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Offline Bill Spight
 Post subject: Opening problems for AI: Problem 43
Post #1 Posted: Mon Aug 10, 2020 7:33 pm 
Honinbo

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Only move problem.

White to play.

Go Diagram
Where is White's only move?
Click Here To Show Diagram Code
[go]$$Wcm18 Where is White's only move?
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . . . . . . . . . . . . . . . |
$$ | . 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.

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Offline Uberdude
 Post subject: Re: Opening problems for AI: Problem 43
Post #2 Posted: Mon Aug 10, 2020 11:38 pm 
Judan

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Given the hint it's the only move it's got to be d4, and if with 2 empty corners it'd be only move to me too as taking the reverse sente means you can still get last empty corner tedomari, but with 3 empty corners d4 allows black to get the last one. I suppose the drop in value from an empty corner to an approach / 3-3 invasion is not as big as the loss white suffers in sente of letting black push to ruin the shape.

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Offline Knotwilg
 Post subject: Re: Opening problems for AI: Problem 43
Post #3 Posted: Tue Aug 11, 2020 1:54 am 
Oza
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Two possibilities:

Go Diagram
Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . . . . . . . . . . . . . . . |
$$ | . X X 1 . . . . . , . . . . . , . . . |
$$ | . 2 O . O . X . . . . . . . . . . . . |
$$ | . . 3 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


The question is: is :w3: necessary?

Go Diagram
Where is White's only move?
Click Here To Show Diagram Code
[go]$$Wc Where is White's only move?
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . 6 . . . . . . . . . . . . . |
$$ | . X X 1 . . . . . , . . . . . , . . . |
$$ | . 2 O 5 O . X . . . . . . . . . . . . |
$$ | . . 4 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


If White plays :w3: elsewhere then the group becomes a floating one. If :w5: at :b6: or ko, it's not much better.

Go Diagram
Where is White's only move?
Click Here To Show Diagram Code
[go]$$Wc Where is White's only move?
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . . . . . . . . . . . . . . . |
$$ | . X X 2 3 . . . . , . . . . . , . . . |
$$ | . 1 O . O . X . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


This is more clearly gote for White.
The result is territorially better than the gote variation above.
I read that Uberdude finds White's shape ruined.
I'm not sure which is better.

Go Diagram
Follow up
Click Here To Show Diagram Code
[go]$$Bc Follow up
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | 3 O X O 1 4 . . . . . . . . . . . . . |
$$ | . X X X O . . . . , . . . . . , . . . |
$$ | . O O 2 O . X . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Right after this, there's ladder aji. White may decide to sacrifice the 4 stones. The first variation doesn't have this aji.

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Offline Joaz Banbeck
 Post subject: Re: Opening problems for AI: Problem 43
Post #4 Posted: Tue Aug 11, 2020 5:46 am 
Judan
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This seems to preserve white's eye space as well as any move.

Go Diagram
Click Here To Show Diagram Code
[go]$$Wcm18
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . . . . . . . . . . . . . . . |
$$ | . X X , . . . . . , . . . . . , . . . |
$$ | . . O . O . X . . . . . . . . . . . . |
$$ | . . W . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

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Offline Kirby
 Post subject: Re: Opening problems for AI: Problem 43
Post #5 Posted: Tue Aug 11, 2020 7:48 am 
Honinbo

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Tygem: 커비라고해
I'd just play here:
Go Diagram
Click Here To Show Diagram Code
[go]$$Wcm18
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . W . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . . . . . . . . . . . . . . . |
$$ | . X X , . . . . . , . . . . . , . . . |
$$ | . . O . O . X . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


or maybe here:
Go Diagram
Click Here To Show Diagram Code
[go]$$Wcm18
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . W . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . . . . . . . . . . . . . . . |
$$ | . X X , . . . . . , . . . . . , . . . |
$$ | . . O . O . X . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Given black's potential for influence on the left..

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Offline Harleqin
 Post subject: Re: Opening problems for AI: Problem 43
Post #6 Posted: Tue Aug 11, 2020 9:33 am 
Lives in sente
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I'd play hoshi in the top right. Taking one of an uneven number of open corners is quite high in priority, and the lower left feels stable enough to me. Top right also protects the ladder. If White took a different corner, Black taking the top right would activate the ladder, so the remaining corners would not be miai at all.

