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Subject: Re: TB's & Castling

Author: Slater Wold

Date: 21:47:00 03/06/02

Go up one level in this thread


On March 06, 2002 at 23:43:10, Robert Hyatt wrote:

>On March 06, 2002 at 20:16:58, Dann Corbit wrote:
>
>>On March 06, 2002 at 19:18:16, Slater Wold wrote:
>>
>>>Hyatt said in an earlier post that TB's don't take into account the ability to
>>>castle because it would be a waste.
>>>
>>>However, when I feed this position into any engine, it solves it in 0.00 as a TB
>>>win.
>>>
>>>[D]5Q1Q/5Q1Q/5Q1Q/5Q1Q/8/6P1/6k1/4KR1R w K -
>>>
>>>It shows 20 possible moves, all from TB's I am guessing.
>>>
>>>I cannot cut and paste the eval, because there isn't one, but I have:
>>>
>>>1.+ - (#4) Rf4
>>>2.+ - (#4) Kd1
>>>3.+ - (#4) Kd2
>>>4.+ - (#4) Ke2
>>>5.+ - (#4) Rf5
>>>6.+ - (#4) Rf6
>>>7.+ - (#4) Rf7
>>>8.+ - (#4) Rf8
>>>9.+ - (#4) Rhg1+
>>>10.+ - (#4) Rh4
>>>11.+ - (#4) Rh5
>>>12.+ - (#4) Rh6
>>>13.+ - (#4) Rh7
>>>14.+ - (#4) Rh8
>>>15.+ - (#5) g4
>>>16.+ - (#5) Rh2+
>>>17.+ - (#6) Rfg1+
>>>18.+ - (#5) Rf2+
>>>19.+ - (#10) Rh3
>>>20.+ - (#11) Rf3
>>>
>>>_Several_ of these moves take castling into accout.
>>>
>>>After Rf4 Kxg3 my TB's show 28 moves.  The first move is 1. + - (#2) O-O, the
>>>last is 28. + - (#15) Rh8.
>>>
>>>I am 100% sure TB's do indeed take castling into consideration.
>>
>>That's right.  They do.  Crafty doesn't care, though.
>
>
>NO.  The EGTBs do _not_ consider castling.  The tables are built without ever
>considering the possibility of one side castling.  Which means that if the
>EGTB probe looks up a position with castling possible, it will get a score
>back that assumes castling is _illegal_ since it doesn't ever include castling
>moves during the EGTB generation phase...

That's what I don't understand Bob.  Why are the TB's returning + - (#2) O-O if
it never takes into account castling?  There is NO eval with this.  Just
straight TB.  But according to you, it cannot, and I am sitting here looking at
it!

It does _NOT_ happen in Crafty, you are correct.  Crafty DOES show an eval, even
under the CB interface.  I am talking about other engines.  Shredder, Frtiz,
Junior, etc.  Perhaps they handle TB's differently.



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