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 Post subject: Opening problems for AI: Problem 22
Post #1 Posted: Tue Jul 07, 2020 7:09 am 
Honinbo

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Click Here To Show Diagram Code
[go]$$Wcm8 White to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . . . X . . . . . . O . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

A problem early in the opening. There are a number of textbook plays to choose from. The one White chose loses 16½% to par, according to Elf. Elf's top choice may come as a surprise, and other bots may disagree. :)

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The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.

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 Post subject: Re: Opening problems for AI: Problem 22
Post #2 Posted: Tue Jul 07, 2020 8:19 am 
Lives in sente
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Press lower right, press upper left, then two-space high shimari upper right. Of course, White might disagree…

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This post by Harleqin was liked by: Bill Spight
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 Post subject: Re: Opening problems for AI: Problem 22
Post #3 Posted: Wed Jul 08, 2020 3:40 am 
Honinbo

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[go]$$Wcm8 Yasui Chitetsu (W) vs. Honinbo Dosaku, 1668-10-03a
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . 1 . . . . . 2 . . . . . |
$$ | . . O , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . a . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . . . X . . . . . . O . . X . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Chitetsu left the top right corner and the bottom left corner as miai and played a pincer in the top left corner. That's a reasonable strategy, except that, starting with AlphaGo, today's top bots do not like the early pincer, as a rule. Elf docks this pincer 16½% to par. Dosaku then enclosed the top right corner, another reasonable choice, which Elf docks 13% to par. :shock: Elf, along with Harleqin, prefers the press at a in the bottom right instead.

Click Here To Show Diagram Code
[go]$$Wcm8 Mainline for :w8:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , X . . |
$$ | . . 3 2 . . . . . . . . . . . . . . . |
$$ | . . . 4 . . . . . . . . . . . . . . . |
$$ | . . 5 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . 8 7 9 . . . |
$$ | . . . , . . . . . , . . . 1 6 , O . . |
$$ | . . . . X . . . . . . O . . X . a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

I don't know about other bots, but for :w8: Elf prefers the shoulder hit against :bc:, which has the advantage of averting the press at 16. :b13:, a, and :b11: are possible replies, but Elf slightly prefers the press at :b9: in the top left corner. Then Black returns to play :b13: in the bottom right. :w14: blocks, :b15: cuts, and then White pulls back with :w16:.

Click Here To Show Diagram Code
[go]$$Bcm17 Mainline for :w8:, continued
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , X . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . a . . . . . |
$$ | . . . . . . . . . . . . 7 X O O . . . |
$$ | . . . , . . . . . , . . 1 O B , O . . |
$$ | . . . . X . . . . . . O 3 2 B . . . . |
$$ | . . . . . . . . . . . . 5 4 6 . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Black now sacrifices the :bc: stones in the corner. For :b23: Elf has a slight preference for a, but the solid connection is sound.

The press from the 5-3 against the 3-4 is a real workhorse. :)

_________________
The Adkins Principle:
At some point, doesn't thinking have to go on?
— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.


Last edited by Bill Spight on Wed Jul 08, 2020 9:00 am, edited 1 time in total.
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 Post subject: Re: Opening problems for AI: Problem 22
Post #4 Posted: Wed Jul 08, 2020 8:30 am 
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Oh, it's White to play. Then I'd be inclined to play kosumi in the lower right. Actually, I'd want to enter lower left, but then Black presses on both sides and attacks the lone stone on the lower side. So, the kosumi lends some support, prevents the press, keeps the black stone weak(ish) and maybe even makes miai of approaching/entering the lower left and upper right.

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This post by Harleqin was liked by: Bill Spight
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 Post subject: Re: Opening problems for AI: Problem 22
Post #5 Posted: Wed Jul 08, 2020 8:49 am 
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Oh, wow. Reminds me of an ancient joseki starting with the, um, 0-space high pincer. Lotus something?

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 Post subject: Re: Opening problems for AI: Problem 22
Post #6 Posted: Fri Jun 04, 2021 10:28 am 
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Speculatively:
Current position:
1. C3 (or C4) is obvious, but clearly too obvious given the comment.
2. So lower right is the tensest situation. W's AI punishment is at O4 I think. Traditional play is Q3 or Q6.

Opp to play
1. Press on lower right then pincer (or even just shimari lower left) is severe.

Past:
1. W getting extra move in lower right probably means W marginally gains.

Check:
1. seen before

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