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Subject: Re: Benefit of tablebases seems to be 2 points!?

Author: Jeremiah Penery

Date: 06:53:51 10/15/99

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On October 15, 1999 at 03:44:30, Ed Schröder wrote:

>>Posted by Marcus Kaestner on October 14, 1999 at 04:01:40:
>>
>>in chessbits 3 i´ve made a test with the nunn-endgames (10 endgame-positions
>>played with both sides). every program one time with, one time without tb´s
>>
>>after abaout 140 games
>>h7.32 earned +5 elo for the tb-version
>>n7.32 earned +12 elo
>>
>>far the best was crafty 16.13 with +65 elo, topping even the score of hiarcs
>>7.32tb
>>
>>marcus
>
>Take this into account: Some programs may have so much chess knowledge in their
>programs that (the current) TB's have zero effect in the end. This will change
>as soon as the 6-man TB's (and up) will come, no doubt..

Definitely.

>Other programs are developed to 100% rely on TB's and therefore have very few
>(or nothing) chess knowledge inside because there is no need for that. I don't
>know in to what extend this is true for Crafty but I am confident Bob will
>tell you.

I don't think there are any programs developed to "100% rely on TB's" so that
they wouldn't have any knowledge about the endgame.  Whatever search/eval they
have will still be quite good (At least in endings where TBs would affect things
- 5 piece or less), it's just that the TBs provide 100% accuracy.

>As a result you can not compare the value (elo gain) of TB's in this way as
>it will depend of what is already inside a program (or not).
>
>Rebel knows the most important ones such as (by head):
>
>- KRK

Yes, this one is easy.

>- KNNK

Of course, this is always a draw.

>- KBNK

This one's interesting, but not really that difficult.

>- KPK

This is pretty easy, too.

>- KRPKR
>- KNPKN
>- KBPKB
>- KQPKQ

<lumping these last 4 together>
I'm a bit skeptical about some of these.  I'm sure it may play even 90%
accurately in these endings, but I'd be willing to bet it couldn't win 100% of
winnable positions from these endings (especially KRPKR and KQPKQ) against an
opponent with the TBs.

>I am sure this list is not complete. Of course the bad-bishop situation is
>covered too. Some others are not covered such as KQKR (Hi Jim!) for which
>Rebel will rely on TB's in the future.

I'm sure Rebel could easily win KQKR without TBs, even against an opponent with
them.  It's an easy ending for computers.

Jeremiah



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