Life In 19x19
http://lifein19x19.com/

How is your positional judgement? Game 27
http://lifein19x19.com/viewtopic.php?f=15&t=17133
Page 1 of 1

Author:  Bill Spight [ Thu Dec 12, 2019 6:28 pm ]
Post subject:  How is your positional judgement? Game 27

Game 27

After :b27: the Elf commentaries, assuming area scoring and a 7½ pt. komi, give one player a winrate estimate of 88½% with 29.6k rollouts. Which player is it?

Click Here To Show Diagram Code
[go]$$Bcm27 White to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . O . . . . O O . O X . |
$$ | . X . , . . . . . , . X . X . , X . . |
$$ | . O X X . . . . . . . . . . . X . . . |
$$ | . O O X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . O . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . O . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . . O . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Enjoy! :D

Author:  TelegraphGo [ Fri Dec 13, 2019 3:58 am ]
Post subject:  Re: How is your positional judgement? Game 27

I pick black. Immediately, white has to take gote making the top group not die, and it's not going to be pretty - black still will have a local advantage in efficiency.
After that, we can compare the bottom left with the bottom right - 3 against 1 for each side, who has it better?

Black has it better. Black will get sente to play in the bottom right. After that, the one white stone on the side at R10 can still be put under pressure, due to the black thickness on the top. That's different from the left side - the one black stone at C9 cannot be put under pressure in the same way, because white is still weak nearby. You can't attack if you're weak.

The last difference is in the upper left - whose stone are more efficient? Black's, by far. W's weakness will come back to bite him later. So black is obviously ahead on board. Is black ahead by more than komi? I say heck yeah. I'm doubling down - I can't even spot any major inefficiencies for B, from a game reconstruction standpoint.

Author:  Knotwilg [ Fri Dec 13, 2019 7:49 am ]
Post subject:  Re: How is your positional judgement? Game 27

Click Here To Show Diagram Code
[go]$$W
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . b . |
$$ | . . . X . . . . O . . . 5 O O 3 O X . |
$$ | . X . , . . . . . , . X a X 2 1 X . . |
$$ | . O X X . . . . . . . . . . . X 4 . . |
$$ | . O O X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . d . . . . . . . . . . . . . . . |
$$ | . . O . O . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . O . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . c O . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . 6 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


I doubt about many things

- Should White play :w5: immediately?
- How important is A locally? And B?
- Is :b6: indeed the biggest point on the board after settling the upper right?
- More in particular: how important is C?
- And how painful is D?
- Who is ahead?

First I thought: Black has the better position. But then I didn't see how he's overcoming the komi. And he really needs to spend another move in the upper left to stabilize.

So I go White, but very hesitantly so.


Edit: still without LZ

Click Here To Show Diagram Code
[go]$$W
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . 7 . |
$$ | . . . X . . . . O . . . 5 O O 3 O X . |
$$ | . X . , . . . . . , . X 6 X 2 1 X . . |
$$ | . O X X . . . . . . . . . . . X 4 . . |
$$ | . O O X . . . . . . . . . . a . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . d . . . . . . . . . . . . . . . |
$$ | . . O . O . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , W . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . O . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . c O . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . 8 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


If we add the exchange of :b6: - :w7: as here, then Black's inefficiency comes to light. The marked White stone is negating his influence and there's a peep at A.

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


This is then a better result for Black. But White gets back the initiative to enlarge the top with :w10: while threatening to clamp at A.


Edit: with LZ now. She agrees with my evaluation of my selected moves. But she disagrees with my move selection:
Click Here To Show Diagram Code
[go]$$W
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 2 . . |
$$ | . . . X . . . . O . . . . O O . O X . |
$$ | . X . , . . . . . , . X . X . 1 X . . |
$$ | . O X X . . . . . . . . . . . X . . . |
$$ | . O O X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . d . . . . . . . . . . . . . . . |
$$ | . . O . O . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , O . . |
$$ | . . X . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . . . . . . . O . . . |
$$ | . . X , . . . . . , . . . . . , . . . |
$$ | . . . c O . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . 6 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


LZ answers :w1: with :b2: and gives Black a firm advantage.

Author:  xela [ Sat Dec 14, 2019 6:09 pm ]
Post subject:  Re: How is your positional judgement? Game 27

Hmm, I keep flip-flopping on this one.
Currently leaning towards black. First guess was white because my feeble human intuition says that white can take the last big point of the fuseki on the lower side. But we've had enough arguments about that recently!

On a closer look, I think N17 is urgent, and the top is about to turn into a big mess that will favour black. Overall white's stones look superficially more efficient, but a bit thin.

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

Not sure what happens next from here, but I think black's thickness at the top left (*) will come in to play.

(*) And these days I'm also quite nervous about using words like thickness or influence...

Author:  dhu163 [ Mon Dec 26, 2022 11:47 am ]
Post subject:  Re: How is your positional judgement? Game 27

R17 seems misplaced when W is crawling on the top as B adding a move can make it bad. Locally S18 was the shape, but that is inconsistent with the crawl.

On the rest of the board, the lower right corner is very big after which R10 extends slightly too far. Most of all the upper left seems better shape for B as W is cramped playing too close to thickness with B14 for D14. M16 is interesting. I didn't think of it. It makes J17 and R17 look worse.

Another problem is B has all 4 corners.

Page 1 of 1 All times are UTC - 8 hours [ DST ]
Powered by phpBB © 2000, 2002, 2005, 2007 phpBB Group
http://www.phpbb.com/