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


This is a copy of the living page "Weak Carpenter's Square" at Sensei's Library.
(OC) 2014 the Authors, published under the OpenContent License V1.0.
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