Groper Train: The Search for the Black Pearl (1984)

Twenty-four years before winning an Academy Award for his affecting musical drama Departures, director Yojiro Takita took the helm for this quirky Pinku eiga about a veteran detective searching for a priceless pearl. The world's largest black pearl has vanished without a trace, and it's up to Detective Ippei to track it down. His only clue is the mysterious words of a dying man, who managed to mutter "Pussy Print!" before slipping away forever. Teaming with the man's younger widow Matsuko, Detective Ippei boards a local train and begins taking prints of the female passenger's vulvas in hopes of matching one to the print that Matsuka's husband had in his possession at the time of his death. This film is also known as "Chikan Densha Shitagi Kensatsu"