Ah, Japan. You've got to love it. Let's analyse that title, which deserves some kind of trash award.
STRIP = yes, the girls all get naked. That's the point of the film. Sleaze, nudity, bad taste... call it what you like, so long as you don't say "pornography". That's obviously part of the intention (which is disturbing), but this film is too gross, violent and abusive to be arousing. If you find it titillating, please go to prison now.
MAHJONG = four-player Chinese game from the Qing dynasty, played mostly in East Asia but these days also increasingly popular in the West. You usually play with 144 tiles, which have names like Dots, Bamboo, Winds, Dragons, Flowers, etc.
BATTLE ROYALE = fight to the death, with one winner left alive at the end.
That's what you get. The film lives up to its title. For what it's worth, its director (Mac P. Forever) has made several films that I could find out about, all with spectacularly trashy posters and some looking like sequels to this one. There's Strip Mahjong Prison (2014), Strip Mahjong Police 24-Hour Naked Battle Royale (2015) and Strip Mahjong Idol Warring States Era Naked Battle Royal (2015). I'm pretty sure mahjong post-dates the Warring States era, but I'm also sure that no one involved in these films will have been worrying about historical accuracy.
The film surprised me. Sleaze I'd been expecting, but not something this nasty. You could make a sexy, consensual version of this film, but only a lunatic would choose to participate in what we see here. It's a TV show. The male host (Hiroaki Kawatsure) is a creepy, gloating molester and rapist who thinks he's funny, while his female co-host (Anzu Sasaki?) is dressed as a maid, says "nya" a lot and thinks the whole thing's fun. I'm not certain which of the film's five actresses was playing her and I didn't do a google image search for them at work because I'd have just found their hardcore porn. These girls weren't hired for their acting skills. They're not even at the "porn star but surprisingly good" level of someone like Asami. Yes, that's right. We're at the low end of the "scary Japanese sleaze where the cast are porn stars" genre.
Anyway, the four contestants get dragged in in chains by a man in a thong and a gimp mask. They're wearing radio-controlled collars (never a good sign) and they don't even know where they are. Kawatsure explains that, "Getting naked is the only worth you have left as human beings. You've all racked up five million yen in debt." If you lose at online mahjong in Japan, apparently this might happen to you.
UPSIDE: the winner gets lots of money.
DOWNSIDE: don't lose.
The mahjong seems to be taken fairly seriously. I don't know the game at all, but there's quite a lot of analysis and character reading, like a poker tournament. I appreciated that. The film's doing its premise properly.
The stripping, on the other hand, is an unpleasant exercise in humiliation. The presenters go out of their way to make the whole thing as degrading as possible for the contestants, often removing the clothes by force and/or in stupid unfunny ways. Plus, of course, removing your last layer of clothes will be the last thing you do before getting killed.
Is it pure misogyny? Actually, no. All the gamers have their own personalities, backstories and attitudes (usually bad). There's an unpleasant, vindictive lawyer who'll bear a grudge just because you beat her in the first round. There's an idol who used to be a delinquent. The meek, blob-like housewife has a shock or two in her backstory. The anti-performances unfortunately make this less effective than it should have been, but the result is a proper, watchable film that also happens to be cheap trash. It's got a sort of integrity. The film also has a last-act twist that's not what I'd have done in that character's position (to put it mildly) but turns the story into a protagonist acting (and avenging), not just reacting.
(There's also a ghastly irony with a wedding ring. That vow to return it to the husband becomes bleak and almost painful if you remember the backstory we've just heard.)
Is this film watchable? Not for normal people, obviously, but it's not ero-guro and I'd give it no more than a four on the Beyond-The-Pale-o-meter. (Zero is something you could find in ordinary cinemas. Three means your family would merely think you were some kind of freak if they caught you watching it. Seven would have them vomiting in buckets, e.g. Daisuke Yamanouchi in 1999-2000. Ten means the filmmakers deserve to be arrested.) It's not horror or a gross-out. There's no gore, although obviously there's nudity.
While discussing this film today, someone asked me if I enjoyed it. I had to stop and think about that. "Enjoy" isn't the word. However it's a much more interesting film than I'd expected (although also more disturbing and abusive). You could almost call it cerebral, in a trashy way.