What is a Gambit in Chess?
A gambit is an opening that involves a sacrifice of material, such as a pawn or piece, in order to achieve concrete advantages in the position. A gambit is used to establish greater control of the ceter, lead in development, weakness in the enemy king protection or pawn structure, or to open lines which can be used for an attack. A gambit is not used to win material, such a maneuver would be properly called a pseudo-sacrifice.
The definition isn’t all that clear, actually. Sometimes a gambit is temporary, with the pawn recovered by force. In other cases, the material cannot be accepted without dire consequences. Then there are established gambits where the material is not recovered immediately, but is normally regained after a few developing moves. This is typical of Queen’s Gambit Accepted (1.d4 d5; 2.c4 dxc4). The Queen’s Gambit Declined (1.d4 d5; 2.c4 e6) is far more common than the Queen’s Gambit Accepted precisely because White is likely to get the pawn back in any case unless Black tried some very risky strategy to hold on to it.
To read more see other Eric Schiller articles on Gambits.