Life In 19x19
http://www.lifein19x19.com/

Opening problems for AI: Problem 22
http://www.lifein19x19.com/viewtopic.php?f=15&t=17621
Page 1 of 1

Author:  Bill Spight [ Tue Jul 07, 2020 7:09 am ]
Post subject:  Opening problems for AI: Problem 22

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. :)

Author:  Harleqin [ Tue Jul 07, 2020 8:19 am ]
Post subject:  Re: Opening problems for AI: Problem 22

Press lower right, press upper left, then two-space high shimari upper right. Of course, White might disagree…

Author:  Bill Spight [ Wed Jul 08, 2020 3:40 am ]
Post subject:  Re: Opening problems for AI: Problem 22

Click Here To Show Diagram Code
[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. :)

Author:  Harleqin [ Wed Jul 08, 2020 8:30 am ]
Post subject:  Re: Opening problems for AI: Problem 22

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.

Author:  Harleqin [ Wed Jul 08, 2020 8:49 am ]
Post subject:  Re: Opening problems for AI: Problem 22

Oh, wow. Reminds me of an ancient joseki starting with the, um, 0-space high pincer. Lotus something?

Author:  dhu163 [ Fri Jun 04, 2021 10:28 am ]
Post subject:  Re: Opening problems for AI: Problem 22

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

Page 1 of 1 All times are UTC - 8 hours [ DST ]
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/