ShapeProblem7/Solution

The trick  

Disaster!

Wrong: forcing Black into good shape  

makes Black play good shape with , and Black can hane free of worry. is a path to death, so it should probably be one space to the left, making a ko.

Correct: forcing Black into bad shape  

forces and gives Black the empty triangle. Next, leaves bad aji. Black has no time to play a because the cut at b now works for White