told, in so many words, that you may not.
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A pin is a piece that cannot move because something more valuable is standing directly behind it.
There is a version where "cannot" is literal - the rules refuse the move - and a version where it just costs you a queen. Start with the literal one, and try to break it yourself.
Your knight on e5 has eight squares, and the rook on e1 is looking straight through it at your king. Try to move the knight - then find a move that sets it free.
Eight knight moves, none of them legal. Notice what this does: your opponent has removed a piece from the game without capturing it. It is still on the board, still worth three points, and completely useless.
Absolute and relative
| the piece behind is | moving the pinned piece is | |
|---|---|---|
| absolute pin | the king | illegal - the board refuses |
| relative pin | anything else, usually the queen | legal, and usually terrible |
A relative pin is the everyday one, and this is what it looks like.
Only three pieces can pin: the queen, the rook and the bishop. A knight attacks single squares rather than lines, so it has nothing to pin along; a pawn and a king have the same problem.
Set one yourself
Black's queen is on d8 with a knight on f6 in front of it. Your bishop is on c1. Pin the knight.
Breaking a pin
Four ways, and it is worth knowing them in order, because the first is usually best and the last is usually the one people try first.
- Move the piece behind. The board above: step the king off the file. There is nothing to pin against any more.
- Capture the pinning piece. Ends the discussion.
- Block the line. Put something cheap between the pinning piece and the pinned one, and the pin evaporates.
- Defend the pinned piece. The weakest answer, because the attacker can simply add another attacker - and the pinned piece can never be one of the defenders of itself.
The one to be suspicious of is number four. A pinned piece attracts attackers the way nothing else on the board does, and each new one is free.
The fork attacks two pieces along two different lines; the pin and the skewer attack two along one. The difference between those two is only which one is in front.
Try it
Pin the knight on f6 to the queen behind it.
Common questions
- What is a pin in chess?
- An attack along a line - a rank, a file or a diagonal - where the piece being attacked has something more valuable directly behind it. Moving the front piece would expose the piece behind, so it is stuck: pinned. Only the queen, the rook and the bishop can pin, because only they attack along lines.
- What is the difference between an absolute pin and a relative pin?
- In an absolute pin the piece behind is the king, so moving the pinned piece is not merely bad - it is illegal, and the board will not let you. In a relative pin the piece behind is anything else, usually the queen: the pinned piece may legally move, it just loses material if it does. Absolute pins are enforced by the rules; relative pins are enforced by arithmetic.
- Can a pinned piece still give check?
- A piece under an absolute pin cannot move at all, so it cannot capture or check - but it still guards the squares it attacks for the purposes of the enemy king. That subtlety costs games: a king may not step onto a square attacked by a pinned knight, even though that knight could never legally take it.
- How do you break a pin?
- Four ways, in rough order of preference: move the piece behind out of the line, capture the pinning piece, block the line between them with something cheap, or defend the pinned piece well enough that the attacker cannot profit from taking it. Attacking the pinning piece with a pawn is the classic version of the last one.
- Why is a pin so strong?
- Because it removes a defender without capturing it. A pinned knight still stands on the board and still guards squares, but it cannot leave, so you can attack it a second and a third time with impunity. Piling attackers onto a pinned piece is one of the most reliable ways to win material at any level.
- Is it good to pin a knight with a bishop?
- Very often - the Bg5 pin against a knight on f6 is one of the most played moves in chess, because it fixes the knight in front of the queen and takes away its control of the centre. It is not free, though: h6 kicks the bishop, and if you retreat along the diagonal the pin can simply be walked out of.
Want to set this up yourself?
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