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Offline Joaz Banbeck
 Post subject: Re: Opening problems for AI: Problem 43
Post #7 Posted: Tue Aug 11, 2020 12:34 pm 
Judan
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I'm highly skeptical of tenukiing to a corner. With Bill's #42 still in mind, I'm seeing honte moves in my sleep.

But I don't like playing the corner either. My gut says that a five point move in gote close to black's strength can't be best.

Perhaps there is a possibility in between.

Go Diagram
A compromise: not corner, but not tenuki.
Click Here To Show Diagram Code
[go]$$Wcm18 A compromise: not corner, but not tenuki.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . . . . . . . . . . . . . . . |
$$ | . X X , . . . W . , . . . . . , . . . |
$$ | . . O . O . X . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

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Offline Uberdude
 Post subject: Re: Opening problems for AI: Problem 43
Post #8 Posted: Tue Aug 11, 2020 2:23 pm 
Judan

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Joaz Banbeck wrote:
This seems to preserve white's eye space as well as any move.

Go Diagram
Click Here To Show Diagram Code
[go]$$Wcm18
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . . . . . . . . . . . . . . . |
$$ | . X X , . . . . . , . . . . . , . . . |
$$ | . . O . O . X . . . . . . . . . . . . |
$$ | . . W . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Not as well as this move, which I can only see advantages and no disadvantages over your move, except perhaps making the opponent lose concentration from the shock of such a bizarre move! How can you go from so right on the last problem to so wrong here?!

Go Diagram
Click Here To Show Diagram Code
[go]$$Wcm18
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . . . . . . . . . . . . . . . |
$$ | . X X , . . . . . , . . . . . , . . . |
$$ | . W O . O . X . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

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Offline ez4u
 Post subject: Re: Opening problems for AI: Problem 43
Post #9 Posted: Tue Aug 11, 2020 3:40 pm 
Oza
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Bill Spight wrote:
Only move problem.

White to play...
Enjoy! :)

Huh? But you said... :scratch:
Bill Spight wrote:
"Tenuki is always an option!"

:D

_________________
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"Short-lived are both the praiser and the praised, and rememberer and the remembered..."
- Marcus Aurelius; Meditations, VIII 21

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Offline Bill Spight
 Post subject: Re: Opening problems for AI: Problem 43
Post #10 Posted: Tue Aug 11, 2020 4:11 pm 
Honinbo

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ez4u wrote:
Bill Spight wrote:
Only move problem.

White to play...
Enjoy! :)

Huh? But you said... :scratch:
Bill Spight wrote:
"Tenuki is always an option!"

:D

:lol:

_________________
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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Offline Gomoto
 Post subject: Re: Opening problems for AI: Problem 43
Post #11 Posted: Tue Aug 11, 2020 4:17 pm 
Gosei

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A hideous insidious riddle it is

I thought about B3

(mild) spoiler
but choose your corner
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Offline Bill Spight
 Post subject: Re: Opening problems for AI: Problem 43
Post #12 Posted: Wed Aug 12, 2020 9:15 pm 
Honinbo

Posts: 10905
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The game is GoGoD 1600-00-00d, between Honinbo Sansa (W) and Rigen. Sansa's play in the top right corner got 0 rollouts, for a loss of 17½% to par, according to Elf.

Game continuation

Go Diagram
Mistake after mistake
Click Here To Show Diagram Code
[go]$$Wcm18 Mistake after mistake
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . d . . . . . . . . . . . . b . . |
$$ | . . . c . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . 1 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . 4 . . . . . . . . . . . . . |
$$ | . X X 2 3 . . . . , . . . . . a e . . |
$$ | . . O . O . X . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Rigen pushed through with :b19: and then peeped with :b21:, another mistake that loses 14½% to par. Elf prefers to play in another corner at one of a - e.

