Charles Aldridge and his partner, Bill Atkinson, glide through the muggy evening in their air-conditioned police cruiser along the scarred facades and dingy brown brick buildings that line Washington's 14th Street corridor, some of the roughest streets in the city's 3rd Police District and one of its highest crime neighborhoods.

Suddenly, Atkinson whips the patrol car through a garbage-strewn back alley before braking it abruptly on Chapin Street NW, a car-lined byway where sidewalk salesmen run a flourishing business hawking illegal drugs. As an assortment of bystanders chant a hostile chorus of "Po-leece, Po-leece," three teen-agers in shirtsleeves hurriedly stuff small, clear-plastic bags into their pants pockets. The two officers suspect that these men may be part of the illicit drug scene, but they remain inside their patrol car. Dope-dealing here has survived countles police shakedowns in the past. After a few minutes, Aldridge and Atkinson end the uneasy standoff by driving on.

In Tokyo, Hideyoshi Yaita and Toshiyuki Terashima seem in control as they mingle unobtrusively with the crowds of midnight revelers that throng Shibuya, one of the city's raucous entertainment districts. Up a narrow lane, the patrolmen nonchalantly approach two young men decked out in the pinstriped zoot suits, bright red shirts and loud neckties that are the unofficial trademarks of the Yakuza, members of Japan's gangster underworld.

Peeking over the rims of their dark glasses, the two pedestrians smile self-consciously and puff nervously on cigarettes as the policemen write down their names, ages and addresses and grill them about jobs and business associates. Officer Terashima checks with his precinct on any arrest warrants that might be pending on the pair and his partner scrutinizes the wallets, folding money and scraps of paper produced after a routine frisk. Word comes that their records are clean and Yaita tells them they are free to go.

Such encounters are common to the daily rounds of these policemen on their vastly different beats in Washington and Tokyo, the lively and affluent capitals of the United States and Japan. In Washington, beat officers like Aldridge and Atkinson face the problems of skyrocketing crime, sometimes unenthusiastic public support, a criminal justice system that some people say encourages repeat offenders because of its easy bail bond guidelines and flagging morale. Widespread drug abuse and the easy availability of handguns make their jobs both difficult and dangerous.

In Tokyo, serious drug abouse is rare and handguns are outlawed. Officers such as Yaita and Terashima patrol their beats, on foot or bicycle, with confidence. A long history of respect for authority and community support for police makes the private citizen a willing ally in the war on crime. For Aldridge and Atkinson, police work is too often a tough and thankless job, they say For Yaita and Terashima, it is the practice of a proud tradition dating back to the centuries of the samurai warrior in feudal Japan.

Compared to Washington, the streets of Tokyo are safe. In 1980, there were 200 murders in Washington. In Tokyo, whose population of 12 million is nearly 20 times larger, there were only 180. The chances of being robbed in Washington were 355 times greater and of being raped nearly 20 times greater. And the number of rapes, murders and muggings in Tokyo actually has fallen in recent years, despite the fact that its population has mushroomed.

On a recent Friday evening, this reporter, who has lived the last seven years in Tokyo, climbed into the back of a police cruiser here for a look at the tougher turf of Washington's 3rd District. On patrol, Officers Atkinson responded to a report of a crippled fruit vendor being mugged. They also took part in a high-speed run to aid a fellow policeman who had gotten himself into a tight spot with sidewalk crapshooters, broke up two separate gaggles of streetside gamblers and stopped a man, wanted for armed robbery, who was urinating in an alley.

On a Friday evening a few weeks earlier, the reporter prowled the beat in Tokyo's active Shibuya district. Patrolmen Yaita and Terashima waded into a knot of drunken college students to break up a brawl in front of a neighborhood bar and wandered into another drinking establishment to politely ask the proprietor to turn down the volume on his juke box. They responded to dozens of people asking for directions and inquiring after lost articles. They issued a fatherly warning to two teen-agers on the evils of cigarette smoking before questioning a ragged-looking vagrant settling down into a doorway for the night and helping an elderly drunk into a taxi for a safe journey home.

Like Washington's 3rd District, Shibuya houses a raft of bars, bistros, striptease joints, movie theaters, fastfood restaurants, commercial businesses, private homes, foreign embassies and public offices. What its neighborhoods -- similar to many others along Tokyo's noisy, over-crowded thoroughfares -- don't have is the high unemployment, low-income housing, the racial and ethnic diversity and, of course, the high rate of serious crime. But the most important differences may be guns and drugs.

Massataka Imaizumi, superintendent general of Tokyo's police, says the main reason the the city's enviably low level of violent offenses has to do with Japan's strict gun control laws. In Japan, handguns are subject to a nationwide ban and miles of red tape are involved in getting permits for the other types of firearms in the hands of the country's few hunters. The fact that "only the police have handguns," he says, gives them an important edge over the country's criminal elements.

