Through an unmarked archway outside the Chinese capital is a rural outpost called Round River Farm where rapists and pickpockets are supposed to be transformed into upright sons of socialism.

Round River is a camp for "reeducation through labor," the lowest tier of China's penal system, and for some the most Orwellian. It is part of a vast network of camps that holds tens of thousands of offenders--petty crooks, troublemakers and political dissidents--for up to three years without so much as a court hearing.

The prosecutor, judge and jailer in these cases is the powerful Public Security Bureau.

"Reeducation through labor is a disciplinary measure, not criminal punishment," said Round River's deputy director, Liu Shili, during a visit by foreign correspondents. "Their crimes are not serious enough to go through the court; our aim is to save them."

While life at Round River surely is Spartan, the farm resembles more a penal work camp than a hardened prison. Inmates work long days tending vineyards, then cram into bare bunkhouses sleeping 15 men side-by-side on wooden planks. With daily drills in Marxist theory, they recite by rote their thanks to the party for giving them "a new lease on life."

But the absence of armed guards, barbed wire and watchtowers creates an atmosphere of reform, albeit enforced with a strong arm. "We learn how to obey laws and serve the motherland," explained Lai Zhiyun, 17, who is serving a one-year term for stealing a bicycle. "Life here is no better or no worse than on the outside."

Although Peking recently has strengthened the rights of due process for the accused, it has kept on the books a 1957 regulation on reeducation through labor that allows local, extrajudicial boards to send suspected offenders to penal farms without trial or legal review.

The regulation has been criticized for giving almost unchecked power to China's shadowy police apparatus--the Public Security Bureau--to sweep the streets of anybody it regards as a social danger. The bureau is empowered to investigate suspects, bring them before "reeducation" boards, help decide innocence or guilt and run the camps.

For the past two years, the bureau has used the rule to round up political activists left over from the brief Democracy Wall movement of 1979.

The regulation also has served as a tool for locking up Chinese considered too close to foreigners. Li Shuang, the avant-garde artist who lived with her French fiance, is serving a two-year reeducation term in one of Peking's three camps.

No such celebrities were said to be residing at Round River, however. Liu, a beefy man dressed in his white, high-collar bureau uniform, insisted there were no "political offenders" or inmates who had "unhealthy" contacts with foreigners.

Liu's breakdown of Round River's 2,410 residents, all male--whom he called "persons looking after the farm"--suggests an arbitrary system of sentencing, with gang rapists and bicycle thieves all serving between one and three years.

Most of the "farm attendants" had been charged with stealing, he said. About a third fell into a catchall category called "hooliganism," which included gang fighters and rapists. A few were serving time for blackmail, gambling and smuggling. The decision to assign an offender to reeducation rather than prison or even harsher "reform-through-labor" camp is based on the seriousness of the crime, according to Liu.

Although they sound a bit like reform schools for wayward youth in the West, reeducation centers here contain inmates of all ages. At Round River, 16-year-old boys shared dormitories with 60-year-old men.

Round River's guards are instructed to treat the inmates sternly but fairly--"like doctors treat patients with infections," said Liu. "We try to use civilized measures. We have very strict discipline, but corporal punishment is strictly forbidden and we are not allowed to curse."

Nevertheless, 40 inmates escaped from the camp in the first half of last year, he said. All were caught, brought back and forced to stay longer as punishment. As a showplace presentable to foreign visitors, Round River offers a sharp contrast to the type of concentration camps described in first-hand accounts by former inmates. According to interviews here and published stories abroad, China operates penal colonies similar to those in the Soviet Union, where food is scarce, labor hard and beatings common.

Even Round River might be less idyllic than depicted for foreign correspondents, according to a former inmate, 26, who said he had spent a year there for fraternizing with a foreigner. "If you didn't want to be a model Communist mouthing all the ridiculous slogans, then they'd beat it into you," he said, displaying wrist wounds he said were from manacles.