1.d4 d5 2.c4 - See Queen's Gambit.
2...dxc4 - Accepted. Black takes the pawn but will have to return it.
3.Nf3 - White develops and prepares to recapture the pawn.
3...Nf6 - Black develops quickly, hoping for active piece play.
White's plans: Play e3 and Bxc4 to recover the pawn with a good position.
Black's plans: Hold the pawn with ...b5 or return it for active piece play.
Watch the moves to understand the opening sequence. Use the controls to replay or auto-play the variation.