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Opening/middlegame problem from my game
http://www.lifein19x19.com/viewtopic.php?f=15&t=7766		 Page 2 of 2
Author:  Uberdude [ Fri Mar 12, 2021 4:08 am ]
Post subject:  Re: Opening/middlegame problem from my game
An update from our superhuman AI future: Katago likes Magicwand's d6 to take the cash! But the other choices discussed here like my q18 were ok too, within a point or two, so as black's leading, by 13-11 points says KG, pick the one you like to play :) . Some discussion on facebook: https://www.facebook.com/groups/go.igo. ... 813291514/
Author:  Knotwilg [ Fri Mar 12, 2021 4:58 am ]
Post subject:  Re: Opening/middlegame problem from my game
A little late to the party, here's my choice, not having read any of the replies:

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


In the middle game we look for opportunities to make territory while attacking. I have marked the major undeveloped or invadable areas and the only weakish group. A move that separates both is the first to think about

Click Here To Show Diagram Code
[go]$$Bc Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X . X X . . . . . C C . . . . C C . |
$$ | . . X O X O . . . . C C . O . . C C . |
$$ | . X O O O . O . . O . . . . . X . . . |
$$ | . . X O O O . . . . . . . . . . . . . |
$$ | . . X X O O . . . . . . . . . X . . . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . C C . . . . C C . |
$$ | . . . O . . . . . , C C . . . , C C . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . O O O X . . . . . . . . . . X . . . |
$$ | X X X . X . . . X X 1 a . . . . X . . |
$$ | O O X O . . . . X W W 2 . . . X O . . |
$$ | O . O , O X . O X W X . . . . , . . . |
$$ | . O O O X . X X W . W W . . . X . . . |
$$ | . . O . X . . . W . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


However, a move at :b1: will only establish 100% life for White's group and not seal off the center.

Click Here To Show Diagram Code
[go]$$Bc Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X . X X a . . . . C C . . . . C C . |
$$ | . . X O X O . . . . C C . O . . C C . |
$$ | . X O O O . O . . O . 2 . . . X . . . |
$$ | . . X O O O . . . . . . 1 . . . . . . |
$$ | . . X X O O . . . . . . . . . X . . . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . C C . . . . C C . |
$$ | . . . O . . . . . , C C . . . , C C . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . O O O X . . . . . . 3 . . . X . . . |
$$ | X X X . X . . . X X . . . . . . X . . |
$$ | O O X O . . . . X W W . . . . X O . . |
$$ | O . O , O X . O X W X . . . . , . . . |
$$ | . O O O X . X X W . W W . . . X . . . |
$$ | . . O . X . . . W . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Another move that separates big areas is :b1:. Giving White territory is affordable, as she doesn't have a lot yet. And the top has an open skirt at A. However after :b3: the moyo at the center and right is perhaps too big and too easy to invade, which will make those moves end up neutral.

Click Here To Show Diagram Code
[go]$$Bc Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X . X X . . . . . C C . . . . . . . |
$$ | . . X O X O . . . . C C . O . . 2 . . |
$$ | . X O O O . O . . O . . . . . X . . . |
$$ | . . X O O O . . . . . . . . . . . . . |
$$ | . . X X O O . . . . . . . . . X . . . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . C C . . . 1 C C . |
$$ | . . . O . . . . . , C C . . . , C C . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . O O O X . . . . . . . . . . X . . . |
$$ | X X X . X . . . X X . . . . . . X . . |
$$ | O O X O . . . . X W W . . . . X O . . |
$$ | O . O , O X . O X W X . . . . , . . . |
$$ | . O O O X . X X W . W W . . . X . . . |
$$ | . . O . X . . . W . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


:b1: here develops the right side and the center in a more modest fashion. I feel however that allowing the invasion in the corner may level things easily for White.

Click Here To Show Diagram Code
[go]$$Bc Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X . X X a . . . . C C 4 3 5 . C C . |
$$ | . . X O X O . . . . C 6 . O 1 . C C . |
$$ | . X O O O . O . . O . . . 2 . X . . . |
$$ | . . X O O O . . . . . . . . . . . . . |
$$ | . . X X O O . . . . . . . . . X . . . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . C C . . . . C C . |
$$ | . . . O . . . . . , C C . . . , C C . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . O O O X . . . . . . . . . . X . . . |
$$ | X X X . X . . . X X . . . . . . X . . |
$$ | O O X O . . . . X W W . . . . X O . . |
$$ | O . O , O X . O X W X . . . . , . . . |
$$ | . O O O X . X X W . W W . . . X . . . |
$$ | . . O . X . . . W . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


This is my choice: Black can fortify the corner, possibly in sente like here. White's increased strength is somewhat overlapping with that on the left. A is still here to reduce the top.

Finally, a word about D6

Click Here To Show Diagram Code
[go]$$Bc Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . X . X X . . . . . C C . . . . C C . |
$$ | . . X O X O . . . . C C . O . . C C . |
$$ | . X O O O . O . . O . . . . . X . . . |
$$ | . . X O O O . . . . . . . 2 . . . . . |
$$ | . . X X O O . . . . . . . . . X . . . |
$$ | . a . O X . . . . . . . . . . . . . . |
$$ | . . . O . b . . . . . . . . . . . . . |
$$ | . . . . . . . . . . C C . . . . C C . |
$$ | . . . O . . . . . , C C . . . , C C . |
$$ | . . . O X . . . . . . . . . . . . . . |
$$ | . . . . X . . . . . . . . . . . . . . |
$$ | . O O O X . . . . . . . . . . X . . . |
$$ | X X X 1 X . . . X X . . . . . . X . . |
$$ | O O X O . . . . X W W . . . . X O . . |
$$ | O . O , O X . O X W X . . . . , . . . |
$$ | . O O O X . X X W . W W . . . X . . . |
$$ | . . O . X . . . W . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


:b1: is gote and saves 4 stones. Additional gain may come from a weakened left side, but A and B look equivalent to save those stones. :w2: would be my way of dealing with the important area as White.


Now I will read the other comments.
Author:  Knotwilg [ Fri Mar 12, 2021 7:29 am ]
Post subject:  Re: Opening/middlegame problem from my game
Uberdude wrote:
An update from our superhuman AI future: Katago likes Magicwand's d6 to take the cash! But the other choices discussed here like my q18 were ok too, within a point or two, so as black's leading, by 13-11 points says KG, pick the one you like to play :) . Some discussion on facebook: https://www.facebook.com/groups/go.igo. ... 813291514/


That's surprising: "face value" is 9 points gote (or "double gote"). With the upper right still in a contested state, very much like in the opening, it is surprising such (large) endgame is bigger. So it means there is substantial effect on the stability of the white stones above it.
Author:  Uberdude [ Fri Mar 12, 2021 12:44 pm ]
Post subject:  Re: Opening/middlegame problem from my game
The pure territory value of d6 is more like 15 points. As well as the 8 from the 4 stones there's White not getting d4 and black getting f5 as E5 becomes sente privilege of whoever connects, plus black gets b9 sente yose tesuji so White saves about 5 points in b8 area.

On top of that's there's the harder to quantify bonus of splitting white so f11 and b12 have better follow-ups, plus some ko threats against corner. Actually maybe 1 more point semedori with A2 as well.
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