D30 - Queen's Gambit Declined
If you have not already done so, take a look at my Queen's Gambit blog for some basic information about the Queen's Gambit.
Playing 2...e6 releases Black's dark-squared bishop, while obstructing his light-squared bishop. By declining White's temporary pawn sacrifice, Black erects a solid position; the pawns on d5 and e6 give Black a foothold in the center. The Queen's Gambit Declined has the reputation of being one of Black's most reliable defenses to 1.d4. In this situation, White will try to exploit the passivity of Black's light-squared bishop, and Black will try to release it, trade it, or prove that, while passive, the bishop has a useful defensive role.
An eventual ...dxc4 by Black will surrender the center to White, and Black will usually not do this unless he can extract a concession, usually in the form of gaining a tempo, by capturing on c4 only after White has played Bd3 first. In the Orthodox Line, the fight for the tempo revolves around White's efforts to play all other useful developing moves prior to playing Bd3.
This second video is a bit long-winded, but there is some tactical and positional theory discussed as well.
The QGD has several different continuations. As I encounter them, I will make follow-up blog posts.
For further reading, checkout my opening study technique.
Feel free to post your QGD games in the forums.