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BlindGroup vs Tapani
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Author:  Tapani [ Mon Aug 28, 2017 9:33 am ]
Post subject:  BlindGroup vs Tapani
Hello,

this is a game between two L19 members - BlindGroup and myself. It was played on IGS with somewhat generous amount of time (maybe 3h total).

We have both annotated the game, and would appreciate any further comments.




EDIT:

For fun I also let Leela analyze the game (2.5 mins per move on a core i7), and plotted the graph of black's win probabilities per move. The horizontal axis is the move (ply) number and the vertical axis indicate black's win probability in percent. Values under 50% mean white has the advantage, values above 50% indicate that black is ahead.

Maybe this helps identifying key moments of the game.
Attachment:
gameplot.png
gameplot.png [ 24.61 KiB | Viewed 6109 times ]


Attachments:
BlindGroup_vs_Tapani_commented_20170828.sgf [9.5 KiB]
Downloaded 561 times
Author:  Bill Spight [ Mon Aug 28, 2017 10:16 am ]
Post subject:  Re: BlindGroup vs Tapani
Just a few quick comments on the early play.

:w6: E-03 is usual.

:b7: Having retained sente, Black can approach the top left corner.

:b13: The J-03 stone is a little far away for this play, perhaps.

:b17: P-08 is more solid.

:b21: O-03, the hanging connection, is superior. P-03 is bad shape.

:b23: I think that J-04 is best.

:w24: I think that J-04 is best.

:b25: Pushes White where he wants to go. Maybe G-04, maybe E-06.

:w26: Good! :)

:b27: Horrible. All you do is to strengthen White, and make bad shape besides.

:w28: Success!
Author:  BlindGroup [ Mon Aug 28, 2017 10:22 am ]
Post subject:  Re: BlindGroup vs Tapani
Tapani wrote:
For fun I also let Leela analyze the game (2.5 mins per move on a core i7), and plotted the graph of black's win probabilities per move. The horizontal axis is the move (ply) number and the vertical axis indicate black's win probability in percent. Values under 50% mean white has the advantage, values above 50% indicate that black is ahead.


That's interesting! I thought the game was much more even in the early middle game. Apparently, not :-)

Move 24: Just to clarify, I thought that you'd need to respond. If not, you might still live, but you'd likely be small and enclosed.
Author:  Tapani [ Mon Aug 28, 2017 9:14 pm ]
Post subject:  Re: BlindGroup vs Tapani
BlindGroup wrote:
That's interesting! I thought the game was much more even in the early middle game. Apparently, not :-)
Blindgroup,

Was also surprised about this. Felt that white was ok if not comfortable, but not yet winning by any means. And how that succesful reduction of the bottom gave white a lasting advantage for 150+ moves! Expected there to be far larger swings in the win chance estimations.


You also ask for feedback on :b81: and :b85:. I am much more curious about :b83:!

Would playing :b83: around R12 be bigger? And if white goes ahead and takes the stones with C8, black can play another stone to protect the huge moyo, maybe at L11.

For what it is worth, your :b85: is Leela's first choice, and your :b81: is Leela's third choice (first choice is K12). After eyeing through the analysis, I am very much surprised how often our moves are so close to some of Leela's top choices. Which in turn makes me suspicious about the moves that are not (like my :w82: threatening the four stones bottom left).
Author:  afar [ Tue Aug 29, 2017 4:32 am ]
Post subject:  Re: BlindGroup vs Tapani
Here's an SGF with some comments:



Black does misplay the early fight a bit (although white does too), but the most interesting question seems to be around how black should get more out of white's invasion on the right side. I've picked out a particular place where black could play more strongly by threatening white's corner - both players could maybe play differently to avoid this, but the important thing is that black didn't try it at all, which lets white get away with the invasion too easily.

Attachments:
BlindGroup_vs_Tapani_commented_20170828.sgf [17.3 KiB]
Downloaded 523 times
Author:  Tapani [ Sat Sep 02, 2017 5:59 am ]
Post subject:  Re: BlindGroup vs Tapani
Thank you for your thorough comments.

After going through them a little more detailed, there are some minor questions:

The comment on move 15 about having a white stone outside black's wall:

So, given the choices between
A:
Click Here To Show Diagram Code
[go]$$Bc
$$ . . . . , . . . |
$$ . . . . . . . . |
$$ . . . . . . . . |
$$ . . . . . . . . |
$$ . . . X . O . . |
$$ . . . . . X X . |
$$ . . . . X X O . |
$$ . X X X O O O . |
$$ . . O O . . . . |
$$ . . . . . . . . |
$$ ----------------+[/go]

and
B:
Click Here To Show Diagram Code
[go]$$Bc
$$ . . . . , . . . |
$$ . . . . . . . . |
$$ . . . . . . . . |
$$ . . . . . . . . |
$$ . . . . . X . . |
$$ . . . . . . X . |
$$ . . . . X X O . |
$$ . X X X O O O . |
$$ . . O O . . . . |
$$ . . . . . . . . |
$$ ----------------+[/go]

the former (A) is more preferrable as white? My gut feeling would have been the other way around - the exchange was good for black.

