BEIJING, JUNE 2 -- In the year since the Chinese army killed hundreds of demonstrators around Tiananmen Square here, other communist countries have witnessed extraordinary political reforms. But China has silenced the calls for democratic change that swept the country last spring.

With seeming ease, through arrests and detentions, political indoctrination sessions and endless investigations of suspected dissidents over the past year, the Communist Party leadership has imposed its will. It now faces little more than dispersed and disorganized dissident forces.

The country remains what a Taiwan writer calls "the world's last and most obstinate Communist stronghold."

And yet, despite a carefully constructed facade of strength and party unity, China's leaders have displayed extreme nervousness at the advent of the first anniversary of the June 3-4 crackdown on the democracy movement.

The authorities sealed off Tiananmen Square today to make way for state-organized activities extending through the weekend. Three dissidents who planned last Thursday to issue an open letter to China's leaders calling for the release of political prisoners suddenly disappeared. A friend of theirs said he fears that the police have detained the three men, pop singer Hou Dejian and scholars Zhou Duo and Gao Xin.

Perhaps more significant than signs of nervousness, the country's leaders appear to be preoccupied with short-range problems. "The leaders have no long-range plans," said a mid-level Chinese government official recently. "All they can do is focus on the problems of the moment."

Chinese and Western analysts say that while university students and their supporters appear to be in a weaker position than a year ago, the government has not solved any of the major problems that triggered the crisis last spring.

"No one has the vision to deal with the big problems that are weighing down," said a veteran Western diplomat in Beijing.

The top leadership, analysts say, consists of an uneasy coalition of potential rivals for power. They are held together by their fear of social unrest and by their connections with the country's elderly senior leader, Deng Xiaoping. Deng, 85, has ostensibly retired but remains the final arbiter on major political decisions.

The entire country appears to be waiting for Deng to pass from the scene before anyone makes a decisive move. The result is that both political and economic policy decisions shift constantly.

"The stalemate at the center is reflected in a loss of direction in economic policy," a foreign economist said.

The mid-level Chinese official, who asked not to be named, predicted that once Deng dies, top leaders will engage in a power struggle and China will face a new round of unrest similar to that which erupted in more than 80 cities a year ago.

"Deng is the only one who gives real authority to this government." he said. "Once he dies, there's no way that they can maintain stability."

The party has imposed a semblance of stability and order on the country, but, if anything, disillusionment with the party leadership has grown rather than diminished over the past year.

Recent interviews indicate that the disenchantment has spread to high levels of the government. For example, friends of a vice minister in Beijing spoke of his scathing remarks about the country's unpopular premier, Li Peng, and the repressive policies Li has come to symbolize. A vice mayor in another major city is said to be equally unhappy with the top leadership.

The two are key officials in the Chinese system, so they do not display open contempt. In public, they conform to the party line.

The recent controversial actions of Xu Jiatun, until early this year the senior Communist Party representative in Hong Kong, are considered to be one more sign of deep divisions within the party leadership. Xu left recently for a lengthy "vacation" in the United States that was not authorized by Beijing, prompting speculation that he had defected.

Xu, 74, let it be known through a Hong Kong magazine last week that he had not defected but was unhappy with Premier Li. Xu had apparently angered Chinese leaders last spring when he showed tolerance for Hong Kong demonstrators supporting the democracy movement in China.

Dissidents released from prison over the past few months indicate that even within China's newly reinforced police force, police officers hold divided views.

Some officers display reluctance to deal sternly with student activists. According to a prison diary that a former detainee brought out of the Qincheng maximum security prison north of Beijing, police guards there showed great sympathy for incarcerated students.

But analysts say that as long as China's military leaders hold firm against dissident influences, none of this "softness" in other Chinese institutions will lead to any major change. The army and the Communist Party are the only two large organized forces in the country.

But if new turmoil erupts, the key question facing the leadership may be whether it can rely on the army.

The army came under severe stress last spring. Some officers declined to move forcefully against student demonstrators. The authorities charged the commander of the army garrisoned around Beijing with failing to follow orders and court-martialed him.

The party recently reshuffled the leaders of all seven of China's military regions. Military analysts said the changes reflected the power balance within the party, and were intended to ensure loyalty to the party while preventing regional leaders from developing their own power bases.

But many of the army's young officers are known to be more liberal than their elders. Over the long run, independent-minded officers might form alliances with civilian counterparts who press for democratic reforms.

Lt. Gen. Yu Yongbo, deputy director of the army's political department, recently warned in a speech that any soldier who participates in demonstrations such as those that occurred here last year will be expelled from the ranks.

Meanwhile, the party leaders face pressing problems with the economy. The government has been pumping billions of yuan, the Chinese currency, into the economy in an effort to curb a dangerous decline in factory production and growing unemployment.

If left unchecked, unemployment could lead to confrontations between the government and restive urban workers.

A 19-month-old economic austerity program aimed at combating inflation has succeeded in its main goal, but has brought the country close to recession. In the first quarter of this year, China's industries registered zero growth in production.

Production is expected to show a rise in the second quarter, in part because of the easing of credit, but economists say that at the same time, the efficiency of China's state-run industries continues to fall.

This is partly because state-run factories cannot lay off surplus workers. Such factories are now paying up to 70 percent of their wage costs to many workers who essentially have nothing to do.

Foreign economists said their Chinese counterparts have lost their nerve, having become unwilling to propose structural changes that would reform the economy. Most of China's economic reforms aimed at transforming a state-run economy into one more responsive to market forces are stalled, they said.

The Chinese economy still depends heavily on a variety of state-provided subsidies and unwieldy systems of pricing and resource allocation.

The economists said that by failing to address fundamental problems, the Chinese leadership may in the end face another round of inflation -- part of a boom-and-bust cycle that has threatened China's development over the past decade.

But the leaders, including even the conservative Li, clearly realize that the austerity program went too far. They have recently reemphasized that reform is not dead and lives on in special economic zones along the South China Sea coast.

"What you see is the pragmatic side of Deng Xiaoping gradually prevailing," said a Western diplomat. "But everywhere you look, you also see nothing but contradictions."

The Chinese government appears to be buying time in the interests of maintaining stability. One recent example: Beijing gave workers wage increases during the first quarter of the year even though industrial production failed to grow during the same period.

"You can't justify this on economic grounds," a Chinese economist told a Western diplomat. "It's the fear of unemployment and unrest that is pushing the government into making silly economic decisions."