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Subject: Re: Promotion frequency

Author: Dann Corbit

Date: 15:28:38 07/23/02

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On July 23, 2002 at 17:48:09, Shane Hudson wrote:

>On July 23, 2002 at 03:11:17, Dann Corbit wrote:
>
>>On July 23, 2002 at 03:04:39, Pham Hong Nguyen wrote:
>>
>>>Hey Dann, I did not say about your test set - yes, all games of that test set
>>>were artificially created to illustrate how important underpromotions are.
>>>However, I am mentioning about _real_ games - other story.
>>
>>Almost all of those positions I posted are from *REAL GAMES*.  Only a very tiny
>>fraction are made up positions.
>>
>>>If you or someone could (or I will do when I have spare time), do a small
>>>research about underpromotions in real games (of any database): count and report
>>>total number of underpromotions / total number of promotions. The statistics
>>>will help us on decision of design.
>>
>>The amount of useful underpromotions in real games will definitely be higher
>>than you think.  If it is as small as one in a million games where
>>underpromotion provides benefit, I will be utterly astonished.
>
>I investigated this once for the purpose of improving material and
>position search times in my database app Scid.
>
>Here are stats on the number of games containing a promotion to each
>type of piece in a database of 594,803 mostly master-level games:
>
>Piece    Games    Freq per 1000 games
>-------------------------------------
>Any      24747         41.61
> Q       24083         40.50
> N         506          0.85
> R         227          0.38
> B          72          0.12
>-------------------------------------
>
>Whether many of those promotions to Rook or Bishop were actually
>useful (superior to a Queen promotion) is anyone's guess. I suspect
>most occurred in situations where the piece will immediately get
>taken anyway.

In a database of 1.7 million games with players of 2000 ELO+, I found 3056
underpromotions.



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