Beginner Exercise 222 / Solution

Ko.  

is the only solution, setting up a ko for the life of the black group. If Black wins, he will capture , making two eyes (well... three, actually).

Failure.  

, hoping to catch the white stones in a connect and die, is a failure. After Black cannot play atari at a because of shortage of liberties. at a, fails similarly.

Two stage ko  

Bill: Black can live by capturing , but that should be a last resort. This is properly a two stage ko. Black should normally play to win it with and .

Continued on the /Discussion page.