When i was doing some Tsumego on OGS i stumbled across the following problem:
https://online-go.com/puzzle/15017There are a few variations to this and in the one, where white connects at R17, black T17 and then white S19 the solution states, that black can live with either A, B or C...
- Click Here To Show Diagram Code
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$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . 2 . |
$$ | . . . . . . . . . . . . . O . O O X X |
$$ | . . . . . . . . . . . . . . O . O O 1 |
$$ | . . . , . . . . . , . . . . . O O X O |
$$ | . . . . . . . . . . . . . . . O X X . |
$$ | . . . . . . . . . . . . . . O X . c . |
$$ | . . . . . . . . . . . . . . O X . b . |
$$ | . . . . . . . . . . . . . . O X X X a |
$$ | . . . . . . . . . . . . . . O O O O . |
$$ | . . . , . . . . . , . . . . . , . O . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
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$$ +---------------------------------------+[/go]
...but i can not really find a way for black to live with any of those options.
A: After
,
hits the vital point:
- Click Here To Show Diagram Code
[go]$$
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . O . |
$$ | . . . . . . . . . . . . . O . O O X X |
$$ | . . . . . . . . . . . . . . O . O O X |
$$ | . . . , . . . . . , . . . . . O O X O |
$$ | . . . . . . . . . . . . . . . O X X . |
$$ | . . . . . . . . . . . . . . O X . . . |
$$ | . . . . . . . . . . . . . . O X . 2 . |
$$ | . . . . . . . . . . . . . . O X X X 1 |
$$ | . . . . . . . . . . . . . . O O O O . |
$$ | . . . , . . . . . , . . . . . , . O . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]
B: After
white answers with
and again i can't find out how black is supposed to live here:
- Click Here To Show Diagram Code
[go]$$
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . O . |
$$ | . . . . . . . . . . . . . O . O O X X |
$$ | . . . . . . . . . . . . . . O . O O X |
$$ | . . . , . . . . . , . . . . . O O X O |
$$ | . . . . . . . . . . . . . . . O X X . |
$$ | . . . . . . . . . . . . . . O X 2 a b |
$$ | . . . . . . . . . . . . . . O X . 1 . |
$$ | . . . . . . . . . . . . . . O X X X c |
$$ | . . . . . . . . . . . . . . O O O O . |
$$ | . . . , . . . . . , . . . . . , . O . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]
Neither A, nor B serve the task and because white has an Atari at A, things like C into B also don't quite work out, as it seems.
C: Similar to B. After white plays the vital point black seems to be shut down:
- Click Here To Show Diagram Code
[go]$$
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . O . |
$$ | . . . . . . . . . . . . . O . O O X X |
$$ | . . . . . . . . . . . . . . O . O O X |
$$ | . . . , . . . . . , . . . . . O O X O |
$$ | . . . . . . . . . . . . . . . O X X c |
$$ | . . . . . . . . . . . . . . O X . 1 . |
$$ | . . . . . . . . . . . . . . O X 2 a b |
$$ | . . . . . . . . . . . . . . O X X X . |
$$ | . . . . . . . . . . . . . . O O O O . |
$$ | . . . , . . . . . , . . . . . , . O . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ +---------------------------------------+[/go]
If black answers at A, white will play Hane into C, after black blocks and if black B, white C does the job immediately. If black plays see i would think that white B kills the black group.
Most of the problems of this collection are well above my current skill, so i wouldn't be surprised if i overlooked some obvious things, but i would be very interested to know what those things are