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 Post subject: How is your positional judgement? Game 26
Post #1 Posted: Sat Dec 07, 2019 12:14 pm 
Honinbo

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Game 26

After :b33: the Elf commentaries give one player an 89½% winrate estimate with 37.7k playouts. Which player is it?

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


Enjoy! :)

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 Post subject: Re: How is your positional judgement? Game 26
Post #2 Posted: Sat Dec 07, 2019 1:52 pm 
Lives in sente
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Black made sixth line territory on the left, but its shape is a bit constricted and doesn't interact with other black stones. The three F14 stones are cutting two strong white groups. White's group on the top left could be surrounded if it were Black's turn, but it's White's turn.

So I choose White.

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 Post subject: Re: How is your positional judgement? Game 26
Post #3 Posted: Sat Dec 07, 2019 2:15 pm 
Tengen
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I vote for white.

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


The double hane really hurts. Black must submit. And because of the cutting points ( marked with circles ) he must continue at least one more or white chops him into pieces. White gets a huge corner in the lower left.

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 Post subject: Re: How is your positional judgement? Game 26
Post #4 Posted: Sun Dec 08, 2019 9:14 am 
Lives with ko

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I prefer white for the following reasons:
+ Black's cutting group is heavy and cuts two rather strong white groups. It can be attacked for benefit and profit, turning the top into territory, getting rid of the bad aji of F17 and wrecking blacks right side. Maybe white doesn't get all of these, but 2 out of 3 ain't bad, as meatloaf sings.
+ Blacks left group has too many cutting points. White can happily do a double hane at its bottom, which is painful for black and helps with a white corner in the bottom left
- The lonely white stone at P4 looks stupid to me. I guess it is a standard way to deal with the low chinese formation at the right, which I don't know yet. So, it is OK and I should go and check senseis-library. Well, I just checked, there is nothing on it on senseis. Looking forward to being enlighted.

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 Post subject: Re: How is your positional judgement? Game 26
Post #5 Posted: Sun Dec 08, 2019 9:35 am 
Gosei
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The obvious party to go with is White, because her position seems to be more active. So let me play devil's advocate and highlight all Black's goodies:

Click Here To Show Diagram Code
[go]$$Wc White to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . O X . . . . . . . O . . . . . |
$$ | . . . O . O . c . , . . . . . X . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . X O O X X X . . . . . . . . b . . |
$$ | . . . X X O O . . . . . . . . . . . . |
$$ | . . . . . X O . . . . . . . . . . . . |
$$ | . . . . . X O . . . . . . . . . . . . |
$$ | . . . , . X O . . , . . . . . , . . . |
$$ | . . . . . X O . . . . . . . . . X . . |
$$ | . . 4 2 X O e . . . . . . . . . . . . |
$$ | . . . 3 1 d . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . a . . . . |
$$ | . . . O . . . . . O . . . . O X . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Let's assume this sequence, even if :w4:'s necessity needs analysis, to allow the temperature at the left side to drop.

Territory
Black has made about 30 points on the left and about 15 points in the lower right seem justified.
White has no defined territory, but there's a lot of potential, especially at the bottom

Influence
White's centre stones are influential, in particular towards the bottom. They have 6 liberties, a healthy number.
Black's central stones may have some influence against the top left stones. We'll investigate the hane. They have five liberties but there's not much room to maneuver.

Otherwise, Black's stones are on the right side and don't have a lot of influence on what happens on the rest of the board.

Sente
Sente's White
Now where's the next action?

a) The lower right is a strange disposition of stones. Did White shoulder hit a 3-4? Following up at A for White will build the centre, but it doesn't look urgent.
b) Black has ignored an approach. Both can follow up with B or WHite can invade the corner, but this too looks like leaving the front too early.
c) The 3 black stones and the top left are the focal area. White can make territory while attacking at C and this is where I would play.
d) there is aji at D or E but Black can decide where to cut later.

But what if Black just leaves the 3 stones for White to swallow and concentrates on other parts of the board?

Click Here To Show Diagram Code
[go]$$Wc White to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . O X . . . . . . . O . . . . . |
$$ | . . . O . O . 1 . , . . . . . X . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . X O O X X X . . . . . . . . b . . |
$$ | . . . X X O O . . . . . . . . . . . . |
$$ | . . . . . X O . . . . . . . . . . . . |
$$ | . . . . . X O . . . . . . . . . . . . |
$$ | . . . , . X O . . , . . . . . , . . . |
$$ | . . . . . X O . . . . . . . . . X . . |
$$ | . . X X X O . . . . . . . . . . . . . |
$$ | . . . O O a . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 2 3 . . . . . . . . . a . . . . |
$$ | . . . O 4 . . . . O . . . . O X . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Maybe there is aji to exploit here.

