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Guess the next move

Posted: Wed Aug 28, 2013 2:41 am
by macelee
From a professional game. Please guess black's next move.
Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . O . . . . . |
$$ | . . O , . . . . . O . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . 1 . . |
$$ | . . . , . . . . . , . . . . . X O . . |
$$ | . . . . . . . . . . . . . . X . X O . |
$$ | . . . . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . O . O . . |
$$ | . . . . . . . . . . . . . X X . . . . |
$$ | . . O . . . . . . . . . . . . O . . . |
$$ | . . . , . . . . . X . . . X . , O . . |
$$ | . . . O . . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . X X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]
Hint: S8 creates a big ko. Black needs two big ko threats to win it (white has a local threat).

Re: Guess the next move

Posted: Wed Aug 28, 2013 2:55 am
by logan
my guess is k17 then force a crosscut (assuming Black wants to force the ko fight so brutely)

Re: Guess the next move

Posted: Wed Aug 28, 2013 7:40 am
by Kirby
C4. If w plays d4, black starts ko at s8. Then as ko threat, b5 to live in corner. Depending on w answer, play again in bottom left corner to threaten life.

Re: Guess the next move

Posted: Wed Aug 28, 2013 7:44 am
by Kirby
Thank you for this type of post. It's good to have posts with content about actual go positions.

Posts about breathing, hours of study time, etc., are interesting, but more subject to bickering and less educational.

Re: Guess the next move

Posted: Thu Aug 29, 2013 2:28 am
by macelee
This game is clearly about creating ko threats before starting a ko fight. Note that white needs to create at least two big threats because black has a local threat. logan has given the correct move.
Click Here To Show Diagram Code
[go]$$Bc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . 1 2 4 . O . . . . . |
$$ | . . O , . . . . 0 O 3 . . . . X . . . |
$$ | . . . . . . . . . 9 . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . O . . |
$$ | . . . , . . . . . , . . . . . X O 7 . |
$$ | . . . . . . . . . . . . . . X 8 X O . |
$$ | . . . . . . . . . . . . . . . X 6 5 . |
$$ | . . . . . . . . . . . . . . O . O . . |
$$ | . . . . . . . . . . . . . X X . . . . |
$$ | . . O . . . . . . . . . . . . O . . . |
$$ | . . . , . . . . . X . . . X . , O . . |
$$ | . . . O . . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . X X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]
Click Here To Show Diagram Code
[go]$$Bcm11 :w14: @ :ws: :w16: @ :b11:
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . 7 X O O . O . . . . . |
$$ | . . O , . . . 5 O O X . . . . X . . . |
$$ | . . . . . . . . . X . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . X . . . . . . . . . . . . . O . . |
$$ | . . . , . . . . . , . . . . . X O X 3 |
$$ | . . . . . . . . . . . . . . X @ 1 O 2 |
$$ | . . . . . . . . . . . . . . . X O X . |
$$ | . . . . . . . . . . . . . . O . O . . |
$$ | . . . . . . . . . . . . . X X . . . . |
$$ | . . O . . . . . . . . . . . . O . . . |
$$ | . . . , . . . . . X . . . X . , O . . |
$$ | . . . O . . . . . . . . . . . X O . . |
$$ | . . . . . . . . . . . . . . . . X X . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]
As seen, black lost many points by starting and not winning the ko, but got good compensation by killing the two stones in ladder.

Kirby's answer is also reasonable. Breaking the corner at C4 and D4 is normally quite huge. However black needs two threats in this game. After C4/D4 exchange, the subsequent ko threats appear to be too small.

The complete game record is at http://www.go4go.net/go/games/sgfview/35783

Re: Guess the next move

Posted: Thu Aug 29, 2013 4:30 am
by wineandgolover
Thanks, macelee.

Like Kirby, I too appreciate these sorts of posts. Even if I did start the "breathing" thread he mentioned. :blackeye:

Re: Guess the next move

Posted: Thu Aug 29, 2013 11:42 am
by macelee
wineandgolover wrote:Thanks, macelee.

Like Kirby, I too appreciate these sorts of posts. Even if I did start the "breathing" thread he mentioned. :blackeye:
I will definitely post more like this one.