Beginner Exercise 132 / Solution

Sub-page of BeginnerExercise132

Alive in seki is alive.


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.

Life without seki  

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

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 :)

Alex: Forgive me for asking, but what happens if black plays like so;

Black Lives?  
Black Lives?  

unkx80: Then W2 captures. Next,

  • if Black a or b, then White connects at B1 to form a bulky five;
  • if Black c, then White d; and
  • if Black d, then White c.

Beginner Exercise 132 / Solution last edited by on May 13, 2016 - 19:16
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