How many movies have Hiroyuki Hoshiyama and Yū Yamamoto collaborated on?

They have worked on 4 movies together! Their first movie together was Mobile Suit Gundam I (1981) while their highest rated movie together was Mobile Suit Gundam III: Encounters in Space (1982). They have not worked together since Techno Police 21C (1982). They are most known for their science fiction films together.