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Subject: Re: impact of early queen exchange on performance

Author: Robert Hyatt

Date: 13:20:52 10/09/02

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On October 09, 2002 at 14:44:45, martin fierz wrote:

>On October 09, 2002 at 14:23:03, Robert Hyatt wrote:
>
>>On October 09, 2002 at 13:28:50, Mike S. wrote:
>>
>>>Percentages, based on a large comp-comp database:
>>>
>>>Engine          | #Games   total  W    B  | total eQE* W/eQE   B/eQE
>>>-------------------------------------------------------------------
>>>Fritz 7         |  784      69%  72%  65% | 59% (#57)   53%     67%
>>>Chess Tiger 14  |  850      66%  71%  62% | 72% (#71)   73%     71%
>>>Shredder 6/-P.  |  743      61%  65%  57% | 58% (#58)   63%     53%
>>>Junior 7        |  799      55%  58%  53% | 41% (#60)   25% !   56%
>>>
>>>*) "eQE" = early queen exchange (within the first 10 moves)
>>>
>>>Fritz 7's white percentage after an early exchange of the queens was 53% only,
>>>compared to it's general white average of 72%! Remarkable also Tiger 14's result
>>>with black: Much better (71% to 62%) without queens. Desastrous was Junior 7's
>>>result with white when the queens were off the board soon: only 25% (in 30 games
>>>of that kind).
>>>
>>>It looks as if the engines each are very different, in how they depend on having
>>>the queen... with Shredder 6/-Paderborn showing the smallest impact.
>>>
>>>For games with Black against Fritz 7 or Junior 7 (and probably against others
>>>too for which I didn't search the statistics), it could be promising to have an
>>>opening book which favours eQE variants... But that of course must not have
>>>"wholes" in other (more common) lines, so it can't be done by simply generate an
>>>opening tree based on an eQE games database only.
>>>
>>>Regards,
>>>M.Scheidl
>>
>>
>>I don't think it is too surprising.  It just highlights a weakness that programs
>>fail to understand
>>basic endgame ideas, and rely more on tactics than on knowledge to move along
>>thru a game.
>>
>>If a program has some basic holes in its knowledge about endgames, then removing
>>the queens
>>is going to highlight those holes.  Or, the inverse, keeping queens on tends to
>>cover up those holes,
>>at least for a while.
>>
>>Programs that don't understand majorities, weak pawns, distant
>>majorities/passers, which minor
>>pieces work best with pawns in various configurations, the fact that pawns on
>>both wings give
>>better winning chances than pawns on one wing, etc, are going to have great
>>trouble with GM
>>players.
>>
>>I've given some examples of things I've had to fix after watching GMs pick on
>>the same hole
>>over and over.  Today I don't see those huge holes cause me a lot of trouble
>>(yes I still have
>>holes, to be sure, but not the building-sized holes some "tactical" programs
>>possess..) and I
>>don't particularly care if queens come off early or not.  If you hear someone
>>complain about
>>an early queen trade, you can rest assured they _know_ they have some serious
>>endgame
>>holes that need work...
>>
>>And you can also rest assured that after the kind of practice Kramnik has had
>>with Fritz, that
>>he _knows_ what kind of holes are there and he's going to park in them every
>>day, since they
>>can't be fixed due to match rules (stupid rules I might add).
>
>just wondering: what do you think fritz' problem is and how would you fix it?
>and do you think you could fix these problems in a single day?
>
>aloha
>  martin


I don't think many problems are "single-day" deals nowadays.  At least not the
ones I
have seen and/or fixed in my code.  The first problem is figuring out what the
"hole" is.
The last major one I had was pointed out by a GM (Roman).   He was patiently
waiting
for me to log on one day and could not wait to "get started".

"Bob, you _must_ do something about this endgame hole.  cptnbluebear has won
four
games in a row with the same theme."

"what is it?"

"Crafty thinks two connected passed pawns are much stronger than two isolated
passed pawns
in a king and pawn ending.  But the king can stop the two connected passers
easily while a
lone king has great trouble with isolated passers, the farther apart they are
the harder they are
to deal with."

That kind of thing.  Not really hard to fix.  Not really easy either.  But the
hard part is finding
what is wrong (recognizing it) rather than fixing it.  That is a place where a
GM "helper" can
make a _huge_ difference.

Fritz (and most commercial programs) are tuned in coarse ways.  Big passed pawn
bonuses.
Big king safety bonuses.  Take away those two features, and it has trouble,
because it doesn't
seem to understand that a majority will turn into a passer one day, but since
the search can't see
the passer it doesn't consider it at all.  Controlling open files is fine.  _if_
the file is useful and
_if_ you _really_ control it.  I've seen more than one program park a rook on
(say) the open
E file, even though black can block that file at will with a bishop.  The rook
can't go to the
7th because Be6 locks it in.  But it is as happy as a pig in slop with that file
even though it can't use
the squares on the opponent's half of the board in any way.

General knowledge.  With specific failures.  Kramnik is exploiting this
ruthlessly...




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