501 Opening Problems and a committee of AIs

[xela]

I've started re-reading 501 Opening Problems and comparing the results with bot analysis. Now I know this unreasonable on a couple of levels:

• If I can learn to play the opening as well as Rob van Zeijst, that's already a big improvement on my current level. The fact that Rob might be outplayed by an AI doesn't matter.
• For puny amateurs like me, learning to play good but not perfect moves that make sense to a human might actually be a better strategy than searching for the "best" (but incomprehensible) move.

Nevertheless, I'm curious as to how much the various opening principles capture objectively good play, and how much comes down to personal style or fashion.

So far I've been through the first 20 problems, and compared the book moves against the output of six different bots (using about a minute of thinking time for each bot). I'm thinking that if six different styles of training and analysis all come up with the same move, then there's a fair chance that it really is the best move. But if strong AIs disagree amongst themselves, there might be some interesting discussions ahead :-)

The bots that I'm using at the moment are:

• Leela Zero with network number 242
• Leela Zero with ELF weights
• Leela Zero with Leela Master weights GX47 -- for a more "human" perspective :-)
• KataGo with 20-block network
• Ray with LZ network number 173 (no particular reason for that number, it's just the one I installed last year and I'm too lazy to change)
• AQ

To me it makes sense to sort the problems into four categories:

1. The bots unanimously agree with the book move.
2. The bots unanimously come up with a move different from the book.
3. The bots don't agree with each other, but at least one of them chose the book move.
4. The bots don't agree, and none of them chose the book move.

I'm guessing the authors of 501OP were looking for positions with a clear-cut first move, so you'd hope to see most problems in class 1 or 2. My results for problems 1-20 were:

• Class 1: problems 3, 9, 14, 18
• Class 2: problems 6, 12
• Class 3: problems 1, 2, 7, 8, 10, 11, 15, 16, 17, 20
• Class 4: problems 4, 5, 13, 19

Below I'll post what I thought were the most interesting positions. (I'm certainly not going to go ahead and post the entire book, but I think five out of 501 is fair use.)

[Uberdude]

Interesting and methodological work xela, thanks, the committee of bots is something I was too lazy to apply rigourously. There was a thread with some similar bot analysis of book problems in the computer go section a while back with Rob's 'Making good shape' and then I looked at some Shuko problems with Elf. Could I suggest relabelling category 2 as 4, and shift 3 and 4 up to 2 and 3 so that they form a continuum of "book right" to "book wrong".

[xela]

Here are five positions where I was at least a little bit surprised by the results. All black to move (actually the first 106 problems in the book are all black to play, I'm not sure why the imbalance!) The book isn't specific about komi (I assumed 7.5 komi for the bot analysis; more likely 6.5 or 5.5 around the time the book was written).

I'll wait a couple of days before revealing which problem is in which class, so you can form your own impressions first.

$$c Position A. Black to play.
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$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position A. Black to play.
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$$ ---------------------------------------[/go]

$$c Position B. Black to play.
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$$ | . . O . . . . . . . . . . . . O O . . |
$$ | . . . . . . . . . . . . . . . X X . . |
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$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position B. Black to play.
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$$ | . . . . . . . . . . . . . . . X X . . |
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$$ ---------------------------------------[/go]

$$c Position C. Black to play.
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$$ | . X X . . . . . . . . . . . . . X . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . , . . . . . X . . . |
$$ | . . X O . . . . . . O . . O . . . . . |
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$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position C. Black to play.
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$$ | . X X . . . . . . . . . . . . . X . . |
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$$ | . . X O . . . . . , . . . . . X . . . |
$$ | . . X O . . . . . . O . . O . . . . . |
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$$ ---------------------------------------[/go]

$$c Position D. Black to play.
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$$ | . . . X O . . O . . . . . X . . . . . |
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$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position D. Black to play.
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$$ | . . O . . . . . . . . . . . . . . . . |
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$$ | . . . X . . . . . . . . . . . . . . . |
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$$ | . . X , O . . . . , . . . . . , X . . |
$$ | . . . X O . . O . . . . . X . . . . . |
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$$ ---------------------------------------[/go]

$$c Position E. Black to play.
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$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position E. Black to play.
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$$ ---------------------------------------[/go]

[xela]

...the committee of bots is something I was too lazy to apply rigourously...

Indeed, creating SGFs for the positions and loading/reloading different files and software took more time than I'd planned for. If I wanted to do more of this, I'd be writing a bunch of scripts to automate the process. (Or contributing to the Kombilo source code to add engine integration there.)

