luskifuski wrote on 10/05/07 at 11:28:48:


The problem is that White is unlikely to keep his d-pawn on d4 for the rest of the game, he will want to exchange on e5 or play d5 at some point. The exact same applies when the bishop is on b6, Black is simply putting pressure on d4, which needs to be defended with a piece, and waits for White to move it. I play a lot of such positions with my bishop on a7 or b6 and it has never been 'buried' for long!

I'd be very interested to see this covered in an update (both 10...Ba7 & 10...Nxa5).  My first instinct is the same as Tony's; frequently Black is forced to sacrifice the b-pawn to relieve some of this queenside pressure in order to find counterplay.

Re. 10...Nxa5, I see only one game in this line, the original game with 10.a5:

[Event "Chigorin mem op"]
[Date "2000.10.31"]
[White "Dolmatov,Sergey"]
[Black "Sivokho,Sergey"]
1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0-0 b5 6.Bb3 Bc5 7.a4 Rb8 8.c3 d6 9.d4 Bb6 10.a5 Nxa5 11.Rxa5 Bxa5 12.dxe5 Ng4 13.Bg5 f6 14.exf6 gxf6 15.Bh4 c5 16.h3 h5 17.Nbd2 Rb7 18.Bd5 Rg7 19.e5 Nxe5 20.Nxe5 dxe5 21.Ne4 Rh6 22.Qf3 Rgg6 23.Rd1 Kf8 24.Be6 Qe8 25.Bxc8 Qxc8 26.Bxf6 Kg8 27.Bg5 Qf8 28.Qxf8+ Kxf8 29.Bxh6+ Rxh6 30.Nxc5 Bb6 31.Nd7+ Ke7 32.Nxe5 Re6 33.Nd3 Rd6 34.h4 Kf6 35.Kf1 Kf5 36.g3 a5 37.Ke2 Re6+ 38.Kd2 Rd6 39.Re1 Kg4 40.Re4+ Kf3 41.Rf4+ Kg2 42.Rf5 b4 43.c4 Bd4 44.Rxa5 Bxb2 45.Rxh5 Bc3+ 46.Kc2 Kf3 47.Rb5 Rd4 48.Nxb4 Rxc4 49.Kd3 Rc8 50.Rf5+ Kg2 51.Nc2 Kh3 52.Ne3 Bb4 53.h5 Rc6 54.Rb5 Bc5 55.h6 Bxe3 56.Rh5+ Kg4 57.Rh4+ Kf3 58.fxe3 Rd6+ 59.Kc4 Rd8 60.h7 Rh8 1-0

Sivokho seems to play very sensibly, but the position looks pretty chaotic: Black's king is stuck in the center, d5 looks weak (the whole d-file, for that matter), White has more space, and while the position would seem to favor Black's bishop pair, I just don't see it, especially since Black will have to expend a few tempi to actually put the bishops on worthwhile squares.  More to the point, I don't really see much way to improve on Sivokho's play.  Maybe 16...c4 17.hxg4 cxb3, but then 18.Nd4 makes for a really nicely placed knight.  For all intents and purposes, White has a pawn for the exchange and the initiative.

All in all, I can see why Black tends toward 10...Ba7.  I'll have to look at this more carefully...

Here I thought I made the best ever presentation of a variation, but yet I get no response I guess I'll have to boost the analyses myself.

After 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0-0 b5 6.Bb3 Bc5 7.a4 Rb8 8.c3 d6 9.d4 Bb6 10.a5 Nxa5 11.Rxa5 Bxa5 12.dxe5 Ng4 13.Bg5 Qd7, white has the blow 14.e6! winning a queen