It's short and simple. One might almost say simplistic. Ryuhei Kitamura and Yukihiko Tsutsumi got drunk together at a film festival and ended up challenging each other to the Duel Project. Each would make a film, following four rules:

Kitamura's film was Aragami and has samurai. Tsutsumi's film though has a more interesting set-up, starring two flat-sharing actresses in Tokyo who secretly hate each other but will still chat in an apparently friendly fashion until someone snaps.

The two girls are Eiko Koike and Maho Nonami. Koike is polite, well educated and slightly psychotic. She writes her name on everything in the fridge and maintains an expression of scary detachment even when attacking you with a samurai sword. She's the reasonable one, up to a point, but she's borderline autistic in her determination that everyone needs to follow her rules and it was probably inevitable that one day she'd find a flatmate wanting to murder her. She's also a virgin, practically penniless and prefers the stage to movies.

Nonami on the other hand is a rich bitch. She got straight into movies with her first job. She's uncouth, she's a bit stupid and she vandalises Koike's potential love life behind her back. Meanwhile Nonami's own love life is sufficiently complicated that she's been responsible for a murder-suicide. She's the one whose body weight is about fifty per cent jewellery, make-up and hair dye.

None of this makes for a deep movie, but it's impressive to see Koike and Nonami turning ever more hostile towards each other. Girls can be scary. They start out polite and friendly, but you can hear their disparaging inner thoughts even as they have their normal conversations. (At one point I wondered if Koike had overheard Nonami's mental comment about her boobs and T-shirt, but I don't think we're meant to be thinking that.) We see all the little irritations with which flatmates rub each other up the wrong way. Someone will get irritated, but bottle it up and pretend that nothing's wrong until she suddenly bursts out with it later. It's all too believable. It almost seems normal.

Then the violence begins. Why do two actresses in Tokyo own a chainsaw? What about the samurai sword, then? This starts earlier than you'd expect and gets pretty brutal, but fortunately Tsutsumi never loses sight of his characters. It doesn't just turn its brain off and switch into Violence Mode. The next level of escalation beyond a punch in the face might be to start smashing things in the fridge that don't have your name on, for instance.

Incidentally the title is an Japanese acronym for a 2-bedroom apartment with a living room, dining room and kitchen.

Is it a good film? I think so, yes. It's the most famous film to date for both Koike and Nonami, for starters. It's hardly layered or complex, but it has the energy and intensity that comes from its cast and crew filming around the clock to meet their deadline. The characters certainly come alive. It also got an appalled laugh from me with the final blood spray. I'll be watching Aragami, if only because it's by Ryuhei Kitamura, but I suspect I'll end up preferring the samurai-less one with two girls, a pen and a toilet lid.