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Question about a tesuji-problem
http://www.lifein19x19.com/viewtopic.php?f=15&t=11973		 Page 1 of 1
Author:  BadukStone [ Sat Jun 27, 2015 3:00 pm ]
Post subject:  Question about a tesuji-problem
In Lee Changho's Selected Tesuji Problems, I've encountered a tesuji-problem which, I think, has two solutions (a and b):


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


'a' was the solution given in the book, and I agree with that, but I think 'b' is also the right move.

My question is whether this problem has two solutions or not.
Author:  Loons [ Sat Jun 27, 2015 6:40 pm ]
Post subject:  Re: Question about a tesuji-problem
My two cents, in a relatively bad currency:

'b' is, in isolation just worse than 'a' if black later decides to sacrifice.
Author:  ez4u [ Sun Jun 28, 2015 7:02 am ]
Post subject:  Re: Question about a tesuji-problem
BadukStone wrote:
In Lee Changho's Selected Tesuji Problems, I've encountered a tesuji-problem which, I think, has two solutions (a and b):


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


'a' was the solution given in the book, and I agree with that, but I think 'b' is also the right move.

My question is whether this problem has two solutions or not.

It appears to have at least 3. :)

Interestingly, the Web Go Board extension that I use took your original asymmetrical 10x11 diagram and turned it into a 10x10 (a previously undiscoverd bug?), changing the problem to the situation below. This appears to have only one solution. What is it?
:study:
Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------------
$$ | . . X . . . . . . . |
$$ | . . . . . . . . . . |
$$ | . X X O . . . . . . |
$$ | . O X O . . , . . . |
$$ | a . O X O . . . . . |
$$ | . O O X O . . . . . |
$$ | b O X X O . , . . . |
$$ | X O X . O . . . . . |
$$ | . X X O . . . . . . |
$$ | . . O O . . . . . . |
$$ ---------------------[/go]
Author:  Knotwilg [ Sun Jun 28, 2015 7:11 am ]
Post subject:  Re: Question about a tesuji-problem
Great catch, Dave!
Author:  Bill Spight [ Sun Jun 28, 2015 8:48 am ]
Post subject:  Re: Question about a tesuji-problem
Very good, Dave! Better problem than the book!
Author:  BadukStone [ Sun Jun 28, 2015 9:00 am ]
Post subject:  Re: Question about a tesuji-problem
Loons wrote:
My two cents, in a relatively bad currency:

'b' is, in isolation just worse than 'a' if black later decides to sacrifice.


Thanks, that makes sense now that I think about it. :scratch:

ez4u wrote:
This appears to have only one solution. What is it?
:study:


I think :b1: (b) is wrong this time, because the throw-in at :w2: works now:

( :b5: at :w2: )
Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------------
$$ | . . X . . . . . . . |
$$ | . . . . . . . . . . |
$$ | . X X O . . . . . . |
$$ | . O X O . . , . . . |
$$ | . . O X O . . . . . |
$$ | 4 O O X O . . . . . |
$$ | 1 O X X O . , . . . |
$$ | X O X 6 O . . . . . |
$$ | 2 X X O . . . . . . |
$$ | 3 . O O . . . . . . |
$$ ---------------------[/go]
Author:  ez4u [ Sun Jun 28, 2015 9:32 am ]
Post subject:  Re: Question about a tesuji-problem
BadukStone wrote:
Loons wrote:
My two cents, in a relatively bad currency:

'b' is, in isolation just worse than 'a' if black later decides to sacrifice.


Thanks, that makes sense now that I think about it. :scratch:

ez4u wrote:
This appears to have only one solution. What is it?
:study:


I think :b1: (b) is wrong this time, because the throw-in at :w2: works now:

( :b5: at :w2: )
Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------------
$$ | . . X . . . . . . . |
$$ | . . . . . . . . . . |
$$ | . X X O . . . . . . |
$$ | . O X O . . , . . . |
$$ | . . O X O . . . . . |
$$ | 4 O O X O . . . . . |
$$ | 1 O X X O . , . . . |
$$ | X O X 6 O . . . . . |
$$ | 2 X X O . . . . . . |
$$ | 3 . O O . . . . . . |
$$ ---------------------[/go]

You are on the right track! So what is the right answer?
Author:  BadukStone [ Sun Jun 28, 2015 10:31 am ]
Post subject:  Re: Question about a tesuji-problem
So I believe that :b1: must be at the same spot as in the book:

Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------------
$$ | . . X . . . . . . . |
$$ | . . . . . . . . . . |
$$ | . X X O . . . . . . |
$$ | . O X O . . , . . . |
$$ | 1 . O X O . . . . . |
$$ | 7 O O X O . . . . . |
$$ | 3 O X X O . , . . . |
$$ | X O X 4 O . . . . . |
$$ | 5 X X O . . . . . . |
$$ | 6 2 O O . . . . . . |
$$ ---------------------[/go]
Author:  SoDesuNe [ Sun Jun 28, 2015 12:49 pm ]
Post subject:  Re: Question about a tesuji-problem
Click Here To Show Diagram Code
[go]$$Bc Same problem as before?
$$ ---------------------
$$ | . . X . . . . . . . |
$$ | . . . . . . . . . . |
$$ | . X X O . . . . . . |
$$ | . O X O . . , . . . |
$$ | 1 . O X O . . . . . |
$$ | . O O X O . . . . . |
$$ | . O X X O . , . . . |
$$ | X O X . O . . . . . |
$$ | 2 X X O . . . . . . |
$$ | . . O O . . . . . . |
$$ ---------------------[/go]


Click Here To Show Diagram Code
[go]$$Bc Increasing liberties
$$ ---------------------
$$ | . . X . . . . . . . |
$$ | . . . . . . . . . . |
$$ | 5 X X O . . . . . . |
$$ | . O X O . . , . . . |
$$ | 2 . O X O . . . . . |
$$ | 4 O O X O . . . . . |
$$ | 3 O X X O . , . . . |
$$ | X O X . O . . . . . |
$$ | 1 X X O . . . . . . |
$$ | . . O O . . . . . . |
$$ ---------------------[/go]
Author:  BadukStone [ Sun Jun 28, 2015 1:36 pm ]
Post subject:  Re: Question about a tesuji-problem
SoDesuNe wrote:
Click Here To Show Diagram Code
[go]$$Bc Same problem as before?
$$ ---------------------
$$ | . . X . . . . . . . |
$$ | . . . . . . . . . . |
$$ | . X X O . . . . . . |
$$ | . O X O . . , . . . |
$$ | 1 . O X O . . . . . |
$$ | . O O X O . . . . . |
$$ | . O X X O . , . . . |
$$ | X O X . O . . . . . |
$$ | 2 X X O . . . . . . |
$$ | . . O O . . . . . . |
$$ ---------------------[/go]

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

You're right, I overlooked this variation. :-?

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