Jay: I'd rather meet c6 than many other set ups by black (eg e6/d5, reverse dragon, KID). Many slav players aren't booked up on the english/reti lines. Earlier in the thread I showed a win against a 2300 player who lost directly out of the opening against me. That doesn't prove anything, but I wouldn't be too worried about c6.

Jay wrote on 04/11/11 at 03:25:48:

No, it wasn't ironic. I deliberately picked lines in DW that were completely different to the DE recommendations.

The whole thing is, g2-g3 is not much good against the Slav.  So if Black's e-pawn is still at home, it makes great sense for him to react to g2-g3 with c7-c6.  I consider this the principal challenge to Marin's move order.  You don't have to be a Slav player to play this way, because White's already committed to g2-g3.

@Jay: Thanks for all that.  However I don't think that those lines with Black's early ...e5 are necessarily relevant to 1.c4 Nf6 2.g3 c6.  Black here would do best, I think, to play more like he does in the Slav or the London.

There is of course the gambit of the c4 pawn, but I'd be surprised if that were a path to advantage for White.  Black has made no concessions at all that I can see, unless you count ...c6 depriving the QN of its ideal square, and that's mighty thin gruel.

Markovich wrote on 04/11/11 at 02:30:41:

First, I will add the setup from Kosten's Dynamic English after looking it up:

1. c4 c6 2.g3 Nf6 3.Bg2 d5 4.Nf6 with the main responses being 4...Bg5, 4...Bf5, 4...dxc4, and 4...g6 with I expect 4...dxc4 probably being the most trying and with the following Kosten continuation:  5.Qc2 b5 6.b3.  Kosten-"Sooner or later White will have to play this move which makes his pawn sacrifice permanent."  Basically he addresses it as a "with compensation" position citing Dzindzichashvili-Bagirov, USSR Ch 1972.

About the isolani:  Kosten gives 1.c4 e5 2.g3 Nf6 3.Bg2 c6 4.d4 dxe4 5.Qxd4 d5 6.cxd5 cxd5 where "Attempting to avoid the IQP by 6...Nxd5 is mistaken", as in Cebalo-Miles, Biel 1986 Black suffered "serious problems in the ending:" 7.Nf3 Nb4 8.Qxd8+ Kxd8 9.Na3 Be7 10.0-0 Be6 11.Bd2 a5 12.Bc3 f6 13.b3 c5 14.Nd2N8c6 15.Ndc4.

I am unsure if Kosten claims that the isolani should be accepted on the three other lines he gives: 4...Bb4+, 4...d6, and 4...e4.

The 4...e4 line was the subject of Palliser's lines in Chapter 2 and exd4 was Chapter 3 from DW: Flank Openings, "Fighting Back against the Kostenites: Part 1 and Part 2"

Palliser believes that Kosten underestimated the strength of 1.c4 e5 2.g3 c6 3.d4 e4 (Part 1).  His Part 2 addresses the alternative of 1.c4 e5 2.g3 c6 3.d4 exd4 because some are not fans of the "closed centres."

Perhaps ironically, Kosten in Chapter 8 "Slaying the Slav" gives 1.c4 c6 2.Nf3 (departing from the repertoire recommendation in Dynamic English) 2...d5 3.e3 Nf6 4.Nc3 e6 5.b3 Bd6 6.Bd2 Nbd7 7.Qc2 0-0 which foregoes the kingside fianchetto advocated in Dynamic English.

The problem from White's point of view is that Black has so many ways to try to keep an extra pawn ! b5, Cd7b6, Be6, Qd5 or a combination ... The practical task for White is very difficult without a good memory.

1. c4 Nf6 2. g3 c6 3. Bg2 d5 4. Nf3 dxc4 indeed Black can keep an extra pawn but different ways. This line was called by Raymond Keene "a dubious gambit" in his book Flank openings from the 70, Marin thinks that White has an edge, an open contreversy !