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Subject: Re: How many different chess positions there exists?

Author: blass uri

Date: 07:41:56 03/16/00

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On March 16, 2000 at 09:18:51, Jari Huikari wrote:

>On March 16, 2000 at 09:02:26, Harald Faber wrote:
>
>>On March 16, 2000 at 07:44:22, Jari Huikari wrote:
>
>>>Sorry folks, but someone asked this in a finnish news group... Has anyone
>>>tried to calculate any value for this? Perhaps someone could tell at least
>>>some minimum and/or maximum values and how they have been calculated.
>
>>>P.S. How many different end game positions there are with few men?
>>>(This should be easier, when EGTBs cover all situations. Or do they?)
>
>>IIRC it was around 10^120 or 10^124 possible positions after 40 moves... :-)
>>(Don't ask me how many of them are finished at that point) :-)
>
>This doesn't help much. :-) IIRC that was number of all different games.
>
>Number of possible positions is certainly lower than number of possible
>games. But how much lower?
>
>					Jari
My program calculated an upper bound(ignoring things like side to move, 50 moves
rule) and found
3.7010630121207222927827147741452119115968e46

Retko v.tomic found a smaller number and I do not remmeber the number but it was
not less that 1e46.

I posted an idea how to improve the bound but a program needs to work some days
to calculate the better bound and it was not important for me to do it.

The main idea of my program was to calculate an upper bound for the number of
legal positions in every material structure and add the numbers.

The improvement of Retko V.Tomic was by identifying more impossible structures.

There was a big number of material structures so the program need to work for
it.

It is possible to add more numbers by calculating the number of legal positions
for more structures when every structure have also some information about the
pawn structure but it can take a long time to add the numbers and it was not
important for me to write the program and let it work for some days.

Uri



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