Mott and Pell streets in Chinatown are full of color and life. There are thick pastries in the windows of dumpling shops, stores crammed with ceramics, apothecaries advertising almond and herb cures for a headache. But the tourists do not notice the gang members who loll, in the evening, outside a local bar.

It is not their style to be noticed.

Unlike New York's other street gangs, the Chinatown gangs do not wear insignia or strut about in heavily studded leather jackets. They do not make a show of carrying weapons, though many do. Some also wear beepers and bullet-proof vests. And although one of their members occasionally will be arrested in a shootout over territory or the random street crime, the main business of the Chinatown gangs, according to police, is extortion.

In Chinatown, their dress is subtle: pressed jeans and short black jackets. Police say their method of intimidation is subtle, too. It begins with a visit to a shopkeeper, a veiled hope that his business will continue to thrive, a request for "money for our little brothers."

It is effective, according to police, with some shopkeepers reportedly making payoffs as high as $1,000 a month. Few of the businesses complain.

"We've seen these kids making pickups going from store to store," said detective James McVeedy, who heads the "Jade Unit," the group devoted to organized crime in Chinatown. "And then you go into the stores and talk to the people and all of a sudden they don't know what you're talking about.... I would say it's a very serious problem.... There are people who say every business in Chinatown, is making a payoff."

"It's a very serious problem," echoed Manhattan district attorney spokesman Mary DeBourbon, whose office oversees the squad. "It's just not right that your average Chinese restaurant owner has to pay money to the gangs... though I don't want to qualify how many pay or who pays because I don't know.... And it is unfortunate there's a reluctance to come forward in some cases with information when they are extorted."

Extortion is not their only line, police said. There have been shoot-outs between gangs over territorial disputes, occasional stickups, and curious deaths, such as the man found in the street with cash in his wallet and bullets in his head.

But Chinatown is not a war zone. Police consider it one of the city's safer areas.Nonetheless, gangs are an on-going problem. In the past two years, according to the Manhattan district attorney, 75 gang members have been sent to jail.

Two weeks ago, in what McVeedy characterized as "your typical incident between young gangsters," members of the rival Ghost Shadows and Flying Dragons crashed a party at New York University given by the school's Oriental Culture Club.

When the fighting stopped, 14-year-old Kin Fum Man, a member of the Ghost Shadows, lay dead, and 16-year-old James Lee, a member of the Dragons, suffered bullet wounds in the chest. That a 14-year old had been carrying a pistol was no surprise to McVeedy.

"In our experience it's the 14- and 13-year-olds who carry the guns when they leave Chinatown," he said. "The do that for two reasons: no one is gonna think that sweet little 85-pound, 4-foot-8 sunshine is carrying a weapon. And if he's caught, he's treated like a juvenile."

Members of the Ghost Shadows also ran into trouble with the law in October, when six of them were arrested and charged with the rape and murder of Rita Nixon, 22, of Portsmouth, Va. Nixon, according to the district attorney's office, had come to Chinatown to do a little sightseeing with friends.

As the evening wore on, she left her friends and stopped by the Golden Dragon Bar. Her body was found behind Public School 65, opposite Catherine Street, on the outskirts of Chinatown. According to police, she had been raped repeatedly and strangled "with a ligature."

McVeedy said Nixon's case was unusual, since Chinatown gang crimes are almost always carried out against Orientals. Even outside Chinatown, that pattern holds, as in a series of robberies against Korean massage parlors.

Some gang crimes involve loan sharking, particularly to persons frequenting Chinatown's floating gambling houses.

"The gangs originally formed in the early '70s to protect the gambling houses," he said. "Then as the gangs got stronger, there was a breakdown in control."

Questions about the hierarchy of the gangs and their relationships to other organizations are answered carefully.

Officers say they have trouble dealing with the gangs because of the way victims are approached.

"A Chinese kid will come in and ask for money -- for their little brothers," McVeedy said. "Or maybe a new business is opening and they come around and ask for opening money -- we've heard $200 to $4,000. They say they should be paid the money so that the opening will be nice and smooth -- so nothing will happen, like a fight or a broken window.

"If they don't get the money, they come back with a few members; they break dishes, they complain about the food... people leave the restaurant. They carry weapons, but they very rarely show their weapons. Or they refer to them with a gesture.... Very subtle.... That's what makes it very difficult to make these case.... The tape won't pick up a gesture."

Neither, he said, will the victims go to the police. "We're making some progress. But that's our biggest problem -- getting the public to come forward."

He theorizes that stepping forward proves so difficult because many Chinatown residents come from Hong Kong, where police corruption was a major problem until about 10 years ago, when a reform campaign was undertaken.