On this particular winter night, 120 men and women have assembled on the edge of Tokyo's Ueno Park for the free bowls of rice and curry that are distributed there three times a week.

A Salvation Army van arrives at 9:45. With little ceremony, volunteers inside begin dishing out the steaming food. Looking chilled despite layers of tattered overcoats and mufflers, the people receive it in silence and steal off to dark benches to eat.

It is the van's third stop of the evening. Earlier, 50 persons were fed outside Tokyo's main railway station and 18 on a street corner in the Tokiwabashi district.

Japan has tackled crime, illiteracy, unemployment and other social ills with a success envied in the rest of the noncommunist world. Yet, homeless people, their possessions bundled into shopping bags, still walk its streets, a reminder that in some cases, Japan is as impotent as other nations.

The Japanese call them furosha -- drifting people. Their numbers are uncertain. The 1980 census recorded only 700 in Tokyo among a total population of 8 million. Yet these days the Salvation Army sometimes feeds 400 a night from a single van.

Some are mentally ill. Others are breadwinners temporarily down on their luck. Many are people who, for whatever reason, have chosen to turn their backs on the great commandments of this highly conformist society: get ahead, keep clean and make your family proud.

"All those considerations I threw away," declared Yoji Mochizuki, a grizzled, 61-year-old who said he has foraged in Tokyo's Ginza district for the past 20 years. "If I hadn't, I could never live this way."

In the winter, the cold drives him and his companions into heated subway stations and underground arcades. There they are found dozing on cardboard, drinking cheap liquor, playing board games or pawing through trash cans for food, drink or newspapers.

Nights they must spend outside. One of the few truly pathetic sights to be seen on the streets of Tokyo are the coffin-shaped shelters that they rig up from cardboard boxes to fend off the winter wind.

Eijiro Uchida, 53, and his wife, Fujie, 61, said they spend the daylight hours gathering cardboard and other refuse for sale to junkyards. They clear about $5 a day. They pass the nights in one of Tokyo's tiny neighborhood parks. "It is cold," Uchida said over Salvation Army food recently, "but we have each other and somehow we manage."

Ordinary Japanese simply ignore the furosha. It is easy to do so. They rarely approach passers-by for change. They drink, but generally not enough to grow boisterous or pass out. In parks, mothers and children play, oblivious to the unwashed man on a bench a few yards away.

But Satoru Saito, a psychologist who is conducting a study of the furosha, said many Japanese feel threatened by this "provocation" of conventional society's values. "The furosha are poor at articulating their philosophy," he said, "but their very existence constitutes a challenge."

Some older people see them as proof that the ethics that made Japan great are on the decline. In the old days, said Tokyo shopowner Yoichi Ueda, "people felt more shame . . . . It was beyond the comprehension of youngsters to join these people. The police, the family, were strong."

In fact, few cities are so hospitable to street people. The jetsam of prosperity is everywhere. Service-conscious restaurants throw out meals if they do not sell in a day; people discard clothes, shoes and other essentials at the first signs of wear.

Government welfare programs can provide $75 a month. Those people willing and able to work can sign on as day laborers at construction sites.

What is not found or earned can be negotiated. Some restaurants feed drifters at the back door in exchange for their prompt departure. "In Ginza, sometimes we get luxury food," said Mochizuki with satisfaction. "If you know the right places, the life here can be fairly easy."

As in the United States, talk like this has fueled debate among government and social workers as to how many are forced into the life and how many choose it to escape responsibility.

Salvation Army Maj. Akiko Sakamoto, who runs the agency's feeding programs, agrees that some are in it for "the lazy life." Efforts to coax people home must focus on the newly down and out. "Once this life starts, they lose not only family and things but also their desire" for normality, she said.

There is no way to separate the two groups, Sakamoto contended, so all must be fed. In addition, neglect could lead them to resort to crime to support themselves, she said, although few furosha are thought to be involved in serious crime.

Salvation Army outreach programs often encounter local resistance. The opening of a rehabilitation house for alcoholics was delayed two years due to neighbors' complaints. Recently, the agency suspended feeding programs in the high-rise Shinjuku entertainment district following protests from local merchants and officials. About 200-300 people inhabit streets and underground passageways there.

Officials there still talk of an incident five years ago at Shinjuku bus terminal in which a deranged homeless man threw gasoline into a bus and lit it. Five persons were killed and 10 others seriously injured.

The ward government now conducts "patrols" against the furosha. As a carrot, officials use invitations to government-run hostels and hospitals. Few accept, however, officials say. As a stick, it urges merchants to stop feeding them and throws water or wet sawdust on spots where they sit or sleep.

These programs began two years ago, but have had "poor results," said Teizo Ito, director of environment for Shinjuku ward. "The main problem is not economics. It is character, mental disease or different moral values."