Gain of tempo

In chess, a tempo is one move spent by a player, not time on the clock. A player gains a tempo when a move improves the position while creating a threat that forces the opponent to spend the next move responding.

A common example is developing a piece while attacking the opposing queen. The developing move was useful anyway, while the queen must move away. One side advances its plan and the other cannot continue its own. Several gains of tempo can create a lead in development.

Gaining a tempo does not award an extra turn or allow two consecutive moves. The advantage comes from unequal functions: one move builds and threatens, while the reply is used mainly to react. Not every threat gains time either. If the opponent can ignore it, answer with an equally useful move, or turn it into an opportunity, the supposed gain may be absent.

The value of a tempo depends on the position. In an open position, one move may decide who castles or opens an attacking line first. In a slow, closed position, the opponent may be able to afford a longer maneuver. Tempi should therefore be judged by their concrete effect, not counted as fixed points.