I let Valkyria play from this position on an old single core P4. It plays out and wins the semeai even before it has to do so.

So by demonstrating this I have shown that with modest computational effort Valkyria thinks it is pretty simple. Or maybe more correctly: Valkyria can see moves that makes the game very simple.

So if Aya resigns a won position it means Aya needs to be improved not all go programs in general.

Also just because Valkyria plays reasonably well in this position does not mean that Valkyria is strong. It just happen to have enough knowledge to handle the tactics with a narrow search in this very position. I am sure there are a lot of positions Aya will outplay Valkyria.

Most MCTS programs used to be light in the sense close to buggy.

This is not more the case and the programs are getting stronger and stronger. But the process of adding knowledge is a trial and error process and different programmers have done different stuff. Also there is the tradeoff between speed and specialized knowledge. I always programmed Valkyria with no fear of slowing it down and I make any change that I think is necessary to play correctly even if the tactics are rare cases. Hence it tends to do well in positions where some program has serious problems. Overall though this does not make Valkyria the strongest program.

So my point is: for most non trivial tactical situations, some go programmers has a solution already. It is not hard to improve playouts. But it is very hard if not impossible to improve playouts for every possible special tactical position.

The question is : how do we tackle tactical positions in a general sense without slowing down playouts too much?

Semeai is a good example. Valkyria is good on simple cases close to the winning capture but there are an unending amount of complex semeai where this knowledge only have an effect deep down in the playouts. Some algorithm of online learning of good tactics seems to be necessary.

Best
Magnus

Quoting Stefan Kaitschick <[email protected]>:

It's childishly simple for a human, large eye against small eye.
Programmers need to find a way to make this a simple position for bots too.
Solving it with great computational effort isn't good enough.

Stefan

Aya resigned in winnning position...
http://files.gokgs.com/games/2011/5/24/ManyFaces1-AyaMC.sgf

But in last position, to save B13 string,
kill B10.
to kill B10, play D6.
to play D6, kill B8.

Semeai is really difficult.

Hiroshi Yamashita


----- Original Message ----- From: "David Fotland" <[email protected]>
To: <[email protected]>; <[email protected]>
Sent: Wednesday, May 25, 2011 12:34 PM
Subject: [Computer-go] ManyFaces vs Aya today (round 8 of the slow bottournament)


In this game, there was a big semeai on the left side. The result was a won
position for Aya, but both Aya and ManyFaces thought that ManyFaces had won
(or perhaps that it was a semeai), so eventually Aya resigned before it was
played out.

A lucky win for ManyFaces, and a position for the report.

David



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