From: jhc@m2lll.uucp (James H. Coombs)
Subject: Re: Spassky-Fischer #8, by Zarkov & me.
Reply-To: jhc@iris.brown.edu.UUCP (James H. Coombs)
Organization: IRIS - Brown University
Date: Tue, 15 Sep 1992 20:18:30 GMT

In article <1992Sep15.083113.15598@husc3.harvard.edu> fry@tara.harvard.edu (David Fry) writes:
>In article <1992Sep15.042354.3529@cs.brown.edu> jhc@iris.brown.edu.uucp (James H. Coombs) writes:

>>I thought 15.O-O-O looked good in part because of 16.Qxd6.  I played through
>>with Zarkov and did not find any problems.  If Black exchanges Queens, then
>>White heads toward the endgame up a pawn.  If Black plays Qa5, White's
>>retreat to d2 leaves Black with a ways to go before building up an attack.

>Byrne says 16.Qd6 Qa5 17.Qa2 b5 gives Black a "tremendous attack."  

But does he address 17.Qd2?

As for the "tremendous attack", well, after 17.Qa3 b5, White exchanges
off the Queens: 18.Qxa5 Nxa5 19.cxb5 axb5 20.Kb1 b4 21.Nb5 Rfc8 22.Bd3
and Black hardly has an easy attack.  Does Byrne give anything beyond
17...b5?

>>Or let's take Zarkov's move: 33.Qc3.  Inferior would be 33...Rxc3,
>>which allows the equalizing 34.Rxc3 Nc5 35.b4 Qa7 36.bxc5 dxc5.  Now
>>37.d6 gives White an advanced passed pawn.  On the other hand, Black
>>has triple connected passed pawns.  Zarkov scores them about even.

>Well, in this line White has the material advantage of a N, B, and R
>for Q and 2P, plus the Black R is temporarily stuck, as you point out,
>and the White knight is head for d5 and f6.

N+B+R ~= 11; Q+P+P ~= 11.  I will give a temporary -5 for Black's
buried Rook, but let's not charge that against Black twice.  Actual
material is roughly even; effective material seems to be on White's
side, but then White's Knight goes nowhere fast.  Or, let's say,
White's forces are also in disarray.  Note that moving that Knight to
d5 requires moving the Rook first (because Black is going to play c4),
and also Black threatens to penetrate on that diagonal.  36.d6 Kf8
37.Rd2 Kg7 and the Rook is out.  A battle remains.  White's King
has no cover, while Black's is tucked away.

>Byrne and DT give 34.Rc3 Nc5 35.b4 Nb7 36.Rfc2 Nd8 37.Rc7 Qf8 38.Rc8
>as winning by, for instance, R2c7 and Rd7. 

Yes, and this clearly indicates the inferiority of 35...Nb7.  I don't
have a lot of faith in what Byrne is publishing because he seems to be
giving us so little and seems to be focusing on obvious but inferior
moves---just the sort of moves that the general readership probably
considers and wants to hear about.

>>Better is 33...Nxc1 34.Qa3 b4 35.Qxa6 Kf8 36.Nc2 b3 37.Kxc1 Ra7 38.Qd3
>>bxc2 39.Rxc2 Ra1+ 40.Kd2 Rh1.  Black has given up a passed pawn for the
>>exchange and the initiative.

>Better is 33...Nc1 34.Qa3 b4 35.Qa4 Kf8 36.Bf1 and the Black knight
>falls and White has the material edge. (Byrne/DT)

Or maybe Byrne writes for a readership that is beyond me!  How does the
Knight fall?  And how does White prevent Black's penetration on g/h,
with the creation of a passed pawn?  36...f6 37.Rc2 fxg5 38.Rxc1 Rxc1+
39.Kxc1 Qa7.  I still don't see the material edge, but if I play too
far beyond what Byrne gives, then I am likely to miss resources that he
sees.

>I think Jim's getting a little carried away with his Zarkov analysis,
>obviously, when comparing lines based on one evaluated at +21 and another
>at +23.

I don't consider any difference less than 50 points significant, and
even then it must persist.  I may have said that this line was +21 and
that was +23, but those were simply the scores.  With a scoring system
of 100 points for a pawn, I didn't think anyone would pay attention to
insignificant differences (although I don't post the scoring each time
and I notice that the lateness has caused some sloppiness in my
writing).

>While I have respect for DT II in tactical positions as an 
>adjudicator of the truth, I don't think even it should be relied upon
>solely in most situations, and I don't think Zarkov should be considered
>*too* seriously in a game between Spassky and Fischer.  It missed,
>for instance, the sac 37...Ra1 and then 40...b4 as the finisher.

I don't know how much respect we should have for DT II.  I have more
confidence in a widely used commercial program, such as Lotus 1-2-3,
and even that must be treated with some skepticism.  I'm sure that it
provides a great datapoint, although, as we have heard from Bob Hyatt,
we have to take human performance limitations into account as well.

As for Zarkov.  Well, it's running at about 2300, has its strengths
and weaknesses, and sees some things that GMs don't and misses others.
If we had more people posting analysis and discussing the games, then I
wouldn't bother with Z.  But most of what we are getting is twaddle
about politics and girlfriends and how to mispronounce people's names.

I also hope that people are not blaming all of my novice analysis on
Zarkov.  I am using Z, but I probe in certain directions, etc.  (All
the scores and those long lists of suggested lines are purely Z).

I am making strong arguments for what I see just as any student would
argue a case strongly.  We wouldn't learn anything if we were to just
sit back and leave it to Byrne/DTII to tell us what to think.  Byrne
could probably demonstrate every win to me; on the other hand, how do I
know that he is not being a little hasty in some parts of the
analysis?  What is that Petrosian said: "Rely but Verify"?  Think for
yourself, etc....

So, if I seem obnoxious or naive about this process.  I can only say
that I am not naive about my own chess skills (striving to reach
mediocrity), and that I am learning from doing this.  I hope that more
people will join the discussion of these games.

--Jim