Then again, there's a fine line between laziness and procrastination. I could be using this time to solve tsumego problems and play games, or keep up with "real life"...

[xela]

Could I suggest relabelling category 2 as 4, and shift 3 and 4 up to 2 and 3 so that they form a continuum of "book right" to "book wrong".

I had in mind a different continuum: "clear-cut" to "confusing" :-)

[xela]

There was a thread with some similar bot analysis of book problems in the computer go section a while back with Rob's 'Making good shape' and then I looked at some Shuko problems with Elf.

Shape problems (and to a lesser extent, other sorts of tesuji) are tricky because the right answer (or urgency) can vary with context. I'd love to have a software tool that will drop a corner position into different full-board contexts to test whether the analysis does or doesn't change.

[gennan]

Could I suggest relabelling category 2 as 4, and shift 3 and 4 up to 2 and 3 so that they form a continuum of "book right" to "book wrong".

I agree that that order would make more sense.

Category 2 seems to be the smallest, so I would say the book is doing pretty OK. Another interesting thing would be to use KataGo to evaluate how wrong the book is when it's wrong (how many points does it lose compared to the AI suggestions).

[Knotwilg]

My unsollicited analysis: what I would play according to traditional theory and so I expect is the book answer (A) and what I think the/some bots will say (B)

$$c Position A. Black to play.
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$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . O . . . . . , . . . . X , X . . |
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$$ | . . . . . . . . . . . . . . . . b . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . X . . . . O . . . . . |
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position A. Black to play.
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$$ | . . . O . . . . . , . . . . X , X . . |
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$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . b . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . X . . . . O . . . . . |
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$$ ---------------------------------------[/go]

$$c Position B. Black to play.
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$$ | . . O . . . . . . . . . . . . O O . . |
$$ | . . . . . . . . . . . . . . . X X . . |
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$$ | . . . . . X . . . . . . . . . X . . . |
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$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position B. Black to play.
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$$ | . . O . . . . . . . . . . . . O O . . |
$$ | . . . . . . . . . . . . . . . X X . . |
$$ | . . . O . . . . . X . . . . . , . . . |
$$ | . . . . . X . . . . . . . . . X . . . |
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$$ ---------------------------------------[/go]

$$c Position C. Black to play.
$$ ---------------------------------------
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . b . . . . . . . . . . . . . X . . |
$$ | . . . O . . O . . X . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . X . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . a . . . . . X . . . |
$$ | . . X O . . . . . . O . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position C. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . b . . . . . . . . . . . . . X . . |
$$ | . . . O . . O . . X . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . X . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . X O . . . . . a . . . . . X . . . |
$$ | . . X O . . . . . . O . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

$$c Position D. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . b . . . . . . O . . . O . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . a X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , O . . . . , . . . . . , X . . |
$$ | . . . X O . . O . . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position D. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . b . . . . . . O . . . O . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . a X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X , O . . . . , . . . . . , X . . |
$$ | . . . X O . . O . . . . . X . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

$$ I think bots will also play A
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . X . . . . |
$$ | . . . , . . O . . X . . . . . , X . . |
$$ | . . a . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . X . . . . . , . . . |
$$ | . . . . . X . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$ I think bots will also play A
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . X . . . . |
$$ | . . . , . . O . . X . . . . . , X . . |
$$ | . . a . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . X . . . . . , . . . |
$$ | . . . . . X . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

[Uberdude]

My analysis (WIP):

A: Class 3.
A side extension on the right from both players' shimaris is the obvious opening lesson of this problem, though I find the position rather unrealistic as I don't see how white c15 could ever get played in a natural flow of the opening before the right side, so maybe the problem is more of a "given the players have played the opening moves in the wrong order, find the one they should have played earlier and do it now". In the middle and low at a most likely book answer, though high at b also possible. Bots generally don't like side extensions so much, but given the corners already have their 2nd move and another urgent bot-style opening move doesn't jump out at me maybe some of them (particularly AQ or Ray, I don't know their style well but I think more 'human') would choose it, so I guess Class 3 (at least 1 but not unanimous bot agreement). But I guess more like attaching to the shimari at c. (Knotwilg's outside attachment is almost always bad against big shimari). Also other side extensions might be possible and I think an old theory book and a bot could possibly both like d. Throwing out other extravagant bot style moves I added e too as an attempt to push the boundary of the top right quadrant moyo and strengthen k17 in sente before you play on the right side, though maybe that's dreaming (it's also trying to make c15 overconcentrated). m3 is another move on the radar but I think books and bots would agree an extension on the right side is bigger.

