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Subject: Re: Interesting test position

Author: Amir Ban

Date: 08:13:36 01/19/98

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On January 19, 1998 at 09:53:18, Robert Hyatt wrote:

>On January 19, 1998 at 07:42:39, Moritz Berger wrote:
>
>>On January 19, 1998 at 00:05:42, Robert Hyatt wrote:
>>
>>>Here's an interesting test position.  This happened in a game on ICC
>>>tonite between Crafty and a human player (actually Halcion running
>>>Crafty if you try to find the game.)
>>>
>>>In this position, Bxe7 seems pretty natural, tactically.  See if your
>>>program can find out in time that it is bad.  This was a blitz game
>>>and Crafty didn't.  Bxe7 fails to Nc4, although Crafty sees the entire
>>>line almost instantly, there is a tiny flaw at the end that makes this
>>>fall apart completely.
>>>
>>>here's the fen:
>>>
>>>2r3k/ppq1ppbp/3nb1p1/4p1B1/6P1/1NP2P2/PP1Q3P/K2R3R w - -
>>>
>>>to avoid losing this game, you'd have to play this in 10 seconds or
>>>so, as it was a 5 0 game I believe...  I certainly can't do it...
>>
>>Fritz 5 (P233 MMX):
>>
>>also likes Bxe7 ... until
>>14s: Rhe1 -0.06 10/27
>>25s: Rhe1 0.19 10/20
>>48s: h4 0.22 10/30
>>139s: h4 0.03 11/36
>>153s: Rhe1 0.13 11/36
>>
>>Hiarcs 6/Fritz engine (P233 MMX):
>>
>>h4 after 1s, never considers Bxe7
>>Qf2 after 141s (Qf2 a5 h4 b5 h5 a4 h6 axb3 hxg7 Kxg7) += 0.65
>>
>>Junior 4.6beta (P233 MMX):
>>
>>2s: Bxe7
>>8s: Bxe7 += 0.81 12 semiply
>>22s: Bxe7 += 0.81 13 semiply
>>114s: Bxe7 += 0.00 14 semiply Bxe7 Nc4 Qd8+ Rd8+ Bf8 Rxf8+ Kg7 Re8 Qc6
>>Bf8+ Kf6 Nc5 Qxf3
>>210s: h4 += 0.60 14 semiply h4 a5 Nc1 f6 Be3 Qc6 Rhf1 b5 Nd3
>
>
>
>As I mentioned in my previous post (re DarkThought) this is a positional
>evaluation issue.  Fritz has code to create open positions where it's
>deep
>search is best-suited to play.  Hiarcs doesn't like to attack at all, so
>its not prefering Be7 is not surprising.  Junior I don't know much
>about,
>but It seems that it also likes to open the position as I am doing in
>Crafty.
>
>This isn't a tactical issue (at first).  I suspect Junior's early
>searches
>were just like mine, ending with Bxg5 and ripping the king-side open,
>until
>it finds the stinger at the end that may draw...


Actually my current version here goes to h4 in 8 seconds on PP200 MHz. A
lucky break perhaps, or unlucky for the 4.6 engine.

Junior is symmetrical, and will look into opening/closing positions
objectively.

Amir




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