BeginnerExercise314/Solution

 

White is incontestable dead now, there are only false eyes left for a second eye.

 

There are four other possibilities to kill, but all would leave ko threats.

 

If Black tenukis, will give live. Now a and b are miai against a black play.

 

When looking at the problem, you should see that is a potential eye. a is false right from the start and b depends on two neighbors being white (a and c).