Nerd subgroups include not only people obsessed with cartoons and computer games, but also pop idols such as Morning Daughter, a music group marketed to kids that has become so popular among otaku that men sometimes attend its concerts wearing kimonos covered in glossy pictures of young band members.
That, along with the child pornography aspect of some adult manga, has led to allegations that some nerds are pedophiles.
Tetsu Ishihara, 34, a computer programmer whose three-room apartment in west Tokyo is filled from floor to ceiling with comic books, does not want to be associated with such charges. Ishihara maintains a growing collection of 130 life-size pillows of female anime characters -- both purchased and self-designed. His favorite is Mio-chan, a female character from a love-simulation computer game in which a high school boy builds up the courage to ask a girl for a first date.
"There are some people who do lose their grip on reality, but that is not me -- or most of us," said Ishihara, a chubby man with glasses who this year started dating a woman steadily for the first time She's an anime artist. "For me, the pillows have been my source of unconditional love, a reminder of when I used to be hugged by my parents. There is nothing strange about it."
Yet some sociologists critical of the nerd culture here have linked it to the high incidence of severe behavioral problems among men under 40. Immersed in role-playing games and comic fantasy worlds, many have found real-life personal conflict difficult to cope with-- one cause, some say, for a massive increase in the social problem of hikikomori , or shut-ins. Now numbering as many as 1 million nationwide, the shut-ins -- mostly men in their twenties or thirties -- typically live in their parents' homes, rarely leaving their rooms.
Otaku behavior is also being blamed, along with social disillusionment following Japan's protracted recession, for the increasing numbers of Japanese youth who have no apparent career ambitions. Instead, many are choosing to work part time -- or not at all -- so they can spend most of their time pursuing their hobbies.
"The Japanese have never been good at verbal communication, but the problem with otaku is that they are so engrossed in their own favorite world and don't have the ability, interest or confidence to interact with other human beings," said Hiroko Mizushima, a legislator in Japan's lower house and a psychiatrist who has studied the subject. "The impact on society is enormous. They just don't want to have close relationships with others."
Nowhere is that more obvious than in Akihabara, where the nerds use their own slang and share a general aversion to even being seen -- one reason, experts say, that many of the new buildings in the district are largely windowless.
The geeks' arrival in Electric Town during the 1990s transformed the area, now lined with images of cartoon characters and shops catering to otaku tastes. Particularly popular are stores specializing in the tiny figures churned out by supermarket bubblegum machines. Men pay $30 or more for the rarest characters.
"Most people think we're weird," said Yamagata, the college student. "That's why we come here."
