BQM 418

    Keywords: Question

HowToLose [5k]: After the marked black stone, is it possible for W to win the race? I put this here not simply because it is a semeai, but because of the surrounding positions; unfortunately, I'm not good enough yet as to be able to think globally enough to answer this question myself.


kb: At first glance, I see it as a seki, because it is too risky for Black to try and kill the White stones.

Semeai, 1-10  

Black should take a liberty with B6 and let White fill the ko at black+circle, turning the entire position into seki.

Black fail  

If Black tries to play the ko by making a threat, say at B1, then White will play at W2, turning the entire situation into a direct ko with White taking first through the sequence to W6, because of the local ko threat White has at W4. White will then ignore any ko threat Black plays and take with W8.

Black dies (W9 at W3)  

If Black omits the exchange at B2 on the second diagram and just takes outside liberties, White will take at W3 and then play W5 regardless of where Black plays and then play W7 to live (Black cannot play there because of damezumari.

White dies (W7 at white+circle, B8 at black+circle)  

If White does not fill at W3 on the second diagram, then White will die by double ko (after White fills at W4 then Black will play at a to kill White).

BQM 418 last edited by Phelan on January 26, 2009 - 06:46
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