If you've never heard of Anno Hideaki, he's the biggest name in anime after Hayao Miyazaki (who employed him on Nausicaa and regarded him highly). He made Neon Genesis Evangelion, which made the biggest splash in anime for a decade when it came out and to date has grossed more than 150 billion yen for Gainax. Later he moved into live-action films, of which this is his second, between Love & Pop (1998) and Cutey Honey (2004).

However what you really need to know about Anno Hideaki is that he's got problems. Evangelion deviated from the original manga in ways that drew on Hideaki's four-year period of depression and his opinion that Japanese otaku are autistic. Despite originally being broadcast in a children's timeslot, the series got ever more dark and psychological as the series progressed, until by the end he'd abandoned traditional narrative logic and had the last two episodes taking place inside the main character's mind. This got him death threats. Later he walked away in mid-run from a series he was directing, His and Her Circumstances (1998), then sort of abandoned the anime industry. He's since returned to do non-directorial work for Gainax and a new Miyazaki collaboration, one of those short films they show at the Ghibli Museum, but these days he's more about live-action.

Anno Hideaki's projects can be light-hearted. Cutey Honey is silly. However he's also prone to putting his mental problems on screen, often in a way that's visually playful and yet also rich and layered thematically. He can be challenging. His finales also tend to be bollocks, or else boundary-pushing explorations of themes and psychology (delete according to taste).

So that's the background. What's more, this is completely and utterly an Anno Hideaki film. It's not as experimental with form as Love & Pop (or so I hear), but even for him this is naked self-exploration. There are two main characters, Ayako Fujitani and Shunji Iwai, and they're both nuts. Fujitani is a cute fruitcake whose hair and face keep changing colour, whose personality changes to match the weather and who tests herself every day on rooftops or train tracks to see if this is the day she'll commit suicide. Meanwhile Iwai is a film director with a background in anime who's pretty much abandoned his life and thinks he can't communicate with other people except through images, but will come out with insightful and almost startling psychological analyses. Both of them are basically Hideaki, as also is the gestalt entity of the two of them combined.

That's the entire film. Fujitani and Iwai do nothing of importance, often together. Other humans occasionally appear, but only for a total of about ten minutes in this 128-minute movie and for most of the time they're not even glimpsed. Instead the world of this film is very much a reflection of the inner weather, so for instance Fujitani is colour-coded red, Iwai is black and the absent elder sister (also metaphorically reality) is blue. There's a striking use of water. There are cartoons.

This probably sounds like a train wreck, but in fact it's fascinating. Hideaki is blasting absolutely everything at his psychological analysis, either in words or images, and he's an extremely clever man with a gift for weird and meaningful visuals.

With hindsight, the film can regarded as split into two halves. The first half is enjoyable because Fujitani is a cute, happy person with an adorable smile, so it's fun and interesting to see her taking Iwai on a tour of the inside of her head. I'd have been happy had it all been just that, but then the second half introduces character development, backstory and a level of literal truth that feels a bit odd after the first half was so clearly metaphorical. To my surprise, it all turned out to be going somewhere. There's also a countdown throughout the movie, starting with "1st day, 31 days before" and inexorably ticking down towards zero hour. I turned out to be wrong about where that was heading, but I might also argue that I'd been correct metaphorically.

The cast is interesting. Iwai is himself a celebrated indie director, but the real surprise is Fujitani. She's the daughter of Steven Seagal and the film is loosely adapting her autobiographical novella about her alienation growing up in Los Angeles. (She's an actor in Japan these days, while her brother Kentaro Seagal is an actor too.) In other words, this film's a exploration of the real lives and psychological issues of both its director and lead actress. What's more, she's brilliant in the role. This shouldn't be surprising given that it's about her, but even so she delivers a colossal performance, especially given that Iwai's basically following her around throughout and hardly ever doing or saying anything. It's almost all Fujitani. She had to be dazzling for the film to be even watchable... and she is. I like the details, like her moments of shyness. She creates a character who's almost unimaginably strange, not to say broken, yet always real and convincing. You like her, despite everything. You want to go on watching her.

Oh, and Megumi Hayashibara gets a voice cameo. There's a famous name from Hideaki's anime days.

This is a fascinating movie, which I'd like more people to see. I love the way it's using visuals and symbolism, in a film that's chosen as its chief theme our relationship with reality. Real life hardly ever seems to intrude, with Iwai being free to take a month off to do nothing and Fujitani, as far as I can see, eating and drinking thin air. (Knowing her real-life background might change one's perceptions here.) The movie's absolutely not for everyone, but it's one of the few important Japanese films of 2000 and I'm delighted to have watched it. Note to self: watch Love & Pop.

Besides, Fujitani really is super-cute when she smiles.