Three-space extension

  Difficulty: Beginner   Keywords: Opening

Chinese 1: 拆三 (chāi sān)
Chinese 2: 三间拆 (sān jiān chāi)
Japanese: 三間ビラキ (sangen biraki)
Korean: -

[Diagram]
Three-space extension on the third line  

B1 is the three-space extension along the third line, like other extensions a big fuseki point which creates a base for the group and prevents White from attacking around the same point. Compared with the two-space extension, the three-space extension develops more quickly, but has the obvious defect at a where White can invade. This is always a consideration when making the three-space extension.


[Diagram]
Three-space extension on the fourth line  

It is also possible to make the three-space extension on the fourth line.

[Diagram]
Mixed three-space extension  

This three-space extension could also be called a very large knight's move extension.

[Diagram]
Three-space extension from a wall  

Here, Black makes a three-space extension from a wall.

[Diagram]
Completing the shape  

Black can follow-up with B1 here to make a robust shape.

[Diagram]
Developing with a one-point jump  

B1, a one-point jump, is another alternative for developing from the three-space extension.

[Diagram]
Perfect shape  

If for whatever reason White plays the diagonal attachment at W1, Black's marked stone ends up ideally placed after the stand of B2 (see extension from a wall). One line closer at a would be over-concentrated, that is, worse, from the point of view of good development.

[Diagram]
Treating one stone lightly  

Depending on the situation, Black may also choose to treat one of the stones in the formation lightly for the sake of development.[1] This type of sequence might be appropriate if White is strong in the upper right, as here. In that case Black a, White b might be good for White, and Black is better allowing W1 in return for B2.

[Diagram]
Variation  

If instead W1, B2 gives Black a wall and nice shape.


[1]

[Diagram]
Approaching strong stones  

Bill: In this particular situation, B2 is problematic because it approaches White's wall, while extending only to a instead of black+circle allows White to play at b.

[Diagram]
Prepare the way  

Bill: To avoid the problems of an immediate extension, B1 - B3 press against white+circle, preparing for a safe extension to B5.



Charles This idea of Bill's, to use the 3-5 point low approach, press, is a bit more subtle than may seem at first glance. For example, B5 is held back one line, giving White much less chance of fighting on this side.


Three-space extension last edited by Unkx80 on August 16, 2008 - 23:45
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