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Questions on joseki

Posted: Sat May 23, 2015 11:45 am
by gostudent
Hi,

The following are some questions I have while I study some joseki patterns. It must be easy for advanced player, but somehow I cannot figure it out. Your help is very appreciated!

Click Here To Show Diagram Code
[go]$$W One joseki variation
$$ -------------------------------
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . 6 5 1 0 a . 7 . . . . .
$$ - . . . X . 2 3 8 . . . . . . .
$$ - . . . . . 4 9 . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . X . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .[/go]


The recommended response for :b8: is for white to push up at :w9:, and this variation continues with :b10:. However, if :b10: is played at (a) instead, white seems to be split. How should white response?


Click Here To Show Diagram Code
[go]$$B :b1: is supposed to be a bad move, but what will B5 plays elsewhere?
$$ -------------------------------
$$ - . . . . . . . . . . . . . . .
$$ - . a 3 . . . . . . . . . . . .
$$ - . 4 O 1 . . . . . . . . . . .
$$ - . 5 X 2 O . X . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . X . O . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .[/go]

In this Joseki variation, :b1: is supposed to be bad, and the suggested variation continues with :b5: as shown. However, what if :b5: is played inside at (a)? I am not sure of the best white response. One variation I've come up is that it will lead to a ko that is not bad for black:
Click Here To Show Diagram Code
[go]$$B ko in corner
$$ -------------------------------
$$ - . 8 9 . . . . . . . . . . . .
$$ - 0 1 X 2 4 . . . . . . . . . .
$$ - . O O X 3 5 . . . . . . . . .
$$ - . 6 X O O . X . . . . . . . .
$$ - . . 7 . . . . . . . . . . . .
$$ - . . X . O . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .[/go]

Note that :w8: is necessary based on my reading, because it seems that if black can play there, one of the two white groups will be killed because of shortage of liberties.


Thank you!

Re: Questions on joseki

Posted: Sat May 23, 2015 12:14 pm
by SoDesuNe
Click Here To Show Diagram Code
[go]$$Bc One joseki variation
$$ -------------------------------
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . X O O W B . O . . . . .
$$ - . . . X a X O B . . . . . . .
$$ - . . . . . X O . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . X . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .[/go]


My understanding is, that the black stones are very heavy and Black is in for a tough fight, especially with the cut at 'a'. Plus, White is happy to have the marked stone to connect the cut, it enables the cut at 'a'.

Click Here To Show Diagram Code
[go]$$Bc :b11: at 'a', :w12: at 'b'
$$ -------------------------------
$$ - . . . 7 . . . . . . . . . . .
$$ - . 1 X 2 5 6 . . . . . . . . .
$$ - a O O X 3 4 . . . . . . . . .
$$ - . 9 X O O b X . . . . . . . .
$$ - . 0 8 . . . . . . . . . . . .
$$ - . . X . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .[/go]


Take the outside. White is good here, I think.

Re: Questions on joseki

Posted: Sat May 23, 2015 11:47 pm
by Uberdude
SoDesuNe, there's an argument to be had over whether white should push at a before connecting, because if you do it afterwards a sensible black player will extend rather than block.

Also in the second diagram black can cut at b instead of answering at 9. Below is a simpler way (next a or b or tenuki).
Click Here To Show Diagram Code
[go]$$Bc
$$ -------------------------------
$$ - . . . . . . . . . . . . . . .
$$ - . 1 X 3 a . . . . . . . . . .
$$ - 7 O O X 2 . . . . . . . . . .
$$ - . 5 X O O . X . . . . . . . .
$$ - . 6 4 . . . . . . . . . . . .
$$ - . . X b O . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .
$$ - . . . . . . . . . . . . . . .[/go]

Re: Questions on joseki

Posted: Sun May 24, 2015 10:28 am
by illluck
Uberdude wrote:SoDesuNe, there's an argument to be had over whether white should push at a before connecting, because if you do it afterwards a sensible black player will extend rather than block.


These things are so clear when explained and yet in games I'd just connect without thinking (granted that push not necessary worth depending on situation, but it wouldn't even cross my mind).

Re: Questions on joseki

Posted: Sun May 24, 2015 5:57 pm
by ez4u
The only example in may database. Clearly this depends on the surrounding position. Note that the original clamp (marked stone) is extremely rare if the gap at 'a' has not been protected already (as in the OP). We had better not call it joseki.
Click Here To Show Diagram Code
[go]$$Bc Seo Pong-su (white) - Yi Se-tol; 34th Wangwi League 2000-07-03
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . O X O O . . |
$$ | . 6 7 8 . . O . . . X O X O O X X O . |
$$ | . 5 O O . . . . . X . X O . O X . O . |
$$ | . . X a . . . . . X X O . O X X O . . |
$$ | . . X O O . . . . . . X X X X X O . . |
$$ | . . 1 X X 4 . . . X . X O O O X O . . |
$$ | . 9 O W 2 3 . . O O . O X . O O O . . |
$$ | . . . . . 0 . . . . . O O X X O X . . |
$$ | . . X , . . . . . , . . X . . X X X . |
$$ | . . . . . . . . . . . . . X . . X X . |
$$ | . . . . . . . . . . . . . X X . X O . |
$$ | . . . . . . . . . X . . . X O X O X . |
$$ | . . . . . . . . O X O . . X . O O X . |
$$ | . . O . . . . . . O X O . X O . X . . |
$$ | . . . , . . . . . O X O O O X X X . . |
$$ | . . O . . X . . X O X . O . O . . . . |
$$ | . . . . . . . . X X O O . O X X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]