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BambooJoint
ControversialStat...

 

Bamboo Joint Is Bad Shape
    Keywords: Tesuji, Shape, Tactics

No, I don't think that the bamboo joint is bad shape ... but.

This was triggered by a discussion on Shape and was also discussed on rec.games.go (autumn 2000, I think).


[Diagram]
Diag.: Bamboo joint

The 'but' above comes from the fact that a bamboo joint has several 'defects' and is therefore often not the best shape to play in a given situation. (See bamboo joint for examples of shapes it is obviously superior to.)

These defects (As I see it) are:

  1. The bamboo joint is heavy/slow.
  2. The bamboo joint has no eye potential.
  3. The bamboo joint can lead to a shortage of liberties. (See [ext] here for an example)

[Diagram]
Diag.: Alternative joints

The black shape on the left is an alternative which, in almost all cases, is as connected as the bamboo joint but at least is slightly lighter? and has a slightly better eye potential.

The white shape on the left has lost some connectivity but gained speed and flexibility.

I am not trying to say that the bamboo joint is bad, but merely that there are sometimes other options which are better.

--MortenPahle

(I think this is a controversial statement and have added it to that list. --Stefan)



Bamboo shape alone, without opponent's stones, loses the point. And the point is that it gives a solid connection and at the same time creates more influence and wider base for escape.

Of course, it has disadvantages, among which the obvious is a ko threat. The fact that you can sacrifice part is an advantage though.

Another disadvantage is that sometimes you regret that you did not take that liberty from your opponent.


[Diagram]
Diag.: Here 'a' seems better than 'b' or 'c'

[Diagram]
Diag.: Alternative joint here is slower :( after white 1.

But if white plays 1 here instead of the marked stone or bamboo she is usually better (a weakness remains though). --HolIgor



This had to happen: I have exactly the same remark and wrote it simultaneously with HolIgor. #:-7

There is a problem with the shape you suggest:


[Diagram]
Diag.: Alternative joints

White 1 attacks the shape of this black group. Black has to connect, but in either of the three options A, B, C, Black is left with an empty triangle.

--Dieter



I agree with all your comments - like I said, I just wanted to warn against always playing the bamboo joint.

(I deleted some drivel I wrote. I was up too late last night.)

--MortenPahle



  • You are right in saying that whether you play the bamboo joint or one of the other shapes depends on the situation, but you seem to suggest that those cases are equally distributed. I don't think so. The bamboo joint is the proper shape in I would say 90% of the cases.

--DieterVerhofstadt



This is a copy of the living page "Bamboo Joint Is Bad Shape" at Sensei's Library.
(C) the Authors, published under the OpenContent License V1.0.