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 Post subject: Opening problems for AI: Problem 23
Post #1 Posted: Wed Jul 08, 2020 2:33 am 
Honinbo

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In this game Black made a textbook play that Elf reckons loses 15½% to par.

Click Here To Show Diagram Code
[go]$$Bcm15 Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . , O . . . . , . . . . . X . . . |
$$ | . . X . O X . . . . . . . . . . . . . |
$$ | . . . . X O O . . . . . . . . . . . . |
$$ | . . X . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . O . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Enjoy! :)

_________________
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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 23
Post #2 Posted: Wed Jul 08, 2020 3:34 am 
Judan

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Click Here To Show Diagram Code
[go]$$B
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . a . . . . . . . . . . . . . |
$$ | . . . , O . . . . , . . . . . X . . . |
$$ | . . X . O X 2 . . . . . . . . . . . . |
$$ | . . . . X O O . . . . . . . . . . . . |
$$ | . . X . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 1 . O . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . O . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Maybe this was the textbook sequence? Black 1 at a also comes to one's mind.

Click Here To Show Diagram Code
[go]$$B
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . 1 . . . . . |
$$ | . . . , O . . . . , . . . . . X . . . |
$$ | . . X . O X . . . . . . . . . . . . . |
$$ | . . . . X O O . . . . . . . . . . . . |
$$ | . . X . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . O . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


I expect AI to play this.


This post by RobertJasiek was liked by: Bill Spight
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 Post subject: Re: Opening problems for AI: Problem 23
Post #3 Posted: Wed Jul 08, 2020 3:53 am 
Honinbo

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In this series I do not generally expect the top bots to agree on the next play, but I do expect them to agree that the human play was a mistake. :)

_________________
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— Winona Adkins

Visualize whirled peas.

Everything with love. Stay safe.


Last edited by Bill Spight on Sat Jun 05, 2021 10:30 am, edited 1 time in total.
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 Post subject: Re: Opening problems for AI: Problem 23
Post #4 Posted: Wed Jul 08, 2020 7:24 am 
Lives in gote

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Click Here To Show Diagram Code
[go]$$Bcm15 Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . c . . . . . . . . . . . . . |
$$ | . . . , O . . . . , . . . . . X . . . |
$$ | . . X . O X . . . . . . . . . . . . . |
$$ | . . . . X O O . . . . . . . . . . . . |
$$ | . . X . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . a . O . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . b . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . d . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . O . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


I've been lurking for a long time, but Bill's excellent series and ready access to a desktop brought me out.

Like Robert my first reaction was that black played 'a'. After more reflection I figured that, with the two adjacent corners for support, 'b' or 'c' was more likely. Based on Uberdude's bible, however, I'd wager that the computer would play 'd'.


This post by pwaldron was liked by 2 people: Bill Spight, Harleqin
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 Post subject: Re: Opening problems for AI: Problem 23
Post #5 Posted: Wed Jul 08, 2020 11:51 am 
Honinbo

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The game is GoGoD 2003-02-19g, the 4th game of the Kisei final between O Rissei (W) and Yamashita Keigo.

Click Here To Show Diagram Code
[go]$$Bcm15 Thick and slow
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . a . . . . . . . . . . . . . |
$$ | . . 2 , O . . . . , . . . . . X . . . |
$$ | . . X . O X . . . . . . . . . . . . . |
$$ | . . . . X W W . . . . . . . . . . . . |
$$ | . . X . X 1 . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . O . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Yamashita's :b15: was new to me. When I was learning go, a was the tesuji to know, played as a sacrifice to weaken or even capture the :wc: stones. Elf reckons that :b15: loses 15½% to par, while a loses only 15%. :shock: The correct answer is none of the above. O replied with :w16: securing the corner and threatening the Black group. Elf reckons that :w16: loses 18½% to par! :shock: :shock:

Click Here To Show Diagram Code
[go]$$Wcm16 Mainline for :w16:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . , O . . . . , . . . . . X . . . |
$$ | . . X . O X . . . . . . . . . . . . . |
$$ | . . . . X O O . . . . . . . . . . . . |
$$ | . . X . X X . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . W . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . b a . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 9 . . . . . . . . . . . . . . . . |
$$ | . . 1 6 . . . . . . . . . . . . . . . |
$$ | . 5 4 7 3 . . . . , . . . . . O . . . |
$$ | . . 8 X . 0 . . . . . . . 2 . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:w16: approaches the bottom left corner, with :wc: as backup. :b17: approaches the bottom right corner. (a and b are also playable, in order of preference.) :w18: plays the press. :b19: does not crawl on the 3d line, but resists. An AI joseki follows.


