BEIJING, OCT. 25 (SUNDAY) -- The most powerful men in China met today at the opening of a Communist Party congress that will endorse policies and a new generation of younger leaders to steer this nation of more than 1 billion people into the 21st century.

The week-long gathering comes at a particularly crucial time for China's leadership as it struggles against more orthodox Marxist philosophies -- and bureaucratic opposition -- to give a sense of permanency to the controversial economic and political reforms it set in motion almost 10 years ago.

This congress, which normally takes places only once every five years, also probably will be the last dominated by China's 83-year-old paramount leader, Deng Xiaoping. So the prelude to this congress, the 13th, has stirred intense political jockeying over the projected succession to power of a Deng protege, Zhao Ziyang, currently premier and acting Communist Party chief, and the future of economic reforms that Deng and Zhao have pioneered.

The economic reforms, far from complete, are designed to transform a centralized, Soviet-model economic system into one more responsive to market forces and the profit motive. Within a decade, they have already markedly improved the living standards of many ordinary Chinese.

Never before have the Chinese revealed so many details in advance of such a congress, nor have they promised the foreign press so much access to the proceedings.

But skeptical diplomats and analysts trying to discern the real meaning of the congress see evidence of bitter infighting. Although top leaders make most of their decisions before the congress, behind a facade of openness and unity, the party's elders have been battling over the promotion of new leaders and policies up until the last minute, these observers said.

Several of the old leaders, now in their 80s, have also strongly resisted efforts by Deng to induce them to retire, these analysts said. The traditional Chinese respect for age has worked against Deng in this case.

Several key positions on the Politburo and influential party advisory commissions have yet to be decided, according to some diplomats and Chinese sources.

Despite the best efforts of Chinese spokesmen to present this as a decisive party congress, foreign analysts say the intricate trade-offs leading up to the meeting will leave many issues unresolved even after the congress ends.

The main uncertainty is whether Deng will be able to step down from the standing committee of the Politburo, which is the most powerful decision-making group. If he is unable to do this, as is strongly rumored at the moment, it would be another sign that the disputes over leadership positions have been difficult to resolve and that Deng's continuing presence is required in order to arbitrate such disputes.

At the center of the proceedings will be Premier Zhao, 68, one of the most urbane leaders the party has ever produced. Zhao's elegant western business suits stand out in the midst of party elders dressed in somber gray suits reminiscent of the late party chairman Mao Tse-tung.

Zhao is supported by one of the most prestigious men in gray, Deng, who still dominates Chinese politics despite his repeatedly stated desire to retire. While much remains uncertain, one move seems sure: Zhao is to be appointed permanent Communist Party general secretary after the congress, placing him in a position to be groomed as Deng's heir apparent.

At every stage in his career, the pragmatic Zhao has performed better than most observers expected. In the late 1970s, he introduced changes in Sichuan, China's largest province, that then became a model for agricultural reforms. In the early 1980s, as a premier with little previous foreign policy experience, he quickly developed impressive diplomatic skills.

Despite his cordial style, Zhao can be tough when the occasion demands. When he met President Reagan for the first time at an international conference in Cancun, Mexico, in 1981, he demanded a halt to U.S. weapons sales to Taiwan.

A highly skilled manager, Zhao knows how to placate traditionalist leaders who worry that China's economic changes are departing from Marxism. Zhao's ousted predecessor, Hu Yaobang, never succeeded in doing this because he circumvented or overruled them.

But unlike Deng, Zhao lacks a network of supporters in the Army, which has traditionally been the key vehicle to power in China. Having spent most of his career in the government rather than in the party, Zhao also has yet to build an effective following among the party elite.

He is much less experienced than Deng in the factional maneuvers that count for more than institutional titles in China. Lacking democratic procedures for the selection of leaders, the Chinese have to rely on consensus-building and power struggles among the party elite.

But recent Chinese history shows how easily an heir apparent can fall from grace.

Mao's designated successor, Hua Guofeng, held real power for only a relatively short period before being outmaneuvered by Deng. Hu Yaobang, elevated by Deng and others to the position of party general secretary in 1980, was forced from power earlier this year after being accused of weakness in the face of student demonstrations.

The job of party general secretary is one that carries high visibility and high risks.

Zhao's smooth style and sophisticated appearance put him in a category with the new look of Soviet leader Mikhail Gorbachev, but he seems to lack Gorbachev's boldness.

Zhao has made clear on several occasions that he would rather remain premier than take the job of party chief. With his "whatever works" philosophy, Zhao seems to be more suited to the administrative tasks of a premier than the ideological leadership required of a party leader.

"I think Zhao will not try to serve out a full five-year term {as party leader}," said a western diplomat here. "I think he will try to move on to a less exposed position."

Deng has told foreign visitors in recent weeks that he intends to step down from the Politburo's five-man standing committee. He has said that he intends to retain only one position, that of chairman of the party military commission, which gives him control of the Army.

But because several traditionalist elders are resisting retirement, Deng may be forced to remain on the standing committee, diplomats said. The committee might be expanded to seven positions for a further balancing of traditionalist and reformist leaders.

In the long run, however, Zhao's success as a political leader may depend on the economy as much as it does on Deng's support. Zhao is expected to try to keep some control over economic reforms.

But a number of party elders have objected that the reforms have caused unacceptable corruption and price increases. Some proposed reforms, they say, depart too sharply from Marxist theory.

A restructuring of China's irrational system of prices, once considered the most important of all the changes, has been put on hold indefinitely, partly because of a fear of inflation.

Despite their criticism, the traditional Marxists have failed to propose alternative plans for moving the economy forward.

Their choice for the premiership is Vice Premier Li Peng, a man who is known to favor central planning more than Zhao. But while Li appears to be more cautious than Zhao, he is not expected to try to reverse reforms, which are producing impressive economic results.

Among the sources of Zhao's strength are the teams of young, reform-minded economists working in research institutes. They have helped him prepare the basic economic report for the party congress.

Zhao and his allies appear to have gained strength in the field of propaganda, where they are normally considered to be weak. In recent months, they have wrested control of the major propaganda organs from the orthodox Marxists.

Two months ago, Zhao managed to curb a mini-purge of liberal intellectuals, which was initiated by the same orthodox Marxists.