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Subject: Re: Meaningless Underpromotions

Author: Dave Gomboc

Date: 21:31:03 08/10/99

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On August 11, 1999 at 00:22:20, Robert Hyatt wrote:

>On August 11, 1999 at 00:04:42, Ratko V Tomic wrote:
>
>> > So if searching one extra ply discovers something interesting,
>> > then =Q will get played.  If searching one extra ply discovers
>> > something bad, then we avoid seeing the 'bad' by playing =R.
>>
>>
>>That lack of common sense in the programs is typical. What is
>>needed is some kind of causal reasoning i.e. it should somehow
>>figure out that the "bad" thing <b>isn't caused by the extra
>>mobility</b> of the Queen relative to Rook. For example, once it
>>is about to pick =R, it should follow through the opponent's
>>moves it found for =Q (where it ran into something bad; it
>>doesn't matter that it isn't check for =R, opponent can still play
>>whatever it did to get out of the check in =Q line). In most cases
>>the result will be worse in the "=R" variation.
>
>
>You are misunderstanding....  it is _not_ a mobility issue.  Because at the
>next ply, the best move is to take the promoted piece, no matter what it is.
>But if the  promotion is a check, that drives the entire line one ply deeper
>than it if is not...

... which implies another reason that it's better to search the promotion to
queen first?  (Namely, that a re-search to a deeper depth due to a check
extension won't be necessary.)

Dave



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