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AnswerKeimaWithKo...
KeimaSlide

 

keima slide and ogeima slide
  Difficulty: Expert   Keywords: Shape

Discussion originally on answer keima with kosumi.

[Diagram]
Answer keima with kosumi (i)

This is another common diagonal response, to a keima slide.


[Diagram]
Answer keima with kosumi (ii)

But when W1 slides from one line further, the jump B is the usual response.

I learned this years ago. Frankly, I have forgotten why. Yesterday I saw Prof. Teigo Nakamura 6-dan. He has the most encyclopedic go knowledge of any amateur I know. He had forgotten why, too. ;-) But he spent a few minutes playing with the position and came up with the answer.


[Diagram]
Black's play

If Black answers WC with BC, later he could play B1 - B7.


[Diagram]
White's play

If White protects with W1, Black has sente; but she threatens to jump in at a. Note that Black had responded at a instead of the kosumi (marked), he would still threaten to play at b, but White would not have a big threat after W1.

--BillSpight

(Moved from answer keima with kosumi.)



Charles Matthews I have wondered about this, having seen something very similar in an old Japanese book on tesuji.[1]

Firstly, there is no 'shape-based' rule.

[Diagram]
Either answer ...

If one looks at this sort of pattern, just somewhere on the side, then Black a and Black b are both commonly seen.

If one specialises to the case of the small high enclosure, then the diagonal move answer is more popular:


[Diagram]
Enclosure, keima slide

B1 here is much more popular than Black at a.


[Diagram]
Enclosure, ogeima slide

B1 is more popular than Black a.

These come from database search: they may contradict the book I read.

Looking, as one should, into the game context, the diagonal move answers do seem to be in the type of position where Black wants to take sente.


[Diagram]
Enclosure, ogeima slide variant

There may be something in the idea that the one-point jump answer B1 here invites W2 and W4, at which point Black would want to add another stone here.


[Diagram]
Enclosure, keima slide variant

In the keima slide case, White's immediate cut with W4 and W6 is possibly tactically. (White would like a good ladder for this, but perhaps that isn't a precondition?)



[1] A 1955 book by Kano Yoshinori. Here are the actual positions.

[Diagram]
First case

B1 is given as correct by Kano. In three pro games, Black instead played tenuki from the corner.


[Diagram]
Second case

B1 here is given as correct. This is more plausible: a low-ranked Korean pro has played a, but as a rule this is what one sees.

Charles Matthews



This is a copy of the living page "keima slide and ogeima slide" at Sensei's Library.
(OC) 2004 the Authors, published under the OpenContent License V1.0.