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BeginnerExercise132

 

Beginner Exercise 132 / Solution
Sub-page of BeginnerExercise132

Alive in seki is alive.

[Diagram]
Seki

David: I've been working on this exercise for a while, and I think the best Black can do is seki.

B1 threatens to make an eye, requiring W2 (see below).

Neither player wants to play at a or b. If Black plays one of them, White makes a bulky five. If White plays a, Black captures and makes two eyes. If White plays b, Black must capture. White may not recapture if the rules forbid repeating positions, but even if the rules allow it, it's a loss of one point in gote.


I think this position is an example of case S1 at Almost Almost Fill, meaning that the inside shape is a killing shape, and neither of its extensions makes a killing shape. According to that page, the groups in such a position are alive in seki regardless of whose turn it is and the number of external liberties.

[Diagram]
Life without seki

If White doesn't play W2 as in the diagram above, Black can live without seki.


[Diagram]
Life without seki


unkx80: Yes, this is the solution.

David: Thanks for your help.

demetria: Good job, David! I like your solution, even though I couldn't make mine work :)




This is a copy of the living page "Beginner Exercise 132 / Solution" at Sensei's Library.
(OC) 2004 the Authors, published under the OpenContent License V1.0.