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TwoSpaceExtension

 

two-space extension - unobvious answers
  Difficulty: Advanced   Keywords: Shape, Tactics

[Diagram]
Diag.: First, the obvious answer

The great virtue of the two-space extension is that it is difficult to cut through. When White plays 1, Black 2 is a simple answer to prevent White separating Black's stones by playing there herself.

It is also the correct answer, in most circumstances. But there are occasions when one wants to play Black 2 at a, b or c for reasons of local shape. It is even possible for Black to jump out at d in response; but that is when Black effectively claims that White 1 is an overplay.

Black 2 as shown in this diagram is in most cases honte, so one should bear in mind that the other plays aren't for general use.


[Diagram]
Diag.: The bulge point

White's follow-up here is White 3, at what would be a bulge point for Black.


[Diagram]
Diag.: Resisting

That would be one reason for Black to play this way. Now White at a would be odd, since if White wanted that result she would have started there.


[Diagram]
Diag.: White can force

Now White has a chance to play some kikashi, with White 1 and 3, and then perhaps a or b. Black has made a thinner shape and White's pay-off is this chance to complicate matters.


[Diagram]
Diag.: The diagonal play

Black 1 here is an interesting example of shape and seems only to be played in the presence of the marked white stone.

Now if White 2 the position becomes tense. Black can try 3. White a, Black b came next in a recent Korean game: Black has cut in good shape.


[Diagram]
Diag.: Comparison

This is better for White, when the white stones on the right were weak.


[Diagram]
Diag.: Inviting a fight

Finally, Black 2 here is suitable when Black wishes to involve White in a fight. Up to White 7 is a predictable result; White must now find a way out, or play more lightly here.

Charles Matthews

Bill: I have added Black 8, which looks like honte to me.
Charles Agreed, but then White at a escapes. When Black is strong locally - the cue for Black 2 - Black may connect otherwise on the left to force White to crawl out with b.


Bill: In 21st Century Go vol. 1, Go Seigen make the following recommendations:

[Diagram]
Diag.: Go Seigen's recommendation (I)

B 3 takes the high ground, giving Black good balance.


[Diagram]
Diag.: Go Seigen's recommendation (II)

B 3 connects underneath. B 5 could also be at a. This is also playable.




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(OC) 2003 the Authors, published under the OpenContent License V1.0.