It's a cold winter's night in Tokyo and 'Mariel' is on her way to work. Painfully underdressed for the weather, the 21-year-old is decked out in a black-and-white Victorian maid's costume that barely covers the tops of her brown thighs. Named after a character from one of Japan's most popular anime cartoons, Hanaukyo Maid Team - about a rich boy who has a huge staff of maids at his beck and call - Mariel will spend her six-hour shift playing a passive host to shy, geeky men who she will address as 'master'. To the men, she is Mistress Mariel: obedient, erotic and hopelessly out of their league. Ride around the points of Tokyo's circular Yamanote railway line on a Friday night and you will find the usual human flotsam winding its way down into the weekend: drunken salarymen hunting cut-price kicks in east Shinjuku; giddy high-school students roaming the youth playground of Shibuya; office ladies window shopping along the upmarket boulevard of Harajuku; and star-crossed couples hovering around the love hotels of Ikebukuro. However, get off at Akihabara, to the northeast of the loop and an area squeezed between the staid bookselling district of Kanda and Ueno Park, and you will find a different breed of thrill seeker. Here, the crowds are overwhelmingly male and single, the dress code is a mix of parkers, backpacks, sensible shoes and thick glasses, and the prize is not a drink or a date, but the latest animated character or computer game. The favourite pit stops are cafes where waitresses in frilly pinafores with names such as Strawberry and Pudding greet customers with an ear-splitting 'Welcome home, master!' You have entered Otaku-land. Once the centre of Japan's electronics retailing industry, the area has been transformed over the past decade into a sort of nerd's paradise, catering to the country's growing ranks of otaku: geeks who obsessively pursue a single hobby such as collecting anime characters, video games and toys. Once viewed with suspicion because of its association with odd, sometimes sex-obsessed loners, otaku culture has grown into an almost mainstream, billion-dollar industry, spawning its own language, customs and cast of deeply eccentric characters. Toshio Uchiyama hoards autographed cards of his favourite 'maidens': women who work in the dozens of so-called maid cafes - boasting names such as Cafe Doll Tokyo, Wonder Parlour and Curio - that have sprung up in the area since 2000. Today, the part-time ryokan (Japanese hotel) clerk is sitting in Angels Cafe doodling a cartoon of a doe-eyed anime character in the visitors' book. The cartoon is excellent; almost feminine in its attention to detail and Uchiyama is looking for words of praise. Sweating beneath thinning hair, he looks up shyly as a young waitress dressed in a frilly Victorian maid outfit approaches. 'Would you like more tea, master?' she asks. 'N-No thanks,' he replies. In the visitors' book he writes: 'When the maids welcomed me, I was a little embarrassed and nervous but I enjoyed myself. I had apple pie and tea. You are very cute, thank you. I'll come again.' Uchiyama says he has written similar notes in virtually every cafe in the district over the past three years. 'I like it because they provide a kind of escape for me,' he says. 'The maids look after me and make me feel special, and I feel healed afterwards.' When he is not checking out the latest cafe or posting pictures of his favourite maids online, Uchiyama contributes to several internet blogs about Inuyasha, a sword-wielding manga character who fights demons, and compiles lists and photos of trains. The shy 34-year-old, in other words, is a trainspotter, although he says locomotives have lost some of their attraction lately. 'I'm much more interested in maids now.' Above Angels Cafe is MIF Maid Massage, where men like Uchiyama come to be pampered by more women in billowing pinafores. The maids - modelled on popular anime characters and rooted in the Japanese love of role-playing - are a mix of the demure and the erotic: large doleful eyes, long legs, big breasts, high-pitched voices and perfect manners. The customer is greeted by a deep bow and a loud 'Welcome master' before a maid drops to her knees to kneed weary otaku shoulders for 3,000 yen ($200) a pop. The ambience in the dimly lit massage room is an odd blend of maternal and sexual, but the maids insist they do arms, hands and shoulders only. 'The guys who come in are normally pretty quiet,' says Shizuku, a pretty teenager who says she is not allowed to disclose any personal details, including her real name or even her age. Like the rest of the maids here, she is attracted to the job by the pay, which is close to double the 700 yen an hour students make in convenience stores and restaurants. The chance to 'act' is also a factor. 'We're playing a role but some [customers] get carried away,' she shrugs. 'They fall in love with our characters and start sending love letters, so we keep our identities secret to discourage stalkers. Some of the girls find it a bit creepy.' Academics say the maid phenomenon is fuelled by growing insecurity about traditional male roles in a country that is rapidly shedding lifetime employment and the nuclear family - the twin poles of male power and identity in Japan. An estimated one million people - known as hikkikomori, or social recluses - have retreated completely from daily life to their bedrooms. Many more have abandoned messy human relationships for a digital or fantasy alternative after lifetimes of consuming anime and manga. 