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 Post subject: Opening problems for AI: Problem 17
Post #1 Posted: Thu Jul 02, 2020 7:43 am 
Honinbo

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Today's problem comes frome GoGoD 1921-07-05a, between Segoe Kensaku (W) and Karigane Junichi, both 6 dan. Elf reckons that :b25: lost 22% in winrate, assuming 7½% komi. OC, this was a no komi game. Both the human play and the AI choice are textbook plays. :)

Click Here To Show Diagram Code
[go]$$Bcm25 Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . X . . X . . . O . . . . |
$$ | . . . , . . . . . , X O . . . , X . . |
$$ | . . . O . . . . . . X O . . . X . . . |
$$ | . . . . . . . . . . . O . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . O . . |
$$ | . . X , . . . . . , . . . . X , X . . |
$$ | . . . . O . . . . O . . O . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

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

Visualize whirled peas.

Everything with love. Stay safe.


Last edited by Bill Spight on Fri Jul 03, 2020 5:37 am, edited 1 time in total.
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 Post subject: Re: Opening problems for AI: Problem 17
Post #2 Posted: Thu Jul 02, 2020 9:33 am 
Honinbo

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Click Here To Show Diagram Code
[go]$$Bcm25 Karigane claims the corner
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . X . . X . . . O . . . . |
$$ | . . . , . . . . . , X O . . . , X . . |
$$ | . . . O . . . . . . X O . . . X . . . |
$$ | . . . . . . . . . . . O . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . O . . |
$$ | . . X , 2 . . . . , . . . . X , X . . |
$$ | . . . 1 O . . . . O . . O . . X . . . |
$$ | . . . 3 . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:w26: stands and :b27: descends. Elf does not like either one, docking :w26: 11½% and :b27: another 18½% to par.


Click Here To Show Diagram Code
[go]$$Wcm26 Mainline for :w26:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . 2 . X . . X 1 . . O . . . . |
$$ | . . . , . . . . . , X O . . . , X . . |
$$ | . . . O . . . . . . X O . . . X . . . |
$$ | . . . . . . . . . . . O . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X 4 . . . . . . . . . . . O . . |
$$ | . . X , 3 . 5 . . , . . . . X , X . . |
$$ | . . . X O . . . . O . . O . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:w26: makes a base for White in the top right and then :b27: makes a one space extension to secure the neighboring Black group on the top side. The :w28: stands in the bottom left, and after :b29: White jumps to :w30: securing White on the bottom side.


Click Here To Show Diagram Code
[go]$$Bcm25 Black takes away White's base
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . 1 . . . 6 4 . |
$$ | . . . O . . . X . . X . . . O 5 2 3 . |
$$ | . . . , . . . . . , X O . . . , X . . |
$$ | . . . O . . . . . . X O . . . X . . . |
$$ | . . . . . . . . . . . O . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . O . . |
$$ | . . X , . . . . . , . . . . X , X . . |
$$ | . . . . O . . . . O . . O . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

The slide, :b25:, undercuts the White group and secures the Black group. It is an important play for both groups. :w26: responds with the jump attachment to the 3-3 in the corner.


Click Here To Show Diagram Code
[go]$$Bcm31 Main line for :b25:, continued
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . X . . . O O . |
$$ | . . . O . . . X . . X . . . O X O X 6 |
$$ | . . . , . . . . . , X O . 3 . , X 4 . |
$$ | . . . O . . . . . . X O . . . X . 5 . |
$$ | . . . . . . . . . . . O . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . O . . |
$$ | . . X , . 1 . . . , . . . . X , X . . |
$$ | . . . . O . 2 . . O . . O . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:b31: strengthens Black in the bottom left corner with sente. Then :b33: cuts White in two in the top right, and White makes life in the corner.

If the slide is so important, perhaps Black might have played it before. Indeed, that is the case.

