How many movies have Shigeru Nishiyama and Toshihiro Sasaki collaborated on?

They have worked on 4 movies together! Their first movie together was Tamayura: Graduation Photo Part 1 - Kizashi (2015) while their highest rated movie together was Tamayura: Graduation Photo Part 3 - Akogare (2015). They have not worked together since Tamayura: Graduation Photo Part 4 - Ashita (2016). They are most known for their animation films together.