Go Diagram
Mainline variation for :b21:
Click Here To Show Diagram Code
[go]$$Bcm21 Mainline variation for :b21:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . 4 . 3 . . |
$$ | . . 2 , . . . . . , . . . . 6 5 . . . |
$$ | . . . . . . . . . . . . . . . O 7 . . |
$$ | . . . . . . . . . . . . . . . 8 9 . . |
$$ | . . . . . . . . . . . . . . . 0 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . . . . . . . . . . . . . . . |
$$ | . X X X O . . . . , . . . . . 1 . . . |
$$ | . . O . O . X . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Elf's top choice for :b21: is on the 4-4 in the bottom right corner, with 68.8k rollouts. After :w22: occupies the last open corner Black invades the top right corner with :b23:. A standard joseki follows, where White builds a wall and Black makes territory.

Go Diagram
Mainline variation for :b21:, continued
Click Here To Show Diagram Code
[go]$$Bcm31 Mainline variation for :b21:, continued
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . a d . . . . . . O . X . . |
$$ | . . O b . . . . . , . . . . O X . . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O X . . |
$$ | . . . . . . . . . . . . . . . O 1 . . |
$$ | . . . . . . . . . . . . . . . 2 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . c 3 . . . . . . . . . . . . |
$$ | . X X X O . . . . , . . . . . X . . . |
$$ | . 4 O . O . X . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Elf's choice for :b33: is the one space jump, but a - d are all playable. :w34: plays to secure the corner.

Only play: Solid wall

Go Diagram
Solid wall. Only play.
Click Here To Show Diagram Code
[go]$$Wcm18 Solid wall. Only play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . . . . . . . . . . . . . . . |
$$ | . X X 1 . . . . . , . . . . . , . . . |
$$ | . . O . O . X . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Elf's choice, the connection at :w18:, gets a whopping 143.8k rollouts. No other play gets as many as 1500 rollouts. If there is another reasonable play, Elf did not find it.

Go Diagram
Mainline variation
Click Here To Show Diagram Code
[go]$$Bcm19 Mainline variation
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 1 . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . 3 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . . . . . . . . . . . 9 7 . . |
$$ | . X X O . . . . . , . . . . 8 5 2 . . |
$$ | . . O . O . X . . . 4 . . . . 6 0 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

After :w18: the players occupy the open corners, and then :w22: plays a three space pincer on the bottom side. :b23: replies with an attachment against :w20:. :w24: hanes on the 3d line and then :b25: plays a counter-hane towards the right side. Atari, connect-connect follow.

Go Diagram
Mainline variation, continued
Click Here To Show Diagram Code
[go]$$Bcm29 Mainline variation, continued
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . . . . . 6 . . . . . X X . . |
$$ | . X X O . . . 2 . 4 3 5 . . O X O . . |
$$ | . 1 O . O . B . . . O . . . . O O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:b29: pushes into the bottom left corner and then :w30: plays a shoulder hit against the long ago pincer, :bc:. Then :b31: plays a 4th line contact play to commence reducing the bottom side.

We have had an earlier problem in this series where the connection to make a solid wall was the answer. But in this case that choice got a humungous number of rollouts, with no other play worth mentioning. I couldn't resist. ;) In this problem the pincer stone was quite close, too close for comfort to a solid wall, and there were no other distractions, except the open cornerns.

Not that White hasn't lost ground in the process of sacrificing two stones on the left side, but now that we have come so far, making a strong wall looks like the best bet by far.

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— Winona Adkins

Visualize whirled peas.

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Offline yoyoma
 Post subject: Re: Opening problems for AI: Problem 43
Post #13 Posted: Wed Aug 12, 2020 10:10 pm 
Lives in gote

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Go Diagram
katago evals:
Click Here To Show Diagram Code
[go]$$Wcm18 katago evals:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . a . . . . . , . . . . . c . . . |
$$ | . . . . . . . . . . . . . . . d . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . . . . . . . . . . . . . . . |
$$ | . X X b . . . f . , . . . . . , . . . |
$$ | . e O . O . X . . . . . . . . . . . . |
$$ | . . g . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Code:
a - 4-4 upper left  : White 49.5%  -0.1pts  (Kata's choice)
b - solid connect   : White 47.1%  -0.2pts  (Elf's "only move")
c - 4-4 upper right : White 46.8%  -0.2pts
d - 5-4 upper right : White 41.5%  -0.9pts  (Game move)
e - shoulder hit    : White 43.6%  -0.7pts
f - block corner    : White 36.1%  -1.7pts
g - descend         : White  4.3% -10.2pts


Kata is not so insistent about connecting. It's a good move, but so is taking the corners. If White takes a corner, Kata also thinks Black can choose taking a corner or playing the forcing push.

