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Opening problems for AI: Problem 7
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Author:  Bill Spight [ Wed Jun 17, 2020 11:50 am ]
Post subject:  Opening problems for AI: Problem 7
Here is another surprisingly early move by Takagawa that Elf really, really does not like. It comes from GoGoD 1952-01-09a, vs. Kitani. Takagawa was on his way to his first Honinbo title.

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

The bottom left corner is pretty much a dead giveaway that Kitani was playing White. It is one of his trademark joseki.

There are many possibilities, so different AI may well have different preferences. But I doubt if any of them likes Takagawa's play.
Author:  Bill Spight [ Wed Jun 17, 2020 12:14 pm ]
Post subject:  Re: Opening problems for AI: Problem 7
Click Here To Show Diagram Code
[go]$$Bcm13 Standard extension
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . O . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . X . . . |
$$ | . . X X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 1 . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , X . . . . , . . . . . X . . . |
$$ | . . . . O X . . . . . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:b13: is a standard, textbook play, but Elf reckons that it loses 21½% to a play against the bottom left corner.


Click Here To Show Diagram Code
[go]$$Bcm13 Bottom side moyo
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . O . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . X . . . |
$$ | . . X X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 4 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . 3 . . . . . . . . . . . . . . |
$$ | . . O 2 X . . . . , . . . . . X . . . |
$$ | . . . . O X . . . . . . 5 . . . . . . |
$$ | . . . . O 1 . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

In Elf's mainline variation, :b13: blocks White's group from the bottom side, and after White solidifies the corner, :b17: stakes out the bottom side. It's an early moyo, but Elf still likes it. ;) I think that this line illustrates that the Black extension on the left side is just not big enough, by comparison.

Click Here To Show Diagram Code
[go]$$Wcm14 Elf's reply
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . O . . . . . . . . . . 5 . . |
$$ | . . O , . . . . . , . . . . . X . . . |
$$ | . . X X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O 2 X 1 . . . , . . . . . X . . . |
$$ | . . 3 . O X . . . . . . . 4 . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

In the actual game, Kitani played :w14: at 15, but Elf prefers the cut by 13%. :b17: still encloses the bottom right corner, but without forming a framework.
Author:  RobertJasiek [ Wed Jun 17, 2020 1:55 pm ]
Post subject:  Re: Opening problems for AI: Problem 7
"standard, textbook play" says nothing about whether it is a locally or globally considered play. The extension is mainly locally motivated.

My applicable global textbook-like advice is: defend the weakest important group first. The lower black group was weaker than the left black group.
Author:  Uberdude [ Thu Jun 18, 2020 2:08 am ]
Post subject:  Re: Opening problems for AI: Problem 7
A year ago Jean-Sébastien Lechasseur found a very normal opening position in which LeelaZero with 2 million playouts preferred Kitani's exotic joseki:

https://www.facebook.com/groups/go.igo. ... 599366514/

Pics copied for those who avoid facebook:

Attachment:
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mainline:
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lzkitani2.jpg [ 83.41 KiB | Viewed 7460 times ]
Author:  Bill Spight [ Thu Jun 18, 2020 3:47 am ]
Post subject:  Re: Opening problems for AI: Problem 7
Thanks, Uberdude. :)

Interesting that White's reply to the Black sagari is to block on the 2d line. The main replies are the stand on the 5-5 or the hanging connection on the 5-6, but Kitani also shows the block in his book, Watashi no Go, vol. 2. :)
Author:  Harleqin [ Fri Jun 19, 2020 8:56 am ]
Post subject:  Re: Opening problems for AI: Problem 7
“Watashi no Go” is quite a title… ^^
Author:  dhu163 [ Fri Jun 04, 2021 9:56 am ]
Post subject:  Re: Opening problems for AI: Problem 7
Speculatively:
Current position:
1. Locally, F2, F4, E5 come to mind. F2 seems to be most common to properly punish W's poor shape, but I worry about making it work with the left. How about F2 D4 E5 D6 C11 J4
2. On the left, D10 or C10 seem natural. D10 F4 O3

Opp to play
1. In lower left, W cut is a move but not very efficient when already on 2nd line. My instinct is C11/D12 ish

Past:
1. Lower left means B probably slightly ahead

Check:
1. close in some places
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