Spot the Empty Triangle

  Difficulty: Beginner   Keywords: Shape

Here are some positions to help you practice not making empty triangles.

Example 1: connection

[Diagram]

Black to play

W1 threatens to capture the marked cutting stones. How can Black best save them (which is often an urgent thing to do).

[Diagram]

Wrong

B2 and BC make an empty triangle.

[Diagram]

Correct

The bamboo joint is a more efficient shape to keep the important stones connected.


Example 2: higher level efficiency

[Diagram]

Black to play?

If Black wants to play here, which is best among a, b, c

[Diagram]

Empty triangle. Too close.

[Diagram]

Still too close.



axd: Why still too close?

Bill: Because of BC. Black already has a base, and is relatively secure. B1 extends from that base without doing much to make it secure. As a rule, then, it is too close. It doesn't accomplish much.

[Diagram]

Normal extension




Counterexample

The only time you should make an empty triangle is if it is backed up by solid reading. Here's the only common example I know of.

[Diagram]

Black to capture 7 white stones

[Diagram]

Failure

[Diagram]

Also Failure

[Diagram]

Also Failure

[Diagram]

Correct (a and b are miai)

Here the empty triangle is necessary.

[Diagram]

In general

In the presence of WC, a move like B1 is often the only way to save the two stones, even though it makes an empty triangle. But always read it out, and remember it may be best to do something else instead of saving them!



This is a copy of the living page "Spot the Empty Triangle" at Sensei's Library.
(OC) 2007 the Authors, published under the OpenContent License V1.0.
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