Why is the old Queen's Gambit Declined (1. d4 d5 2. c4 e6) hardly ever seen anymore, especially when compared to the Semi Slav and the Slav. I suppose that bad bishop is just too bad - except in the Tartakower. Can anyone point me in the direction of some QGD games that show me why everyone prefers the semi Slav nowadays?
I use the QGD as my main defense to 1.d4. It is very solid. The problem is that it doesn't produce the complications of the Semi-Slav (or King's Indian). You just have to play good moves, slowly improve your position, and capitalize on your opponents mistakes to win. The Lasker is one of my favorites. Karpov couldn't even get much of an edge against it (played by Yusopov). Black trades most of the minor pieces off and frees his light squared bishop. I also like the rock-solid Orthodox. In that one, you play to trade pieces and get in e5. I haven't used the Tartakower much, but it does seem to produce good winning chances.
One of the bigger problems you will face is the QGD exchange variation. You have to learn a few of the variations and try to get something going on the kingside before white gets in b4, b5, and bxc6 (creating a queenside pawn weakness for black).
In summary, the QGD is solid and fine but produces fewer chances to complicate than more "modern" defenses.
You will find the QGD in the games of the older masters (Lasker, Capablanca, Alekhine, etc). In fact, almost every game of the Capablanca-Alekhine World Championship (1927) was a QGD.
Further Reading:
How To Think Ahead In Chess - A BASIC Repertoire book with the Lasker Defense (to 1.d4).
Play The Queen's Gambit By Marovic is very nice.
Queen's Gambit And Catalan For Black --- not much text but tons of analysis on the Orthodox, Lasker, Tartakower, Exchange, and others.
Here is a nice lecture on the Lasker on a website
http://www.kenilworthchessclub.org/games/java/2007/lasker-kenilworth-repertoire.htm
Reason: The Exchange QGD
1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.cxd4 exd4 5.Bg5 Be7 6.Qc2 c6 7.e3 0-0 8.Bd3 Nbd7 9.Nge2 Re8 10.f3 Nf8
Gives White easy play and Black few winning chances.
QGD is played frequently from the Nimzo-Indian move order 1.d4 Nf6 2.c4 e6 3.Nf3 d5 as the above variation is not possible, (also the Exchange QGD with Nf3 is not really possible due to White bringing his king's knight out too early), here Black can play Bf5 and solve the problems of his queen's bishop.
An alternative for Black is however to play the Alatorsev Variation with 1.d4 d5 2.c4 e6 3.Nc3 Be7!?
Here again White cannot get this nice Exchange QGD given above.
You have to be ready for 1.d4 d5 2.c4 e6 3.Nc3 Be7 4.cxd4 exd4 5.Bf4, when either 5...c6 or my favourite 5...Nf6 is possible. After 6.e3 then 6...Bf5!? can be played, with complicated (but fun for Black) play!!
I agree with the comments about the exchange variation. As a QGD player, that variation is the one I most fear. Partly because of the 15th game in the Kasparov/Short World Championship match. Kasparov had a winning position by just controlling the centre with pawns. He made it look so simple and like the variation was a forced win for white.
I choose to play the semi-slav mainly because of the complications that can arise and how the pieces are developed. It sometimes seems more like a system than a reactionary opening, at least to me. The regular QGD never appealed to me because it fights for small things that an amateur player like myself strugles to understand in an active game.
I guess I'm agreeing with just about all of the posts above me. 🙂