I've had the thought that this might be a good way to play against London/Torre types:  1...c5 2. c3 e6 3. Nf3 Nc6.

A couple of thoughts about 1...c5 2. d5:

--if Black is aiming for a Schmid, it allows the possibility of f4 plus Bb5+ (analogous to the Flick-Knife Attack in the Modern Benoni).  I seem to recall Charlie "Sniper" Storey claiming that to be lost for Black, or something similarly apocalyptic.
--Don't play like this:  2...Nf6 3. Nc3 e6 4. e4 ed? 5. e5.

RdC wrote on 07/28/15 at 08:36:39:

Yes, that's why I said "more or less". I would personally be happy to reach a ...c5 Tromp as Black with White having lost the 3.Bxf6 option (and also 1.d4 Nf6 2.Bg5 c5 3.Nc3!?, though that's considered less critical), but this is a matter of taste of course.

Back to the main topic 1.d4 Nf6 2.Nf3 c5 3.d5: It occured to me that the most "minimalist" approach for anyone who is not normally a Benoni or Benko player would be 3...b5 4.c4 Bb7!?, which is just one line of the Benko with a limited amount of theory. This would require learning and being comfortable with 3...b5 4.Bg5 as well.

There's even the move order 1.d4 c5, which cuts out the Trompowsky more or less, but allows the Morra Gambit (2.e4!?) - though not many 1.d4 players will go that way.

I think you should first of all decide which type of Benoni you're going to play if White just goes d5 and c4. At least consider the Benko Gambit if you haven't already. Two of the recent repertoire books on it also include lines against this "Pseudo-Benoni" - by Aveskulov and S. Kasparov. As does the one by N.V. Pedersen if I recall correctly. And if Nf3 is already in, you don't have to worry about sharp, declined Benko lines like 5.f3, 5.e3 and 5.Nc3. Though the accepted lines and the b6 lines, both critical, are still on the table (the latter only if Black plays either 3...b5 4.c4 g6 or 3...g6 4.c4 b5).

Another option is to specialize in the sharp Blumenfeld Gambit. You would then have to decide if 3.d5 e6 4.c4 b5 or 3.d5 b5 4.c4 e6 is the better move order; the former allows 4.Nc3 while the latter allows 4.Bg5 as "anti" or "pseudo" options.

Thanks for the info everyone.

I'm going to start playing this and see how it works. I did find a rare book on it called "Queen's Pawn Opening Pseudo-benoni: 1. D4 Nf6 2. Nf3 C5 3. D5" by Schneider and Erdelyi, though being a small book, published originally in Spanish in 1971, I don't know if it would be worth the high price.

I guess I'll just look at games where GMs have played this as Black and play through them solitaire. I know there are some games where Judit Polgar has played this. Is there anyone here who already plays this as Black? If so what has your experience been?

Basically 2...c5 can become various Benonis or various other things (including some "d-pawn specials," though it may indeed discomfit some players of such openings).  "Benoni" requires d5 by White.

As Black, after 1.d4 Nf6 2.Nf3 I become uneasy because I know one of those "attack" openings is probably coming, like the Torre, Colle, Colle-Zuckertort, Barry, Stonewall etc.

I saw that 2...c5 was scoring well, and also by playing it someone wouldn't need to learn a separate system for each different d4 attack opening. So I want to start playing it, but I have no idea what it is. I read it was a Benoni, but is it the Modern Benoni, Czech Benoni, or Old Benoni? And what transpositions if any could occur between the Benonis in this situation? Does anyone here play 2...c5 and if so, what has been your experience and can you recommend any sources of further information about this?