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 Post subject: Opening problems for AI: Problem 47
Post #1 Posted: Sat Aug 22, 2020 9:30 am 
Honinbo

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White to play.

As always, assume komi.

Click Here To Show Diagram Code
[go]$$Wcm18 White to play. Extend or enclose?
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . O . . O . . . . |
$$ | . . O , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . a . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . X . . . . . . . . . . . b . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . X , O . . . . , . . . . O , . . . |
$$ | . . . . . . . . X . . X . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Which is better for White, a or b?

Enjoy! :)

How we got here.
Click Here To Show Diagram Code
[go]$$Bc Shusaku kosumi, wedge
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . 6 . . . . |
$$ | . . 4 , . . . . . , . . . . . , 3 . . |
$$ | . . . . . . . . . . . . . . . 7 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , 8 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . 1 , . . . . . , . . . . a , . . . |
$$ | . . . . . . . . . . . . . . . 2 . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:b7: plays the Shusaku kosumi, which is almost certainly playable. But the modern AI style is the press at a. The wedge, :w8:, prevents a Black framework on the right side. It is probably playable, but may be a minor error.

Click Here To Show Diagram Code
[go]$$Bcm9 Traditional base
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . 7 . . . . . . 6 . . O . . . . |
$$ | . . O , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 2 . . |
$$ | . . . 9 . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . B , 8 . . . . , . . . . 4 , . . . |
$$ | . . . . . . . . 5 . . 3 . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

:b11: seems a bit far from the corner to be a good counterpincer. However, after :w12:, :b13: forms a traditional base on the side as well as a 5 space extension from the :bc: stone in the bottom left corner.

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 Post subject: Re: Opening problems for AI: Problem 47
Post #2 Posted: Sat Aug 22, 2020 11:35 am 
Tengen
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Kaya handle: Test
Letting the black stone at R5 get loose causes more problems than it first appears.
It splits white into two groups, and both start to look unstable because of the presence of the two circled black stones, both of which are part of groups that already have modest eye space.

Click Here To Show Diagram Code
[go]$$Bc Black 5 might be better at 'c'
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . O . . O . . . . |
$$ | . . O , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . B . . |
$$ | . . O . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . 2 . . . . |
$$ | . . . . . . . . . . . . 5 . . . O . . |
$$ | . . . X . . . . . . . . . 3 . 1 . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . X , O . . . . , . . 4 . O , . . . |
$$ | . . . . . . . . X . . B . . . O . c . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


So to prevent the above diagram, if I were white, I'd play 'b'.

Click Here To Show Diagram Code
[go]$$Wcm18 White to play. Extend or enclose?
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . O . . O . . . . |
$$ | . . O , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . a . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . X . . . . . . . . . . . 1 . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . X , O . . . . , . . . . O , . . . |
$$ | . . . . . . . . X . . X . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


This post by Joaz Banbeck was liked by: Bill Spight
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 Post subject: Re: Opening problems for AI: Problem 47
Post #3 Posted: Sat Aug 22, 2020 1:46 pm 
Lives in sente
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'a' has a certain classical flow to it, and I guess that this is the game move (and that it is from the Edo period).

I'd like to play 'b' nowadays, because it seems to have more impact (to my modernized eyes). The most important aspect seems to me that it takes control of that quadrant (John's diagonal), but it also significantly increases the potential for making a big territory there. That two groups are more or less connected afterwards is just another way to look at it (tangential thought: this is the good kind of connection, through mutual control, not through dame).

Looking at 'a', while classically one might congratulate it for preventing a black extension, it seems quite thin. On the other hand, it makes somewhat miai between connecting to the upper left or extending/limiting to the lower left. Then again, if Black just invades, White has to handle two groups. Maybe this is the kind of complications that White wants in a no-komi game, but I don't like it.

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 Post subject: Re: Opening problems for AI: Problem 47
Post #4 Posted: Sat Aug 22, 2020 8:00 pm 
Lives in gote

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Bill Spight wrote:
Click Here To Show Diagram Code
[go]$$Wcm18 White to play.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . O . . O . . . . |
$$ | . . O , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . a . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . X . . . . . . . . . . . b . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . X , O . . . . , . . . . O , . . . |
$$ | . . . . . . . . X . . X . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


I think it has to be 'b', for two reasons. To start, it forms a good sized territory. It also builds strength (thickness?) to deal with the lower right and adjacent sides.

'a' is going to risk getting overconcentrated when black pushes down, plus Black has the choice of activating the stone in the lower right corner.



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 Post subject: Re: Opening problems for AI: Problem 47
Post #5 Posted: Sat Sep 19, 2020 3:41 am 
Lives with ko

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Click Here To Show Diagram Code
[go]$$Wcm18 White to play. Extend or enclose?
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . O . . O . . . . |
$$ | . . O , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . a . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . X . . . . . . . . . . . b . . . |
$$ | . . . . . . . . . . . . . . . . X . . |
$$ | . . X , O . . . . , . . . . O , . . . |
$$ | . . . . . . . . X . . X . . . O . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


When seeing this position have not a good feeling as white.

My first impression would be to play b because I feel it is an urgent point comparing to point "a" which looks "only" a big point.

But after white "b" I am not happy with my fuseki because I see all black stones working properly though I feel overconcentrate in the bottom left corner with already five stones invested, a thickness which do not look very efficient on the adjacent black groups and in addition I guess black stones R5 has still bad aji.

Feeling my fuseki was not good, I think I am behind in the game and finally I am wondering if "a" would not be better to try and complicate the game.

Concerning the fuseki the move :w8: is maybe the beginning of my problems but I am not sure.


This post by Gérard TAILLE was liked by: Bill Spight
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