Bulky Ten In The Corner

    Keywords: Life & Death, Shape

The Bulky ten in the corner is a big empty group without cutting points that still is not territory.

Black can play at any of the 7 marked intersections to live outright with 9 points of territory, but black+circle is best because it leaves either no ko threats or only one tiny one (depending on the rules). ​ White-to-move plays white+circle.


start of main lines

[Diagram]

B4 is elsewhere

B6 is at k or s. ​ (Note that White has already taken gote.)


Seki

[Diagram]

B8 can be at either of the indicated points

Reminder: ​ Although _the indicated sequence_ is sente, White took gote to get to the start of this diagram.


mannen-ko

[Diagram]

Either player can make seki, or throw in for a ko that favors Black.


slightly-safe Ko

[Diagram]

B8 is a big ko threat

If White ignores Black's ko threat, then White plays W9 at circle, which kills Black. ​ If circle is still empty then after Black retakes the ko, Black's followup is capturing W5 to live with 9 points under territory scoring. ​ If White retakes the ko, then Black can back down from it with black+circle. ​ (If Black would do that without having played a ko threat, then Black should not play this line.)


after Black backs down

[Diagram]

direct ko for seki

After Black backs down, the ko's swing becomes 9 points under territory scoring. ​ White wins it with white+circle for a seki in which White captured 1 net Black stone. ​ After black+circle, Black wins it by playing either of the other 2 marked points.


Black takes gote for points

B8 prevents a mannen-ko.


This is a copy of the living page "Bulky Ten In The Corner" at Sensei's Library.
(OC) 2023 the Authors, published under the OpenContent License V1.0.
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