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A Go Problem for you to solve!
http://lifein19x19.com/viewtopic.php?f=15&t=677
Page 1 of 2

Author:  Kirby [ Fri May 28, 2010 1:38 pm ]
Post subject:  A Go Problem for you to solve!

Save the marked stones!

Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . . . O O O B O X X . . . . . , . . . |
$$ | . . . . X X O O . . . . . . . . X . . |
$$ | . . . . X . . . . X . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Disclaimer: I did not come up with this problem on my own. I modified it slightly from another source.

Author:  Chew Terr [ Fri May 28, 2010 2:00 pm ]
Post subject:  Re: A Go Problem for you to solve!

An attempt!
Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . 6 1 O O O B O X X . . . . . , . . . |
$$ | . . 4 2 X X O O . . . . . . . . X . . |
$$ | . . 5 3 X . 8 7 . X . . . . . . . . . |
$$ | . . . . O . 9 . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . O O O . . . |
$$ | . . . . . . . . . . . . . O X X X . . |
$$ | . . . . . . . . . . . . O X . . . . . |
$$ | . . . . . . . . . . . . O X . . . . . |
$$ | . . . . . . . . . . . . O X . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Click Here To Show Diagram Code
[go]$$Wcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . O X O O O B O X X . . . . . , . . . |
$$ | . . O O X X O O b . . . . . . . X . . |
$$ | . . X X X . O X 1 X . . . . . . . . . |
$$ | . . . . O . X 2 a . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . O O O . . . |
$$ | . . . . . . . . . . . . . O X X X . . |
$$ | . . . . . . . . . . . . O X . . . . . |
$$ | . . . . . . . . . . . . O X . . . . . |
$$ | . . . . . . . . . . . . O X . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


'a' and 'b' are miai to kill/rescue.

Author:  daniel_the_smith [ Fri May 28, 2010 2:02 pm ]
Post subject:  Re: A Go Problem for you to solve!

Is it supposed to be harder than this?

EDIT: yes, yes it is. I missed something simple.

Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . . . O O O B O X X . . . . . , . . . |
$$ | . . . . X X O O . . . . . . . . X . . |
$$ | . . . . X 4 2 1 . X . . . . . . . . . |
$$ | . . . . O 5 3 . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . . . O O O B O X X . . . . . , . . . |
$$ | . . . . X X O O 2 3 . . . . . . X . . |
$$ | . . . . X . 6 1 4 X . . . . . . . . . |
$$ | . . . . O . 7 . 5 . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Author:  Chew Terr [ Fri May 28, 2010 2:08 pm ]
Post subject:  Re: A Go Problem for you to solve!

Daniel:
I'm probably missing something, but I think your first diagram might not work if white plays atari with 4, instead.
Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . . . O O O B O X X . . . . . , . . . |
$$ | . . . . X X O O . . . . . . . . X . . |
$$ | . . . . X 8 2 1 5 X . . . . . . . . . |
$$ | . . . . O 6 3 4 . . . . . . . . . . . |
$$ | . . . . . . 7 . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

or
Click Here To Show Diagram Code
[go]$$Bcm1 8 at 1, but what has the ladder breaker
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . . . O O O B O X X . . . . . , . . . |
$$ | . . . . X X O O 7 . . . . . . . X . . |
$$ | . . . . X 5 2 1 6 X . . . . . . . . . |
$$ | . . . . O . 3 4 . . . . . . . . . . . |
$$ | . . . . . . . 9 . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Author:  Kirby [ Fri May 28, 2010 2:13 pm ]
Post subject:  Re: A Go Problem for you to solve!

