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Subject: Re: Neverending story with incomplete tablebases

Author: Uri Blass

Date: 01:51:49 08/10/03

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On August 10, 2003 at 03:43:05, Harald Faber wrote:

>On August 10, 2003 at 02:24:47, Uri Blass wrote:
>
>>On August 09, 2003 at 19:11:16, Harald Faber wrote:
>>
>>>On August 09, 2003 at 05:55:43, Tony Hedlund wrote:
>>>
>>>>How can J8 allow game 14 to end as a draw?
>>>
>>>
>>>This is no serious question, isn't it?
>>>It has been posted and mentioned approx. 1,000,000 times. It is the problem of
>>>incomplete tablebases. AFAIK you/SSDF uses the "Fritz Endgame Turbo". Based on
>>>the Chessbase marketing it consists of 4 CD-roms with "the most important
>>>endgame tablebases". Based on what you saw in this game, what many many others -
>>>include me - have seen in similar positions, it is crap.
>>>Let me ask you a question. If your answer is yes, do I win a price?
>>>Here is the US-$1,000,000 question:
>>>Are you missing at least one of these files in your tablebase-directory?
>>>
>>>kqbkp.nbb.emd
>>>kqbkp.nbw.emd
>>>kqbkn.nbb.emd
>>>kqbkn.nbw.emd
>>>kqbkb.nbb.emd
>>>kqbkb.nbw.emd
>>>kqbkr.nbb.emd
>>>kqbkr.nbw.emd
>>>kqbkq.nbb.emd
>>>kqbkq.nbw.emd
>>>
>>>
>>>If you had them all(!), Junior 8 would have mated.
>>
>>Did you look at the game?
>
>
>Uri,
>how else would I know of the concretely missing tablebases?
>BTW I expand my list with kqkpp.nbb.emd and kqkpp.nbw.emd. ;-)
>See the reason below. ;-)
>
>
>>Junior8 blundered in a position when there were 6 pieces in the board
>>and there was no winning capture that leads directly to tablebase position
>>(the only possible capture in the game QxP could lead to a draw and Junior8 did
>>not draw because of playing it)
>
>
>OK, Uri, the great "non-believer".
>I loaded this game into MY Junior 8. Guess what?
>Plays: 89.Be5 #7/8.
>Shall I post the mate lines MY Junior with ALL 5-man plays?
>A) 89...Kh7 90.Qxg7#
>B) 89...Kh6 90.Qxg7+ Kh5 91.Bf6 e5 92.Qg5#
>C) 89...Kh5 90.Qxg7 Kh4 91.Qg6 Kh3 92.Qg3#
>D) 89...Kg5 90.Qf3
>and now
>1. 90...Kg6 91.Qg4+ Kh6 (91...Kf7 92.Qf4+ Ke7 93.Qg5+ Kd7 94.Qxg7+ Ke8 95.Kc6
>Kd8 96.Qf8# etc.) 92.Qxg7+ Kh5 93.Bf6 e5 94.Qg5#
>2. 90...Kh6 91.Qg4 g5 92.Bf6 Kg6 93.Qxg5+ Kf7 94.Qg7+ Ke8 95.Qe7#
>3. 90...Kh4 91.Qg3+ Kh5 92.Bf4 and 93.Qg5#
>
>Junior 8 also plays 90.Be5+!
>If black takes the bishop, voila! Perfect TB position kqkpp.
>Do you NOW believe that it HAS to do with missing tablebases?

I know about tablebases problem under chessbase when the interface controls the
game and not the engine in tablebases position.

My point is that in the relevant case there was no 5 piece tablebases position
so the interface never took control.

This was not a case when the engine got a tablebases position and could not win
it so the problem is not missing tablebases.

>
>
>>Here is the final position
>>
>>[D]2Q5/1K4p1/4pk2/8/8/8/7B/8 w - - 0 92
>>
>>Are you sure that the problem is a tablebases problem?
>
>
>YES!!! Such games have been posted about 1,000,000 times which cannot be
>reproduced with a COMPLETE set of tbs.

I know about games when an engine got KPP vs KP but could not win because of not
having KQP vs KP but I did not know about games when the engine never got a
tablebases position and missed a simple win because of not having tablebases(I
am talking about a simple win and missing some transition to a tablebases
position that is not trivial to win without tablebases is not defined by me as a
simple win)
>
>
>>I think that the problem is the engine and I also do not agree that the ssdf has
>>to give the engines all the tablebases because a good engine should know to play
>>with part of the tablebases.
>>
>>Uri
>
>
>Uri,
>you have always a special own point of view, but this problem of missing
>tablebases is not Junior-only. Maybe Tony can try some other engine on this game
>too?!

I am sure that in this case most engines will have no problem even with the same
missing tablebases.

Uri



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