Click Here To Show Diagram Code
[go]$$Bcm19 Variation for :b19:
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . 1 . . . . . . |
$$ | . . . O . . . 3 . . X . . . O . . . . |
$$ | . . . , . . . . . , X O . 2 . , X . . |
$$ | . . . O . . . . . . a O . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . X , . . . . . , . . . . X , X . . |
$$ | . . . . O . . . . O . . O . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

In the game Black played :b19: at a, but Elf prefers the slide, albeit by only 2%.

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

Visualize whirled peas.

Everything with love. Stay safe.


Last edited by Bill Spight on Sat Jun 05, 2021 10:10 am, edited 3 times in total.
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 Post subject: Re: Opening problems for AI: Problem 16
Post #3 Posted: Thu Jul 02, 2020 10:42 am 
Judan

Posts: 6706
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Rank: UK 4 dan
KGS: Uberdude 4d
OGS: Uberdude 7d
This seems like the kind of position where marking the last move (and being the players knowing it) can lead you astray:
Click Here To Show Diagram Code
[go]$$Wcm20 Was this last area?
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . 6 . . . . . . |
$$ | . . . O . . . X . . X . . . O . . . . |
$$ | . . . , . . . . . , 2 1 . . . , X . . |
$$ | . . . O . . . . . . 4 3 . . . X . . . |
$$ | . . . . . . . . . . . 5 . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . . O . . |
$$ | . . X , . . . . . , . . . . X , X . . |
$$ | . . . . O . . . . O . . O . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Click Here To Show Diagram Code
[go]$$Wcm22 Or this?
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . X . . X . . . O . . . . |
$$ | . . . , . . . . . , X O . . . , X . . |
$$ | . . . O . . . . . . X O . . . X . . . |
$$ | . . . . . . . . . . . O . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 3 , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 1 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 2 . . . . . . . . . . . . O . . |
$$ | . . X , . . . . . , . . . . X , X . . |
$$ | . . . 4 O . . . . O . . O . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Given the big gap from e3 to k3 and that c10 is low, I'm going to say white c2 is not a severe attack so top is more important. If white defends at g4 then is a good time for black to take the corner.

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 Post subject: Re: Opening problems for AI: Problem 17
Post #4 Posted: Thu Jul 02, 2020 11:08 am 
Honinbo

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Sorry, Uberdude. I didn't notice my typo. For the last diagram I wrote :b21: when I meant :b19:.

Here is the relevant game sequence.

Click Here To Show Diagram Code
[go]$$Bcm19 Moves 19 to 24
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . a . . . . . . |
$$ | . . . O . . . 3 . . X . . . O . . . . |
$$ | . . . , . . . . . , X O . . . , X . . |
$$ | . . . O . . . . . . 1 O . . . X . . . |
$$ | . . . . . . . . . . . 2 . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 6 , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 4 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 5 . . . . . . . . . . . . O . . |
$$ | . . X , . . . . . , . . . . X , X . . |
$$ | . . . . O . . . . O . . O . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Elf prefers a to each of :b19: and :b21:, to :b19: by 2%, to :b21: by 10½%.

_________________
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 17
Post #5 Posted: Fri Jun 04, 2021 10:22 am 
Lives in gote

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Rank: UK 2d Dec15
KGS: mathmo 4d
IGS: mathmo 4d
Speculatively:
Current position:
1. I only see either M17 or N18. N18 seems more normal shape but in this case I'm not sure. A B move at Q12 will be urgent soon.
2. P9 may eventually be big
3. C13 is nice.
4. D2 is big, but seems submissive when there is such a big gap from C3 to K3.

Opp to play
1. M17 is obvious. to settle W's weak group and weak shape, leaving big follow ups at F17 and R18/R11
2. O5 is very nice.
3. C2 is a big point with some attack
4. F5 builds the lower side.

Past:
1. Seems balanced. On upper side, B's two space seems overconcentrated, but B has sente to attack W's shape, so perhaps I actually like B overall. Still, W's wide extension at E3 to K3 seems hard to punish.

Check:
1. close enough

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