BQM 504

    Keywords: Question
[Diagram]
Close low approach  

erikpan: Are there any favoured responses to the somewhat strange 'kosumi' approach shown here? The only moves that spring to mind for me are a block at a (seems bad for shape) or a pincer somewhere around the points marked b.

To answer your question, replying at a to the White approach at W1 is a basic shape move called a stretch. This stretch accomplishes several goals:

  • increases Black's liberties while decreasing White's liberties
  • begins to create a base for the Black stone in the corner
  • denies White access to the corner...the 3-3 point is often critical to controlling the corner

After the stretch, the single White stone is significantly weaker.

Celebrir: It may be useful to see what happens if Black pincers.

Willemien: How about c (see more below)


[Diagram]
Blacks idea  

This looks nearly like a 3-3 Point Invasion, which normally is good for Black. But what happens if White doesn't play W2 at 3-3 ?

[Diagram]
Better for White  

Now Black has two separated groups and White got the corner, which is a bad result for Black. Therefore the marked move was a bad one. Andy: White didn't "get" the corner since this shape is not alive in the corner yet.

[Diagram]
Good (enough) for black  
[Diagram]
Block at 4-4?  

willemien How about blocking at the other side and building a moyo along the upper side?


kb: In a game, I would block at the 3-3 95% of the time. Black then has 5 liberties to White's three, the whole corner, and the whole top side. The diagram below is the best White can do afterwards.

[Diagram]
Block at 3-3  

kb: If White pushes up Black practically wins the game. Look how much Black gains!

[Diagram]
Block at 3-3  
[Diagram]
Block at 3-3  

BQM 504 last edited by Dieter on January 13, 2012 - 17:20
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