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Interesting problem
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Author:  Shaddy [ Fri Aug 12, 2011 11:24 am ]
Post subject:  Interesting problem
Click Here To Show Diagram Code
[go]$$c White to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . X O O O O . . |
$$ | . . . . . . . . . . . X . X . . X . . |
$$ | . . . . . . . . . . . . . X O O X . . |
$$ | . . . . . . . . . . . . O O X X . . . |
$$ | . . . . . . . . . . . . O X X . X . . |
$$ | . . . . . . . . . . . X X O . O . . . |
$$ | . . . , . . . . . , . . . O . , O O . |
$$ | . . . . . . . . . . . . X O . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


White to escape with his three stones.
Author:  Marcus [ Fri Aug 12, 2011 11:35 am ]
Post subject:  Re: Interesting problem
N15 stands out as a good initial move to me ... reading ...
Author:  HermanHiddema [ Fri Aug 12, 2011 12:11 pm ]
Post subject:  Re: Interesting problem
Only the empty triangle at M13 works. L12 is interesting, but fails. The other variations quickly end in a ladder:

[sgf-full]http://www.lifein19x19.com/forum/download/file.php?id=1079[/sgf-full]


Attachment:
File comment: analysis
diagram.sgf [1.55 KiB]
Downloaded 802 times
Author:  Kirby [ Fri Aug 12, 2011 1:45 pm ]
Post subject:  Re: Interesting problem
Maybe I should change goals in go, and make it my goal to be as good as Herman... :-p

I struggled with this problem and did not find the solution.
Author:  tchan001 [ Fri Aug 12, 2011 4:05 pm ]
Post subject:  Re: Interesting problem
Look at Herman's avatar and you'll know what is the most important goal of go in Herman's mind.
Author:  tchan001 [ Fri Aug 12, 2011 4:18 pm ]
Post subject:  Re: Interesting problem
Quickly! We must show Herman the Igo Hatsuyoron problem 120 and see what his analytical mind produces.
Author:  Shaddy [ Fri Aug 12, 2011 5:00 pm ]
Post subject:  Re: Interesting problem
Hmm. That was pretty quick. Let's see who can solve this one...
Click Here To Show Diagram Code
[go]$$c
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . O O O . O . . . |
$$ | . . . . . . . . . O O X X . . . O . . |
$$ | . . . . . . . . O . . X . X X X . O . |
$$ | . . . , . . . . . X X X X X O X . O . |
$$ | . . . . O O O O . X O O O X O X . O . |
$$ | . . . . . . . . X O . . . O O X . O . |
$$ | . . . . . . . . . O . . . . . . . O . |
$$ ---------------------------------------[/go]


Black to live. I showed this problem at Congress a few times, Tabemasu was the only one who got it.
Author:  HermanHiddema [ Sat Aug 13, 2011 6:52 am ]
Post subject:  Re: Interesting problem
Nice one :)

There is death in the hane, of course. But the real tesuji here is the later L1:

[sgf-full]http://www.lifein19x19.com/forum/download/file.php?id=1083[/sgf-full]


Attachments:
diagram-1.sgf [894 Bytes]
Downloaded 737 times
Author:  Shaddy [ Sat Aug 13, 2011 8:41 am ]
Post subject:  Re: Interesting problem
Wow, I'm impressed. Here's one from the Igo Hatsuyoron..

Click Here To Show Diagram Code
[go]$$c
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . X X . X X X O O O . . |
$$ | . . . . . . . . . O . O O O B B O . . |
$$ | . . . , . . . O . . . . . X O B O . . |
$$ | . . . . . . O . X . . . . . O B . . . |
$$ | . . . . . . . X . . . . . . O B . O . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Black to play.
Author:  Tryss [ Sat Aug 13, 2011 9:27 am ]
Post subject:  Re: Interesting problem
Nice ladder :mrgreen:
Author:  HermanHiddema [ Sat Aug 13, 2011 11:03 am ]
Post subject:  Re: Interesting problem
Oooh, I like that one.

