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Can This Shape Live??
http://www.lifein19x19.com/viewtopic.php?f=4&t=15469		 Page 1 of 1
Author:  jeffb99 [ Sat Feb 24, 2018 12:44 pm ]
Post subject:  Can This Shape Live??
I'm playing white and thought the corner was fairly settled. It was early in the game and I tenuki-ed to a strategic spot elsewhere. I just wasn't paying enough attention. A few moves later, my opponent (black) made the shape-stealing inside move at R18. :shock: I groaned and figured my entire group was now dead and the corner was his (about a 20 point flip). Its a friendly game played across a table and we spent some time seeing if there was a way to save my stones. We could not. I let the corner go and moved on..and lost by about 20 points! :(

Is this group dead? If not, what are the steps for life?

THanks!

--Jeff

Click Here To Show Diagram Code
[go]$$c Alive or Dead?
$$ ------------------
$$ . . . . . . . . . . |
$$ . . . . X O . Y . . |
$$ . . . . X O . . . . |
$$ . . . . X X O O . . |
$$ . . . . X O O . . . |
$$ . X . . . X X X . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . X . O . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |[/go]
Author:  EdLee [ Sat Feb 24, 2018 9:20 pm ]
Post subject: 
Hi Jeff,
One continuation -- capture race: :study:

Click Here To Show Diagram Code
[go]$$W
$$ ---------------------
$$ . . . . . 7 6 . 4 . |
$$ . . . . X O . X . 5 |
$$ . . . . X O 1 . 2 8 |
$$ . . . . X X O O 3 9 |
$$ . . . . X O O . 0 . |
$$ . X . . . X X X . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . X . O . . |[/go]
Click Here To Show Diagram Code
[go]$$Wm11 Approach ko (?)
$$ ---------------------
$$ . . . . 4 O X 5 X . |
$$ . . . . X O 3 X 2 O |
$$ . . . . X O O 1 X X |
$$ . . . . X X O O O O |
$$ . . . . X O O . X . |
$$ . X . . . X X X . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . X . O . . |[/go]
Maybe W can do better than a ko ?
If it's an approach ko, then you can also figure out its value
( ~36+ points; but :black: needs 1 approach move before it becomes a direct ko to threaten :white: . )

Variation: :study:
Click Here To Show Diagram Code
[go]$$W
$$ ---------------------
$$ . . . . 0 7 . 6 5 . |
$$ . . . . X O . X . 4 |
$$ . . . . X O 1 . 2 . |
$$ . . . . X X O O 3 9 |
$$ . . . . X O O . 8 . |
$$ . X . . . X X X . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . X . O . . |[/go]
Click Here To Show Diagram Code
[go]$$Wm11
$$ ---------------------
$$ . . . . X O . X O 4 |
$$ . . . . X O . X 1 X |
$$ . . . . X O O 3 X . |
$$ . . . . X X O O O O |
$$ . . . . X O O 2 X . |
$$ . X . . . X X X . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . X . O . . |[/go]
Click Here To Show Diagram Code
[go]$$Wm11
$$ ---------------------
$$ . . . . X O . X 6 X |
$$ . . . . X O . X 5 X |
$$ . . . . X O O O X 7 |
$$ . . . . X X O O O O |
$$ . . . . X O O X X 8 |
$$ . X . . . X X X . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . X . O . . |[/go]
Click Here To Show Diagram Code
[go]$$W
$$ ---------------------
$$ . . . . X O . X X X |
$$ . . . . X O . X O X |
$$ . . . . X O O O . O |
$$ . . . . X X O O O O |
$$ . . . . X O O X X X |
$$ . X . . . X X X . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . X . O . . |[/go]

Variation: :study:
Click Here To Show Diagram Code
[go]$$W
$$ ---------------------
$$ . . . . 0 . 7 6 5 . |
$$ . . . . X O . X . 4 |
$$ . . . . X O 1 . 2 . |
$$ . . . . X X O O 3 9 |
$$ . . . . X O O . 8 . |
$$ . X . . . X X X . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . X . O . . |[/go]
Click Here To Show Diagram Code
[go]$$Wm11
$$ ---------------------
$$ . . . . X . O X O 4 |
$$ . . . . X O . X 1 X |
$$ . . . . X O O 3 X . |
$$ . . . . X X O O O O |
$$ . . . . X O O 2 X . |
$$ . X . . . X X X . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . X . O . . |[/go]
Click Here To Show Diagram Code
[go]$$Wm11 Approach ko (?)
$$ ---------------------
$$ . . . . X . O X 6 X |
$$ . . . . X O . X 5 X |
$$ . . . . X O O O X 7 |
$$ . . . . X X O O O O |
$$ . . . . X O O X X 8 |
$$ . X . . . X X X . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . X . O . . |[/go]
Author:  EdLee [ Sun Feb 25, 2018 12:40 am ]
Post subject: 
Hi Jeff,

Do you remember the sequence that led to the game shape ?
Click Here To Show Diagram Code
[go]$$
$$ -------------------
$$ . . . . . . . . . |
$$ . . . X O . . . . |
$$ . . . X O . . . . |
$$ . . . X X O O . . |
$$ . . . B W O . . . |
$$ X . . a B X X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . O . . |[/go]
Whatever happened around the ( :bc: - :wc: - :bc: ) exchange, but :white: didn't cut at (a)...

Compare:
Click Here To Show Diagram Code
[go]$$
$$ -------------------
$$ . . . . . . . . . |
$$ . . . X O . . . . |
$$ . . . X O . . . . |
$$ . . . X X O O . . |
$$ . . . X x O . . . |
$$ X . . . X X X . . |
$$ . . . . . . . . . |
$$ . . . . . . . . . |
$$ . . . . X . O . . |[/go]
W could use that extra (x) liberty... :study:
Author:  Joaz Banbeck [ Sun Feb 25, 2018 11:07 am ]
Post subject:  Re: Can This Shape Live??
My initial reaction is to not waste time trying to defend those two ugly stones at P17/P18, and escape with the rest of the group while he captures the two stones. The goal is to create options of S14 and S18.

Click Here To Show Diagram Code
[go]$$c
$$ ------------------
$$ . . . . . . . . . . |
$$ . . . . X O . X C . |
$$ . . . . X O . . . . |
$$ . . . . X X O O W . |
$$ . . . . X O O . . . |
$$ . X . . . X X X C . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |
$$ . . . . . X . O . . |
$$ . . . . . . . . . . |
$$ . . . . . . . . . . |[/go]


I don't have time this morning to read it out, but I thought that it should be considered as a possible third option between completely dead and completely alive.
Author:  jeffb99 [ Sun Feb 25, 2018 1:44 pm ]
Post subject:  Re: Can This Shape Live??
Thanks for the ideas. We looked at the possibility of sacrificing the 2 P stones and trying to escape with the other 4 down the side but didn't see a way to make it work. Black moves to S14 and/or T14 cuts off that avenue of escape.

I guess this highlights the importance of preventing "shape-stealing" moves and making a critical defensive play that might be gote but secures an important area. Painful lesson.

--Jeff
Author:  Joaz Banbeck [ Sun Feb 25, 2018 3:44 pm ]
Post subject:  Re: Can This Shape Live??
Joaz Banbeck wrote:
My initial reaction is to not waste time trying to defend those two ugly stones at P17/P18, and ...


After playing with it a while, I've come to the conclusion that the other four stones are ugly too. :-? I can't find anything better than Ed's approach ko.
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