Pinning
Pinning is a chess tactic. A piece is pinned if it's interposing. Moving it would reveal a discovered check (in which case, it cannot be moved — an absolute pin) or a discovered attack of a more valuable piece (in which case, it most likely should not be moved — a relative pin).[1]
As with skewering and discovered attacks, pinning can only be performed by pieces that can move a variable distance — in other words, the line pieces.
References
- "It may be defined as an attack on a piece which screens a second piece from attack... [Absolute pin] is the term we use when the King is the screened piece." 1001 Winning Chess Sacrifices and Combinations Fred Reinfeld, 1955, ISBN 0-87980-111-5, p. 12
Further reading
Practice
- "Practice: The Pin" Lichess
Tactics: Discovered check | Double check | Forking | Pinning | Protection | Skewering
