What shall I wear... call girl or nun outfit?

Japan is the spiritual home of the fashion victim. The very same people who look so seamlessly elegant - and so much themselves - when gliding through the narrow lanes in kimono, approach the styles of the rest of the world as if they were racing through a jumble sale with blinkers on. The current trend - I can see it outside my window here - is for girls to affect shocking yellow hair, extreme artificial tans and eight-inch platform heels that make walking next to impossible (and driving so hazardous that the Japanese government, in response to several fatalities, has had to ban them from the driver's seat).

At the same time, the Japanese are more assiduous about pursuing fashion than any other people I know, and it is not unusual, even during a recession, to see college students spending hundreds of pounds on a Prada backpack, before disappearing into flats scarcely larger than a telephone booth. Public surfaces are everything. In recent decades, Japanese designers, from Hanae Mori to Issey Miyake, have expanded the language of haute couture , and Japanese innovations, such as the sushi bar, and the ultra-minimalist colour scheme, have affected fashions everywhere. But walk down the streets of Tokyo, and you will see shy mothers clad in hot pants that would make Madonna blush, and fresh-faced boys in hip-hop shorts best suited to America's drug-ridden inner cities. In Japan, more than anywhere, fashion is how people travel (out of themselves, out of Japan and, especially, out of the place the self occupies in Japan).

The final idiosyncrasy of the Japanese aesthetic, which complicates all of this, is that the culture is obsessed with youth (even as, like any traditional society, it venerates the old). Purity is the highest good in Shintoism - the girls who sell trinkets in Shinto shrines still dress in the white of vestal virgins - and innocence, or youthfulness, is so prized that high-school baseball tournaments, for example, are followed more religiously than professional games. Even Japanese males will say they prefer the kawaii (cute) to the kirei (beautiful), and Audrey Hepburn, to this day, is worshipped more than Marilyn Monroe. The tendency is so pronounced, in fact, that the whole culture could be said to be afflicted with a "Loli-com" (the typically hybrid Japanese term that is a contraction for "Lolita complex"). When Rei Kawakubo gave her ground-breaking company the name Comme des Garçons, she was saying something about how Japan sees the world, but even more about how Japan sees itself.

For those interested in how these strands converge - but probably for few others-the book to consult is Fruits . As tropi-coloured and evanescent as a bag of Opal Fruits, the book consists of full-page photographs - page after page of them - of Japanese teenagers dressed in the outlandish, tragi-comic styles that their photographer, Shoichi Aoki, rather kindly dubs "street fashion". In the terminally trendy Tokyo area of Harajuku, and to a lesser extent in other cities across Japan, you will see (at 3pm on Sunday afternoons, especially) bands of kids done up in fashion statements violently lost in translation. Delicate beauties disfigured with Tomahawks, dark girls made up to look like Alice in Wonderland in pink, self-pierced advertisements for self-restraint and others whose ghostly white eye-shadow and lipstick make them look like ghouls - all show off their misjudgements with a perkiness and eagerness that is sometimes the most curious aspect of all. For those not as smitten as Aoki is, Fruits might better be called Nuts .

Part of the inadvertent interest of these pictures, for western eyes, is that, in taking over items from the West, these kids strip them of all context; the girls who match leopard-skin shoes with Smiley buttons probably do not know quite how strange they look. In recent years, according to Aoki's short foreword, the Japanese young have begun to make foreign styles their own, no longer slavishly copying them, as their elders did, but mixing and matching - sampling, almost, as if they were creating the sartorial equivalent of a hip-hop record - by putting a geisha's traditional hair pin with a kaftan, or cutting up an old kimono to make a skirt. Much of this is probably lost on the unsuspecting viewer (part of "tracksuit fashion", Aoki explains, is that the plastic rings along its sides create a "harmonious jingling sound when heard from a distance"), but for Aoki it represents a revolution that needs to be documented. In 1994, he started a magazine called Fruits , consisting of pictures of kids seen along the streets, and, in cult-mad Japan, the magazine became a mini-cult that is now, in these pages, being shared with the rest of the world.

As you page through the unbroken series of relentlessly strange and poppy pictures, the first name and age of each subject printed in the lower corner, perhaps the most interesting thing you will find is the brief caption at the bottom, telling you where the items were acquired and what they are meant to connote. Though Vivienne Westwood and Jean Paul Gaultier are as popular as you might expect, the names of the local shops selling these clothes are even more revealing: Egoist, Hysteric Glamour, Jane Marple. And the styles on view are as eclectic as modern Japan itself - people dress as pink kittens, as Gary Cooper in High Noon ; they dress as sepulchral nuns and Indian princesses. Many of them apparently aspire to look like cartoons (taking their cues from manga comic-books and anime films). Some of the subjects photographed are two years old.

