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Subject: Re: Anti-GM - Is the Original Rebel Example Sound?

Author: Don Dailey

Date: 08:38:49 07/19/98

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On July 18, 1998 at 20:28:44, Howard Exner wrote:

>On July 18, 1998 at 03:52:14, blass uri wrote:
>
>>
>>On July 17, 1998 at 14:02:14, Howard Exner wrote:
>>
>>
>>>Here's what I'm getting in this position:
>>>1. Rxe6 fxe6 2. Bh6 a6 3. Bxa6 Qc7 4. Nxe6 Qc6 5. Bxb7 Qxb7 6. Re1 Qc6
>>>7. Qf3 Ne5 8. Ng7+ Kd8 9. Qe4 Bf6 10. Nc5
>>
>>after 7.Qf3 my programs play N7f6
>
>This move, N7f6 is better than what I proposed. I realize that most the
>computer programs will consider this quite hopeless for white now. But
>just to satisfy my curiousity do you mind if we continue on a bit.
>Does the next set of moves look reasonable to you.
>
>7 ...N7f6 8.Nac5 Rg8 9. Nd3
>
>We've come 9 moves from the original position and part of my assessment on this
>requence of moves is pretty well in line with what Bruce Moreland posted a while
>back that he spoke to Im's and one Gm and they said it was a complicated
>position. So Rxe6 does stir up a hornet's nest. But despite the high eval
>computers give to black for the resulting position the position does have
>that element of an uncastled black king. It is well sheilded by by its pieces
>but how will black undertake anything, given its pieces being preoccupied
>with sheilding the king? That's my reasoning for playing on a bit.
>
>After white plays Nac5 how would your programs autoplay this game out?
>Would they manage to keep building on Black's big material advantage?
>
>If the computers are correctly assessing the position now with the
>black king in the middle then I'll join Bob in saying the move, while
>complicating things, is nevertheless unsound. Ditto for agreeing with
>fca who started this thread.
>
>Also has anyone played the game out using Bh6 or Qa3 as the first move?
>After 9 moves of play in these lines what is the eval? That could save us time
>too as the original intent of this thread was to see if Rxe6 was any
>worse than other first choices. If other first choices were "losing"
>also then perhaps the entire example is the wrong choice, as fca
>originally suggested.
>
>Either way the verdict falls I'm enjoying analysing this position. Puzzles
>have always intiqued me and chess seems to have an unlimited supply of them.

There are a couple of issues.  One has do with whether the line is
ultimately sound and the other has to do with its value as an Anti-GM
move.   I think the second question is more interesting, the first
is just a interesting puzzle.

It occurs to me that if you're willing to make your program take more
risks, then the consequences are that it will sometimes lose some
games.  That is the whole idea of risk, take a chance to get a chance.
I am assuming that is a big part of anti-GM play, giving the program
some judgement or bias toward risk but I don't really know what Ed
has is mind here.   It doesn't always have to be extra risk.

I would like my program to a little more opportunistic about when
to sacrafice material.  Unless I'm extremely conservative about
this I am assuming that when I have it about right, it will error
on both sides occasionally, sac unsoundly and not sac when the
opportunity exists.   I would hope that even the unsound sacrafices
don't all lead to a loss against imperfect opponents.

I think it is possible that a good anti-GM implementation could
make your program play more moves that are technically losing
but also cause it to get better results in practical play.  It's
also possible that you implement Anti-GM strategies without
weakening the program at all.

- Don



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