Monday, November 19, 2007

Another London Question

I have not had much time for this blog during the last month but my next couple of months look a little less busy. Anyway, it's now long overdue to return to the London questions that I took up in my entry of September 26.

Q2: After 1.d4 d5 2.Bf4 Nf6 3.e3 c5 4.c3 Bf5 (Dia) you give two moves for White, 5.Nf3 and 5.Qb3, but what's wrong with 5.dxc5?

A2: 4...Bf5?! is a very rare move; it has only been played in three games. That should have been reason enough for us to suspect that it might be quite a poor move. And it indeed seems that the closest White comes to a refutation of 4...Bf5 is to accept the pawn with your suggestion 5.dxc5! (and not our routine move 5.Qb3 which only seems sufficient for a very small plus). There are lines where Black gets a nice centre for the pawn and murky lines like 5...Nc6 6.Nf3 Ne4!? 7.b4 g5!? 8.Nxg5 Nxg5 9.Bxg5 Bg7 10.Bb5 but sufficient compensation is nowhere to be seen.

I no longer have any idea why we missed this rather obvious pawn win. The obvious explanation is the fact that humans are so used to see hanging c-pawns (e.g. in the Queen's Gambit) which are only indirectly defended that we become blind to the possibility of capturing them and hanging on to them. However, this isn't a really satisfactory explanation as we used chess programs extensively to check our analysis. And even if the pawn win isn't immediately obvious to the human eye, there is no computer program that will miss it. In theory it should be possible to trace the correspondence between me and mr. Kovacevic and the ChessBase files we exchanged and establish who did the original analysis of this line and whether there were any discussion about the line. But as I see it that would be rather tedious and quite pointless research.

As a consequence of the above conclusion, the lines given with 5.Nf3 appear rather meaningless and should instead have been discussed under the more popular move-order 2.Bf4 Nf6 3.e3 c5 4.Nf3 Bf5 5.c3 and now Black has either 5...Nc6 - which leads to a well known position - or the popular mistake 5...e6? which might well have deserved a diagram in the book and will get one here: (Dia)

According to MegaBase 2007 this position has occurred in no less than 33 games but only in ten of them White has found the tactical stroke 6.Bxb8!. Now 6...Qxb8! 7.Bb5+ Kd8 allows Black to fight on in a bad position, and in Zimmer-Mosthaf, Hassloch 1997 Black actually won a quite weakly played game.
However, probably in shock, Black more frequently has continued 6...Rxb8? 7.Bb5+ Ke7 8.dxc5 after which he with some justification already could resign.

1 comment:

Anonymous said...

Hi Sverre, thanks for starting to answer my questions. On my second question I thought 5 dxc5 was the best move but I lost a game with it in a tournament so I wasn't sure. Anyway, I forgot to ask you two other questions I have. Here they are:

After 1 d4 d5 2 Bf4 Nf6 3 e3 c5 4 c3 Nc6 5 Nd2 Bf5 6 Qb3 Qd7 7 Ngf3 c4 8 Qb5 you give 8...e6 for black. What should white do against 8...Nh5?

In that same line, if black plays 6...Qc8 instead of 6...Qd7, you recommend 7 Ngf3 but you also show that black can equalize against that. Is 7 dxc5, with the idea 7...e5 8Bg5, a possible improvement?