Re: [computer-go] Pattern matching - example play

[Heikki Levanto <heikki@xxxxxx>]

On Mon, Nov 29, 2004 at 07:43:01PM +0100, Frank de Groot wrote:
> > Same kind of thing happens when people try to memorize joseki - they can
> > handle players who stick to josekis, but are totally lost when a player
> > deviates from the book line, because they do not understand the meaning
> > behind every move in those josekis.
> 
> 
> Yes. This is why I made the pattern module, it knows all variations ever
> played in half a million games of which 52,000 pro.
> Should really perform better than a standard Joseki library put in by a
> person.

Sorry, personally I find this hard to believe. Yes, sure it can learn
all the sequences ever played, but that is only half of the art of
joseki, if even that. If you look in a joseki book, there are lots of
sequences, but also a lot of explanations, like "If black wants to pick
a fight, he can play here. White can simplify things and avoid the
fighting by playing there, but if that is what he wants, he should have
played there three moves earlier". That kind of information will be
awfully hard to extract from game records.

> > There are also cases where extracting the right information from a pro
> > game must be quite hard. For a simple example, consider a joseki that
> > depends on a ladder that goes across the whole board - there are many of
> > those. If the ladder is favourable, the joseki is good, but if not, it
> > leads into a serious catastrophe. You never see the ladder in pro games,
> > both players know it long before it has happened, and choose variations
> > accordingly. I would imagine it to be awfully hard to extract the
> > knowledge that such a ladder was considered and found to work.
> 
> Yes in fact I have considered to hash in ladder info into the patterns and
> decided not to do that.

I do not mean the simple case where a ladder is already on the board,
but where the experienced players will consider the most likely
variation, knowing that there is a question of a ladder some moves
ahead, and choose their first move based on the working of that ladder.
Since both players know this much already, the ladder never materializes
on the board, and yet it has affected the decisions of both players for
a few moves. This kind of information can be encoded manually into a
library, but will be awfully hard to extract automatically.


> Of course a good Go program is always a hybrid of all kinds of approaches.

That we can agree on.


-H

-- 
Heikki Levanto   "In Murphy We Turst"     heikki (at) lsd (dot) dk

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