Pin
Immobilizing an enemy piece by attacking it from behind a more valuable piece (or the king) that cannot afford to move out of the way.
Key Ideas
- An "absolute pin" is against the king — the pinned piece legally cannot move at all.
- A "relative pin" is against a piece other than the king — moving is legal, but usually loses material.
- Only bishops, rooks, and queens can pin, since only they attack along an open line.
- A pinned piece's normal defensive value is often neutralized entirely, since it cannot move to help elsewhere.
How It Works
A pin uses a long-range piece — a bishop, rook, or queen — to attack an enemy piece that has a more valuable piece (or the king) directly behind it on the same line.
If the piece behind is the king, the pin is "absolute": the pinned piece is not merely inadvisable to move, it is flatly illegal to move, since doing so would expose the king to check.
If the piece behind is anything else (say, a queen), the pin is "relative": moving the pinned piece is legal, but usually loses material, so in practice it is treated as immobilized just the same.
Famous Games
The Ruy Lopez's namesake pin
The Ruy Lopez opening's entire early strategy (Bb5 pinning the knight on c6) is a textbook relative pin used as a long-term positional weapon rather than a quick tactic.
Watch & Learn
Video lessons come and go, so instead of linking a specific clip that might disappear, here's a live search for this exact topic:
▶ Search YouTube for "chess pin tactic explained examples"