How many movies have Jouji Nakata and Umanosuke Iida collaborated on?

They have worked on 6 movies together! Their first movie together was Towa no Quon 1: The Ephemeral Petals (2011) while their highest rated movie together was Towa no Quon 3: The Complicity of Dreams (2011). They have not worked together since Towa no Quon 6: Eternal Quon (2011). They are most known for their science fiction films together.