How many movies have Hiroyoshi Koiwai and Nobuhiro Watsuki collaborated on?

They have worked on 5 movies together! Their first movie together was Rurouni Kenshin Part I: Origins (2012) while their highest rated movie together was Rurouni Kenshin: The Final (2021). They have not worked together since Rurouni Kenshin: The Beginning (2021). They are most known for their adventure films together.