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501 tesuji problems #92, what is the profit?
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Author:  cyclops [ Fri Aug 23, 2013 3:16 am ]
Post subject:  501 tesuji problems #92, what is the profit?

After my yesterday failure I'll try to be more modest by just asking a question.

Click Here To Show Diagram Code
[go]$$Bc find b's tesuji
$$ | . . . . . . . . .
$$ | . . , . . . . , .
$$ | . . . . . . . . .
$$ | . . O . . . . . .
$$ | . O . O . . O . .
$$ | . O O X X X O . .
$$ | . . X O O O X O .
$$ | . . X X . X X . .
$$ | . . . . . . . . .
$$ +------------------[/go]

Problemstatement:
B's stones are confined to the bottom. How can he create some aji to help him break out into the open.

Click Here To Show Diagram Code
[go]$$Bcm1 nuki
$$ | . . . . . . . . .
$$ | . . , . . . . , .
$$ | . . . . . . . . .
$$ | . . O . a 2 . . .
$$ | . O . O . . O . .
$$ | . O O X X X O b .
$$ | . . X O O O X O .
$$ | . . X X 1 X X . .
$$ | . . . . . . . . .
$$ +------------------[/go]

If white plays :w2:, B can aim at a which gives W bad aji in combination with the cutting point b.

Click Here To Show Diagram Code
[go]$$Bcm1 failure
$$ | . . . . . . . . .
$$ | . . , . . . . , .
$$ | . . . . . . . . .
$$ | . . O . . 2 4 . .
$$ | . O . O . 1 O . .
$$ | . O O X X X O . .
$$ | . . X O O O X O .
$$ | . . X X 3 X X . .
$$ | . . . . . . . . .
$$ +------------------[/go]


Question:
I dont see b's profit clearly in this exchange. If w wants to avoid the aji he can play his 2 one point lower.
Is B forcing W to make a choice?

Author:  lobotommy [ Fri Aug 23, 2013 4:16 am ]
Post subject:  Re: 501 tesuji problems #92, what is the profit?

If we agree that aji is some kind of potential, that if you take 3 stones white has dilemma: defend in gote, or take sente but leaving aji behind may be dangerous.
So yes, taking stones these stones which creates aji is a correct solution.

Author:  cyclops [ Fri Aug 23, 2013 5:04 am ]
Post subject:  Re: 501 tesuji problems #92, what is the profit?

lobotommy wrote:
... that if you take 3 stones white has dilemma: defend in gote, or take sente but leaving aji behind ...

thx for your answer. But I fail to see that :w2: in my first hidden diagram is W's sente. It seems gote so W will prefer to play solid to prevent B's profit. BTW, I don't doubt the correctness of the book's solution but I cant see b's profit from it.

Author:  HermanHiddema [ Fri Aug 23, 2013 5:42 am ]
Post subject:  Re: 501 tesuji problems #92, what is the profit?

That's just an incredibly subtle position, and the profit is very vague. In plenty of positions, white would tenuki rather than play :w2:.

The solution is really only a solution because the problem statement specifies that it is considered valuable for black to create aji here.

As to the alternative:

Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . .
$$ | . . , . . . . , .
$$ | . . . . . . . . .
$$ | . . O . 4 a . . .
$$ | . O . O 3 2 O . .
$$ | . O O X X X O b .
$$ | . . X . . . X O .
$$ | . . X X 1 X X . .
$$ | . . . . . . . . .
$$ +------------------[/go]


Now there is still aji with the cutting points a and b.

THe book's solution:

Click Here To Show Diagram Code
[go]$$Bc
$$ | . . . . . . . . .
$$ | . . , . . . . , .
$$ | . . . c a d . . .
$$ | . . O . 3 2 . . .
$$ | . O . O b . O . .
$$ | . O O X X X O . .
$$ | . . X . . . X O .
$$ | . . X X X X X . .
$$ | . . . . . . . . .
$$ +------------------[/go]


White has some more flexibility. Now he can choose a or b, and if he chooses a and black plays b, he then has options c and d.

