The Queen's Gambit is a 'double queen pawn' game, when both players push their d-Pawns on the first move. It begins with 1.d4 d5 2.c4 (diagram), and if Black accepts the gambit with 2...dxc4, then White can take the center with e4, simultaniously attacking Black's weakling on c4. The Queen's Gambit Declined is when Black does not take the gambited Pawn, and instead defends his own with 2...e6 or 2...c6.