A pin is a tactic where a piece is stuck in place because moving it would expose a more valuable piece — or the king — sitting directly behind it on the same line. Only the long-range pieces can pin: the bishop, rook, and queen, along the ranks, files, and diagonals they control.
A pinned piece is half-frozen. If the piece behind it is the king, the pin is absolute — moving is flat-out illegal, because you can never expose your own king to capture. If the piece behind is merely valuable (a queen behind a knight, say), the pin is relative — you can move the pinned piece, but you usually won’t want to hand over the bigger piece.
The 10-second version
- A pin freezes a piece against something more valuable behind it.
- Absolute pin = pinned to the king = the piece legally can’t move.
- Relative pin = pinned to a big piece = it can move, but at a cost.
A quick example
The bishop on g5 lines up g5–f6–e7–d8, straight through the knight on f6 to the king on d8. The knight is absolutely pinned: if it stepped aside, the bishop would be giving check to the king, which isn’t allowed. That knight is stuck defending the diagonal — a perfect target to pile more attackers onto, since it can’t run.
Related terms
This is the short version — our full pin guide walks through pinning, exploiting, and breaking pins, and you can train the pattern on the pin puzzles page. Browse the tactics hub or the chess glossary for more. The pin’s near-twin is the skewer — same idea, valuable piece in front instead of behind — and it teams up nicely with the fork and the discovered attack.
Mini-FAQ
What’s the difference between a pin and a skewer? In a pin, the less valuable piece is in front and the valuable one is shielded behind it. In a skewer, the valuable piece is in front and gets forced to move, exposing the piece behind.
Can you break a pin? Sometimes. You can block the line, challenge or trade the pinning piece, or move the piece behind out of the way (only possible with a relative pin — never an absolute one).
Written and fact-checked by the Chess Lab Academy Editorial Team (AI-assisted, human-edited) · Position legality-checked with python-chess · Definition verified against Wikipedia and standard references · Last verified 2026-07-13 · How we verify content.