Spare tempo

A spare tempo is an available move saved until the moment when passing the critical turn to the opponent matters. A tempo is one move in chess. The spare move is often a pawn advance that does not immediately change the essential relationship between the kings or other pieces.

Its value appears in zugzwang, a position in which being required to move worsens the result. If both kings are correctly placed but one side must yield, a pawn move elsewhere can act as a legal way to wait. The opponent must then leave a square or weaken the position.

Pawn moves cannot be taken back, so spare tempi should be counted and preserved. A move qualifies only if it keeps the important features intact; a pawn move that loses material or opens an entry is not a free wait. Triangulation creates a similar change of turn through a piece route, while a spare tempo is usually stored in the pawn structure.