When asked to explain what effect they are trying to achieve, some of the kids say "trance" or "erotic alien" or "EGL (Elegant Gothic Lolita)"; but a few say, simply, "being selfish", or that they are trying in their clothes to evoke "sweet bacteria" or "a free lunch". And though most, asked their "current obsession", say things such as "knitting" or "happiness" or "skipping rope", a few say that their dream is "to be accepted" or to "self-implode", or, in one case, simply, "crying". For most, one suspects, the real current obsession is just being current and obsessed. Japan remains a society of eccentrics and hobbyists (as of public conformists), and fantasy is as precisely measured, and as unobtrusively practised, as reality itself.

There is, of course, an innocence to teenagers matching tartans with spiked hair, and they are unlikely, I suspect, to call themselves "sculptures" or even "personalised artwork", as Aoki does; yet deeper than this is a confusion about the world at large that is part of what makes Japan so confusing to the world at large. The same girls who dress like strippers hold hands in these pictures and make peace signs for the camera; the boys who wear dresses would probably never dream of saying they were transvestites. Part of the strangeness of Japan, for a foreigner, is that call girls often dress like ladies, while ladies (and teenage girls who would boast of being virgins) dress like call girls. Nine-year olds walk around with T-shirts on which English four-letter words are printed (their meaning, of course, unguessed at); even the most chic "office ladies" sport panda handbags with their Gucci dresses. Part of the wistfulness of Fruits comes from the fact that otherwise-attractive kids seem to be doing everything they can to deform themselves, or to look older than their parents; part of it comes from the inescapable sense that these children are looking for something, and not finding it.

Fruits is aimed, I would guess, at art college students, and people with so rococo a sense of cool, or camp, that they regard these costumes as art more than fashion (in deference to Cocteau's maxim that "Fashion must be beautiful first, and ugly afterwards. Art must be ugly first, thus beautiful afterwards"). Yet it is dangerous, I think, to make too much of all this. Along the King's Road, or in West Hollywood, someone may dress up as Johnny Rotten as a way to say something about himself and about the society around him (and he may, further, carry a copy of Jane Austen in his back pocket, as if to play off, and with, and against, your sense of who he is); in irony-free Japan, however, surfaces, as Oscar Wilde might have said, are the most revealing thing of all; and these outrageous styles have very little to do, I suspect, with who these people are, or what they think. The same kids who dress up as mutants will, when they are 20, slip into Chanel (or become conventional housewives); all they want is a chance to spend a lot of money and look distinctive for a moment (and in trend-addicted Japan, styles change so quickly that the "street fashion" trend Aoki first saw in 1996 is already, he says, beginning to vanish, which is why he is chronicling its forms as if they were the relics of an endangered indigenous tribe).

There is no doubt that a culture with more uniforms than any other I know will prompt more anti-uniforms; and in a place where people still like to dress in black and drive white cars there is allure in the flash, the noisy and the promiscuously jangled. It may also be true that these outfits serve a little of the same purpose as the sado-masochistic comic books that Japanese businessmen read on trains, or the love hotels where people, disappearing into a room made to look like a spacecraft, become someone else for two hours. The Japanese are notably pragmatic when it comes to taking off and putting on roles: when you visit a 19th-century British house in Kobe, you will find costumes on hand that enable you, for a moment, to become a character in a Brontë novel. You don the clothes, a photographer clicks, the moment is converted into a small eternity, and then you return to being yourself.

The single most shocking thing about the kids mixing Sid Vicious with Snoopy is that, if you stop one on the street and ask him for directions, he will prove more soft-spoken and polite than his father. The schoolgirls who trawl for "compensated dates" with businessmen - in order to subsidise their shopping expeditions - wear loose white socks with their school uniforms as if to advertise their looseness; the ones in fishnet stockings and torn tops are often decorous to a fault (and their parents would not be very concerned about them at all). The Japanese language is as mishmashed and multinational these days as its costumes, and looking at these pictures, I thought I understood the new Japanese word, gurotesuku . Then I remembered myself at 18, walking around London in a poncho, amazed at how very cool and exotic I must look.

Pico Iyer, a 14-year resident of Japan, is the author, most recently, of The Global Soul .