Race to capture in the corner

    Keywords: Tesuji, Tactics

In Japanese, sekitou shibori, or "stone pagoda squeeze". See two-stone edge squeeze for the general pattern.

[Diagram]

Corner problem

[Diagram]

Race to capture

W1 and W3 initiate a race to capture which White will win, because of the special properties of the corner.

[Diagram]

Continuation 1

[Diagram]

Continuation 1



If Black now connects at a, we have a fight between a group with an eye and a group without eye (Richard Hunter calls it a Type 3 fight in his work on Counting Liberties). There are no internal liberties. White has three outside (exclusive) liberties, Black too, but White is to play.

[Diagram]

Continuation 2 (not good)

It is tempting to play the squeeze but it is wrong, again given the special properties of the corner.

[Diagram]

Continuation 2 (not good)

[Diagram]

Continuation 2 (not good)



This is one possible continuation. It is a Type 3 fight again. Black has one exclusive liberty in the eye (WC captured) and counts the internal liberty at a as well as the approach liberties b and c. That's four liberties. White counts the circled liberties and has three. So even if White starts now (at c for example), White loses the semeai - but Black has to answer.


This is a copy of the living page "Race to capture in the corner" at Sensei's Library.
(OC) 2004 the Authors, published under the OpenContent License V1.0.
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