Chew Terr wrote:
Daniel:
I'm probably missing something, but I think your first diagram might not work if white plays atari with 4, instead.
Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . . . O O O B O X X . . . . . , . . . |
$$ | . . . . X X O O . . . . . . . . X . . |
$$ | . . . . X 8 2 1 5 X . . . . . . . . . |
$$ | . . . . O 6 3 4 . . . . . . . . . . . |
$$ | . . . . . . 7 . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

or
Click Here To Show Diagram Code
[go]$$Bcm1 8 at 1, but what has the ladder breaker
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . . . O O O B O X X . . . . . , . . . |
$$ | . . . . X X O O 7 . . . . . . . X . . |
$$ | . . . . X 5 2 1 6 X . . . . . . . . . |
$$ | . . . . O . 3 4 . . . . . . . . . . . |
$$ | . . . . . . . 9 . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


It's a good point that you've brought up. However, what if white does something similar to what you've just described, and plays :w1: at :b2: in the second diagram of your solution?


edit:
By the way, I've edited the original diagram a bit. Daniel's corresponds to what the problem says now.

Author:  Chew Terr [ Fri May 28, 2010 2:26 pm ]
Post subject:  Re: A Go Problem for you to solve!

Kirby, thanks, I missed that in my diagram. Blind spot or tinted glasses, I guess.

Author:  Solomon [ Fri May 28, 2010 2:52 pm ]
Post subject:  Re: A Go Problem for you to solve!

Chew Terr wrote:
An attempt!
Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . 6 1 O O O B O X X . . . . . , . . . |
$$ | . . 4 2 X X O O . . . . . . . . X . . |
$$ | . . 5 3 X . 8 7 . X . . . . . . . . . |
$$ | . . . . O . 9 . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . O O O . . . |
$$ | . . . . . . . . . . . . . O X X X . . |
$$ | . . . . . . . . . . . . O X . . . . . |
$$ | . . . . . . . . . . . . O X . . . . . |
$$ | . . . . . . . . . . . . O X . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Click Here To Show Diagram Code
[go]$$Wcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . O X O O O B O X X . . . . . , . . . |
$$ | . . O O X X O O b . . . . . . . X . . |
$$ | . . X X X . O X 1 X . . . . . . . . . |
$$ | . . . . O . X 2 a . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . O O O . . . |
$$ | . . . . . . . . . . . . . O X X X . . |
$$ | . . . . . . . . . . . . O X . . . . . |
$$ | . . . . . . . . . . . . O X . . . . . |
$$ | . . . . . . . . . . . . O X . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


'a' and 'b' are miai to kill/rescue.

This doesn't work. :w1: in the last diagram is incorrect, if W plays like this then B can't kill:
Click Here To Show Diagram Code
[go]$$Wcm1 Can't net + ladder doesn't work.
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . O . O O O B O X X . . . . . , . . . |
$$ | . . O O X X O O 2 . . . . . . . X . . |
$$ | . . X X X 4 O X 3 X . . . . . . . . . |
$$ | . . . . O . X 1 7 . . . . . . . . . . |
$$ | . . . . . . . 6 . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . O O O . . . |
$$ | . . . . . . . . . . . . . O X X X . . |
$$ | . . . . . . . . . . . . O X . . . . . |
$$ | . . . . . . . . . . . . O X . . . . . |
$$ | . . . . . . . . . . . . O X . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Author:  Jordus [ Fri May 28, 2010 4:18 pm ]
Post subject:  Re: A Go Problem for you to solve!

Here is a try....
Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . . . O O O B O X X . . . . . , . . . |
$$ | . . . . X X O O . . . . . . . . X . . |
$$ | . . . . X . . 1 . X . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Author:  Solomon [ Fri May 28, 2010 4:35 pm ]
Post subject:  Re: A Go Problem for you to solve!

Jordus wrote:
Here is a try....
Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . . . O O O B O X X . . . . . , . . . |
$$ | . . . . X X O O . . . . . . . . X . . |
$$ | . . . . X . . 1 . X . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

This is like proving a theorem by writing "Suppose that" and nothing else.

Author:  Kirby [ Fri May 28, 2010 5:00 pm ]
Post subject:  Re: A Go Problem for you to solve!