Washington's own ban on handguns has failed to stem the flow of "Saturday-night specials" into the District, according to Police Chief-designate Maurice Turner, because of their easy availability in outlying communities. "We still recover about the same number of handguns here each year as we did before the ban went into effect," he says. oAdd to this a new influx of cheap, high-grade heroin and you have a recipe for violent, drug-related crimes.

The grave problem of handguns and drug abuse does not exist in Japan. "Unlike the U.S., there has never been any democratic principle [here] giving the individual the right to bear arms to protect himself," says Imaizumi. "So no connection has been established between people's daily lives and the use of guns." Historically, the Japanese have also taken a dim view of drug use and today the possession or selling of narcotics or stimulants, including marijuana, carry stiff criminal penalties. In Japan, alcohol is still seen as the only socially acceptable means of blotting out worldly cares.

In Japan, Imaizumi explains, only one drug maker is authorized to produce stimulants. Authorities keep a close check on their use by doctors and clinics. Japanese sensibilities have been rocked in recent years by news that the country's gangster organizations are operating an expanding network that imports these drugs from Southeast Asia, and drug-related arrests have risen accordingly. Still, by American standards, the problem is almost microscopic.

Japanese gangsters content themselves, for the most part, with selling protection and overseeing the operations of legally borderline businesses such as bars, cabarets and massage parlors. Street prostitution, a factor in Washington's high-crime rates, is rare in Tokyo and tough zoning laws have helped drive much of the massage parlor trade outside city limits.

Rodwell M. Catoe, deputy chief in charge of Washington's 3rd District, says the vast profits reaped by dealers in illegal drugs here "far outweighs" the resources, in terms of money and manpower, his department has to combat the trade. Controlling the traffic in heroin, marijuana and cocaine in the 14th Street area, he says, "is like trying to plug up a sieve."

One problem may be the more tolerant attitudes of Americans toward illegal drug usage. Officer Aldridge, who has read about Japanese intolerance of any kind of drug activity, says, "Here you've got people from varying backgrounds thrown in together." While people may criticize the heroin problem, he said, "they see cocaine as an upper-class way to get off."

Another difference between the two cities is the way in which police officers patrol their beats. In Washington, the city's 3,639 uniformed officers spend much of their time cruising the streets in patrol cars and responding to calls for police assistance. In Tokyo, nearly half the number of policemen per capita, most of the city's 41,078 policemen are assigned to the approximately 1,200 "koban," the small, neighborhood police stations, which are located throughout the city. There are usually anywhere from three to a half-dozen officers on duty and they mostly patrol on foot or bicycles.

In Turner's view, the Washington police have lost some of their rapport with the community since the city switched from a primarily foot-patrol force in the mid-1960s to today's stress on car patrol. Turner says that Tokyo's system gives the officer on the beat "a close personal relationship with the people of the community which helps pinpoint those individuals who might be involved in crime.

"I don't believe we can adopt the Japanese system in toto," he goes on, "because we have more crime and more calls to respond to. But I do believe that when the individual police officer has a chance to break bread with members of the community, to give congratulations on births and condolences on deaths that it is an effective way to establish dialogue with the community." When Turner takes active command of the District's force on July 1, he says one of his priorities will be to put more men out walking the streets.

Turner says that, compared to Japan, "America is a more inherently violent society." To be sure, Japan, a homogenous nation of 117 million, is virtually free of the ethnic, cultural and social diversity that at the same time complicates and adds spice to America life. This tradition of nonviolence in Japan's tightly knit, rigidly hierarchal society has proved an effective deterrent to crime. In contrast to the stress Americans place on the rights and responsibilities of the individual, the Japanese take their cues from the links of loyalty and obligation within the group.

"When someone commits a crime in Japan," says Imaizumi, "it is not only seen as a disgrace for the individual, but for his parents, his wife and children, his employers and his home town." Japan's constitution contains clauses protecting individual civil liberties, but the letter of the law is often submerged by the weight of these close personal relationships. Individuals who step on the wrong side of the law are frequently required to make a formal, usually written, apology for their sins. As first offenders, they are apt to be treated less severely by the police and the courts.

Such inbred respect for authority translates freely into what many Americans might interpret as a disturbingly cozy relationship between the public and the police. Beat police in Japan pay daytime calls on private homes in their jurisdictions at least once each year to question residents on the number, ages and kin relations of individuals in their households and to check on neighborhood activities in general.

"The Japanese are taught to obey authority," notes Turner, who visited Japan a few years ago to watch the Tokyo police in action. But Americans, he says, tend to "become vocal and rebellious and attempt to reverse [what they would perceive as] infringements on their civil liberties."

"If you started knocking on doors in this town," says Steve Hawkins, a patrolman who grew up in a District neighborhood, "most people would tell you to go take a walk."

