Page 2 of 2

Re: Joseki Question

Posted: Thu Nov 14, 2013 8:11 am
by Kirby
@ez4u:
Thanks for linking to your comment in the other post.

You, too, seem to have mentioned the opportunity for white to exploit 'a':
Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . . . . . . . . . . . . 3 . . 1 4 . |
$$ | . . . , . . . . . , . X . e O O X 2 . |
$$ | . . . . . . . . . . . . . O X . d . . |
$$ | . . . . . . . . . . . . . b X . X . . |
$$ | . . . . . . . . . . . . . . c W a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]
Could you provide some examples? I think if I understand this part, it really answers what I was curious about. Why is 'a' so threatening here and not when black 2 is at 'd'?

Re: Joseki Question

Posted: Thu Nov 14, 2013 8:14 am
by Kirby
Bill Spight wrote:
Kirby wrote: The best I have come up with so far is that maybe this allows white to play this way because of black's shape (if black tenuki after white defends cut):
Click Here To Show Diagram Code
[go]$$Wcm1
$$ --------------------------------------
$$ |. . . . . . . . . . . . . . . . . . .|
$$ |. . . . . . . . . . . . . . . 3 . . .|
$$ |. . . . . . . . . . . . . . . . O . .|
$$ |. . . , . . . . . , . X . . O O X X .|
$$ |. . . . . . . . . . . . . O X 5 7 8 .|
$$ |. . . . . . . . . . . . . 1 X 6 X . .|
$$ |. . . . . . . . . . . . . . 2 O 0 9 .|
$$ |. . . . . . . . . . . . . . . . . . .|
$$ |. . . . . . . . . . . . . . . . . . .|
$$ |. . . , . . . . . , . . . . . , . . .|
$$ |. . . . . . . . . . . . . . . . . . .|
$$ |. . . . . . . . . . . . . . . . . . .|
$$ |. . . . . . . . . . . . . . . . . . .|
$$ |. . . . . . . . . . . . . . . . . . .|
$$ |. . . . . . . . . . . . . . . . . . .|
$$ |. . . , . . . . . , . . . . . , . . .|
$$ |. . . . . . . . . . . . . . . . . . .|
$$ |. . . . . . . . . . . . . . . . . . .|
$$ |. . . . . . . . . . . . . . . . . . .|
$$ ---------------------------------------[/go]
Click Here To Show Diagram Code
[go]$$Wcm11
$$ --------------------------------------
$$ |. . . . . . . . . . . . . . . . . . .|
$$ |. . . . . . . . . . . . . . . O . . .|
$$ |. . . . . . . . . . . . . . . . O . .|
$$ |. . . , . . . . . , . X . . O O X X .|
$$ |. . . . . . . . . . . . . O X O O X .|
$$ |. . . . . . . . . . . . . O X X X 2 .|
$$ |. . . . . . . . . . . . . . X O X O .|
$$ |. . . . . . . . . . . . . . . . . 1 .|
$$ |. . . . . . . . . . . . . . . . . . .|
$$ |. . . , . . . . . , . . . . . , 3 . .|
$$ |. . . . . . . . . . . . . . . . . . .|
$$ |. . . . . . . . . . . . . . . . . . .|
$$ |. . . . . . . . . . . . . . . . . . .|
$$ |. . . . . . . . . . . . . . . . . . .|
$$ |. . . . . . . . . . . . . . . . . . .|
$$ |. . . , . . . . . , . . . . . , . . .|
$$ |. . . . . . . . . . . . . . . . . . .|
$$ |. . . . . . . . . . . . . . . . . . .|
$$ |. . . . . . . . . . . . . . . . . . .|
$$ ---------------------------------------[/go]
But this seems rather sloppy for white.

Ideas?
Whatever you may think of :w9:, :w5: and :w7: are vulgar plays.

Besides which, after :w3: it is easy for Black to throw away his corner stones. :)
I very much agree. You are correct in that I thought something like white 9 must have been a weakness present in the given variation compared to joseki, but like I said, it feels sloppy.

Perhaps "vulgar" is a better way of putting it than sloppy. In any case, it doesn't seem correct, which is why I am curious about the apparent solution of white having potential at 'a':
Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . . . . . . . . . . . . 3 . . 1 4 . |
$$ | . . . , . . . . . , . X . e O O X 2 . |
$$ | . . . . . . . . . . . . . O X . d . . |
$$ | . . . . . . . . . . . . . b X . X . . |
$$ | . . . . . . . . . . . . . . c W a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]
It's still not clear to me about why 'a' is so different here than if black 2 is at 'd'.