$$c Position A. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . O . . e . . , . . . . X , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . b a . . |
$$ | . . . . . . . . . . . . . . . d . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . c O . . |
$$ | . . X . . . . . X . . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position A. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . O . . e . . , . . . . X , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . b a . . |
$$ | . . . . . . . . . . . . . . . d . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . c O . . |
$$ | . . X . . . . . X . . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

B: Class 1 but becomes class 3 with meta-reasoning.
Pretty sure book wants to hane at head of 2 with a, and would have thought all bots would agree, but given xela selected this position as interesting I guess at least one of them doesn't want to play it, but probably most do. Or maybe he did want to include a unanimous agreement one as an example! Also this is related to a position from the Shibano on AI thread JF posted: in 5th diagram of viewtopic.php?p=249084#p249084 following white's attachment and black's extend up it's like black decided to extend instead of hane in this shape where he has the opportunity to play the better hane. But I can't really convince myself a strong bot would play something else (I marked a few other moves on the policy network) so maybe back to class 1...

$$c Position B. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . c . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . b . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . e . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . a O O . . |
$$ | . . . . . . . . . . . . . . . X X . . |
$$ | . . . O . . . . . X . . . . . , . . . |
$$ | . . . d . X . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position B. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . c . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . b . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . e . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . a O O . . |
$$ | . . . . . . . . . . . . . . . X X . . |
$$ | . . . O . . . . . X . . . . . , . . . |
$$ | . . . d . X . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

C: Class ?
Reducing the lower side with its bad coordination of a moyo and low 3rd line stone using a shoulder hit at a is probably the book answer, and bots likely like it too. Another idea is the gentler b, hoping that white answers at j4 and then black can press and develop the centre and right with m4 and o4, a classic combo of the kind books teach you, though it does feel white is maybe being overly cooperative. Nothing else looks as urgent to me, though if black doesn't reduce the lower side and white gets to grow (is it kakoi?) with k6 black probably doesn't cry so much as it's still not so spectacular for white. The top left is fairly open, but I'm not really sure what I or a bot would do there.

$$c Position C. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . O . . O . . X . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . X . . |
$$ | . . . O . . . . . b . . . . . . . . . |
$$ | . . X O . . . . . a . . . . . X . . . |
$$ | . . X O . . . . . . O . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position C. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . O . . O . . X . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . X . . |
$$ | . . . O . . . . . b . . . . . . . . . |
$$ | . . X O . . . . . a . . . . . X . . . |
$$ | . . X O . . . . . . O . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

[Bill Spight]

$$Bc Position A'. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . O . . . . . , . . . . X , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . 3 . . |
$$ | . . . . . . . . . . . . . . 5 . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . X . . . . . W . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$Bc Position A'. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . O . . . . . , . . . . X , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . 3 . . |
$$ | . . . . . . . . . . . . . . 5 . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . X . . . . . W . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

When White has a keima enclosure in the bottom right, is the textbook move, the point being that it threatens and threatens .

$$Bc Position A. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . O . . . . . , . . . . X , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 2 . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . X . . . . W . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$Bc Position A. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . O . . . . . , . . . . X , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 2 . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . X . . . . W . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

But with the ogeima enclosure, the problem with is that is a good extension, because of the weakness of the enclosure.

$$Bc Position A. Reduction?
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . O . . . . . , . . . . X , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . , 7 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . . , . . . . . , . . . . 1 3 O 6 . |
$$ | . . X . . . . . X . . . . W 2 4 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$Bc Position A. Reduction?
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . O . . . . . , . . . . X , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . , 7 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . . , . . . . . , . . . . 1 3 O 6 . |
$$ | . . X . . . . . X . . . . W 2 4 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Black would like to reduce with - . However, White will surely not play .

$$Bc Position A. Pincer?
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . O . . . . . , . . . . X , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . 2 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . X . . . . W . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$Bc Position A. Pincer?
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . O . . . . . , . . . . X , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . 2 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . X . . . . W . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Another human idea is to approach the enclosure with , because of its weakness. OC, White is likely to pincer.

$$Bc Position A. Light reduction
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . O . . . . . , . . . . X , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . , 3 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . 1 . . . . |
$$ | . . . , . . . . . , . . . . . 2 O . . |
$$ | . . X . . . . . X . . . . W . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$Bc Position A. Light reduction
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . O . . . . . , . . . . X , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . , 3 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . 1 . . . . |
$$ | . . . , . . . . . , . . . . . 2 O . . |
$$ | . . X . . . . . X . . . . W . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Another reducing play, which seems to have escaped notice by humans, is . Then if , has help from . My guess is that at least one bot will play , but it will not be the human play, nor will it be the unanimous bot choice.

