Beginner Exercise 58 / Solution

Solution.  

is the only correct move. If tries to destroy the eye at the top, White can block at . With the marked stone, Black connect at a will be immediately captured (see the diagram below). So is effectively captured, and White lives.

at is met by at , effectively making two eyes.

After the capture  

After the capture, a and b are miai to secure another eye.

Failure  

White has only one eye.