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Go problem for 2015 new year
http://www.lifein19x19.com/viewtopic.php?f=10&t=11288
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Author:  macelee [ Wed Dec 31, 2014 7:11 am ]
Post subject:  Go problem for 2015 new year

A tesuji problem from a professional game I just processed. Black ignored the ko threat :w2:. So he must have a plan for his central group. Note the group is separated because the marked stones cannot be saved. This problem requires some reading but is not too difficult.

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

Author:  Elom [ Wed Dec 31, 2014 10:20 am ]
Post subject:  Re: Go problem for 2015 new year

Hey! No peeking. Think about shortage of liberties.

Nice and easy.
Click Here To Show Diagram Code
[go]$$B
$$ +---------------------------------------+
$$ | . . . . . . . . . X . O . O . . . . . |
$$ | . . . . . . . . X . X X O O O . . . . |
$$ | . . X X . . . O X . X X X O X . O . . |
$$ | . . O O . . . . X X O X O X . X O . . |
$$ | . . . . . . . X . . O O O . . . X . . |
$$ | . . . . . . . . . X O X X X X X O . . |
$$ | . . . . . . . . . O X O O O 4 X O X . |
$$ | . . . . . . . . X X X . . 3 2 O X . X |
$$ | . O O X . . . . X O O . O O 1 O X X . |
$$ | . X X X . . . . . X O . O X X X O O . |
$$ | . O X X X O . . . 5 6 9 X . . O . O . |
$$ | . O O X O . . . . . 7 8 X O X O . O . |
$$ | . . X O . . . . . . . O O X X X O . . |
$$ | . . . . . . . . . O O O X O X . O . . |
$$ | . . . . . . . . O O X X X O X O . . . |
$$ | . . . O . O X X O X . . . O . # O . . |
$$ | . . . . . X O O X . X X . O . # O . . |
$$ | . . . . O O O X . X . . X O # O O . . |
$$ | . . . . . O X X . O X . X . . . . . . |
$$ +---------------------------------------+[/go]

From here, it's hard for white to stop black connecting. Even if white put's 7 in atari, black can play over 9 and it's over.

Author:  macelee [ Wed Dec 31, 2014 12:28 pm ]
Post subject:  Re: Go problem for 2015 new year

To answer Elom:


What if I do this now? You can only follow up with 'a', saving some but not all stones.

Click Here To Show Diagram Code
[go]$$W
$$ +---------------------------------------+
$$ | . . . . . . . . . X . O . O . . . . . |
$$ | . . . . . . . . X . X X O O O . . . . |
$$ | . . X X . . . O X . X X X O X . O . . |
$$ | . . O O . . . . X X O X O X . X O . . |
$$ | . . . . . . . X . . O O O . . . X . . |
$$ | . . . . . . . . . X O X X X X X O . . |
$$ | . . . . . . . . . O X O O O O X O X . |
$$ | . . . . . . . . X X X . . X O O X . X |
$$ | . O O X . . . . X O O a O O X O X X . |
$$ | . X X X . . . . . X O . O X X X O O . |
$$ | . O X X X O . . . X O X X . 1 O . O . |
$$ | . O O X O . . . . . X O X O X O . O . |
$$ | . . X O . . . . . . . O O X X X O . . |
$$ | . . . . . . . . . O O O X O X . O . . |
$$ | . . . . . . . . O O X X X O X O . . . |
$$ | . . . O . O X X O X . . . O . # O . . |
$$ | . . . . . X O O X . X X . O . # O . . |
$$ | . . . . O O O X . X . . X O # O O . . |
$$ | . . . . . O X X . O X . X . . . . . . |
$$ +---------------------------------------+[/go]

Author:  ez4u [ Thu Jan 01, 2015 4:39 am ]
Post subject:  Re: Go problem for 2015 new year

Elom wrote:
Hey! No peeking. Think about shortage of liberties.

Nice and easy.
Click Here To Show Diagram Code
[go]$$B
$$ +---------------------------------------+
$$ | . . . . . . . . . X . O . O . . . . . |
$$ | . . . . . . . . X . X X O O O . . . . |
$$ | . . X X . . . O X . X X X O X . O . . |
$$ | . . O O . . . . X X O X O X . X O . . |
$$ | . . . . . . . X . . O O O . . . X . . |
$$ | . . . . . . . . . X O X X X X X O . . |
$$ | . . . . . . . . . O X O O O 4 X O X . |
$$ | . . . . . . . . X X X . . 3 2 O X . X |
$$ | . O O X . . . . X O O . O O 1 O X X . |
$$ | . X X X . . . . . X O . O X X X O O . |
$$ | . O X X X O . . . 5 6 9 X . . O . O . |
$$ | . O O X O . . . . . 7 8 X O X O . O . |
$$ | . . X O . . . . . . . O O X X X O . . |
$$ | . . . . . . . . . O O O X O X . O . . |
$$ | . . . . . . . . O O X X X O X O . . . |
$$ | . . . O . O X X O X . . . O . # O . . |
$$ | . . . . . X O O X . X X . O . # O . . |
$$ | . . . . O O O X . X . . X O # O O . . |
$$ | . . . . . O X X . O X . X . . . . . . |
$$ +---------------------------------------+[/go]

From here, it's hard for white to stop black connecting. Even if white put's 7 in atari, black can play over 9 and it's over.

Elom has the right idea. Only the execution seems suspect.

