Hane at the Head of Two Stones

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  Difficulty: Beginner   Keywords: Shape, Tactics, Proverb
[Diagram]

The head of two

This proverb says that in a position like the one in this diagram, playing hane with Black a or White b (facing the center) is a very big move. If one is faced with a position like this, it is hardly ever good to play somewhere else on the board. The difference between these two moves is simply too large.

[Diagram]

Black hane

[Diagram]

White hane


[Diagram]

Hane at the head of two stones

Why is hane at the head of two stones so important? A typical sequence is B2 to B5. We observe the following:

  • White's influence increased significantly.
  • Black is pushed down with limited expansion? opportunities.
  • Black has a cutting point at a and the black+circle chain has only three liberties. This induces weaknesses around b (see eye-stealing tesuji), which is a burden to Black.

In some circumstances, W3 may choose to simply pull back at W5. But similar observations apply.


Enfors: More newbie questions: Wouldn't c be better than W5, to create two Tiger mouths, which would also protect the cutting point above c?

Dieter: whether a solid connection is better than a trumpet connection is a debate which is governed by the local, and most often even global situation. Basically, the trumpet connection is, as you say, locally connecting all stones, while the solid connection here will leave the other cutting point depend on a ladder. The drawback of a trumpet connection is that there are two peeping forcing moves available for the opponent, which potentially turn the whole construction into a dango.

There is some talk about this debate at the trumpet connection page, but I believe it is worthy of a page of its own. I'll leave this here for some time, then move it.

Enfors: Ah yes. I see now. At the time, I didn't notice that the cutting point left above c is ladderable.

tapir: Another issue for the trumpet connection is what happens after Black d. With a solid connection White most of the time will play hane, with a trumpet connection Black can cut in sente.



Author: AndreEngels, (WikiMasterEdit by Dieter).


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This is a copy of the living page "Hane at the Head of Two Stones" at Sensei's Library.
(OC) 2012 the Authors, published under the OpenContent License V1.0.
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