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Subject: Re: KBNKP [a miniature study,mate in 34]

Author: Uri Blass

Date: 00:19:53 03/30/01

Go up one level in this thread


On March 30, 2001 at 01:43:57, Christophe Theron wrote:

>On March 29, 2001 at 14:21:14, Robert Hyatt wrote:
>
>>On March 29, 2001 at 14:08:06, Christophe Theron wrote:
>>
>>>On March 29, 2001 at 08:50:14, José Antônio Fabiano Mendes wrote:
>>>
>>>>  An interesting miniature by a Russian composer(sorry,I can't remember
>>>>  his name) I came across the other day:
>>>>  [D]2N5/8/8/8/7p/8/7B/4K2k w
>>>>     The _only_ winning move is 1.Bb8!! [mate in 34]
>>>
>>>
>>>Do I have a bug?
>>>
>>>Chess Tiger 14.0 and Gambit Tiger 2.0 both announce mate in 28 (that means they
>>>think it is a mate in 29 starting from your position).
>>>
>>>The line is:
>>>
>>>00:32:36.2	 Mate in 28	20	354603928	Bb8 Kg2 Ne7 h3 Bh2 Kf3 Ng6 Kg4 Kf2 Kf5 Nf4
>>>Ke4 Kg3 Kd4 Kxh3
>>>
>>>
>>>I do not have all the tablebases installed, and it is why Tiger needed half an
>>>hour on my K6-2 450 to find the mate (24Mb hash).
>>>
>>>
>>>    Christophe
>>
>>
>>Your PV is definitely wrong.  The move Ng6 above is not optimal.  Kd2 is mate in
>>30, after Ng6 it is mate in 31.  Kf2 after Kg4 is also non-optimal and takes you
>>back to a mate in 31 for the 3rd time.  After Kxh3 above it is a mate in 28 for
>>white from that point forward.
>>
>>
>>
>>However, it is possible this is an artifact of not having the right databases.
>>ie the P might turn into a knight in some variations and give check, rather than
>>just into a Q which might be worse.
>>
>>with all 5 piece files I get mate in 34 as I posted in a different post.
>
>
>OK, thanks.
>
>Indeed, I do not have all 5 men TBs installed. I have just installed the first
>CD (1/2) of the Endgame Turbo product from ChessBase.
>
>Sarah has posted in another message that Tiger announces instantly a mate in 34
>with all TBs installed. No surprise as the root position has 5 pieces. :)
>
>
>    Christophe

It is clear that there something is wrong here.

There are two possibilities

a)Tablebases are right and Tiger is wrong.
b)Tiger is right and tablebases are wrong.

I have nothing against Tiger but For some reason I guess that a is correct.

Playing a game between Tiger as white and Tiger with all the relevant tablebases
with black can give us more information.

Uri



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