This problem is an extension of Beginner Exercise 41.
White plays at . As Black cannot play at a, Black can only play at
...
White's throw-in at is a tesuji. Black still cannot play at a because of shortage of liberties.
If Black plays at ,
sets up a snapback and Black is left with a false eye.
Here a and b are miai, so Black has only one eye.
Defending at automatically destroys any possible eye at
.
kills.
makes an eye here. Again,
makes an throw-in...
Another throw-in at , which makes the eye false.
This diagram does not need any further explanation.
at