[Computer-go] 7x7 Go is weakly solved

[Aja Huang]

It's the work by Chinese pro Li Zhe 7p.

http://blog.sina.com.cn/s/blog_53a2e03d0102vyt5.html

His conclusions on 7x7 Go board:

1. Optimal komi is 9.0.

2. Optimal solution is not unique. But the first 3 moves are unique, and the first 7 moves generate 5 major optimal solutions.

3. There are many variations not affecting final score.

Aja

[Horace Ho]

Is the video available online?

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[Thomas Wolf]

On Sun, 29 Nov 2015, Aja Huang wrote:

> It's the work by Chinese pro Li Zhe 7p.
> http://blog.sina.com.cn/s/blog_53a2e03d0102vyt5.html
> His conclusions on 7x7 Go board:
> 1. Optimal komi is 9.0.

Who can enforce a win with this komi?

Thomas

> 2. Optimal solution is not unique. But the first 3 moves are unique, and the first 7 moves generate 5 major optimal solutions.
> 3. There are many variations not affecting final score.
>
> Aja
>
>

[Aja Huang]

On Mon, Nov 30, 2015 at 1:19 AM, Horace Ho <hor...@gmail.com> wrote:

Is the video available online?

I couldn't find any video but in the web page you can click in the slide show.

Here is another interesting Chinese article arguing that Li's results should be presented in Chinese or Ing rules, rather than Japanese rules:

http://bbs.weiqitv.com/forum.php?mod=viewthread&tid=14346&extra=page%3D1&_dsign=5721321a

Aja

[Aja Huang]

On Mon, Nov 30, 2015 at 1:33 AM, Thomas Wolf <tw...@brocku.ca> wrote:

On Sun, 29 Nov 2015, Aja Huang wrote:

It's the work by Chinese pro Li Zhe 7p.
http://blog.sina.com.cn/s/blog_53a2e03d0102vyt5.html
His conclusions on 7x7 Go board:
1. Optimal komi is 9.0.

Who can enforce a win with this komi?

Li's optimal solution is Black has 9 more points in terms of Japanese rules. So, with komi 9.0 it's draw.

Aja

[Erik van der Werf]

Hi Aja,

This result seems consistent with earlier claimed human solutions for 7x7 dating back to 1989. So what exactly is new? Did he write a program that actually calculates the value?

Best,

Erik

[Aja Huang]

Hi Erik,

On Mon, Nov 30, 2015 at 10:37 AM, Erik van der Werf <erikvan...@gmail.com> wrote:

Hi Aja,

This result seems consistent with earlier claimed human solutions for 7x7 dating back to 1989. So what exactly is new? Did he write a program that actually calculates the value?

Did you mean 7x7 Go was weakly solved before?

Aja

[Petr Baudis]

On Mon, Nov 30, 2015 at 11:52:47AM +0000, Aja Huang wrote:
> Hi Erik,
>
> On Mon, Nov 30, 2015 at 10:37 AM, Erik van der Werf <
> erikvan...@gmail.com> wrote:
>
> > Hi Aja,
> >
> > This result seems consistent with earlier claimed human solutions for 7x7
> > dating back to 1989. So what exactly is new? Did he write a program that
> > actually calculates the value?
> >
>
> Did you mean 7x7 Go was weakly solved before?

I think the question is whether it was exhaustively searched (can be
mathematically proven / reproduced) or just (thoroughly) investigated
by a human.

Petr Baudis

[Erik van der Werf]

On Mon, Nov 30, 2015 at 12:52 PM, Aja Huang <ajah...@google.com> wrote:

Hi Erik,

On Mon, Nov 30, 2015 at 10:37 AM, Erik van der Werf <erikvan...@gmail.com> wrote:

Hi Aja,

This result seems consistent with earlier claimed human solutions for 7x7 dating back to 1989. So what exactly is new? Did he write a program that actually calculates the value?

Did you mean 7x7 Go was weakly solved before?

It depends on what you mean by 'weakly solved'. If we take the definition from https://en.wikipedia.org/wiki/Solved_game:

'Provide an algorithm that secures a win for one player, or a draw for either, against any possible moves by the opponent, from the beginning of the game.'

then no, I did not mean that, and that's why I asked you if he actually wrote a program that does this for 7x7.

Strong humans players including some pro's claimed to have solved 7x7 already back in 1989 (see my phd thesis for a reference), but AFAIK they did not implement an algorithm, so just like most of the other small board results by humans these were never really proofs in a strict sense.

Best,
Erik

[Marc Landgraf]

Google translate on the article tells, that there is no algorithm, but that they combined human and computer power on a larger scale to explore all variations. It can't be proven that the result is correct, but the likelihood is ~100%.

[Aja Huang]

On Mon, Nov 30, 2015 at 12:20 PM, Erik van der Werf <erikvan...@gmail.com> wrote:

It depends on what you mean by 'weakly solved'. If we take the definition from https://en.wikipedia.org/wiki/Solved_game:

'Provide an algorithm that secures a win for one player, or a draw for either, against any possible moves by the opponent, from the beginning of the game.'

then no, I did not mean that, and that's why I asked you if he actually wrote a program that does this for 7x7.

By 'weakly solved' I just directly translated his claim in the Chinese article. From the text it's not very clear to me whether he actually wrote a program. Looks like he didn't write a program and he solved it by mathematical proof with his Go knowledge since he is a pro.

Aja

 

Strong humans players including some pro's claimed to have solved 7x7 already back in 1989 (see my phd thesis for a reference), but AFAIK they did not implement an algorithm, so just like most of the other small board results by humans these were never really proofs in a strict sense.

Best,
Erik