This post by yoyoma was liked by 2 people: Bill Spight, ez4u
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Offline Bill Spight
 Post subject: Re: Opening problems for AI: Problem 43
Post #14 Posted: Wed Aug 12, 2020 10:28 pm 
Honinbo

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yoyoma wrote:
Go Diagram
katago evals:
Click Here To Show Diagram Code
[go]$$Wcm18 katago evals:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . a . . . . . , . . . . . c . . . |
$$ | . . . . . . . . . . . . . . . d . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . . . . . . . . . . . . . . . |
$$ | . X X b . . . f . , . . . . . , . . . |
$$ | . e O . O . X . . . . . . . . . . . . |
$$ | . . g . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Code:
a - 4-4 upper left  : White 49.5%  -0.1pts  (Kata's choice)
b - solid connect   : White 47.1%  -0.2pts  (Elf's "only move")
c - 4-4 upper right : White 46.8%  -0.2pts
d - 5-4 upper right : White 41.5%  -0.9pts  (Game move)
e - shoulder hit    : White 43.6%  -0.7pts
f - block corner    : White 36.1%  -1.7pts
g - descend         : White  4.3% -10.2pts


Kata is not so insistent about connecting. It's a good move, but so is taking the corners. If White takes a corner, Kata also thinks Black can choose taking a corner or playing the forcing push.


This is great! :)

Elf apparently developed a blind spot that kept it from exploring alternatives. It is extremely rare for it to like a play so much that it gives it over 100k rollouts.

How many rollouts does KataGo give these different options?

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

Visualize whirled peas.

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Offline Uberdude
 Post subject: Re: Opening problems for AI: Problem 43
Post #15 Posted: Thu Aug 13, 2020 1:11 am 
Judan

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I've seen Elf (v2 I think) have a blindspot and some % winrate change when shown the shockingly unusual move 3 of a 3-4 point instead of a 4-4. Other bots are less blinkered and more reliable for analysis IMO.

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Offline Bill Spight
 Post subject: Re: Opening problems for AI: Problem 43
Post #16 Posted: Thu Aug 13, 2020 6:29 am 
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Uberdude wrote:
I've seen Elf (v2 I think) have a blindspot and some % winrate change when shown the shockingly unusual move 3 of a 3-4 point instead of a 4-4. Other bots are less blinkered and more reliable for analysis IMO.


Well, the bots are at present good tools to assist a human analyst, but I would not rely upon any computer program alone for analysis. They are not trained to be analysts. Now, lightvector has used human games in training KataGo to make it better for analysis, but the main impetus for bot development is to increase its overall playing strength. The same seems to be true for chess engines, some 25 years or so since the first superhuman engines appeared. Chess engines still have well known blind spots. :)

Ordinarily I would not be surprised that KataGo or any other bot would prefer a different play than Elf. From what little information I have, a concordance rate between bots of around 80% is not unexpected. I do expect bots to agree about sufficiently bad human errors, which is the case here. KataGo figures a winrate loss for Sansa's play at 8%, about half the loss that Elf figures, but that's in line with how differently they estimate winrates. I am however surprised that, having spent at least 143.8k rollouts on this position, Elf did not pick up KataGo's top choice and give it at least 1500 rollouts.

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— Winona Adkins

Visualize whirled peas.

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Offline ez4u
 Post subject: Re: Opening problems for AI: Problem 43
Post #17 Posted: Thu Aug 13, 2020 6:37 am 
Oza
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Bill Spight wrote:
yoyoma wrote:
Go Diagram
katago evals:
Click Here To Show Diagram Code
[go]$$Wcm18 katago evals:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . a . . . . . , . . . . . c . . . |
$$ | . . . . . . . . . . . . . . . d . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | X . X O . . . . . . . . . . . . . . . |
$$ | . X O O . . . . . . . . . . . . . . . |
$$ | . O X O . . . . . . . . . . . . . . . |
$$ | . X X b . . . f . , . . . . . , . . . |
$$ | . e O . O . X . . . . . . . . . . . . |
$$ | . . g . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Code:
a - 4-4 upper left  : White 49.5%  -0.1pts  (Kata's choice)
b - solid connect   : White 47.1%  -0.2pts  (Elf's "only move")
c - 4-4 upper right : White 46.8%  -0.2pts
d - 5-4 upper right : White 41.5%  -0.9pts  (Game move)
e - shoulder hit    : White 43.6%  -0.7pts
f - block corner    : White 36.1%  -1.7pts
g - descend         : White  4.3% -10.2pts


