Beginner Exercise 288 / Solution

Solution  

Black fights a ko for life.

Failure  

Black can secure an eye at the bottom with , but then White will destroy the eye on top with and kill the whole black group. After that, black is reduced to one eye: a and b are miai.

 

This also kills (black c does not make an eye: it's auto atari met by white d) but is inferior, giving black one more ko threat.

Failure  

This looks like another way to make ko ... except that a is a false eye, so black is dead in this diagram. White could also play at (next diagram): in either case, black can't make a second eye at the bottom.

Variation for  

If black a next, then white b. Or if black b, then white a.