Weak Carpenter's Square

    Keywords: Life & Death
[Diagram]
Weak carpenter's square  

The weak carpenter's square is a carpenter's square without the connection at the corner of the shape. The vital point is the same, but this time White kills the corner by playing at a.

That is, the fact that the white+circle stone here is white, rather than Black, changes a the status of the group from ko to unsettled status.

Bill: Quick question: Does the weak carpenter's square need the white+circle stone? With that stone there White can kill by cutting, for instance.

willemien No

[Diagram]
Also a Weak carpenter's square  

This is also a Weak Carpenters Square.

[Diagram]
White can kill  

After W9 a and b are miai a White play a creates a squared four while a White play at b forces black to connect at c reducing his eyespace to a bulky five


Table of contents Table of diagrams
Weak carpenter's square
Also a Weak carpenter's square
White can kill
White can kill
variation
Endgame technique
Weak carpenter's square
not really a carpenter's square
not really a carpenter's square
[Diagram]
White can kill  

There are many ways for white to kill after W1. This is just one variation After W5, B6 at W7 is an auto atari so Black has no other option than to let white connect at W7.

[Diagram]
variation  

After W5 a and b are miai


Discussion

[Diagram]
Endgame technique  

If Black has secured life by playing on the vital point, there is an important endgame technique for White to remember: the forcing moves at 1 and 3.


[Diagram]
Weak carpenter's square  

There's no stone at the marked point, but White a kills nonetheless.

-- unkx80


[Diagram]
not really a carpenter's square  

What about this one? Klaus



[Diagram]
not really a carpenter's square  

Here's one sequence. Bob McGuigan

Book references


Weak Carpenter's Square last edited by willemien on March 10, 2009 - 21:58
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