How many movies have Tsutomu Yamada and Yukiko Tachibana collaborated on?

They have worked on 8 movies together! Their first movie together was Mibōjin geshuku: Shitamo kashimasu yojōhan (1977) while their highest rated movie together was Porno: Chan-chaka-chan (1978). They have not worked together since Mibōjin geshuku: Hatsu nurashi (1980).