Big bulge

  Difficulty: Intermediate   Keywords: Joseki, Shape
[Diagram]
Big bulge  

The big bulge is the shape formed by three stones with a keima-keima-ogeima relationship, as shown here. It's a good shape because it's flexible, but also very well connected. However, it has a weakness when it comes to eyeshape. It looks like a rotated and stretched bulge. With one stone added, it becomes the throwing star shape.

This term is coined in Charles Matthews' book [ext] Shape Up!. This shape is also known as boomerang shape.


Examples in professional play

[Diagram]
Move 115  

A big bulge appears when B1 plays steadily for influence in the centre, to counter-act White's power there. (The game is Takagi Shoichi-Kobayashi Koichi (B) 1988-01-07.)

[Diagram]
Move 27  

This shape also occurs in Yu-Ch'ang-hyeok-Yi Se-tol (B) played 2000-12-20. This game (but not the particular move) is commented in Go-World #91 pp. 33-39.


Examples in joseki

[Diagram]
One big bulge joseki  

A common joseki that involves this big bulge shape is a 4-4 point one space low pincer invasion block joseki. The shape is formed by B2-B6-B8.

[Diagram]
Another big bulge joseki  

Another joseki that involves this shape comes from the 4-5 point 4-3 approach keima joseki. It looks like this, with black+circle-B2-B8 forming the shape.


Weakness

[Diagram]
The shape point  

Uberdude This shape does have a weakness, that I will forever remember as my teacher Willzhang, a chinese 6 dan, exploited it brilliantly. I forget the exact position, but I had some floating stones in the middle dominated by my opponent's thickness that were trying to make eyes. I played the big bulge shape, and he played at the shape point below which took away all my eyes. In the end I died. In the review he said I should have played the slower but more secure SakeBottleShape.


See also


Big bulge last edited by Sebastian on September 13, 2010 - 00:23
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