Oops, I missed this one earlier.

It's a very difficult question, as there are so many playable lines for both sides. I guess that the 'main line' with 1 d4 Nf6 2 c4 e6 3 Nc3 Bb4 4 Qc2 0-0 5 a3 Bxc3+ 6 Qxc3 b6 7 Bg5 Bb7 8 f3 h6 9 Bh4 d5 10 e3 Nbd7 is still very important and gets played quite a bit at the top level (see for example Topalov-Leko and Sokolov-Hansen in ChessPub - ECO code E32). Otherwise of course there's Adorjan's 6...b5, which is probably less common than it should be, while Rozentalis's 7...Ba6 is an interesting deviation for Black.

There haven't been too many significant advances in theory here. White most popular way of dealing with this line is still 1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.Qc2 0-0 5.a3 Bxc3+ 6.Qxc3 b5 7.cxb5 c6 8.Bg5 cxb5 9.e3, returning the pawn immediately. Recently White has tried 8 a4!? but this looked a bit suspect in the following game:
Van Wely,L (2675) - Iordachescu,V (2550)
4th IECC Istanbul 2003

1.d4 Nf6 2.c4 e6 3.Nc3 Bb4 4.Qc2 0-0 5.a3 Bxc3+ 6.Qxc3 b5 7.cxb5 c6 8.a4 a6! 9.bxa6 Ne4 10.Qc2 d5 11.e3 Nxa6 12.Bxa6 Bxa6 13.Ne2 c5 14.dxc5 Qa5+ 15.Bd2 Nxd2 16.Qxd2 Qxc5 17.0-0 Rfb8 18.Rfb1 Qb4 19.Nc3 Bc4 20.Qd4 Qb3 21.h3 h6 22.a5 f6 23.Ra3 Qb4 24.Ra4 Qb3 25.Qc5 e5 26.Ra3 Qc2 27.b4 Rc8 28.Qb6 Kh8 29.b5 Rab8 30.Qd6 Rd8 31.Qc5 Rbc8 32.Qb4 d4 33.exd4 exd4 34.Nd1 Rd5 35.b6 Rb5 36.b7 Rb8 37.Qxb5 Bxb5 38.Rxb5 Qxd1+ 39.Kh2 Qc1 40.Rab3 Qc6 41.Rb6 Qc7+ 42.g3 d3 43.a6 d2 44.a7 d1Q 45.a8Q Qdd8 46.Qa6 Qc5 47.Rb2 Qcd4 48.R6b4 Qe5 49.Rc2 Qee7 50.Rbb2 Qed7 51.Qa7 Kh7 52.Rd2 Qxd2 53.Rxd2 Qxd2 54.Qxb8 Qxf2+ ½-½

(see ChessPub [ECO code E32] for annotations to this game)

Have there been any developments in Adorjan's novelty in the classical Nimzo (4. Qc2 o-o 5. a3 Bxc3+ 6. Qxc3 b5!?)  I read about the line in Watson's Secrets of Modern Chess Strategy but the book was released in the late 90s and I was wondering if the assessment of this line has changed since from unclear?  Thanks for any replies in advance!  This is a really cool website and forum!

How can Black equalise against the 4 Qc2 0-0 5 a3 Bxc3+ 6 Qxc3 b6 7 Bg5 Bb7 8 f3 h6 9 Bh4 d5 10 e3 Nbd7 11 cxd5  line? After Nxd5 12. Bxd8 Nxc3 13. Bh4 Nd5 14. Bf2 c5! 15. e4! black has to choose where to put his knight! For example:
15... Ne7 16. Ne2! Rac8 17. Nc3 cxd4 18. Bxd4 Rfd8 19. Rd1! and in my opinion white is still slightly better here.
so 15... Nf4!? and now the big question is why Kramnik against Naiditsch, Dortmund 2003 refrained from the critical  16. Bb5 Rad8 17. Ne2! Nxg2?! 18. Kf1 f5 19. d5!! which looks very good for white!
Does anybody have a clue?

Here are the games (they are from the latest The Week in Chess)

Baburin-Pinter,
Austrian League 2003

1 d4 Nf6 2 c4 e6 3 Nc3 Bb4 4 Qc2 0-0 5 a3 Bxc3+ 6 Qxc3 b6 7 Bg5 Bb7 8 e3 d6 9 f3 Nbd7 10 Bd3 c5 11 Ne2 Rc8 12 Qb3 cxd4 13 exd4 Ba6 14 Rc1 h6 15 Bxf6 Nxf6 16 Qa4 Bb7 17 0-0 Bc6 18 Qd1 Qd7 19 b4 a6 20 Nc3 Qa7 21 Kh1 Rfd8 22 Qe2 Ba8 23 Rfd1 Rb8 24 Rb1 Re8 25 a4 Qc7 26 Qf2 ½-½



Baburin-Kosten
Austrian League 2003

1 d4 Nf6 2 c4 e6 3 Nc3 Bb4 4 Qc2 0-0 5 a3 Bxc3+ 6 Qxc3 b6 7 Bg5 Bb7 8 e3 d6 9 f3 Nbd7 10 Bd3 Rc8 11 Ne2 c5 12 Qb3 Qc7 13 Rc1 Ba6 14 Qd1 h6 15 Bh4 d5 16 0-0 dxc4 17 Bxc4 Bxc4 ½-½

All the best,

John Emms

Hi Tony,

4 Qc2 0-0 5 a3 Bxc3+ 6 Qxc3 b6 7 Bg5 Bb7 8 f3 h6 9 Bh4 d5 10 e3 Nbd7 11 cxd5 is still probably White's best chance of an edge, although Kasparov was quite happy to play this as Black against Kramnik in their 2000 World Championship match. The only other thing that may be something for White is 8 Nf3, followed by Nd2 etc. I think Black has to play more accurately in these lines than against f3, e3, Bd3, Ne2 etc.

All the best,
John

Hi Tony,
What Baburin played (12 Qb3) isn't really critical. It looks like Black has a few ways of obtaining a reasonable position (12...d5 and 12...h6 13 Bh4 d5 also look okay to me). In general I don't think the lines with e3, f3, Bd3, Ne2 are much for White, although Bareev has had a bit of success with them. 
All the best, John