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Opening problems for AI: Problem 43
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Author:  Bill Spight [ Mon Aug 10, 2020 7:33 pm ]
Post subject:  Opening problems for AI: Problem 43

Only move problem.

White to play.

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


Enjoy! :)

Author:  Uberdude [ Mon Aug 10, 2020 11:38 pm ]
Post subject:  Re: Opening problems for AI: Problem 43

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.

Author:  Knotwilg [ Tue Aug 11, 2020 1:54 am ]
Post subject:  Re: Opening problems for AI: Problem 43

Two possibilities:

Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
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$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . 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?

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.

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

Click Here To Show Diagram Code
[go]$$Bc Follow up
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
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$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X X . . . . . . . . . . . . . . . . |
$$ | 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.

Author:  Joaz Banbeck [ Tue Aug 11, 2020 5:46 am ]
Post subject:  Re: Opening problems for AI: Problem 43

This seems to preserve white's eye space as well as any move.

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

Author:  Kirby [ Tue Aug 11, 2020 7:48 am ]
Post subject:  Re: Opening problems for AI: Problem 43

I'd just play here:
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:
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..

Author:  Harleqin [ Tue Aug 11, 2020 9:33 am ]
Post subject:  Re: Opening problems for AI: Problem 43

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.

Author:  Joaz Banbeck [ Tue Aug 11, 2020 12:34 pm ]
Post subject:  Re: Opening problems for AI: Problem 43

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.

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

Author:  Uberdude [ Tue Aug 11, 2020 2:23 pm ]
Post subject:  Re: Opening problems for AI: Problem 43

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

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?!

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]

Author:  ez4u [ Tue Aug 11, 2020 3:40 pm ]
Post subject:  Re: Opening problems for AI: Problem 43

Bill Spight wrote:
Only move problem.

White to play...
Enjoy! :)

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

:D

Author:  Bill Spight [ Tue Aug 11, 2020 4:11 pm ]
Post subject:  Re: Opening problems for AI: Problem 43

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:

Author:  Gomoto [ Tue Aug 11, 2020 4:17 pm ]
Post subject:  Re: Opening problems for AI: Problem 43

A hideous insidious riddle it is

I thought about B3

(mild) spoiler
but choose your corner

Author:  Bill Spight [ Wed Aug 12, 2020 9:15 pm ]
Post subject:  Re: Opening problems for AI: Problem 43

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

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.

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.

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

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

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.

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.

Author:  yoyoma [ Wed Aug 12, 2020 10:10 pm ]
Post subject:  Re: Opening problems for AI: Problem 43

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.

Author:  Bill Spight [ Wed Aug 12, 2020 10:28 pm ]
Post subject:  Re: Opening problems for AI: Problem 43

yoyoma wrote:
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?

Author:  Uberdude [ Thu Aug 13, 2020 1:11 am ]
Post subject:  Re: Opening problems for AI: Problem 43

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.

Author:  Bill Spight [ Thu Aug 13, 2020 6:29 am ]
Post subject:  Re: Opening problems for AI: Problem 43

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.

Author:  ez4u [ Thu Aug 13, 2020 6:37 am ]
Post subject:  Re: Opening problems for AI: Problem 43

Bill Spight wrote:
yoyoma wrote:
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 11504 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 11504 times ]

Author:  Bill Spight [ Thu Aug 13, 2020 7:35 am ]
Post subject:  Re: Opening problems for AI: Problem 43

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.

Author:  Gomoto [ Thu Aug 13, 2020 7:39 am ]
Post subject:  Re: Opening problems for AI: Problem 43

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



The only move now ;-)

Author:  dhu163 [ Mon Dec 26, 2022 9:10 am ]
Post subject:  Re: Opening problems for AI: Problem 43

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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