How many movies have Koichi Usami and Yasufumi Soejima collaborated on?

They have worked on 2 movies together! Their first movie together was Origin: Spirits of the Past (2006) while their highest rated movie together was Donten: Laughing Under the Clouds - Gaiden: Chapter 1 - One Year After the Battle (2017). They have not worked together since Donten: Laughing Under the Clouds - Gaiden: Chapter 1 - One Year After the Battle (2017).