Author:  cyclops [ Fri Aug 23, 2013 3:25 pm ]
Post subject:  Re: 501 tesuji problems #92, what is the profit?

thx, herman. I gradually believe the problem is too difficult for me. No problem accepting so. I hope to live in Groningen some time soon.

Author:  ez4u [ Fri Aug 23, 2013 4:37 pm ]
Post subject:  Re: 501 tesuji problems #92, what is the profit?

cyclops wrote:
thx, herman. I gradually believe the problem is too difficult for me. No problem accepting so...

I am not sure that is the right lesson to take away. IMHO, this problem rather stretches the boundary of what we usually mean by "tesuji". For the record...

The shape arises from a rare variation of the large avalanche when Black in the first game below (White in the original problem) turns outward with :b1:. The earliest appearance in GoGoD is this game. Kitani indeed captured with :w10:
Click Here To Show Diagram Code
[go]$$Bc Kitani Minoru (White) - Fujisawa Kuranosuke; Oteai 1937-11-03,04
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . . . . . . O . . . . |
$$ | . . . , . . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . . . . . . . . . . . . . 3 X 2 6 . |
$$ | . . . . . . . . . . . . . . . O X 8 . |
$$ | . . . . . . . . . . . . . . . O X 0 . |
$$ | . . X , . . . . . , . . . . 9 O X 4 . |
$$ | . . . . . . . . . . . . . 7 O X O O . |
$$ | . . . . . . . . . . . . . . 1 X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


Overall there are ten games in GoGoD with the problem shape. Four times the player captured the three stones (the "tesuji"). The other six times they played elsewhere. For example...
Click Here To Show Diagram Code
[go]$$Wc Fujisawa Hideyuki (White) - Takemiya Masaki; 11th Hayago Championship 1978-10-07
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O 1 . . . . . . . . . . . . . . |
$$ | . X X O X 9 . . . . . . 0 . . . . . . |
$$ | . 4 O X 7 . . . . , . . . . . X . . . |
$$ | . . O X . . . . . . . . . . . . . . . |
$$ | . 8 O X . . . . . . . . . . . . . . . |
$$ | . 6 2 O 3 . . . . . . . . . . . . . . |
$$ | . . 5 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . . . . , . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


As a quick sanity check, I flipped fifty moves ahead in the six games with a tenuki. Neither player returned to settle the gap in this shape within fifty moves in any of the six games. As Herman wrote, the aji here is indeed very subtle.

Author:  Unusedname [ Fri Aug 23, 2013 4:59 pm ]
Post subject:  Re: 501 tesuji problems #92, what is the profit?

Click Here To Show Diagram Code
[go]$$Bcm1 failure
$$ | . . . . . . . . .
$$ | . . , . . . . , .
$$ | . . . . . . . . .
$$ | . . O . . 2 4 . .
$$ | . O . O . 1 O . .
$$ | . O O X X X O . .
$$ | . . X O O O X O .
$$ | . . X X 3 X X . .
$$ | . . . . . . . . .
$$ +------------------[/go]


Well if you change the move order you can see that pushing at 1 is aji keshi.
in the second diagram the exchange 3 for 4 is terrible.

Click Here To Show Diagram Code
[go]$$Bcm1 nuki
$$ | . . . . . . . . .
$$ | . . , . . . . , .
$$ | . . . . . . . . .
$$ | . . O . a 2 4 . .
$$ | . O . O . 3 O . .
$$ | . O O X X X O b .
$$ | . . X O O O X O .
$$ | . . X X 1 X X . .
$$ | . . . . . . . . .
$$ +------------------[/go]

Author:  HermanHiddema [ Sat Aug 24, 2013 11:03 am ]
Post subject:  Re: 501 tesuji problems #92, what is the profit?

cyclops wrote:
thx, herman. I gradually believe the problem is too difficult for me. No problem accepting so. I hope to live in Groningen some time soon.


More players in Groningen is always a good thing! :D

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