Today, there is relatively little of the one-time open hostility toward the police in the District. Washington's force is generally acknowledged to be highly professional and is made up of a diverse group of individuals, including veteran beat officers and a newer breed of young college-educated officers who intend to make police work a career. There is relatively little of the open hostility in this town that shades police-community relations in some big American cities. But the history of those relations here over the last 20 years has, in some cases, engendered a certain mutual uneasiness.

The police of Washington say that a small but growing population of youngsters commit most of the crime, and dealing with this group of repeat offenders has taken a toll on police morale. "You can't really blame the courts, because they are swamped with caseloads," says Atkinson. "But if you see someone with a pattern of violent crimes who is let out pending trial, chances are that he'll probably commit another two or three crimes before he's brought to trial on the first."

Another factor in flagging morale in Washington, virtually unheard of in Tokyo, is the beatings and shootings of patrolmen on their beats. Such incidents don't occur in Washington with any great frequency either, but when they do, Aldridge says it "affects us all in one way or another. Some get bitter and take it out on citizens; others just give up and get hopeless, and a few just get more determined to do a good job." Aldridge says he has filed 13 separate complaints of physical abuse against private citizens in his 11 years on the job. But the citizen attacks on him have never led to prosecution, he says, because "I haven't been injured seriously enough."

In contrast, Sgt. Yaita and his colleagues work within a web of public support and confidence. "We get cooperation from the people and, in turn, the people depend on the police and have their trust." In Tokyo, the issues that Washington police grouse about -- low pay, favoritism in promotion, poor working conditions and low criminal conviction rates -- are rarely heard. Public complaints of police corruption and brutality are also rare. When cases involving police misconduct do arise, Superintendent Imaizumi says, "The newspapers treat it as a sensational story, in the same way as if a teacher commited a crime. This shows that the people place high expectations in the police."

"This attitude of cooperation with the police hasn't changed since the feudal days," he said. "There have always been good relations between the two sides." He attributes this to the fact that today's Japanese law enforcement officers see themselves as the direct descendants of the samurai warriors who created the nation's modern police force just over a century ago. Imaizumi explains that the samurai, who administered Japan's feudal government for more than 300 years, maintained a proud tradition of public service based on Bushido, or The Way of the Warrior, their stern code of moral ethics.

"Since the old days, police officers have kept that warrior spirit," he says, "and they think that if they don't carry out their duties properly society will become a bleak place."

Japanese police administrators keep that spirit alive through the intensive program of training they demand of new recruits. In contrast to the 24-week basic training that rookie police in Washington are required to undertake, their Japanese counterparts are subjected to a full year of schooling. The curriculum focuses on basic police techniques but also stresses expertise into judo, karate and other martial arts. Before becoming full-fledged officers, they put in another year on the beat under the steady gaze of veteran patrolmen. After an additional two months of rigorous classroom work, new officers are given their first official assignment and are required to return to the policy academy every few years for refresher courses.

The high sense of mission among Tokyo police is enhanced by a proven track record. In 1980, according to the Tokyo police, 93 percent of the reported murder cases were solved, 62 percent of the robberies, 80 percent of the rapes and 46 percent of all crimes, including petty offenses. In Washington, like other big American cities, such rates were considerably lower -- 71 percent of the murders, 25 percent of the robberies and 62 percent of the rapes.

The way police in the two cities feel about their jobs is conditioned by a mix of similar ideals and somewhat different daily realities, the reporter learned, after curbside ramblings with both. Aldridge, tall, ruggedly handsome and affiable, is the typical all-American police officer. The ex-Marine, expert marksman and former high school football star, says, "I wanted to be a cop ever since I was a little kid. I feel that I was placed on this earth for a definite purpose and feel that the community needs the protection I supply."

Like many of his colleagues on the District force, Aldridge lives in the suburbs with his wife and daughter because, he says, "I wouldn't subject my family to the crime-ridden areas that exist here [in Washington] -- it'd be crazy." His wife, he says, is now resigned to the dangers of his job. "She pretty much accepts the fact that this is my career . . . there are very few times that I've come home with much more than scuffed shoes."

In Tokyo, Sgt. Yaita says that he decided to become a police officer because, "it's a manly job -- it's work worth doing." Yaita is bespectacled, serious and the holder of black belts in several martial arts. He lives in the city with his wife and infant son and says that his wife is proud to be married to a policeman. Yaita has never been physically attacked while on duty; one of the biggest headaches for him and his collegues on the Shibuya beat is handling the numerous drunks that stagger near their koban each night.

But unlike Yaita, Aldridge says that most of his initial idealism for his job has now faded and he sees himself holding the line against a rising tide of crime. "I still have a little bit of a dream that I'm going to contribute to making this place [Washington] a little safer," he says, ". . . but there have been a lot of heartaches along the way."