WHEN a young Filipina, one of many new Asian migrants in Tokyo, recently visited her neighborhood public bath, she violated all Japanese etiquette.She stood up while taking a shower in the washroom for women, splashing her fellow bathers who, as almost all Japanese do, squat on stools when washing up before a hot soak. She also wore a bathing suit. Complaints from the women about the "outside person" reached the ears of Michihiro Okuda. For the past few years, he has kept a record of how Japanese in Tokyo react to the wave of other Asians moving into the city. "Tokyo is going through a big change right now," says Dr. Okuda, a sociologist at Rikkyo University. "The Japanese believe they have a homogeneous society, but Tokyo is fast becoming a mixed city." In the past decade, as wages have risen and more Japanese shun manual-labor jobs, thousands of Asians, mainly Chinese, Filipinos, Thais, Koreans, and Iranians, have migrated to Tokyo, either legally or illegally. These immigrants often live in old, dilapidated wooden houses, filling the population gaps in central Tokyo where business has not cared to build or residents can no longer afford a large home. Local officials do not release figures on how many foreigners live in their districts, fearing such data might give a bad image. But Okuda has dug out the figures and says about 6 percent of the population in many inner wards of Tokyo are non-Japanese Asians. And his informal sampling of illegal immigrants indicates that the actual numbers may be closer to 15 percent. In one area called Ikebukuro, for instance, so many non-Japanese Asians can be found that it has been tagged "little Hong Kong." Many stay for just a few years, hoping to move on to the United States or Canada. While such polyglot neighborhoods are common in New York or Los Angeles, they are new to Tokyo. In the US, Okuda says, there is discrimination against minorities, but rarely are they treated as aliens, as in Japan. Their Japanese neighbors at first complain about the Asians making too much noise, misplacing garbage for pickup, or even that they do not remove their shoes indoors, as Japanese do. But, notes Okuda, such complaints are becoming fewer, based on surveys during the past three years. "The attitude of Japanese in Tokyo communities is slowly changing," he says. Some community leaders now actually help Asians find apartments, having discovered they help revive declining neighborhoods. "Their minds are opening up," he says. "Japanese generally do not have a good image of other Asians. But when they live together, they find that Asians can be even more polite than today's young Japanese. "These Asians have a custom of helping each other. Eventually the Japanese around them will recognize this sense of community, which they themselves are losing." Tokyo's mixed communities have become a testing ground for what many Japanese say is a need for the country to globalize. But what is often meant is that Japan must go to the world, while the world should never come to Japan. For the first time, the government this year referred to Tokyo as a "world city" in its long-term plan. "At the community level - that's where internationalization starts," Okuda says.