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Answer Keima with Kosumi
Path: GoProverbs   · Prev: TheEmptyTriangleIsBad   · Next: RespondToAttachmentWithHane
  Difficulty: Advanced   Keywords: Proverb, Shape

This means to play kosumi (diagonal move) when your opponent plays a keima (knight's move) approach to your stone. Your kosumi will be on the point that the approach aimed at. It also aims at a shoulder hit (katatsuki) against your opponent's stone.


[Diagram]
Diag.: Knight's move cap

Here's an example. Black 1 is played to reduce White's framework. White 2 is correct shape in reply. Charles Matthews.



Take for example the following situation that often arises in a handicap game:

[Diagram]
Diag.: Kosumi answer

White approaches at 1 (keima in relation to Black's corner stone). Next Black plays at 2 answering a keima with kosumi. After White 3 and Black 4, White will stabilize her group with a play around a. Note that the aim of Black 2 is not to secure territory in the corner. White can still invade at b later on. Instead it denies White 1 access to the corner, thus keeping this stone from easily securing a base: the white group remains weak. --ArnoHollosi, 1d



BillSpight: Actually, Black 2 is a kosumitsuke. I would have thought that answering keima with kosumi meant something like this:

[Diagram]
Diag.: Kosumi reply

But this, while joseki, is slow, and is usually avoided. The kosumi-tsuke is good to know, but also relies on the surroundings. You would not typically respond with either kosumi or kosumi-tsuke to a keima kakari.

So how come this is a "proverb"? Aside from here, I have seen it only on Jan van der Steen's list, and did not find an explanation there.

The other way around makes more sense:


[Diagram]
Diag.: Answer kosumi with keima

Black 2 is a keima response to the kosumi of White 1. That is joseki.



Oct., 2001: The light dawns!

[Diagram]
Diag.: Answer keima with kosumi

In this situation Black answers the keima of White 1 with the kosumi of Black 2. This is a common joseki. (These days, Black 2 is often omitted or delayed. There are other good options for Black, too.)


[Diagram]
Diag.: Answer keima with kosumi (ii)

This is another common kosumi response to a keima.


[Diagram]
Diag.: Answer keima with kosumi (iii)

But when White plays ogeima, the tobi is the usual response.

(I learned this years ago. Frankly, I have forgotten why. ;-) Maybe somebody who knows can add an explanation for the difference in response.)

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]
Diag.: Black's play

If Black answers the ogeima with kosumi (both marked), later he can play Black 1 - Black 7.


[Diagram]
Diag.: White's play

If White protects with White 1, 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 White 1.

--BillSpight





Path: GoProverbs   · Prev: TheEmptyTriangleIsBad   · Next: RespondToAttachmentWithHane
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