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Subject: Re: A comparison of engines' evaluation

Author: Christopher A. Morgan

Date: 08:58:56 01/01/03

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Some actual play results for the position:

In my 1.9 million game database I found 1,821 games with this position.

Results, decided games:

	870 games 1-0
	622 games 0-1

In rated games with average ELO 2500 or more,

	12 games 1-0
	12 games 0-1

In rated games with average ELO 2400 or more,

	40 games 1-0
	28 games 0-1

A couple of examples:  Kasparov played three games as white only, beating Anand
and Picket, and drawing with Short in a rapid game.  Short played six games,
five as white, with score of 1-1 in decided games.

On January 01, 2003 at 10:30:15, Sune Fischer wrote:

>On January 01, 2003 at 08:48:39, Omid David Tabibi wrote:
>
>> r1bqk1nr/pppp1ppp/2n5/2b1p3/1PB1P3/5N2/P1PP1PPP/RNBQK2R b KQkq b3 0 4
>>
>>The Evans Gambit, arising after 1.e4 e5 2.Nf3 Nc6 3.Bc4 Bc5 4.b4, is a good
>>example of positional material sacrifice. By sacrificing his b pawn, white gains
>>a number if precious tempos, thus seizing the opening initiative. While the 4.b4
>>gambit might not be better than the other 4th moves here, it usually reaches a
>>balanced position in which white has enough compensation for the sacrificed
>>pawn.
>
>So your saying that _usually_ white gets _enough compensation_, so the position
>should ideally be evaluated at 0.00?
>
>To put it in a different way, how often is this played by the top players, is it
>sound, or is it a patzer gambit?
>
>Actually, I would be a bit worried if my program showed 0.00 or advantage for
>white :)
>
>My guesstimate would be 0.30-0.50 advantage for black is the "correct"
>evaluation, ie there _is_ compensation for the pawn, but it is doubtfull if
>there is _enough_.
>
>-S.
>>Now let us see how the top engines evaluate this position. There is not much
>>tactics involved here, so this gives us a good opportunity to compare the
>>programs' evaluation (their chess knowledge).
>>
>>In the table below, the evaluation of each engine is recorded after 1 minute
>>analysis (since the evaluation is largely positional, no significant score
>>change was noticed from one ply to another, so most probably even deeper
>>searches will not change the result):
>>
>>
>>Engine            Score
>>------            -----
>>Junior 7           0.06
>>Fritz 7           -0.41
>>Shredder 6.02     -0.33
>>Chess Tiger 14    -0.82  (Gambit Tiger 2 also produced the same score)
>>Hiarcs 8          -0.84
>>Crafty 19.1       -0.81
>>
>>
>>Interesting points:
>>
>>    - Junior 7 was the only program who evaluated the position realistically.
>>
>>    - Gambit Tiger 2 which is tuned for sacrificial play, did not evaluate
>>      the position differently from Chess Tiger 14.
>>
>>    - Hiarcs 8 which is said to incorporate the most chess knowledge, displays
>>      the least chess understanding in this position! (Conclusion: more chess
>>      knowledge does not necessarily mean better evaluation.)
>>
>>Omid.
>>
>>P.S. An analysis of Fritz 8 and Shredder 7 will be appreciated.



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