At move :w24:, you also suggest white J4, and show lines where black responds with H3 and H6. The reason I (white) did not play J4 was because I worried about black H5. Could not see if I was aliveor out after something like:
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . X . . . . X . O . . |
$$ | . O . . . . . 1 . . . . . . . . . . . |
$$ | . . O , X . . . O O . . . . . X O . . |
$$ | . O X X . . . 2 X . . 4 . . X X O . . |
$$ | . . . . . . . 5 3 . . . . . X O O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]

Maybe, but it felt risky at the time.

Anyway, thanks once more for taking the time to review our game.
Author:  dfan [ Sat Sep 02, 2017 7:18 am ]
Post subject:  Re: BlindGroup vs Tapani
Depending on the situation on the right side, this kind of possibility can be pretty annoying to Black:
Click Here To Show Diagram Code
[go]$$Wc
$$ . . . . , . . . |
$$ . . . . . 3 . . |
$$ . . . . . . . . |
$$ . . . . . . . . |
$$ . . . X . O 1 2 |
$$ . . . . . X X . |
$$ . . . . X X O . |
$$ . X X X O O O . |
$$ . . O O . . . . |
$$ . . . . . . . . |
$$ ----------------+[/go]

Maybe :w3: should be in a slightly different place, but you get the idea.
Author:  afar [ Sat Sep 02, 2017 5:17 pm ]
Post subject:  Re: BlindGroup vs Tapani
Tapani wrote:
Thank you for your thorough comments.

After going through them a little more detailed, there are some minor questions:

The comment on move 15 about having a white stone outside black's wall:

So, given the choices between
A:
Click Here To Show Diagram Code
[go]$$Bc
$$ . . . . , . . . |
$$ . . . . . . . . |
$$ . . . . . . . . |
$$ . . . . . . . . |
$$ . . . X . O . . |
$$ . . . . . X X . |
$$ . . . . X X O . |
$$ . X X X O O O . |
$$ . . O O . . . . |
$$ . . . . . . . . |
$$ ----------------+[/go]

and
B:
Click Here To Show Diagram Code
[go]$$Bc
$$ . . . . , . . . |
$$ . . . . . . . . |
$$ . . . . . . . . |
$$ . . . . . . . . |
$$ . . . . . X . . |
$$ . . . . . . X . |
$$ . . . . X X O . |
$$ . X X X O O O . |
$$ . . O O . . . . |
$$ . . . . . . . . |
$$ ----------------+[/go]

the former (A) is more preferrable as white? My gut feeling would have been the other way around - the exchange was good for black.


The first version has some awkwardness for both players, but black has the more obviously weird shape. dfan has already pointed out one line that white can aim at, whereas in the second (normal 3-3 invasion) variation white has no real forcing moves on the outside. This is a key point in judging the quality of positions, and can have very major implications on later fighting.

Also note that the wall is facing the 'wrong' way with respect to the bottom side and black's existing stones. I don't think that's unforgivable here, but it plays into how the position has to be judged.

Quote:
At move :w24:, you also suggest white J4, and show lines where black responds with H3 and H6. The reason I (white) did not play J4 was because I worried about black H5. Could not see if I was aliveor out after something like:
Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . X . . . . X . O . . |
$$ | . O . . . . . 1 . . . . . . . . . . . |
$$ | . . O , X . . . O O . . . . . X O . . |
$$ | . O X X . . . 2 X . . 4 . . X X O . . |
$$ | . . . . . . . 5 3 . . . . . X O O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]

Maybe, but it felt risky at the time.

Anyway, thanks once more for taking the time to review our game.


It's fair to be worried about this, but ultimately it's just one of those fighting things where you have to play the strong way and learn if it works or not. If the J4 move is not forcing, and does not live, then the shoulder hit is bad. But, it's such a strong local move that black will normally find it hard to resist, especially so early in the game.

I think your variation can be immediately improved:

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


It seems most obvious to just play the connection above, keeping an eye on black's weaknesses; it will be hard for black to kill if white is threatening to break through and separate black's own groups. If black does not protect, white can move out there. If black does protect, white can try to find a stronger way to play to threaten the stones on the bottom, for instance:

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


or

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


White's cut at the marked point seems quite concerning for black. White also has lots of liberties, as there's a free push (and other potential escapes) by playing above :b7: .

These lines are just from a quick glance and maybe I missed something, but the key point is that white's primary line of thought is 'how can I break out or at least cause black many weaknesses if he seals in'. By getting many forcing moves on the outside, white can hopefully end with quite a large area on the inside, and then come back to kill black's stones there.
Author:  BlindGroup [ Mon Sep 04, 2017 5:15 pm ]
Post subject:  Re: BlindGroup vs Tapani
I'm sorry for the delay, but thank you all for your comments. (I got sick last week...) Very helpful!
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