Tsumego From Games 21

  Difficulty: Beginner   Keywords: Life & Death, Problem

This happened to me in a 9x9 game on KGS today. I thought my corner is safe, but then Black played the marked stone. How can White defend the lower left corner?

Bill: Play there before Black does.
White to defend  

In the end I made a seki and lost the game.


Dave: It does seem to be too late...

White to defend  

White is helpless.

Bill: Therefore White has nothing better than to pass at move 5, accepting seki.

10,000 year ko  

Bill: If Black has no ko threat, he can still make a 10,000 year ko.
(Note: White cannot take and fill.)

White to defend  


exswoo: Actually, if Black plays this sequence, I think White can force a no result under Japanese rules...although I'm not sure if that's actually a valid strategy :)

Bill: White can keep doing this, but it costs one point each time. Eventually Black can sacrifice his stones and still win.
exswoo: Wouldn't the super ko rule forbid that?
Bill: Depending on the variant of the superko rule, it would prevent W9.
Dave: Although it does not work, that is quite a clever idea that I did not notice. Black can also play W9 or a instead of B4 to achieve seki. I just thought B4 looked nicer, which is a careless approach to tsumego :-) Well done exswoo!
exswoo: Why, thank you :) It would've been even better if it did work but oh well. I wonder if there are any tsumego problems out there where this strategy is the correct answer?

Dieter: Yes Sir, may I suggest problem 85 of the amazing Kanazawa Tesuji Series, also known as Gokyo Shumyo.

Tsumego From Games 21 last edited by CharlesMatthews on June 4, 2003 - 17:30
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