Click Here To Show Diagram Code
[go]$$Wcm26 Mainline for :w16:, continued
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . , O . . . . , . . . . . X . . . |
$$ | . . X . O X . . . . . . . . . . . . . |
$$ | . . . . X O O . . . . . . . . . . . . |
$$ | . . X . X X . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . O X . . . 5 7 . . . . . . . . . . |
$$ | . O X O O 1 3 4 6 8 . . . . . O . . . |
$$ | . . X X . X 2 . . . . . . 2 . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

White pushes to build a wall in exchange for territory.

Better play for :b15:. Enclose the bottom left corner.

Click Here To Show Diagram Code
[go]$$Bcm15 The Black group is OK.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . b . . . . . |
$$ | . . . , O . . . . , . . . . . X . . . |
$$ | . . X . O X . . . . . . . . . . . . . |
$$ | . . . . X O O . . . . . . . . . . . . |
$$ | . . X . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 1 a . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . O . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Elf's top choice is to play the large knight's enclosure of the bottom left corner, with a in second place, and certainly playable. No other play is on Elf's radar, i.e., gets more than 1.5k rollouts. I would not be too surprised if another top bot chose b. In any event, it is not urgent to do anything about the Black group in the top left corner.


Click Here To Show Diagram Code
[go]$$Bcm15 Mainline for :b15:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . 3 . . 2 . . . . . |
$$ | . . . , O . . 4 . , . . . . . X . . . |
$$ | . . X . O X . . . . . . . . . . . . . |
$$ | . . . . X O O . . . . . . . . . a . . |
$$ | . . X . X . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 1 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . O . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

This same position occurs in GoGoD 2000-01-29b, between Cho Chikun (W) and Kataoka Satoshi. I chose to use its variations, as they have many more rollouts (26.4k) than those in the O vs. Yamashita game.

After :b15: encloses the bottom left corner, the top right corner becomes important. (White could also approach at a.) :w16: approaches from the top side, :b17: pincers, and :w18: bolsters White's position there, in a nice flow of the stones.

Click Here To Show Diagram Code
[go]$$Bcm15 Variation 2
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 6 8 . . . . . . . . . . . . . . . . |
$$ | . 3 7 O . . . 9 . . . . . . . . . . . |
$$ | . . . , O . 0 . . , . . . . . X . . . |
$$ | . . X . O X . . . . . . . . . . . . . |
$$ | . . . . X O O . . . . . . . . . . . . |
$$ | . 5 X . X . . . . . . . . . . . . . . |
$$ | . . 4 . . 2 . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 1 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . O . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Starting with :w16: White boxes Black in, but then :b23: gets to play on the top side with sente. Not that getting boxed in is good, but in exchange Black gets :b15: and takes sente.

_________________
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 23
Post #6 Posted: Wed Jul 08, 2020 1:31 pm 
Gosei
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Click Here To Show Diagram Code
[go]$$B Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . , O . . . . , . . . . . X . . . |
$$ | . . X . O X . . . . . . . . . . . . . |
$$ | . . . . X O O . . . . . . . . . . . . |
$$ | . . X . X . . . . . . . . . . . . . . |
$$ | . . . . . c . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . 1 . . . . . . . . . . . . . . . |
$$ | . . . a . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . b . . . . . . . . . . . . . . . |
$$ | . . . c . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . O . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


I expect this is the textbook play, or maybe A. Reinforcing a 3-4 corner stone is LZ's opening gospel, so I expect B (or even C) is the better move.
White's possible move at C troubles me though. Maybe that's the textbook play?

Click Here To Show Diagram Code
[go]$$Bcm15 Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . , O . . . . , . . . . . X . . . |
$$ | . . X . O X . . . . . . . . . . . . . |
$$ | . . . . X O O . . . . . . . . . . . . |
$$ | . . X . X . . . . . . . . . . . . . . |
$$ | . . . . . 2 . . . . . . . . . . . . . |
$$ | . 3 . O . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 1. . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . O . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Robert's suggestion for the classical move at :b3: here looks submissive, even after the :b1: - :w2: exchanvge.


This post by Knotwilg was liked by 2 people: Bill Spight, pwaldron
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 Post subject: Re: Opening problems for AI: Problem 23
Post #7 Posted: Fri Jun 04, 2021 10:29 am 
Lives in gote

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Rank: UK 2d Dec15
KGS: mathmo 4d
IGS: mathmo 4d
Speculatively:
Current position:
1. D6 comes to mind as a pincer shimari. B's group in the upper left already has a one space extension and access to corner and side, though it is short on liberties.
2. G16 to fight might be exciting but W F12 seems dangerous especially as W still has C16 or B16. In that case perhaps F17 is a tesuji. Or just sacrifice with H17?
3. F12 is proper but seems too slow when W can settle comfortably on left.

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. By memory, I think this joseki is meant to be good for B but I haven't seen it for many years.

Check:
1. close enough

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