That was ghastly. Whatever you're expecting from that title, it's worse... and what's hardest to stomach is that this film thinks it's a lovable, inoffensive sex comedy. We're meant to be enjoying it. It has a happy ending. The hero is a short, hapless man in thick-framed glasses, like a bland Jerry Lewis, and he might trip for no reason while going up a few stairs. There's even "quack parp squeak" comedy music, like a Carry On film.
WHAT THE FILM THINKS IT IS
A rather pathetic, henpecked bloke gets his hands on an invisibility serum and uses it for naughty fun! No one gets hurt and it's all harmless. After all, women enjoy getting raped, don't they? Give it a few moments and they're soon moaning and asking for more.
WHAT IT ACTUALLY IS
Theoretically, to be honest, it's not that different from Western sex comedies of the time. It's pretty tame. It's got silly stuff like giving someone a laxative and pushing aside a traffic warden to let a violator escape justice. The intention was clearly for this to be a bit of good-natured fun... and it would have only taken a few minor cuts for it to become that. Our hero (Ippei Nakamura) is a loser and easily dominated by the women around him. Almost all his sex is fully consensual and the rest of it tends to be heading that way fast.
Frankly, it's offensive mostly because of that word "rape" in the title, selling a fantasy that this is what rape is like. (Japan still has an ongoing problem with that. Convicted rapists don't always even do time in prison.) That title's an imperative, by the way. It's encouraging or ordering an Invisible Man to commit rape. You read that and you're bristling, in no mood to take anything in the intended spirit. Half of this film's problems could be fixed by renaming it... and, in fairness, imdb says it's known in English as "Lusty Transparent Man". That's not what it says in Japanese, though.
Lots of justifications are created for Nakamura's behaviour. These include:
1. Shockingly, Nakamura has a wife (Momoko). They've having sex in the film's opening scene. Everything he does in this film is cheating on her. She's tougher and more forceful than him, though, and she insists on using a condom. He doesn't like that.
2. There's a predatory lesbian (Kurokawa-sensei) who commits sexual assault against other women. Our hero will give her a taste for men.
3. At one point, Momoko's on the point of going to a love hotel with another man. (She's being dragged by him and saying "no", though, because she's changed her mind.) She also doesn't seem to have a problem with getting assaulted by Kurokawa-sensei and her dildos.
4. A woman is reading a book called "Deep Throat".
The film also has poor special effects and illogical visuals. (a) When Nakamura has sex with a woman in a public bath, why isn't he displacing any water? Shouldn't we be able to see a water-hollow of his body shape? (b) When he steals some food off someone's plate, it disappears with a ping. We don't see it being lifted into the air, chewed or swallowed. (c) When Kurokawa-sensei knocks unconscious a couple for the crime of proposing marriage, she does this by kneeing the man in the groin (okay) and later punching the woman in the midriff (eh?). (d) The translucent penis is just weird, although it's only in one early sequence.
They have a good special effect for when the Invisible Man gropes boobs, though. I also liked the bit where Nakamura starts sneezing after his first invisibility session, because you'll catch cold if you run around naked, invisible or otherwise.
I was about to say that the film front-loads all its worst material, but on reflection I'm not sure that's true. It just feels that way, because the early scenes will fill you more with hate. Kurokawa-sensei rapes another woman in the middle of her office, in broad daylight, without even bothering to hide or lock the door. Anyone could walk in (and Nakamura does). I couldn't believe in it. At one point our hero flips three young-looking schoolgirls' skirts. The finale has him stripping and having sex with Kurokawa-sensei while she's delivering an academic presentation. It's meant to be funny. It's horrible.
There are people who say the film's almost the same as American teen films like Zapped! or Invisible Maniac. They're not wrong, but paradoxically that's what makes its take on rape so objectionable. It's trying to give us light, comedy rape that's a bit of harmless fun. I'd sooner watch the Guinea Pig films.