Araban wrote:
Jordus wrote:
Here is a try....
Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . . . O O O B O X X . . . . . , . . . |
$$ | . . . . X X O O . . . . . . . . X . . |
$$ | . . . . X . . 1 . X . . . . . . . . . |
$$ | . . . . O . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

This is like proving a theorem by writing "Suppose that" and nothing else.


The result trivially follows :)

Author:  daniel_the_smith [ Fri May 28, 2010 7:47 pm ]
Post subject:  Re: A Go Problem for you to solve!

The continuation is left as an exercise for the reader.

Author:  fwiffo [ Fri May 28, 2010 8:35 pm ]
Post subject:  Re: A Go Problem for you to solve!

Click Here To Show Diagram Code
[go]$$Bm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . . 2 O O O B O X X . . . . . , . . . |
$$ | . . . . X X O O 9 . . . . . . . X . . |
$$ | . . . . X 8 3 4 7 X . . . . . . . . . |
$$ | . . . 1 O . 6 5 . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

If white doesn't play :w2:, black plays there and captures three stones.

Click Here To Show Diagram Code
[go]$$Wm10
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . . O O O O B O X X . . . . . , . . . |
$$ | . . . . X X O O X . . . . . . . X . . |
$$ | . . . . X O 1 O X X . . . . . . . . . |
$$ | . . . X O 3 O X . . . . . . . . . . . |
$$ | . . . . 4 . 2 . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]


Sneakier resistance:
Click Here To Show Diagram Code
[go]$$Bm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . . a O O O B O X X . . . . . , . . . |
$$ | . . . . X X O O . . . . . . . . X . . |
$$ | . . . . X 2 3 4 . X . . . . . . . . . |
$$ | . . . 1 O 5 . b . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |[/go]

Black has a and b as miai.

Author:  Jordus [ Fri May 28, 2010 10:39 pm ]
Post subject:  Re: A Go Problem for you to solve!

Quote:
This is like proving a theorem by writing "Suppose that" and nothing else.


I thought the read-out after that first move is blatantly obvious...

After reading what everybody else said... all but one. make that two, so far have read the same thing I have....

Author:  GoCat [ Fri May 28, 2010 10:45 pm ]
Post subject:  Re: A Go Problem for you to solve!

@fwiffo:

What happens if white plays 2 at D15? (Sorry I don't have the diagram thing figured out.)

I was also looking at your choice for 1 (which I really thought was the solution), but white doesn't have to connect solidly, does he? If 2 at d15, then your move 8 puts the 3 black stones in atari. And, as far as I can tell, if white 2 at d15, then black cutting at c16 doesn't amount to much.


That said, the sequence could work out longer -- I just can't see it.

Author:  hiyayang [ Sat May 29, 2010 3:36 am ]
Post subject:  Re: A Go Problem for you to solve!

I think it is one of the problems that can be solved pretty much based on logical analysis alone.

It is quite obvious that black has to capture one of the white groups to save its own.

How is black going to capture the white stones marked below? Here is a plan, which doesn't quite work yet, due to ladder and liberty:

Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . . 1 W W W B O X X . . . . . , . . . |
$$ | . . 3 2 X X O O . . . . . . . . X . . |
$$ | . 7 6 4 X . . . . X . . . . . . . . . |
$$ | . . 8 5 O . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


and continuation --

Click Here To Show Diagram Code
[go]$$Bcm9
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . . X W W W B O X X . . . . . , . . . |
$$ | . . X O X X O O . . . . . . . . X . . |
$$ | 5 X O O X T . . . X . . . . . . . . . |
$$ | 4 2 O 8 O T . . . . . . . . . . . . . |
$$ | 7 3 1 6 . T . . . . . . . . . . . . . |
$$ | . . . 9 . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


For this to work, black needs to occupy the three marked spots.

