How many movies have Masaru Igami and Mitsuteru Yokoyama collaborated on?

They have worked on 4 movies together! Their first movie together was Ninjascope: The Magic World of Ninjas (1967) while their highest rated movie together was Akakage: 3-D Adventure Movie (1969). They have not worked together since Akakage: 3-D Adventure Movie (1969). They are most known for their science fiction films together.