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Fun little 9x9 problem
http://www.lifein19x19.com/viewtopic.php?f=15&t=11011		 Page 1 of 1
Author:  leichtloeslich [ Sun Nov 02, 2014 4:58 am ]
Post subject:  Fun little 9x9 problem
Click Here To Show Diagram Code
[go]$$Bc
$$ +-------------------+
$$ | . . . . . . . B . |
$$ | . . . . . . O X . |
$$ | . . , O . X O X . |
$$ | . . . . O O O O X |
$$ | . O O O X X X X . |
$$ | . X X O X . O X . |
$$ | . . , X X . O O . |
$$ | . . . X O O . X . |
$$ | . . . . . . . . . |
$$ +-------------------+[/go]


From one of my DGS games (that's still going on). Chinese rules with 7.5 komi, black's last move is marked.
White to win (I think, at least). Should be doable for any SDK.

Solution:
Click Here To Show Diagram Code
[go]$$Wc
$$ +-------------------+
$$ | . . . . . . . X . |
$$ | . . . . . . O X . |
$$ | . . , O . X O X . |
$$ | . . . . O O O O X |
$$ | . O O O X X X X . |
$$ | . X X O X . O X . |
$$ | . . , X X . O O . |
$$ | . 5 . X O O . X 1 |
$$ | . . . . 3 . 4 2 . |
$$ +-------------------+[/go]

This looks like a winning sequence, as I don't see how black can prevet seki from this position. (In fact, given that white has a bigeye, black might actually die, but seki is obviously enough for white.)

Also, I don't think black can play 2 at 4, since white has a nice ko-threat at j5, while black doesn't have any threats big enough to overcome komi, it seems. (I'm a bit sketchy on that one, actually.)

There may be other variations that also work, but this seemed easiest to me.

If you found the solution, here's a picture of dog that looks like he is impressed with your reading ability
Image
Author:  DrStraw [ Sun Nov 02, 2014 6:14 am ]
Post subject:  Re: Fun little 9x9 problem
As the game is still going on I do not think it is appropriate to comment.
Author:  leichtloeslich [ Sun Nov 02, 2014 6:31 am ]
Post subject:  Re: Fun little 9x9 problem
DrStraw wrote:
As the game is still going on I do not think it is appropriate to comment.

Actually I'm black, and my opponent (white) blocked at g9 in the posted position.
I immediately fixed my bad aji, told him that he missed his chance (imho) and gave him the variations.

So I don't see how discussing this position could possibly be unethical, as its variations are no longer relevant to the game. (Which technically isn't finished yet, but not so technically, there's only one yose point for white left and after that black wins by 4 points, so it kind of is finished already.)
Author:  DrStraw [ Sun Nov 02, 2014 7:19 am ]
Post subject:  Re: Fun little 9x9 problem
Ah, okay. That was not made clear. The line you showed was the one I thought of. I see nothing to prevent it.
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