Re: Joseki Question

Posted: Thu Nov 14, 2013 8:36 am
by Kirby
Comparing the potential of 'a' in the following:
Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . . . . . . . . . . . . 3 . . 1 4 . |
$$ | . . . , . . . . . , . X . . O O X 2 . |
$$ | . . . . . . . . . . . . . O X . . . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . . . . . . . . . . . . . c W a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]
and
Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . . . . . . . . . . . . 3 . . 1 4 . |
$$ | . . . , . . . . . , . X . . O O X . . |
$$ | . . . . . . . . . . . . . O X . 2 . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . . . . . . . . . . . . . . W a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]
In the first case, 'b' and 'c' could be locally sente fow white, so the marked white stone could possibly have more potential:

Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . . . . . . . . . . . . 3 . . 1 4 . |
$$ | . . . , . . . . . , . X . . O O X 2 . |
$$ | . . . . . . . . . . . . . O X . . . . |
$$ | . . . . . . . . . . . . . . X . X c . |
$$ | . . . . . . . . . . . . . . . O O b . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]
Is this the power of the difference in stone placement here?

Re: Joseki Question

Posted: Thu Nov 14, 2013 8:38 am
by ez4u
Kirby wrote:Snip... In any case, it doesn't seem correct, which is why I am curious about the apparent solution of white having potential at 'a':
Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . . . . . . . . . . . . 3 . . 1 4 . |
$$ | . . . , . . . . . , . X . e O O X 2 . |
$$ | . . . . . . . . . . . . . O X . d . . |
$$ | . . . . . . . . . . . . . b X . X . . |
$$ | . . . . . . . . . . . . . . c W a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]
It's still not clear to me about why 'a' is so different here than if black 2 is at 'd'.
If White descends at :w1: below, Black would like to be able to play from below around "a" to prevent White extending. However, :w3: is sente so Black has no eyes here.
Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . O . . O X . |
$$ | . . . , . . . . . , . X . . O O X X . |
$$ | . . . . . . . . . . . . . O X b 4 . . |
$$ | . . . . . . . . . . . . . . X . X 3 . |
$$ | . . . . . . . . . . . . . . . O 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . a . . . . |
$$ | . . . , . . . . . , . . . . . a a . . |[/go]
If the marked exchange below has happened already, then something like "a" will cut White off so even the damage at :w3: does not matter.
Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . O . . O X . |
$$ | . . . , . . . . . , . X . . O O X X . |
$$ | . . . . . . . . . . . . . O X . . . . |
$$ | . . . . . . . . . . . . . W X . X 3 . |
$$ | . . . . . . . . . . . . . . B W 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . a . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]
When Black plays the marked stone below instead of "a", the descent at "b" pretty much goes away as a threat. So White goes ahead and exchanges :w1: for :b2: before finishing with :w3: or "c" in the corner.
Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . 3 . . . |
$$ | . . . . . . . . . . . . . . . . O c . |
$$ | . . . , . . . . . , . X . . O O X a . |
$$ | . . . . . . . . . . . . . O X . B . . |
$$ | . . . . . . . . . . . . . 1 X . X . . |
$$ | . . . . . . . . . . . . . . 2 O a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . . . . . |[/go]

Re: Joseki Question

Posted: Thu Nov 14, 2013 8:42 am
by HermanHiddema
Kirby wrote:
Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . . . . . . . . . . . . 3 . . 1 4 . |
$$ | . . . , . . . . . , . X . . O O X 2 . |
$$ | . . . . . . . . . . . . . O X . . . . |
$$ | . . . . . . . . . . . . . . X . X c . |
$$ | . . . . . . . . . . . . . . . O O b . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]
Is this the power of the difference in stone placement here?
Yes. The follow-up at c is powerful, and then the position of :b2: makes all the difference.

