Semeai, anyone?

SoDesuNe · Post by **SoDesuNe** » Tue Oct 22, 2013 9:42 am

Since the problem in the Damezumari thread was finally solved, I thought, why not present another interesting problem, which involves a lack of liberties? =)
This funny one is from Go/Segeo's Tesuji Dictionary vol. 1. It's rated B, so within these books it is of intermediate difficulty.

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

schawipp · Post by **schawipp** » Tue Oct 22, 2013 3:05 pm

Just an initial guess...:

SoDesuNe · Post by **SoDesuNe** » Tue Oct 22, 2013 11:47 pm

schawipp wrote:Just an initial guess...:

I would start with J2, which forces a white response around K3 (otherwise w loses the G4 stones). White cannot respond at H2 because of J4. If w connects at K3 I would connect at H2. Now, the lower black stones have 5 liberties which seems favorable with respect to the white E3 group. Side variation: If w replies at K2 instead of K3, J4 does not kill G4 (self atari at K3 ;-) ), however b gets H2 in sente and can play F2 afterwards - again 5 liberties - and the keft w stones will die.

Or is black supposed to kill all of the w stones? That would come quite as a surprise for me... :scratch:

Edit: Starting right away with F2 - E2 - E4 may look tempting, but w can stretch to E1. In the following semeai b can only get the single C2 stone but not more. Thus, b needs to gain an additional liberty first.

post scriptum:

schawipp · Post by **schawipp** » Wed Oct 23, 2013 2:00 am

I tried a bit harder and put my thoughts into an SGF:

SoDesuNe · Post by **SoDesuNe** » Wed Oct 23, 2013 2:34 am

Very nice work, indeed!

But... =D

HermanHiddema · Post by **HermanHiddema** » Wed Oct 23, 2013 2:51 am

SoDesuNe wrote:Very nice work, indeed!

But... =D

Just for reference: Here is the main line from the answer. The - -exchange seems to make sure White cannot push through at after . Though, I think with capturing six White stones, White's position will surely collapse.
Anyway, I think pushing in at first is better style since when White does not answer at , you don't need to kill Ko-threats with and so on.
$$Bc Black to play
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . X X . . . . . . . . . |
$$ | . . . X . . X X O O X . . . . X . . . |
$$ | . . . . . X O O O X O O O O . . . . . |
$$ | . . X X . X O 4 3 X . . X . . X . . . |
$$ | . . X O O O X O O 6 O O X . X . . . . |
$$ | . X O . 2 1 X 7 5 . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+
Click Here To Show Diagram Code
[go]$$Bc Black to play $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . X X . . . . . . . . . | $$ | . . . X . . X X O O X . . . . X . . . | $$ | . . . . . X O O O X O O O O . . . . . | $$ | . . X X . X O 4 3 X . . X . . X . . . | $$ | . . X O O O X O O 6 O O X . X . . . . | $$ | . X O . 2 1 X 7 5 . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]
It's White's turn again and he can still try something wicked : D

Click Here To Show Diagram Code: [go]$$Wc white can try :w1: $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . X X . . . . . . . . . | $$ | . . . X . . X X O O X . . . . X . . . | $$ | . . . . . X O O O X O O O O . . . . . | $$ | . . X X . X O O X X . . X . . X . . . | $$ | . . X O O O X O O O O O X . X . . . . | $$ | . X O . O X X X X . . . . . . . . . . | $$ | . 1 . . . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Click Here To Show Diagram Code: [go]$$Wc white is hoping for this $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . X X . . . . . . . . . | $$ | . . . X . . X X O O X . . . . X . . . | $$ | . . . . . X O O O X O O O O . . . . . | $$ | . . X X 6 X O O X X . . X . . X . . . | $$ | . 2 X O O O X O O O O O X . X . . . . | $$ | 8 X O . O X X X X 7 . . . . . . . . . | $$ | . 1 . 3 5 4 . . 9 . . . . . . . . . . | $$ +---------------------------------------+[/go]

Click Here To Show Diagram Code: [go]$$Wc black should play the vital point immediately $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . X X . . . . . . . . . | $$ | . . . X . . X X O O X . . . . X . . . | $$ | . . . . . X O O O X O O O O . . . . . | $$ | . . X X . X O O X X . . X . . X . . . | $$ | . . X O O O X O O O O O X . X . . . . | $$ | . X O . O X X X X . . . . . . . . . . | $$ | . 1 . 2 . . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Click Here To Show Diagram Code: [go]$$Wc black wins the semeai $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . X X . . . . . . . . . | $$ | . . . X . . X X O O X . . . . X . . . | $$ | . . . . . X O O O X O O O O . . . . . | $$ | . 0 X X 6 X O O X X . . X . . X . . . | $$ | . 3 X O O O X O O O O O X . X . . . . | $$ | 4 X O 9 O X X X X . . . . . . . . . . | $$ | . 1 7 2 5 8 . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Click Here To Show Diagram Code: [go]$$Wc :b10: @ :bc: creates a stone tower tesuji $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . X X . . . . . . . . . | $$ | . . . X . . X X O O X . . . . X . . . | $$ | . . . . . X O O O X O O O O . . . . . | $$ | . . X X 8 X O O X X . . X . . X . . . | $$ | 5 3 X O O O X O O O O O X . X . . . . | $$ | 4 B O 9 O X X X X . . . . . . . . . . | $$ | 7 1 . 2 6 . . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

SoDesuNe · Post by **SoDesuNe** » Wed Oct 23, 2013 5:25 am

Not the answer from the book but seems to work nonetheles : ) Great, congratulations schawipp and HermanHiddema!

Click Here To Show Diagram Code: [go]$$Bc Book answer 1 - :b9: seems more straightforward regarding possible variations but is not very intuitive $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . X X . . . . . . . . . | $$ | . . . X . . X X O O X . . . . X . . . | $$ | . . . . . X O O O X O O O O . . . . . | $$ | . . X X . X O 4 3 X . . X . . X . . . | $$ | . 0 X O O O X O O 6 O O X . X . . . . | $$ | . X O . 2 1 X 7 5 . . . . . . . . . . | $$ | . 8 . . . 9 . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

Click Here To Show Diagram Code: [go]$$Bcm11 Book answer 2 $$ | . . . , . . . . . , . . . . . , . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . X X . . . . . . . . . | $$ | . . . X . . X X O O X . . . . X . . . | $$ | . . . . . X O O O X O O O O . . . . . | $$ | . 7 X X 5 X O X X X . . X . . X . . . | $$ | 9 O X O O O X O O O O O X . X . . . . | $$ | 1 X O 4 O X X X X 8 . . . . . . . . . | $$ | . O 6 3 2 X . . . . . . . . . . . . . | $$ +---------------------------------------+[/go]

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