More than four years after the violent Cultural Revolution ended with the arrest of its radical leaders, China today began the long-awaited Gang of Four trial. It is designed to serve as much as a signpost for the future as a condemnation of past excesses.

At 3 p.m., Mao Tse-tung's widow, Jiang Qing, and nine other once powerful leaders, some now so aged and feeble that they needed the help of nurses, were led by bailiffs into a courtroom near Peking's historic Tienanmen Square and instructed to stand behind a long metal bar as the chief judge announced their names.

A five-minute televised version of this dramatic moment, broadcast tonight, focused on a dignified and defiant Jiang Qing, the 67-year-old former screen actress turned political radical, who led the Gang of Four Politburo members during the most devastating stages of the Cultural Revolution.

For the next 140 minutes, the chief prosecutor read aloud a 20,000-word indictment charging the defendants with 48 offenses ranging from a plot to assassinate the late chairman Mao and stage an armed coup d'etat to persecuting over 500,000 Chinese officials and ordinary citizens, including more than 34,000 who died in just a handful of incidents.

The cavernous courtroom was filled with nearly 900 spectators representing victims of the chaotic decade and every geographic, political, ethnic and professional group. All were invited to Peking by the government to witness China's first show trial.

For the millions of Chinese who suffered during the economically disastrous and frequently bloody period from 1966 to 1976, the trial provides a chance to bury this unhappy era with full sanction of the government. Through nightly television broadcasts, full newspaper accounts and even trial photographs sold by party units, the Chinese will be given an extraordinary glimpse at the downfall of their former tormentors.

In a more lasting way, the trial could determine the course of Chinese politics for years to come. As an acute official attack on radicalism, the case is seen as a harsh setback to the Maoist strategy for China's development, which relied on spiritual rather than material incentives, forced collectivization and an autarkick foreign policy.

For the team of China's new pragmatic officials led by Deng Xiaoping, the trial could provide enough political momentum to uproot residual leftists in the Communist Party, the state bureaucracy and military who oppose Deng's more moderate policies stressing market forces in the economy and conciliation with the West.

More than half of China's 38 million party members joined during the Cultural Revolution, most of them ideologically pure but unskilled office workers. Today, they remain in low and middle levels of the bureaucracy, often unwilling to implement the policies crafted at the Politburo level.

Some diplomatic observers believe the trial is just a harbinger for dozens of smaller tribunals throughout the nation where smaller leaders of the Cultural Revolution would be prosecuted, purged from the party and removed from their public positions.

Within the top echelons of the party, the trial also gives the 76-year-old Deng a lever to discredit his Politburo opponents and assure a smooth succession for his like-minded allies after he dies or retires.

The offical who stands to lose the most during the trial is the one who gained the most during the Cultural Revolution -- party Chairman Hua Guofeng. Elevated by Mao in the early 1970s from the obscurity of a provincial party post, he was named premier in 1976 and handpicked by Mao to become chairman after his death in September 1976.

A minister of security in the mid-1970s, Hua was responsible for the prison where many of today's leaders were kept during the Cultural Revolution. He is also said to have favored the sweeping arrests of demonstrators in Tienanmen Square in April 1976, an outburst that was blamed on Deng and led to his second ouster from the party.

At this point, there is no indication that the trial will turn against Hua or delve into the Tienanmen incident, but diplomats here believe that the evidence against other Cultural Revolution leaders as well as recent subtle newspaper attacks on Hua are part of a strategy to force his resignation as chairman at the party congress next year.

Hua's position has gradually slipped since the 1977 return to power of Deng. Despite his junior ranking as vice premier of the State Council, Deng has grasped the initiative in Chinese politics and has begun installing younger, energetic allies with pragmatic outlooks into high party and state posts.

The process began bearing fruit at the national People's Congress last summer when Hua gave up his post as premier to Zhao Ziyang, who earned his reputation by revitalizing the economy of Deng's home province of Sichuan.

A longtime Deng protege, Hu Yaobang, was made general secretary of the party and has taken over day to day activities of that huge bureaucracy.

Deng, in the view of some Sinologists, would like to remove Hua, who has continuing ties with frustrated bureaucrats, military officers and members of the secret police and could serve as a rallying point for their oppostion to Deng's "modernization" policy.

The trial is closed to the foreign journalists on the grounds that it deals with national security secrets.