How many movies have Koichi Murasawa and Satoshi Arai collaborated on?

They have worked on 1 movie together! Their first movie together was Kaze no Shounen: Ozaki Yutaka Towa no Densetsu (2011) and was their highest rated movie together. They have not worked together since Kaze no Shounen: Ozaki Yutaka Towa no Densetsu (2011).