Click Here To Show Diagram Code
[go]$$Wc White to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . 7 6 4 5 . . . . . . . . . . . . |
$$ | . . . . O X 3 . . . . . . O . . . . . |
$$ | . . . O . O 2 . . , . . . . . X . . . |
$$ | . . X 9 8 0 . . . . . . . . . . . . . |
$$ | . . X O O X X X . . . . . . . . b . . |
$$ | . . . X X O O . . . . . . . . . . . . |
$$ | . . . . . X O . . . . . . . . . . . . |
$$ | . . . . . X O . . . . . . . . . . . . |
$$ | . . . , . X O . . , . . . . . , . . . |
$$ | . . . . . X O . . . . . . . . . X . . |
$$ | . . X X X O . . . . . . . . . . . . . |
$$ | . . . O O 1 . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . a . . . . |
$$ | . . . O . . . . . O . . . . O X . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


White could defend against the aji, but then Black gets a major forcing sequence at the top.

Click Here To Show Diagram Code
[go]$$Wc White to play
$$ ---------------------------------------
$$ | . . . . 9 7 . . . . . . . . . . . . . |
$$ | . . 6 O X X O . . . . . . . . . . . . |
$$ | . . 8 3 O X O . 5 . . . . O . . . . . |
$$ | . . 2 O 1 O X 4 . , . . . . . X . . . |
$$ | . . X O X O . . . . . . . . . . . . . |
$$ | . . X O O X X X . . . . . . . 0 . . . |
$$ | . . . X X O O . . . . . . . . . . . . |
$$ | . . . . . X O . . . . . . . . . . . . |
$$ | . . . . . X O . . . . . . . . . . . . |
$$ | . . . , . X O . . , . . . . . , . . . |
$$ | . . . . . X O . . . . . . . . . X . . |
$$ | . . X X X O . . . . . . . . . . . . . |
$$ | . . . O O O . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . a . . . . |
$$ | . . . O . . . . . O . . . . O X . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


All depends on the vulnerability of Black's top central stones. Black has a lot of territory here.

Finally let's look if Black really has to play as submissively as in the first diagram.

Click Here To Show Diagram Code
[go]$$Wc White to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . 6 . . . . . . . . . . . . . |
$$ | . . . . O X . . . . . . . O . . . . . |
$$ | . . . O . O 4 . . , . . . . . X . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . X O O X X X . . . . . . . . . . . |
$$ | . . . X X O O . . . . . . . . . . . . |
$$ | . . . . . X O . . . . . . . . . . . . |
$$ | . . . . . X O . . . . . . . . . . . . |
$$ | . . . , . X O . . , . . . . . , . . . |
$$ | . . . . . X O . . . . . . . . . X . . |
$$ | . . 5 2 X O e . . . . . . . . . . . . |
$$ | . . . 3 1 d . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . O . . . . O X . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


This leads to a kind of exchange that I can't evaluate.

Overall I think the position is at least easier for White. Black has to do more adventurous stuff to make something out of the position.

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 Post subject: Re: How is your positional judgement? Game 26
Post #6 Posted: Mon Dec 09, 2019 1:48 am 
Lives in gote

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I like white here. Black's shape on the left side feels very inefficient, especially if white plays around C6 or C7 next.

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 Post subject: Re: How is your positional judgement? Game 26
Post #7 Posted: Mon Dec 09, 2019 2:05 am 
Lives in gote

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And after looking at the other responses and checking with KataGo (warning: contains spoilers) --
Click Here To Show Diagram Code
[go]$$Wc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . O X . . . . . . . O . . . . . |
$$ | . . . O . O . . . , . . . . . X . . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . X O O X X X . . . . . . . . . . . |
$$ | . . . X X O O . . . . . . . . . . . . |
$$ | . . . . . X O . . . . . . . . . . . . |
$$ | . . . . . X O . . . . . . . . . . . . |
$$ | . . . , . X O . . , . . . . . , . . . |
$$ | . . . . . X O . . . . . . . . . X . . |
$$ | . . . 2 X O . . . . . . . . . . . . . |
$$ | . . . 3 1 . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . O . . . . O X . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Everyone else is assuming black can't get away with :b2: at :w3:. But why not? I can't actually see a sequence that's devastating for white.

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

Here, :w3: and :w7: are captured. White can rip off the two stones above :w9:, but is this really any worse than being submissive as in the first diagram? KataGo says yes, but only just under two points worse in a position where white is already more than ten points down. (If :w3: at :b4:, black is slightly better off.) So maybe it's worth black trying the more complicated line?

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 Post subject: Re: How is your positional judgement? Game 26
Post #8 Posted: Mon Dec 09, 2019 6:15 pm 
Lives in gote

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Black. Seems like White G16 is the only move and Black does have that weak group in the area but how valuable is that really?

White has probably 12~ points on top after whatever happens there. Some potential in top left and... the bottom-ish? It is not enough.

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