Gokyo Shumyo, Section 1, Problem 15 / Solution

Black lives  

Black 1 makes eyes at a and b.

Continuation  

If White captures at 2, Black recaptures at the marked stone.

Wrong  

Connecting at 1 cares too much about the two stones and not enough about shape. After 4, four stones on the second line in the corner are dead.

Wrong (ii)  

(4 at marked)

White destroys an eye at either a or b.