'You have to ask: how far can Japanese popular culture go?' says Yuko Kawanishi, a sociologist at Tokyo Gakugei University. 'These men are increasingly losing the ability to interact with real human beings with real feelings and flesh and emotions like them. It is too overwhelming for them to deal with a woman so they don't bother. And there is already a huge commercial culture catering to them.' Japan's genius for incorporating and repackaging the unlikeliest trends can be seen all over Akihabara. At Hiyoko-ya cafe, the traditional izakaya bar has been given a makeover that would have most corporate samurai spluttering into their beer. The bottles stocked around the counter are capped with figurines of the customers' favourite maids and male guests well into their 30s have adorned the bar with their own 30cm-tall anime dolls. The waitresses happily comply when asked to comment on the plastic partners.'She's so cute, master,' says one. Businesses in the area have cashed in on the maid phenomenon. Hair salons and book stores have been redecorated to look like the bedrooms of teenage girls, with twee touches such as red hearts, pink cushions and teddy bears attracting not just otaku but regular customers too. In Cafe & Kitchen Cos-Cha, the maids change costumes to mimic the most popular anime character of the day. Maids have even invaded the local flesh trade, but while Akihabara has its fair share of sex businesses, insiders say most otaku would much rather fantasise than partake. 'That would spoil it for me,' says Uchiyama, visibly shuddering. The term coined to describe this otaku affection for dolls, anime characters and maids is moe, literally meaning 'blooming' but closer to the idea of perfect unrequited love. For some otaku, it is the ultimate expression of human affection in the cyberspace age. 'Real women have never treated me well,' says Toru Honda, a sort of otaku guru, who has written a bestselling book about his virtual life and claims to spend one million yen a month on his obsession. 'My electronic friends have never let me down.' In the maid cafes, otaku are kept at a distance by the waitresses, who stay strictly to their allotted roles. But in the real world, some worry these lonely single men could be dangerous. Many are steeped in pornographic internet culture and flit around the edges of mainstream society, working part time and meeting few other people except fellow otaku. In a notorious recent case, Kaoru Kobayashi, whose apartment was described as a shrine to pornographic anime, kidnapped and murdered a seven-year-old girl. The otaku taboo, and the slightly queasy feeling the term triggers in many Japanese, has lessened, however, as its economic importance has grown. According to a survey last year by Tokyo think-tank Nomura Research Institute, the market for otaku pop culture, defined mainly as comics, computer games and electronics (but excluding maid cafes) is now worth more than 400 billion yen annually. Spokesman Takeshi Nomura says the impact of geeks 'can no longer be ignored by businesses'. The phenomenon penetrated mainstream culture last year with the massive success of movie Densha Otoko (Train Man), an allegedly true story about a 22-year-old who stumbles from his cyber-cocoon into a flesh-and-blood relationship with a woman he rescues from a train groper. The growing acceptance of otaku culture has led to a development that has taken virtually everyone by surprise: Akihabara geek chic. Sprinkled among the painfully shy men in maid cafes across the district you can increasingly find shy young female fans looking for a boyfriend. 'I know some people find otaku creepy but I think they're cute and a little mysterious,' says 19-year-old Reina Takeda, who sips lemon tea in the Pinafore Cafe with a friend, Emi. 'It's hard work striking up a conversation, but they often turn out to be really sweet.' The waitresses, too, take a lighthearted approach to the odder obsessions of their male customers, one of whom insists on showing his drawings of more gloopy-eyed, impossibly long-legged cartoon figures. 'What harm does it do?' asks 22-year-old Rugiri, who sports a striking set of anime contact lenses in addition to the standard frilly get-up. 'It's their life and there are worse things they could be doing. Personally, I'm more afraid of men who look normal on the outside.' Around the corner, a line of young men and women stretches down three flights of stairs outside Home Cafe, one of the most popular maid establishments in Akihabara and one that has been featured on several television programmes. Masayuki Ishimori and Yu Banno have travelled from Nagoya (about two hours by train from Tokyo) to visit the district. Both look disappointingly normal - handsome even - with not a plastic figurine, hand-held electronic game or pair of thick glasses between them. 'We heard about the cafe on TV,' says Ishimori. 'The maids looked good. I suppose my reason for coming is sexual titillation,' he laughs. Banno disagrees. 'That's not it at all. It's a sort of fantasy experience. I mean, women in real life don't usually listen to us or call us master. It's like going to a play.' Inside, about two dozen men and a sprinkling of women are greeted by beaming smiles beneath lace hats, the sound of starched pinafores swishing between tables and the smell of soap and perfume. Maids bow at each table before kneeling and using both hands to pour tea and milk. One young man looks like he is about to be transported to heaven. 'The problem with real life is that it always disappoints,' says Honda. 'Why take a chance?'