How many movies have Naoko Masui and Seiji Matsuda collaborated on?

They have worked on 3 movies together! Their first movie together was Magical Sisters Yoyo & Nene (2013) while their highest rated movie together was Demon Slayer -Kimetsu no Yaiba- The Movie: Mugen Train (2020). They have not worked together since Demon Slayer -Kimetsu no Yaiba- The Movie: Mugen Train (2020). They are most known for their fantasy films together.