fixedpiece

Fixedpiece is a term used in chess endgame theory to describe a piece whose mobility is effectively immobilized by the position of other pieces or pawns. A fixed piece remains able to influence the position from a narrow scope, but moving it would typically worsen the player's overall situation. The concept is closely related to pins, blocks, and immobility, yet it emphasizes the functional restraint on a specific piece rather than a general loss of activity.

Definition and scope. A piece becomes fixed when any practical move would lead to a negative consequence, such as losing material, allowing a tactical sequence, or opening lines for the opponent. For example, a rook or bishop that is restricted by its own pawns or by a closed pawn structure may act as a static barrier while not contributing to active play. The term is used most often in endgame analyses and chess problem studies to explain positions where a piece’s lack of mobility is a key feature of the evaluation.

Mechanisms. Fixed pieces arise from pins to a valuable piece or king, from being stationed behind own pawns that cannot advance, or from a strategic setup where moving the piece would create decisive tactical or material losses. In some endgames, fixed pieces serve as anchors that stabilize a favorable king march or restrict the opponent’s counterplay.

Strategic role. Fixed pieces can create long-term advantages by occupying key squares, controlling important lines, and enabling coordinated pawn breaks or king activity elsewhere. They often contribute to zugzwang or to a precise sequence that converts an advantage into a win.

See also: pin, immobilization, endgame theory, chess problem composition.