[Knotwilg]

LZ on position 1 (3000 playouts)

$$c Position A. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 4 3 . . . . . . . . . . . . . . . |
$$ | . . . 2 1 . O 8 . X . . . . . . . . . |
$$ | . . . O . . 6 5 9 , . . . . X , X . . |
$$ | . . O . . 0 7 c . . . . . . . . . . . |
$$ | . . . . . a b . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . X . . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position A. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 4 3 . . . . . . . . . . . . . . . |
$$ | . . . 2 1 . O 8 . X . . . . . . . . . |
$$ | . . . O . . 6 5 9 , . . . . X , X . . |
$$ | . . O . . 0 7 c . . . . . . . . . . . |
$$ | . . . . . a b . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . X . . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

LZ surprisingly finds most potential in playing a move where White is already strong. The idea is probably to overconcentrate White in that corner and influence the rest of the board.

$$c Position A. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . O . . . . . , . . . . X , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . 6 . 4 . . . |
$$ | . . . . . . . . . . . . . . . 5 1 . . |
$$ | . . 2 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . 3 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . X . . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position A. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . O . . X . . . . . . . . . |
$$ | . . . O . . . . . , . . . . X , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . 6 . 4 . . . |
$$ | . . . . . . . . . . . . . . . 5 1 . . |
$$ | . . 2 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . 3 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . X . . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Bill's textbook move is 1% worse by my LZ setup and results in a fairly peaceful sequence

$$c Position A. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . 3 O 6 . X . . . . . . . . . |
$$ | . . . O a 4 1 2 . , . . . . X , X . . |
$$ | . . O . . . 5 . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . X . . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position A. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . 3 O 6 . X . . . . . . . . . |
$$ | . . . O a 4 1 2 . , . . . . X , X . . |
$$ | . . O . . . 5 . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . X . . . . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

LZ sees a lot of possible starting moves in the upper left. One of the leaning moves suggested here is her 3rd choice. Black can fight at A next.

On position 3

$$c Position C. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . O . . O . . X . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . X X . . . . . . 3 . . . . . . X . . |
$$ | . . . O . . . . . 5 4 . . . . . . . . |
$$ | . . X O . . . . . 1 2 . . . . X . . . |
$$ | . . X O . . . . . . O . . O . . . . . |
$$ | . . . . . . . . 6 . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position C. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . O . . O . . X . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . X X . . . . . . 3 . . . . . . X . . |
$$ | . . . O . . . . . 5 4 . . . . . . . . |
$$ | . . X O . . . . . 1 2 . . . . X . . . |
$$ | . . X O . . . . . . O . . O . . . . . |
$$ | . . . . . . . . 6 . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

No surprises here

On position 4

$$c Position D. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . O . . . O . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . 1 . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . 9 . . . . . . . . |
$$ | . . X , O . . . . 8 3 4 a . . , X . . |
$$ | . . . X O . . O 0 5 2 7 . X . . . . . |
$$ | . . . . . . . . . 6 . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position D. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . O . . . O . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . 1 . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . 9 . . . . . . . . |
$$ | . . X , O . . . . 8 3 4 a . . , X . . |
$$ | . . . X O . . O 0 5 2 7 . X . . . . . |
$$ | . . . . . . . . . 6 . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

LZ wants to actively defend the lower left. She thinks Black's ahead.

[xela]

Position A: my results.

Note: I'm not in any way saying that this is the "right" answer. I'm just an amateur player messing about with software that I only partly understand. Others may run different hardware/software/settings combinations and get different results. And I'm very happy for the stronger players on this board to critique my reasoning and interpretation.

Position A is problem 1 from the book. (No, position B is not problem 2!) "Obviously" we're meant to play around the middle of the right side. But where exactly? Low or high? At the midpoint, or can you afford to stretch a bit further? And is there anything interesting to do in the top left?

