[Computer-go] Congratulations to Zen!

Jason House jason.james.house at gmail.com
Mon Apr 4 05:32:27 PDT 2011


On Apr 4, 2011, at 8:15 AM, Hideki Kato <hideki_katoh at ybb.ne.jp> wrote:

> About round9:
>> In round 9, stv played move 35 as shown in the diagram to the left, 
>> against Fuego128t. I believe that the upper left white group is now 
>> dead, as "bent four in the corner".
> "Bent four in the corner" is a Japanese rule and cannot be applied 
> with Chinese rules, in which L&D problems should be solved by playing 
> and this case is a Ko.  I have no idea why

Why white is unconditionally dead is a bit tricky. If white A5, then black will play A7. The key to why the ko is unimportant is recognizing that white can not initiate it. If white plays A4 or B9, they are simply dead. All black must do is wait until everything else is settled, then initiate the exchange B9, A6, A8, A9, B9. At that point, white is in Atari and has no ko threats... AKA, white is unconditionally dead.


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