This is called the Benoni Defense-- actually the Old Benoni, since in modern play Black usually waits a couple of moves before playing c7-c5.

It is too soon to tell if the opening is going to be an old Ben-oni or a modern Ben-oni. 1...Nf6 2.c4 c5 is the standard move order for modern Ben-oni. After White plays d5, Black will play the ...e6 break and set up the KID household (fianchetto the Kings Bishop and O-O). When Black sets up the KID household and then plays ...c5, it is called the the Yugoslav KID which can transpose to Ben-oni formations. In the old Ben-oni, Black does not set up a KID household. The old Ben-oni is an ancient opening of Yiddish origins that pre-dates the KID. Note that at this point the game is not committed to a Ben-oni but could also become a Benko gambit

1dxc5 Qa5+,blitzkov

This is a fine refutation of White's move. The Queen will be well-positioned on c5 for the moment after taking the pawn. White would have been better off playing 2.d5 instead.

By not playing d5, White avoids the modern Ben-oni.

yes

Agreed. 3...Qxc5 was the entire point of 2...Qa5+.

Yes, I also wondered - but perhaps its Queen got such a shock that it forgot to take my pawn!

Strange. I think White ought to simply give back the pawn and develop (e2-e4, Nf2, Nc3, etc).

Agreed. Especially as, were black to take the pawn now, he'd have wasted a tempo as well - white has developed his bishop to d2 for free.

dunno - maybe testing the waters!

Well... it prepares Bg7 attacking b2.

that is moves?

This at least is an okay place for the Bishop. Black will have trouble dealing with it (though it does box in the Queen Knight).

attack rook (faileds)

What extra pawn? Anyway, e2-e4 is the best move here, so good on White for sticking to solid play.

@bwaa: the pawn on c5. He could have protected with 6.b4.

you not take!

Qh5+ may be a consideration too. Just to take away black's castling rights. Already, it seems black's king will be exposed whichever side it goes to.

I disagree. White ought to have a significant advantage here. He's much better developed and Black has nothing useful he can do with himself in the forseeable future.

All that I meant was *Point* it was equal.

@jkarp: no, White took a pawn at move 2 and now Black takes back so it's equal in points.

Why 9.Qf3? The Queen was much more useful where she was, and now the Knight can't develop to its natural square. White is wasting an awful lot of time (Bd2 is a bit mysterious too!).

Well if 13.exf5 Bxa1. I guess.

Ahh, I see now, carnic

but its a failed pawn attack I believe!

Yes, indeed! - mostly when I see my annotated game and/or by the engine's analysis I often wonder why I haven't done the obvious when actually playing....

Big mistake. Keeping pressure on c3 was the point of Nb8-d7-b6. Now Black wins a Rook for free.