A university assistant professor spends his days researching. A hidden camera is installed at a reverse soap shop run by a friend of his, and he studies techniques by observing the reactions of female customers...
Unfortunately the movie Maruhi sennyû: Gyaku soap tengoku is not yet available on HBO Max.
| Directing | Sachi Hamano | Director |
| Writing | Kuninori Yamazaki | Screenplay |
| Crew | Joji Tanaka | Cinematography |
| Crew | Kanemi Kawanaka | Cinematography |
| Crew | Naka Ueda | Cinematography |
| Lighting | Kazuo Akiyama | Lighting Technician |
| Lighting | Yoshiyuki Tomasu | Lighting Technician |
| Lighting | Nobuaki Yasuda | Lighting Technician |
| Sound | Hiroaki Yabunaka | Music |
| Editing | Shōji Sakai | Editor |
| Directing | Shigeo Moriyama | Assistant Director |
| Production | Shizuo Suzuki | Producer |
| Costume & Make-Up | Yoriko Ogawa | Makeup & Hair |
| Camera | Kazutaka Okazaki | Still Photographer |
