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Subject: Re: Promotion frequency

Author: Pham Hong Nguyen

Date: 18:00:49 07/23/02

Go up one level in this thread


On July 23, 2002 at 18:28:38, Dann Corbit wrote:

>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.

You all have excellent data. Dann, could you continue to check Shane Hudson'
idea: if those underpromotions are really necessary (if not, lose or draw) or
just because they will be taken on next move?



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