Now we turn our attention to the other white group and see if black can take the three spots while threatening to capture that group:

Click Here To Show Diagram Code
[go]$$Bcm1
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . . . O O O B O X X . . . . . , . . . |
$$ | . . . . X X O O 7 . . . . . . . X . . |
$$ | . . . . X 5 2 1 6 X . . . . . . . . . |
$$ | . . . . O . 3 4 . . . . . . . . . . . |
$$ | . . . . . . . 9 . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


and continuation --

Click Here To Show Diagram Code
[go]$$Wcm10
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . . . O O O B O X X . . . . . , . . . |
$$ | . . . . X X O O X . . . . . . . X . . |
$$ | . . . . X X O O O X . . . . . . . . . |
$$ | . . . . O a X O 1 . . . . . . . . . . |
$$ | . . . . . . b X . 2 . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


White is left with two options, a or b.

If white a, black plays out the variation Chew Terr gave in his first post to extend the liberties before filling b to capture white group.

If white b, black takes a --

Click Here To Show Diagram Code
[go]$$Wcm12
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O O . . . O O . . . . . . . . . . |
$$ | . . O B B B B B O . O . . . . X . . . |
$$ | . . . W W W B O X X . . . . . , . . . |
$$ | . . . c X X O O X . . . . . . . X . . |
$$ | . . . . X X O O O X . . . . . . . . . |
$$ | . . . . O 2 X O O . . . . . . . . . . |
$$ | . . . . b 4 1 X 3 X . . . . . . . . . |
$$ | . . . . . a . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . O . . . . |
$$ | . . . . . . . . . . . . . O . . . . . |
$$ | . . . . . . . . . . . . O . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Now black is ready to capture the marked white stones in the sequence shown earlier.

White may still resist with options like a, b or c, but black will capture one of the groups regardless. I will leave that as an exercise. :)

Author:  Solomon [ Sat May 29, 2010 7:04 am ]
Post subject:  Re: A Go Problem for you to solve!

Jordus wrote:
Quote:
This is like proving a theorem by writing "Suppose that" and nothing else.


I thought the read-out after that first move is blatantly obvious...

After reading what everybody else said... all but one. make that two, so far have read the same thing I have....

That's funny, because everyone prior to when you posted were also incorrect. I should also mention this is a dan-level problem.

Author:  GoCat [ Sat May 29, 2010 7:26 am ]
Post subject:  Re: A Go Problem for you to solve!

@hiyayang: Very nice. Now if I can just get to the point where I can do all that in my head, during a game....

Author:  MountainGo [ Sat May 29, 2010 8:17 am ]
Post subject:  Re: A Go Problem for you to solve!

I've been working on this, and I haven't found the solution yet, but I have the feeling it's going to be one of those ridiculously long, crazy ones.

Author:  Chew Terr [ Sat May 29, 2010 8:46 am ]
Post subject:  Re: A Go Problem for you to solve!

Hiyayang: Wow, even more complex than I'd thought!

Kirby:
Thanks, this is a really cool problem. It sprawls over a large scale and has a lot of things that seem to almost work, except for the hidden trap. Cool problem, thanks for sharing.

Author:  Solomon [ Sat May 29, 2010 9:10 am ]
Post subject:  Re: A Go Problem for you to solve!

Those who are up for a challenge may want to consider this slightly different problem (also cut away the excess from Kirby's problem with a shorter ladder-breaker). The thing about the problem posted by Kirby is that E13 is suboptimal play from White in response to Black E14:

Click Here To Show Diagram Code
[go]$$Bcm1
$$ -------------------------
$$ | . . . . . . . . . . . .
$$ | . . O O . . . O O . . .
$$ | . . O X X X X X O . O .
$$ | . . . O O O X O X X . .
$$ | . . . . X X O O . . . .
$$ | . . . . . . . . . X . .
$$ | . . . . . . . . . . . .
$$ | . . . . . . . . . . O .
$$ | . . . . . . . . . . . .[/go]

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