Answer Keima with Kosumi

  Difficulty: Advanced   Keywords: Shape, Proverb

More correct title: Answer Keima Approach with Kosumi

Kosumi after keima approach  

B2 is what the proverb is about. It is only one of several useful answers to W1. The usefulness depends on the surroundings to a great extent. See the end of this page for more.

Below a mix of examples and completely different moves and shapes:

Here's an example. B1 is played to reduce White's framework; W2 is correct shape in reply. -- Charles Matthews.

Answer keima slide with kosumi  

In this situation Black answers the keima slide of W1 with the kosumi of B2. This is a common joseki. -- Bill Spight

Bob McGuigan:

Another Joseki  

Here's another well-known joseki example of a kosumi response to a keima approach.

Other discussion

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.

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

Kosumi answer  

White approaches at W1 (keima in relation to Black's corner stone). Next Black plays at B2 answering a keima with kosumi. After W3 and B4, White will stabilize the group with a play around a. Note that the aim of B2 is not to secure territory in the corner. White can still invade at b later on. Instead it denies W1 access to the corner, thus keeping this stone from easily securing a base: the white group remains weak. -- Arno Hollosi

Bill Spight: Actually, B2 is a kosumi-tsuke. I would have thought that answering keima with kosumi meant something like this (Shusaku kosumi):

Isn't there another joseki when white plays at '1', black responds at the position which white had played '3' and then white will play a hane and the joseki continues...? Random Passerby?

Kosumi reply  

But this, while joseki, is very solid, 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.

This seems to be a misconception these days, as the kosumi response to the keima kakari is seen often in pro play. -- Anon

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:

Answer kosumi with keima  

B2 is a keima response to the kosumi of W1. That is joseki, also.

Bob McGuigan: First, all proverbs have exceptions and are only meant to suggest a proper way to play. The correct move in a situation always depends on the over-all board position. In the preceding diagram W1 is a kosumi but doesn't have the same relationship to the corner 3-4 stone. Also, B2 is not the only joseki response to W1, there are several "non-keima" possibilities.

Bill: Yes, Bob, all proverbs have exceptions, but you could also say, "Answer keima with keima", or any one of a variety of responses. This is not a question of exceptions. It takes some thought to come up with examples where the kosumi is the correct response. This is a proverb?????

(Later.) I did a Google search. The source of this so-called proverb seems to be this page. ;-)


AJP: From the Nihon Ki-in's Handbook of Proverbs (Volume I) where it is listed as: "play the kosumi against the keima." In all of the examples the kosumi is Shusaku-esque in that it answers a keima approach by taking the critical shape point illustrated here in order to prevent a follow-up pressing move by the opponent at the same spot. Fittingly enough, the point a now becomes an important point. The proverb does seem to be liberally overinterpreted on this page. :)

Bill: Thanks, Andy. As the page history indicates, everybody was guessing about what it meant. Now we know. :-)

.Bob: Well I was responding to the previous post. But it is a more-or-less standard shape move to respond to a keima approach (from below) with a kosumi. WHo knows what a "proverb" is exactly anyhow.

See also keima slide and ogeima slide.

Answer Keima with Kosumi last edited by lumpydumpy on July 16, 2014 - 22:34
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