How many movies have Hideki Onuki and Kazuo Umezz collaborated on?

They have worked on 6 movies together! Their first movie together was Kazuo Umezu's Horror Theater: Diet (2005) while their highest rated movie together was Kazuo Umezu's Horror Theater: Snake Girl (2005). They have not worked together since Cat-Eyed Boy (2006). They are most known for their horror films together.