OSAKA, Japan -- "What kind of relations do the police have with this community?"
A man in his 50s ran his fingers over the gray stubble on his cheek last night and repeated the question with a smile of disbelief.
"Look around for yourself and see what kind of relations they have."
To his left were three overturned and burned-out cars, to his right a row of overturned soda pop machines, some of the victims of five nights of anti-police riots, the worst urban disturbances Japan has had in 17 years.
Facing him five-deep behind rows of metal shields, ranks of helmeted riot policemen stood blocking an alley leading to the neighborhood police station.
At the other end of the alley, in front of the station, volleys of rocks and occasional Molotov cocktails arched through police searchlights, thrown by a few dozen active rioters surrounded by one or two thousand onlookers.
The riots broke out Tuesday when workers in Airin, one of Japan's biggest slum neighborhoods, learned that a policeman in the local station had been accused of taking thousands of dollars in bribes and of tipping off gangsters in advance of raids.
Airin, home to thousands of transients, street people and addicts, was showing how far an exception it is to what most of the world thinks it knows about Japan.
In the country where police come from all over the world to study Japanese officers' close relations with their neighborhoods, Airin is a place where grievances against the police run long and deep.
In a society known for affluence and elegant clothing, Airin is a place to see patches, lined faces and crooked bodies.
In a society known for stability and family life, Airin is a place to see rooming houses that rent by the week to men only.
In a society known for its workers' determination, Airin is a place to see men with faces twisted and expressionless from life's defeat.
In a society known for lifetime employment and factory jobs, Airin is a place to hire men for a day or a week at a time. In Airin, these jobs are assigned by agencies often connected to the Yakuza, Japan's underworld network.
Last night, men in the neighborhood said that underworld control over their jobs was what set Airin aflame after workers found out that police had accused an officer of what many Japanese have long suspected: taking bribes from the Yakuza.
"We have to pay a commission to the Yakuza for every day's work," the man in his 50s said.
"That policeman was getting a cut of the money we paid and helping the people who cheat us."
By last night, the steam seemed to be going out of the rioting, which has injured more than 160 people, mostly policemen, and produced scores of arrests, mostly of young men and speakers who incited them.
But for the first four nights, the crowds seemed to swell steadily, reaching a peak estimated at 1,600 Friday night before plainclothes policemen working the crowd began systematically picking up ringleaders.
Wandering crowds built barricades of street dividers and overturned cars, piling bicycles around the blockades and often setting them ablaze.
Some shops were looted and a railway station was damaged when an adjoining row of wooden storefront buildings went up in flames Thursday night. The crowd pelted firefighters with rocks and firebombs as they fought in vain to save the shops.
At the peak of the disturbances, agitators with bullhorns led the crowd in shouting slogans at the police.
They called the police "gangsters' lapdogs" and demanded that senior officers "come out and kneel before the workers."
Police Chief Masahiro Tsubakihara has apologized for the offenses of which the officer is accused.
Residents said last night that after the first days of confrontation, the disturbance has been rekindled repeatedly by the arrival of motorcycle gangs and other groups of young toughs from other cities and other parts of Osaka.
Often, especially at the peak of the looting Thursday, they said, the atmosphere seemed more like a party than like a protest.
Determined to avoid spreading the disturbance, police have kept thousands of reserve riot troopers in out-of-sight places nearby, while a few thousand have rotated in shifts to block streets and alleys nearest the station.
When the crowd gets too close, and the rocks and firebombs come in too fast, the police use water cannons mounted on trucks to drive the rioters back.