Kata is not so insistent about connecting. It's a good move, but so is taking the corners. If White takes a corner, Kata also thinks Black can choose taking a corner or playing the forcing push.


This is great! :)

Elf apparently developed a blind spot that kept it from exploring alternatives. It is extremely rare for it to like a play so much that it gives it over 100k rollouts.

How many rollouts does KataGo give these different options?


First, here is katago's policy. Elf's preferred play is high but not as high as the upper left.
Attachment:
Bill number 43 policy.jpg
Bill number 43 policy.jpg [ 131.65 KiB | Viewed 20315 times ]

Of course the PO's depend on how long we search. :)
But after 2.8 million... (note my komi was set to 6.5 points and therefore the winrates are quite different)
Attachment:
Bill number 43 analysis.jpg
Bill number 43 analysis.jpg [ 80.91 KiB | Viewed 20315 times ]

_________________
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"Short-lived are both the praiser and the praised, and rememberer and the remembered..."
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This post by ez4u was liked by: Bill Spight
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Offline Bill Spight
 Post subject: Re: Opening problems for AI: Problem 43
Post #18 Posted: Thu Aug 13, 2020 7:35 am 
Honinbo

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ez4u wrote:
First, here is katago's policy. Elf's preferred play is high but not as high as the upper left.
Attachment:
Bill number 43 policy.jpg

Of course the PO's depend on how long we search. :)
But after 2.8 million... (note my komi was set to 6.5 points and therefore the winrates are quite different)
Attachment:
Bill number 43 analysis.jpg


This is great, Dave! Many thanks. :salute: :salute: :salute:

Two comments. First, with only 521 playouts, KataGo's evaluation of Sansa's 5-4 move in the top right has a large margin of error. Elf does better in this regard, by inheriting the evaluation from its best reply to that move. I expect that yoyoma does even better, by making the play itself to get its evaluation with several thousand rollouts.

Second, even though I have no experience with KataGo, I think that the 3% winrate difference between KataGo's choice and Elf's, with 1.6M and 147K rollouts, respectively, puts Elf's choice in the doubtful category.

The fact that Elf concentrates on one play to the virtual exclusion of others indicates that it likes that play. However, that does not mean that other bots will like it much. Therefore, this will be the last "only move" problem.

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Visualize whirled peas.

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Offline Gomoto
 Post subject: Re: Opening problems for AI: Problem 43
Post #19 Posted: Thu Aug 13, 2020 7:39 am 
Gosei

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Quote:
Therefore, this will be the last "only move" problem.



The only move now ;-)

This post by Gomoto was liked by: Bill Spight
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Offline dhu163
 Post subject: Re: Opening problems for AI: Problem 43
Post #20 Posted: Mon Dec 26, 2022 9:10 am 
Lives in gote

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KGS: mathmo 4d
IGS: mathmo 4d
Speculatively:
Current position:
1. D4 is very standard. B3 is met by tenuki because D4 is already only threatening 13 points, half a move, and B has aji of E2 and F5. Later, B can still play D4 and D3 potentially in sente. The biggest difference is probably when B threatens the E5 cut, say if B has D8 later (though small). Even if B B3 is sente on W C2 later, the local side territory is similar +4 in centre, -4 on side if B G3 was dead. However, B3 has a clear loss in the centre. Sometimes B3 is correct, but that is mainly when B already say has a move at F2, or W does. Getting thick has its own extra value of connecting groups so that the groups is more moves away from death and may either tenuki more or play stronger counterattacks.

Opp to play
1. D4

Past:
1. This is usually premature for W to play like this and although G3 is misplaced, W is taking gote and B3 isn't sente.

Check:
1.
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