How many movies have Masatoshi Kai and Shuichi Hirata collaborated on?

They have worked on 4 movies together! Their first movie together was Patlabor 2: The Movie (1993) while their highest rated movie together was Jin-Roh: The Wolf Brigade (1999). They have not worked together since Naruto the Movie: Legend of the Stone of Gelel (2005). They are most known for their animation films together.