Computer Chess Club Archives


Search

Terms

Messages

Subject: Re: Bad bishop?

Author: Bruce Moreland

Date: 10:01:04 06/12/98

Go up one level in this thread



On June 12, 1998 at 08:09:44, Vincent Diepeveen wrote:

>the hardest part though as you already pointed out above is a bishop
>which is
>bad, just because there is only 1 pawn at the wrong color, which is not
>even
>blocked.
>
>I'm having massive problems to make my program this last part clear.

Right.  Humans discuss bad and good bishops without defining the term,
and when they define the term they leave huge holes in their
definitions.  They'll apply the same term to totally different
situations without even realizing that they've done it.

So if you try to code based upon these definitions, you end up with a
program with an incomplete understanding, and it makes decisions that a
strong human would not make, and it ends up mis-playing a position.

I am not a big believer in whining or excuses, I'm not someone who
mentally raises my program a position or two in the final tournament
standings in order to compensate for bugs which I found during the
tournament and fixed right after.  I am responsible for my own bugs,
they are defects in my program and in me, and if I didn't have them my
program would be better, and I would be better, but it does and I'm not.

That said, mine had some big problems at Aegon '97, and from my
viewpoint they were mostly about bishop eval.  My thing was trying to do
what I told it to do, and ended up mis-playing positions, because my
terms were both wrong and large.

To some extent I have fixed this, but to a large extent I still have
these problems, but I rarely see a classic bad bishop anymore.

One of my problems at Aegon involved a case where I had a nice g7
bishop, or so the program thought, but the opponent had a c3/d4/e5 pawn
chain.  Actually there were e5/e6 and d4/d5 rams.  The problem, if I
remember right, was that I didn't have any control of c5, or my c7 pawn
was gone or something, so I couldn't put pressure on the long diagonal,
so my bishop was bad despite there being aproximately zero of my pawns
on its color.  If I could have levered with ... c5, things may have been
different.  This was a case where my pawns were mostly OK for my bishop,
but my opponent's pawns were not.

In other cases, the pawns seem like they would mess up the bishop, but
don't, because the bishop is both A) outside the chain, and B) hitting
important squares.  It's hard to evaluate this case because even though
you can detect A, you still have to detect B, which is harder, or you
will make mistakes.

bruce




This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.