How many movies have Gab-jin Han and O Jae-ho collaborated on?

They have worked on 3 movies together! Their first movie together was Special Investigation Unit: The Case of College Girl Lee Nan-hee (1973) while their highest rated movie together was Special Investigation Unit: The Life of Miss Kim Su-im (1974). They have not worked together since Special Investigation Unit: One-Armed Kim Jong-won (1975). They are most known for their crime films together.