After 4 I think Black just continues with the blunt 5 and 7 to create the maximum reduction in liberties. If White tries to atari out, there is no answer to 9. As far as I can see, all alternatives produce a similar result.
Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . X . O . O . . . . . |
$$ | . . . . . . . . X . X X O O O . . . . |
$$ | . . X X . . . O X . X X X O X . O . . |
$$ | . . O O . . . . X X O X O X . X O . . |
$$ | . . . . . . . X . . O O O . . . X . . |
$$ | . . . . . . . . . X O X X X X X O . . |
$$ | . . . . . . . . . O X O O O 4 X O X . |
$$ | . . . . . . . . X X X 5 6 3 2 O X . X |
$$ | . O O X . . . . X O O . O O 1 O X X . |
$$ | . X X X . . . . . X O 9 O X X X O O . |
$$ | . O X X X O . . . 8 7 . X . . O . O . |
$$ | . O O X O . . . . . . . X O X O . O . |
$$ | . . X O . . . . . . . O O X X X O . . |
$$ | . . . . . . . . . O O O X O X . O . . |
$$ | . . . . . . . . O O X X X O X O . . . |
$$ | . . . O . O X X O X . . . O . X O . . |
$$ | . . . . . X O O X . X X . O . X O . . |
$$ | . . . . O O O X . X . . X O X O O . . |
$$ | . . . . . O X X . O X . X . . . . . . |
$$ ---------------------------------------[/go]

Author:  Elom [ Thu Jan 01, 2015 7:52 am ]
Post subject:  Re: Go problem for 2015 new year

Elom wrote:
Hey! No peeking. Think about shortage of liberties.

Nice and easy.
Click Here To Show Diagram Code
[go]$$B
$$ +---------------------------------------+
$$ | . . . . . . . . . X . O . O . . . . . |
$$ | . . . . . . . . X . X X O O O . . . . |
$$ | . . X X . . . O X . X X X O X . O . . |
$$ | . . O O . . . . X X O X O X . X O . . |
$$ | . . . . . . . X . . O O O . . . X . . |
$$ | . . . . . . . . . X O X X X X X O . . |
$$ | . . . . . . . . . O X O O O 4 X O X . |
$$ | . . . . . . . . X X X . . 3 2 O X . X |
$$ | . O O X . . . . X O O . O O 1 O X X . |
$$ | . X X X . . . . . X O . O X X X O O . |
$$ | . O X X X O . . . 5 6 9 X . . O . O . |
$$ | . O O X O . . . . . 7 8 X O X O . O . |
$$ | . . X O . . . . . . . O O X X X O . . |
$$ | . . . . . . . . . O O O X O X . O . . |
$$ | . . . . . . . . O O X X X O X O . . . |
$$ | . . . O . O X X O X . . . O . # O . . |
$$ | . . . . . X O O X . X X . O . # O . . |
$$ | . . . . O O O X . X . . X O # O O . . |
$$ | . . . . . O X X . O X . X . . . . . . |
$$ +---------------------------------------+[/go]

From here, it's hard for white to stop black connecting. Even if white put's 7 in atari, black can play over 9 and it's over.


macelee wrote:
To answer Elom:


What if I do this now? You can only follow up with 'a', saving some but not all stones.

Click Here To Show Diagram Code
[go]$$W
$$ +---------------------------------------+
$$ | . . . . . . . . . X . O . O . . . . . |
$$ | . . . . . . . . X . X X O O O . . . . |
$$ | . . X X . . . O X . X X X O X . O . . |
$$ | . . O O . . . . X X O X O X . X O . . |
$$ | . . . . . . . X . . O O O . . . X . . |
$$ | . . . . . . . . . X O X X X X X O . . |
$$ | . . . . . . . . . O X O O O O X O X . |
$$ | . . . . . . . . X X X . . X O O X . X |
$$ | . O O X . . . . X O O a O O X O X X . |
$$ | . X X X . . . . . X O . O X X X O O . |
$$ | . O X X X O . . . X O X X . 1 O . O . |
$$ | . O O X O . . . . . X O X O X O . O . |
$$ | . . X O . . . . . . . O O X X X O . . |
$$ | . . . . . . . . . O O O X O X . O . . |
$$ | . . . . . . . . O O X X X O X O . . . |
$$ | . . . O . O X X O X . . . O . # O . . |
$$ | . . . . . X O O X . X X . O . # O . . |
$$ | . . . . O O O X . X . . X O # O O . . |
$$ | . . . . . O X X . O X . X . . . . . . |
$$ +---------------------------------------+[/go]


I can just imagine that happening in one of my games :)

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


or--

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


so--

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


but--

Click Here To Show Diagram Code
[go]$$B
$$ +---------------------------------------+
$$ | . . . . . . . . . X . O . O . . . . . |
$$ | . . . . . . . . X . X X O O O . . . . |
$$ | . . X X . . . O X . X X X O X . O . . |
$$ | . . O O . . . . X X O X O X . X O . . |
$$ | . . . . . . . X . . O O O . . . X . . |
$$ | . . . . . . . . . X O X X X X X O . . |
$$ | . . . . . . . . . O X O O O O X O X . |
$$ | . . . . . . . . X X X . . X O O X . X |
$$ | . O O X . . . . X O O . O O X O X X . |
$$ | . X X X . . . . . X O . O X X X O O . |
$$ | . O X X X O . . . . X O X 1 O O . O . |
$$ | . O O X O . . . . . . X X O X O . O . |
$$ | . . X O . . . . . . . O O X X X O . . |
$$ | . . . . . . . . . O O O X O X . O . . |
$$ | . . . . . . . . O O X X X O X O . . . |
$$ | . . . O . O X X O X . . . O . # O . . |
$$ | . . . . . X O O X . X X . O . # O . . |
$$ | . . . . O O O X . X . . X O # O O . . |
$$ | . . . . . O X X . O X . X . . . . . . |
$$ +---------------------------------------+[/go]
If this is correct (unlikely), it's a nice tesuji :) now I'll check the next post.

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