Re: [computer-go] Modern brute force search

[Don Dailey <drd@xxxxxxx>]

Richard,

Vincent is NOT saying that there  is a player who knows the best line.
He  is saying that  if a  hypothetical computer  was built  that could
calculate the best line, the top players would commit it to memory.

Of course I think Vincent underestimates the difficulty of doing this.
I doubt there is a single "best line", there must be many ways to play
a perfect game of GO.

Just as a silly  example, let's say it turns out that  Chess is a draw
from the  opening position.  Both  white and black players  must learn
every possible way to achieve this result.  Let's say that it's a draw
against all  20 of  the first possible  moves.  The black  player must
learn the correct  response to every one of these  20 moves because he
doesn't  know  which  white  will  choose.   The  white  player  could
specialize in just one of those first moves.  However it will probably
be  the  case that  black  has more  than  one  "drawing" response  to
whatever  move white chooses.   White will  be forced  to know  how to
respond to each  of these.  Each player can  take turns "specializing"
in one  subtree at each  point, but it's  easy to see this  will still
quickly mushroom out of control.

A really  strong human would  benefit enormously from  this knowledge,
perhaps the  equivalent of several  hundred ELO rating points,  but it
still wouldn't guarantee  a draw because he simply  could not remember
the whole tree of possibilities.    What a really great player could 
attempt to do is memorize enough of the tree to get him to positions
he feels very comfortable with, but this wouldn't be fool-proof.

In GO, it's  even more unlikely that even a  top player could memorize
enough sequences  to play perfectly, and  I even doubt  it would bring
the  level of  play up  very much  since it  would probably  be common
practice to quickly get away  from the most "obvious" continuations in
order to nullify the memorization.

- Don





   Date: Thu, 11 Nov 2004 08:21:20 -0600
   From: Richard Brown <rbrown@xxxxxxxxxxxxxxxxx>

   Vincent Diepeveen wrote:
   > In whatever game we play.
   > 
   > The 361 stone go database will beat of course every player very easily,
   > just like a 32 stone database in chess will beat the strongest players very
   > easily.
   > 
   > The reality is of course that by the time we have a 32 stone database and
   > that there will be a 361 stone database for go, that players have looked
   > into it and already know the best line by head.

   Really?  Do you know a go player who knows the "best line"?  Wow!

   > So they can win with white in chess and with black in go very easily when
   > using the optimum line.

   Well, sure, theoretically.  That is to say, _if_ they know the optimum line.

   Again, I must ask, who is this go player, who knows the optimum line?

   I think that the rest of the go world would like to meet this great master!

   -- 
   Richard L. Brown             Office of Information Services
   Senior Unix Sysadmin         University of Wisconsin System
				780 Regent St., Rm. 246
   rbrown@xxxxxxxxxxxxxxxxx              Madison, WI  53715

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