How many movies have Aika Kawasaki and Mari Okada collaborated on?

They have worked on 6 movies together! Their first movie together was Rurouni Kenshin: New Kyoto Arc: Cage of Flames (2011) while their highest rated movie together was The Anthem of the Heart (2015). They have not worked together since maboroshi (2023). They are most known for their animation films together.