Re: Joseki Question

Posted: Thu Nov 14, 2013 8:47 am
by Kirby
Thanks, everyone. I think I finally understand the benefit of R15. :tmbup:

Re: Joseki Question

Posted: Thu Nov 14, 2013 9:38 am
by Bill Spight
Kirby wrote:
Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . . . . . . . . . . . . 3 . . 1 4 . |
$$ | . . . , . . . . . , . X . e O O X 2 . |
$$ | . . . . . . . . . . . . . O X . d . . |
$$ | . . . . . . . . . . . . . b X . X . . |
$$ | . . . . . . . . . . . . . . c W a . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]
It's still not clear to me about why 'a' is so different here than if black 2 is at 'd'.
Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . O . . O X . |
$$ | . . . , . . . . . , . X . . O O X X . |
$$ | . . . . . . . . . . . . . O X . . . . |
$$ | . . . . . . . . . . . . . . X . X 3 . |
$$ | . . . . . . . . . . . . . . . W 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]
How does Black reply to :w3:? :)

Edit: We seem to have a consensus. :)

Re: Joseki Question

Posted: Thu Nov 14, 2013 9:49 am
by HermanHiddema
Bill Spight wrote:
Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . O . . O X . |
$$ | . . . , . . . . . , . X . . O O X X . |
$$ | . . . . . . . . . . . . . O X . . . . |
$$ | . . . . . . . . . . . . . . X . X 3 . |
$$ | . . . . . . . . . . . . . . . W 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]
How does Black reply to :w3:? :)

Edit: We seem to have a consensus. :)

Equally important: how does black reply to :w1:?

Hane may seem tempting, but:
Click Here To Show Diagram Code
[go]$$Wc Black resigns
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . O . . O X . |
$$ | . . . , . . . . . , . X . . O O X X . |
$$ | . . . . . . . . . . . . . O X . . . . |
$$ | . . . . . . . . . . . . . . X . X 3 . |
$$ | . . . . . . . . . . . . . . . W 1 2 . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]
:cry:

Re: Joseki Question

Posted: Thu Nov 14, 2013 9:59 am
by Bill Spight
A little bit of history.
Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . X . a O 1 X . . |
$$ | . . . . . . . . . . . . . O X 2 . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . . . . . . . . . . . . . . W . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]
The taisha ( :wc: ) dates to the mid 20th century. At first, :b2: was a common response to :w1: , obviously threatening the cut at "a".
Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 3 . . |
$$ | . . . , . . . . . , . X . . O 1 X . . |
$$ | . . . . . . . . . . . . . O X . 4 . . |
$$ | . . . . . . . . . . . . . . X . 2 . . |
$$ | . . . . . . . . . . . . . . . W . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]
:b2: was tried, as better shape, and after :b4: White is peeping at a bamboo joint.
Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . . , . . . . . , . X . . O 1 X . . |
$$ | . . . . . . . . . . . . . O X . 6 . . |
$$ | . . . . . . . . . . . . . 3 X . 2 . . |
$$ | . . . . . . . . . . . . . a 4 W . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]
In that case, why not play :w3: to force :b4:, which Black would not necessarily play after :b6: . After :b6: Black might play the hane at "a" instead.
Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . 5 . . |
$$ | . . . , . . . . . , . X . . O 1 X 6 . |
$$ | . . . . . . . . . . . . . O X . . . . |
$$ | . . . . . . . . . . . . . 3 X . 2 . . |
$$ | . . . . . . . . . . . . . . 4 W . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]
But then, having played :b4: , why not play :b6: instead of the bamboo joint? Without the bamboo joint, :b4: looks good, and White may regret :w3: .

This gives us the "old joseki" mentioned above. :)

Re: Joseki Question

Posted: Thu Nov 14, 2013 10:01 am
by Bill Spight
HermanHiddema wrote:
Bill Spight wrote:
Click Here To Show Diagram Code
[go]$$Wc
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . O . . O X . |
$$ | . . . , . . . . . , . X . . O O X X . |
$$ | . . . . . . . . . . . . . O X . . . . |
$$ | . . . . . . . . . . . . . . X . X 3 . |
$$ | . . . . . . . . . . . . . . . W 1 . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]
How does Black reply to :w3:? :)

Edit: We seem to have a consensus. :)

Equally important: how does black reply to :w1:?

Hane may seem tempting, but:
Click Here To Show Diagram Code
[go]$$Wc Black resigns
$$ +---------------------------------------+
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . O . . O X . |
$$ | . . . , . . . . . , . X . . O O X X . |
$$ | . . . . . . . . . . . . . O X . . . . |
$$ | . . . . . . . . . . . . . . X . X 3 . |
$$ | . . . . . . . . . . . . . . . W 1 2 . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . , . . . . . , . . . . . , . . . |[/go]
:cry:
Some people are easily tempted. :mrgreen: