Japan's schoolgirls set the trend

The district called Shibuya, a seething nest of shops and restaurants on the western side of Tokyo, is one of those places which inspires the feeling of being old, square and ugly in anyone over the age of about 21.

This is the youth and fashion capital of Japan, as central and symbolic in popular culture as Carnaby Street or the Boulevard St Michel, and it is the domain of two distinctive species, each in their own way symbols of modern Tokyo. The first is the black crows, huge demonic apparitions, which fly into the city every day to feast on the bags of rubbish deposited on the streets. The second are the joshi kosei - Japanese high school girls.

Japan must be the only country in the world where it is considered fashionable for young women to be seen in their school uniforms, and every weekend and weekday evening, they flock to Shibuya in their distinctive plumage. The blue and white sailor suits are drastically customised: the pleated skirts hitched up to alarming heights, the white socks are worn many sizes too large and held up with specially bought glue (known as ruusu - loose - sokkusu, they are mistakenly believed to flatter plump calves). The school satchel is adorned with a variety of toys, chief among them a ubiquitous white cat known as Hello Kitty; somewhere there will be a plastic fob containing a photograph of the owner and her boyfriend obtained from a machine called a Print Club. Inside the bag will be a mobile phone, or at least a pager, a book of Print Club photographs, a silver lipstick and a make-up kit, including a set of crescent-shaped stencils used for applying an eyebrow pencil. The whole ensemble will have cost several hundred pounds.

Other nations fetishise their schoolgirls, and in Japan too there is a lively trade in pornographic school girl magazines, discarded school girl underwear and even themed brothels, where prostitutes dressed as teenagers submit to their clients in mocked up classrooms. But Japanese high school girls are unique in the degree to which they wield economic power. The Tamagotchi, the electronic "pet" which became a worldwide craze after catching on among Japanese girls, is just the most dramatic example of the remarkable potential of the Japanese youth market. Over the last two years, a small industry has sprung up dedicated to predicting and harnessing its tastes and spending.

No country is so susceptible as Japan to consumer booms and trends (or buumu and torendo as they are known here) but there are several reasons why the high school girl is a marketeer's dream. For a start, and despite the continuing sluggishness of the economy, she is well off. Sixty-eight per cent of Japanese teenagers, according to a survey by the Japan Youth Research Institute, receive a regular allowance; the average pocket money is 20,000 yen a month, nearly pounds 100. Japanese birth rates are going down, just as life expectancy is increasing, with the result that smaller and smaller numbers of children have ever larger numbers of older relations to spoil them. The phenomenon is known among marketeers as the "six pockets" - regular cash handouts from both parents and from two sets of grandparents.

But more exciting still is the speed with which new products and fashions spread among the teenage population. The Tamagotchi, more than 20 million of which have been sold worldwide, was not advertised at all in Japan. Instead the manufacturer, Bandai, relied entirely on word of mouth. Two months before its launch, samples of the toy were sent out to the trend- hungry teenage magazines; 20 articles were published before the toy was even on sale, reaching some 20 million readers. A month before, a limited number of the toys were sold in just five carefully chosen shops in Tokyo and Osaka. By the time it went on general release a year ago, demand was intense: in the first week, sales of the Tamagotchi exceeded the company's target for the first year.

"Most university students, for instance, have a small group of friends - outside that circle they don't have to talk to anyone they don't want to," says Hiroaki Morita, president of a marketing company which carries out market research and promotion through a carefully monitored network of school children. "But at school, they are crammed together all day, 50 in a classroom." Formerly, children were usually educated in their home town; these days parents are more inclined to look further afield for the best school, and trends which take root in one school are carried back home along the commuter train lines. The lines of communication are further strengthened by mobile technology - no self-respecting Japanese girl is without a mobile phone, or at least a pocket pager, with which to keep in touch and pass on the latest news.

Mr Morita's company, the curiously named Teen Networkship, exploits this capacity for fashion and rumour by means of 2,000 teenage volunteers. The network members are given free samples of soft drinks, sweets, cosmetics, and toys; in return they are asked to report back on the reaction among their friends. The client company gains useful feedback on the appeal of its new product, as well as access to the teenage rumour mill. "If we give a new product to 1000 high school students, each of them might show it to 20 people," says Mr Morita. "That's 20,000 people who become aware of it. Then there's the people they tell, and the people they tell ..." Best of all, Mr Morita's marketing guinea pigs don't cost him a yen.

How long this state of affairs will last is anyone's guess. Bandai, manufacturer of the Tamagotchi, is squeezing every drop of marketing potential out of its toy - as well as Tamagotchi pencil sharpeners and Tamagotchi key rings, interested parties can now buy Tamagotchi knickers and even official Tamagotchi curry. A new generation of Tamagotchi, featuring angels, fish and woodland creatures, as well as the original egg, have been rushed out; there is a similar toy aimed at boys, featuring battling monsters.

If there is a sense of desperation about all this, perhaps it is justified. Adult Japan, after all, is trembling on the edge of a recession, even a full-scale stock market meltdown. If either of these come about the world of the high school girl cannot fail to be affected; the carefree joshi kosei may disappear as dramatically as she arrived, in a haze of white socks and sailor suits.