From: fry@zariski.harvard.edu (David Fry)
Newsgroups: rec.games.chess
Subject: Re: Spassky-Fischer #8, by Zarkov & me.
Date: 15 Sep 92 23:06:59 GMT
Article-I.D.: husc3.1992Sep15.190707.15616
Organization: Harvard Math Department

In article <1992Sep15.201830.24418@cs.brown.edu> jhc@iris.brown.edu.UUCP (James H. Coombs) writes:
>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:
>>Byrne says 16.Qd6 Qa5 17.Qa2 b5 gives Black a "tremendous attack."  
>
>But does he address 17.Qd2?

Again, I'm sorry for the typo. I meant 17.Qd2, not Qa2.

>[....deleted analysis based on the typo....] 
>
>>>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.

When comparing a Q versus some combination pieces and pawns, adding
the points together is not very useful.  The evaluation depends on the type of
position, but I think that in most positions, a N,B,R is better than a
Q and 2P.

In this position, if 37.d6 c4 then 38.d7 Kd8 38.Rd2 and the Black
R is still trapped, his pieces are tied down and a big White
piece invasion is underway.  With just his Q, Black will have trouble
advancing his black pawns.  I think a freeing move like ...f6 will
just give White more control of black squares.

If 37.d6 Kf8, White has the option of Nd5 and Nf6, possibly
coupled with d7 and Rd2 at some point, or opening the f-file with
f4 and supporting the d-pawn with the e-pawn.  Of course White
has to pay attention to the Black Qside pawns and invasions by the
Q, but I don't think it's a big issue.

I'm not even sure that 36.bc is even the best move.  36.Rfc2 may be
better, I don't know.

In any case, this whole thing is started by the phrase "all the
winning chances." In all the variations, I think the resulting
positions certainly show that White has a better chance to *win*.
Byrne doesn't necessarily mean there's a forced win.  If at the end of
the each variation you say, "Black looks okay here.  He hasn't lost
yet.  What's White do now?" the answer is "They play chess, and White
will probably have a better situation."

>>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.

...Qa7 may be better than ...Nb7. But it's not Byrne's job in the NYT
column to publish exhaustive analysis like we're engaging in here.  He
gives an important line or two that demonstrate the possibilities of
the position.

>>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.

You just showed a line in which the knight falls.  Afterwards the
material will be R+P for B+N, which is nearly level as far as material
goes, but the Black Q pawns are very weak, and I think the B+N will be
enough.  Also, just because Black has a passed pawn on the Kside
doesn't necessarily mean anything.  He has to be able to push it
without losing it or getting mated, which would be hard.
In anycase, I think 36....f6 37.f4 may be a stronger line.
There's no hurry to get the knight.

Again, just showing winning chances.

>>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).

I think just stating the scores gives them more importance than they
deserve, like nightly Presidential polls. I like the fact that you
included in the tabulations as a curiousity factor, but not because
they necessarily say anything useful about the position.

>>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.

Barring the usual fears of bugs in computer programs, I think it's
safe to respect DT II in tactial situations.  And I don't think
commercial programs are less likely to be buggy. That's another
topic.

>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.

I think we all appreciate Jim's postings and they're not at all
obnoxious!  I just think you're expecting some forced win in every
variation from Byrne or at least a number like "+35" because these are
things you get from Zarkov.  Sure, you should question Byrne, but just
because Zarkov doesn't agree with him doesn't mean anything.  I'll
take Byrne/DT over Zarkov any day.  Most of Zarkov's 2300 rating comes
in tactical situations, I'm sure, which means it probably has a rather
weak positional sense.  

I agree completely on the need for some analysis here.  That's why I'm
contesting these issues.

David Fry                                  fry@math.harvard.edu
Division of Applied Sciences               fry@huma1.bitnet
Harvard University                      ...!harvard!huma1!fry
Cambridge, MA  02138            
Newsgroups: rec.games.chess