This one's straight up my alley. Lots of variations to read out, most of them only just failing after 15 moves :lol:

[sgf-full]http://www.lifein19x19.com/forum/download/file.php?id=1087[/sgf-full]


Attachments:
diagram-2.sgf [1.9 KiB]
Downloaded 650 times
Author:  Shaddy [ Sat Aug 13, 2011 11:23 am ]
Post subject:  Re: Interesting problem
Not quite! White has a better resistance. This problem ain't from the Igo Hatsuyoron for nothing :rambo:
Author:  HermanHiddema [ Sat Aug 13, 2011 12:05 pm ]
Post subject:  Re: Interesting problem
Shaddy wrote:
Not quite! White has a better resistance. This problem ain't from the Igo Hatsuyoron for nothing :rambo:


Oh wait, K3 immediately, instead of L7, otherwise white makes ko by playing K3 and J4
Author:  Shaddy [ Sat Aug 13, 2011 12:41 pm ]
Post subject:  Re: Interesting problem
Still wrong. You missed something deeper- Black cannot live unconditionally.
Author:  tchan001 [ Sat Aug 13, 2011 11:42 pm ]
Post subject:  Re: Interesting problem
Shaddy wrote:
Wow, I'm impressed. Here's one from the Igo Hatsuyoron..

Click Here To Show Diagram Code
[go]$$c
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . X X . X X X O O O . . |
$$ | . . . . . . . . . O . O O O B B O . . |
$$ | . . . , . . . O . . . . . X O B O . . |
$$ | . . . . . . O . X . . . . . O B . . . |
$$ | . . . . . . . X . . . . . . O B . O . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Black to play.

Actually this problem is not strictly from Igo Hatsuyoron as it is in essense derived from a problem in Xuan Xuan Qi Jing. Please compare with http://senseis.xmp.net/?XuanxuanQijingProblem150

In the newest Chinese version of Igo Hatsuyoron "Research on Weiqi Fa Yang Lun", it is listed in the appendix as problem #13 from the Xuan Xuan Qi Jing with the name 采樵势 (cai qiao shi). If we use the newest version of Igo Hatsuyoron as the reference, then there should also be an additional black stone at K8.
Author:  Kirby [ Sun Aug 14, 2011 7:20 am ]
Post subject:  Re: Interesting problem
To me, more impressive than the problem is that Herman missed something...
Author:  Shaddy [ Sun Aug 14, 2011 6:42 pm ]
Post subject:  Re: Interesting problem
Perhaps, Kirby, on seeing the solution you'll realise why: it's a really hard-to-find move if you're not looking specifically for it.

The solution:

This is one ordering, it seems other orders are also possible
Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . X X . X X X O O O . . |
$$ | . . . . . . . . . O 7 O O O B B O . . |
$$ | . . . , . . . O . . 0 8 5 X O B O . . |
$$ | . . . . . . O . X . . 9 3 2 O B . . . |
$$ | . . . . . . . X . . . . 6 1 O B . O . |
$$ | . . . . . . . . . . . . . . 4 . . . . |
$$ ---------------------------------------[/go]

4 cannot capture, because black will connect underneath and live.
Click Here To Show Diagram Code
[go]$$Bc
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . 5 . . . . . . . . |
$$ | . . . . . . . . X X 2 X X X O O O . . |
$$ | . . . . . . . . 6 O X O O O B B O . . |
$$ | . . . , . . . O . 1 O O X X O B O . . |
$$ | . . . . . . O . X 7 3 X X O O B . . . |
$$ | . . . . . . . X 8 . . . O X O B . O . |
$$ | . . . . . . . . 9 . . . . 0 O . . . . |
$$ ---------------------------------------[/go]

4 fills. 8 is the strongest resistance for White: it breaks the ladder on the left and stops black's snapback on the right. Black can now only get ko.
Author:  tchan001 [ Sun Aug 14, 2011 7:31 pm ]
Post subject:  Re: Interesting problem
Actually Shaddy, there is another line for Black which prevents the placement of your "strongest resistance for white" at j2. In the second diagram, Black can play 1 at k2 instead of k4. But the result will still be ko as per your line.

Let me show you my solutions sgf which incorporates the works for this problem including the missing Black stone in Igo Hatsuyoron (from newest Chinese edition). Of course, the ideas are not really mine as I'm just a weak kyu ;)
Author:  Shaddy [ Sun Aug 14, 2011 10:17 pm ]
Post subject:  Re: Interesting problem
Hm, I'd missed that before. Thanks, tchan!
Author:  HermanHiddema [ Mon Aug 15, 2011 1:49 am ]
Post subject:  Re: Interesting problem
How did I ever miss that?! :blackeye:

Great problem :)

I was already exploring variants like this:

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