How many movies have Mototsugu Watanabe and Rui Hizuki collaborated on?

They have worked on 2 movies together! Their first movie together was Kaikan Heroine: Breasts Shakedown (2019) while their highest rated movie together was Beautiful Breasts Serenade: Erotic Fair Skin (2020). They have not worked together since Beautiful Breasts Serenade: Erotic Fair Skin (2020).