Here are some candidate moves:

$$c Position A. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . e . O . . X . . . . . . . . . |
$$ | . . . O . . . . . , . . . . X , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . b a . . |
$$ | . . . . . . . . . . . . . . . d c . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . X . . f . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position A. Black to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . e . O . . X . . . . . . . . . |
$$ | . . . O . . . . . , . . . . X , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . b a . . |
$$ | . . . . . . . . . . . . . . . d c . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . X . . f . O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

The book answer is 'a'. The book tends not to go in for long explanations, so there is no discussion of 'a' versus 'b', 'c' or 'd'. To me, playing half way between the black and white positions just feels right, although I can't say why. I'm guessing low rather than high because it feels like you can turn the area in front of the shimari into territory.

Four out of six bots chose 'b'. The other two suggested 'e' instead.

Specifically:

• LZ-242 preferred 'b' (42.6% winrate, 10k playouts), with 'e' in second place (42.5% winrate, 2.3k playouts).
• For LZ-ELF, 'b' was the only move seriously considered (ignoring things with only a few hundred playouts) but was more optimistic, with a winrate of 47.3%, 20k playouts.
• GX47 chose 'b' (47.5%, 22k playouts) but with 'e' as a close second (47.5%, 8.9k) and had 'a' not too far behind (46.1%, 4.8k).
• KataGo chose 'e' (45.5%, 10k, score -1.1), followed by 'a' (44.4%, 1.8k, -1.5) then 'b' (44.1%, 1.5k, -1.6) and 'c' (44.9%, 1.3k, -1.3).
• AQ chose 'a' (48.9%, 152k) followed by 'b' (49.6%, 69k) and 'c' (48.9%, 20k).
• Ray chose 'e' (46.5%, 124k) followed by 'b' (44.2%, 26k) and 'f' (45.7%, 12k)
• Noone chose 'd'. If 'b' and 'c' are playable, then why not 'd'?

This was with about a minute of thinking time for each engine.

Can we get any insights into the choices by looking at followup moves? Here are some sequences with KataGo evaluations (including people's suggestions above). It's interesting to see that some of the human-suggested moves are evaluated as pretty close to the bot moves, yet the bots don't explore them without prompting.



The invasion at 'e' seems to end in sente, so black still gets to play on the right first (but would you get the same answer if a different AI played it out?) I'd been wondering if top left and middle right were miai, but it appears not. When black plays in the middle right, white replies with O16 (but the continuations vary according to black's choice among 'a' through 'd').

The book move at 'a' looks about as good as 'e' when analysed in more depth. Black doesn't get territory in front of the shimari though, it turns into an interesting trade.

Finally, just for fun, I changed the shape of the bottom right shimari, and found that this does indeed change KataGo's preferred moves on the right (although the top left is still favourite).

$$c Position A, alternate reality.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . a . O . . X . . . . . . . . . |
$$ | . . . O . . . . . , . . . . X , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . b . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . c . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . X . . . . . O . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code

[go]$$c Position A, alternate reality.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . a . O . . X . . . . . . . . . |
$$ | . . . O . . . . . , . . . . X , X . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . b . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . c . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . X . . . . . O . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

• 'a': 47.0% winrate, 10k playouts, score -0.4
• 'b': 46.7% winrate, 1.8k playouts, score -0.5
• 'c': 46.0% winrate, 3.8k playouts, score -0.8

[xela]

B: Class 1 but becomes class 3 with meta-reasoning.
Pretty sure book wants to hane at head of 2 with a, and would have thought all bots would agree, but given xela selected this position as interesting I guess at least one of them doesn't want to play it, but probably most do. Or maybe he did want to include a unanimous agreement one as an example!

Have you by any chance been watching (or reading) The Princess Bride?

I'll get to this in a day or two, sorry to keep you in suspense!

[Knotwilg]

LZ's variations on Position A, with my own comments (she speaks in sequences only)

[Bill Spight]

It's interesting to see that some of the human-suggested moves are evaluated as pretty close to the bot moves, yet the bots don't explore them without prompting.

Path dependency in learning, both in human and bots. The human learning is cultural, as it takes place over many lifetimes.

One interesting thing is how close different alternatives are in winrate. We can't really say that one move is better than another. Ono of those moves, that is. Unlike some amateurs claim, the opening does matter.

Edit: It seems to me that bots frequently make high extensions, particularly long ones. Probably for them those long extensions are not really territorial moves.