Ptero wrote on 07/11/07 at 15:16:43:
Well, to me 19.e5 (instead of Fritz's 19.exd5 - maybe Fritz "wants" to open the position for the white bishops!?!) looks rather unpleasant for black, both after 19...Rfc8 20.Ba5 (preventing ...Ne8-Nc7, ...b4 ...Bb5 ideas) or 19...Ne8 20.Bb6.
Thank you for pointing this out. I guess I am guilty of doing some "quick and dirty analysis" here,
paying too much attention to the machine's principal variation, neither looking at it's second best option
nor really at the board …
Sorry!
In fact, if left alone, Fritz 8 keeps thinking that 19.exd5 is very slightly better than 19.e5 for quite some time.
Upon being "recommended" 19.e5, however, after a while it begins to appreciate the positive sides of this move.
But even then, having explored a few variations that might evolve after 19.e5, Fritz insists that Black remains
slightly better, with evaluations somewhere in the range from -0.10 to -0.20, but never getting close to 0.00 or
even rising to positive values.
More specifically, after 19.e5 Ne8 (19...Rfc8 20.Ba5 Ne8 with the idea 21...f6 is also fine for Black according
to the machine) 20.Bb6 Rc8, Fritz "wants" to follow up with 21...f6 after almost every legal 21. move by White
(with 21...Rxc3 being an option, too) and, if need be, assist it by a further ...g5 if White plays f4. After that,
depending on what White does, Black may redeploy his pieces with, e.g., ...Kf7 and ...Rg8.
Of course, all this may not mean much, and Rybka (or Khalifman, for that matter) may have other ideas.
Or one might think that, perhaps, the computer in general doesn't properly "understand" the disadvantages and
advantages of the white doubled c-pawns. But then, this is what Robin Smith has to say about the issue on page 33
in his book "Modern Chess Analysis" (Gambit, 2004):
"It is well known that certain pawn-structures are weak. Isolated pawns, doubled pawns,
backward pawns, numerous pawn islands, etc., are all known to be weak by almost every
club player ... and program. The trouble is, they aren't always weak. The key quality of
weak pawns that makes them weak is that they tend to be easy to attack and/or hard to defend.
Yet sometimes so-called weak pawns cannot be easily attacked and are easy to defend.
In such cases, "weak" pawns may instead turn out to be strong! Doubled pawns may allow
open files for one's rooks and/or control critical squares, or an isolated pawn might restrain
one's opponent, etc. And because pawn-structures tend to be fairly constant features of a position,
one might assume that such exceptions are again not handled well by programs. On the contrary.
Since compensation for weak pawns is frequently dynamic in nature, open files and diagonals for
quick attacks for example, while in the past programs had great difficulty with pawn-structures,
computer programs of today usually handle these exceptions very well."He then proceeds to give some examples.
So, in the position in question, after 19.e5 it may come down to a matter of taste which side to prefer.
It would be interesting to hear what someone like Mikhail Gurevich had to say about this rather French-type position ...