How many movies have Kazunobu Sanpei and Shizuo Nakajima collaborated on?

They have worked on 3 movies together! Their first movie together was Godzilla vs. Megalon (1973) while their highest rated movie together was Godzilla vs. Mechagodzilla (1974). They have not worked together since Terror of Mechagodzilla (1975). They are most known for their action films together.