I have an apology to make. I ended my review of Uzumaki by calling it "a movie to show to anyone who doubts that the Japanese are mad." I've since watched Suicide Club, which was deranged enough to set me wondering about Japan's national psyche.

No, really. There isn't a more conformist country in the world, yet they're famous for perversion, odd behaviour and for making films like this one. I'm going to speculate that since it's historically been a country where you're basically expected to behave like everyone else, people's natural strangeness ended up warping the entire society. Then there's the Japanese relationship with death. Suicide was traditionally seen as a good thing, while it's completely normal to read over there that someone's randomly murdered their entire family because of their big overdraft. People jumping in front of trains are common enough to be a nuisance.

All of which leads up to the fact that Suicide Club is completely and utterly Japanese. The idea of a Hollywood remake of Battle Royale is merely repugnant. I don't know if they'd even be capable of remaking this, which unsurprisingly won the Jury Prize for "Most Ground-Breaking Film" at the Fantasia Film Festival. All films send you on a journey, usually involving the characters. However in this case, it involves the more basic question of "what the hell am I watching?" This is the first review I've written in which it's daunting just trying to convey the simple facts of what I'm talking about.

We start with 54 Japanese schoolgirls waiting for an underground train. Some are ordinary-looking and some are attractive. They're normal, lively kids. They're also standing amid the usual crowd of commuters. If nothing else, this film portrays more strongly than most what it's like actually to be in Japan. It feels as if they just took cameras outside and wandered around shooting whatever they saw. Later on we'll also see stand-up comedians, a J-pop girl band with an average age of twelve and an outdoor food stand about the size of a Punch and Judy booth. Anyway, those schoolgirls join hands and jump in front of the train. The Suicide Club has struck.

The film does have a proper plot, although you might be surprised by the bit where it turns into The Rocky Horror Picture Show, complete with a musical number. The last 10-15 minutes are surreal too. The whole thing is weird, yes, but in the context of a mostly serious film about lots of people killing themselves in increasingly bloody ways. This is one gory movie. It's not a splatter film in the sense of "blatantly an excuse to throw guts at the camera", but it's far from shy about throwing around innards. Sometimes it's funny. Sometimes you watch people getting ready to kill themselves and it's downright disturbing. Then sometimes it's both funny and horrifying at the same time, as in the scene where I was convinced someone was about to be sick in a bag he'd just found containing a severed head. These bags always contain severed heads.

It's not a head. Ewwww. Okay, I'd never seen that before.

I don't know if I'd call this a horror film. It's not scary. No one's generally in danger from anyone but themselves. However the effect it's trying to have on the viewer is extreme enough to target it at the horror fan demographic, like a more whacked-out Battle Royale.

Astonishingly it works. Against all the odds, I never felt that writer-director Sion Sono had lost control of his story. The secret is tone. When we first meet those 54 schoolgirls at the beginning, it's filmed in fly-on-the-wall style and we have no idea which way it's going to go. All we know is that in a film called Suicide Club, it probably won't mean rainbows and butterflies. Gradually the tension builds as it becomes increasingly clear what these girls are going to do... and then bouncy jolly music comes on the soundtrack and they jump, sending up fountains of blood that splash around so liberally as to turn the scene into slapstick. I couldn't stop laughing! Maybe I'm sick. Maybe I'm depraved. I dare say normal people wouldn't get the joke, but this film has truly awesome gore comedy.

That's the tone of this film. Unpredictable. It's also very Japanese in its occasionally casual attitude towards people killing themselves. Dang it to heck, someone jumped off that building and landed on me. Ah, I see mummy is slicing up her hand with a carving knife. Is there anything on television?

Harsher critics than me might say that Sion Sono had a great idea for a film, but less interest in its plot. It's certainly true that Usumaru Furuya, the creator of the tie-in manga, was told not to copy the movie's plot but instead to write his own story. The Suicide Club manga is thus more straightforward and easy to understand than the movie and features more solid character development. Oddly enough though, the film's sequel, Noriko no shokutaku (2005), is apparently a smaller-scale, introspective piece. I hadn't been interested in the idea of a sequel trying to outdo this already extreme original, but in that I'm mildly interested.

Hmmm. Having said all that, I shouldn't overstate my case. This film is far from being non-stop schizophrenic mayhem, but instead for much of its running time feels fairly normal. One of the key weapons in its arsenal is the ability to shift its tone back to the level of "no, really, this is a proper film".

Most of these children and teenagers had never acted before, but you'd never know. There's also an awesomely cool policeman, who's this grizzled bald Japanese guy with a moustache and the ability to look as if he's hitting on schoolgirls while simply talking to them on the station platform. I could talk about this film all day, but I should probably stop here before I start building it up into something it's not, or perhaps giving too many clues to the plot. This film is at once sober and hilarious, realistic and gross, surprisingly thoughtful and yet wildly over the top. It's taking its subject matter seriously, but in a very Japanese way. It's an experience.