how to beat the trompowsky?

Greek IM Andreas Tzermiadianianos in New In Chess Yearbook #78, 2006, suggests 5. c3 as "A Safe Try for a Small Advantage". Which by the way was the title of his survey!

ericmittens, after Qb6, White's Queen sure can bring up quite a storm, but I just don't like that pawn on d5 obstructing me from playing d5 AND preventing me from allowing my Knight to develop properly. Therefore, I look forward to disposing of White's pawn on d5 as soon as possible. Will Qb6 contribute to this? If so, can you please provide a sequence of moves (recommended on the board) so that I know how to continue accurately?

Also, can I play Qa5+ and take the pawn? And what if White replies by d6?

so?

I play as Black 1.d4 Nf6 2.Bg5 d5 3.Bxf6 gxf6.

Leads to interesting play and I can't find any advantage for White anywhere.

Well, the move 3.d5!? in the 2...c5 tromp is known as the vaganian gambit. White is more or less forced to sacrifice his b2 pawn but in return he gets a nice center and development. As black you pretty much have to live with this if you want to play the 2...c5 line. According to theory black can get good play but white will always have more space. The main line goes like this.

Yes, there is a lot less space for Black here.....you mean I have no chance to take the annoying d5 pawn and have to be content with having a cramped position(but an active Queen)?

Is there another way to prevent Black from being so cramped?

Can't Black play Ne4 at move 5?

To be honest I haven't once played against the vaganian gambit OTB, most people just play Bxf6 on move 2. Though if I ever did I wouldn't worry, black has a nice position at the end of the above line. Black's pieces are well-placed, the e4 pawn is a target, black has play down the c-file, and there is still a pawn break (g6) available...a very pleasant position for black.

If you're really averse to having less space you might want to consider the 2...d5 lines in the tromp.

White seldom plays the h pawn forward....so it is impracticable.

Did you mean at move 3 of "1.d4 Nf6 2.Bg5 c5 3.d5 Ne4"?

Yes I think you can because in my repertoire against the Tromp the same position may arise after 1.d4 Nf6 2.Bg5 Ne4! 3.h4!? c5 4.d5

Imo (from my study of the opening), 2...Ne4! is the best Black response, but to play this Black is required to study the variation well because if not, there is a very high probability that Black can go wrong. And the amount of theory to memorize is very huge!

2...c5! is probably the most effective response, but you should be able to live with the line suggested by ericmittens.

2...e6 is also common and probably comfortable for QGD players. But I'm not impressed with Black position here and I always have a feeling that Black should have an advantage from White playing the Tromp (either by playing 2...Ne4 or 2...c5)

2...d5!? is hopeless imo. Well, marvellosity stated that he couldn't find any advantage for White anywhere (after 3.Bxf6! gxf6?!). But Black also has no advantage imo (if not at all a drawback). The doubled f-pawns is disliked by many players. If you take it with e-pawn (3...exf6), it is like playing the "drawish" Ruy Lopez Exchange. Okay, to be honest, I think taking the bishop with g-pawn (3...gxf6?!) is weak because at some point later White can play e4! giving Black horrible pawn islands.

 To say 2.... d5 is hopeless is ridiculous , given that it scores about 47% , same as 2... Ne4 which you seem to like.  Also , after 3 Bxf6 both recaptures are roughly equal according to my database though I prefer to recapture with the e pawn. Recapturing with the g pawn leads to a larger percentage of decisive games , with both white and black winning more games while exf6 leads to a larger % of draws.

I agree that c5 is best.

No one suggested this yet

I think we agree on everything except the wording :))

2...Ne4! scores the same with 2...d5 because 2...Ne4 line has many inferior lines for Black.

2...d5 3.Bxf6 gxf6?! is decisive but not many White players play e4!, the reason for the question mark.

2...d5 3.Bxf6 exf6 is okay but as you said, lead to a large number of draws and this is hopeless if Black should play for a win. But to be honest, I dropped playing the Tromp because I couldn't win this very line against computer (and that's also one reason why I underestimate the Tromp)

EDIT (ADDITION):

The main reason why I regarded 2...d5 as hopeless is because I have a believe that Black should play for a win in the Tromp. I cannot accept ordinary responses such as 2...e6 and especially 2...d5. I believe 2...d5 is theoretically stronger than 2...e6, but 2...e6 has a bit of sharp end.

A national coach (the most respected here) thinks that the Tromp is very strong and for White's advantage. He convinced me to play the Tromp. But during my study I found that the advantage seemed to be for Black. But I still wanted to play the Tromp as a surprise weapon untill I gave up beating the 2...d5. For the line of 1.d4 Nf6 2.Bg5 d5 I didn't study other lines except for 3.Bxf6 because if I didn't take the Knight I couldn't find a justification to move with 2.Bg5, tho 3.e3 seems better but has so many possibilities. I just couldn't afford the time studying the White side of an opening variances where I am happy with the Black side of it.

then the french happens.  :(

LOL yes it seems you can throw just anything to the Tromp.

1. d4 Nf6 2. Bg5 Ne4 3. Bf4 Nc6!? is an interesting idea. Black wants to meet 4. d5 with ..e5!

Wrong, I'm afraid.

e4 is a pretty weak move for White in the 3...gxf6!? line. Black gets all kinds of exciting play with ideas like Rg8, f5, and play against the now weak d pawn.

Clearly e4 is pretty critical and I've looked into it quite a lot. I can't even find a line for White where he equalises if he tries e4.

Well, it is your line (mine is 2...Ne4 and alternative is 2...c5) so you must have studied it well, but I still have the feeling that I'm right.

My mostly played defense against 1.e4 is the Sicilian Classical variation. And the strongest line for White is the Richter-Rauzer attack where Black also has a doubled f-pawn and an awkwardly placed king. So I have studied the defense deeply to survive from the "bad" position. When playing the Scandinavian against weak opponent I also often double my f-pawn to get similar position. From those I don't think I will miss some "special" merit in this Tromp position (But I will find out).

Back to the Tromp, playing as White I will worry the bishop pair. But I think White is not in bad shape so White must be able to exchange the bishop. One strategy is of course to exchange pieces so White gets a better endgame due to better pawn structure.

The one way Black can prevent horrible pawn island is to play ...c6 instead of ...c5, but this will hemm in the queenside bishop especially if you also play ...f5. And this is very passive, a combination of two bad positions from the Sicilian and the QGD (and this may create an opposite-color bishops).

First, let's see an example where Black plays ...c5:

Now, let's see an example where Black plays ...c6:

So that's it. Tho it is only example, what I can see is:

(1) Black has a bad pawn structure that will most probably lead to an inferior endgame (tho the possible opposite-color bishops situation may increase the drawing chances)

(2) White is not in defensive position (but Black) so White has the resources to defend or force pieces exchange, especially against the potentially dangerous bishop pairs.

(3) White's d4-pawn is not weak if you prepare c3 to support it.

You have the feeling, I have the hard analysis on my laptop :)

I know which one I trust.

Anyway, 4.Nc3 is a very unusual move for White there. Black should as usual respond with an immediate 4...c5!, which scores 59% for Black from 262 games in my database (this has transposed to a Veresov - 4.Nc3 played only 27 times with the Tromp move order).