In a nation led by revolutionary war heroes, Hu Haobang never commanded any army. He never has governed a province or run a government ministry. His speeches seldom reach beyond party aparatchiks. Few foreigners ever have met him, and the mere mention of his name among diplomats here inevitably prompts the joke, "Who's Hu?"

Yet the man just chosen to be the new chairman of China's Communist Party, the world's largest, will be called upon in coming years to demonstrate the kind of political wisdom and administrative skill needed to guide a nation of 1 bilion people through some of the most drastic economic and social changes since this socialist state was founded 32 years ago.

Although formally named on Monday, Hu has acted as party chairman since last year when Hua Guofeng lost out in a power struggle and unofficially resigned.

Hu will be aided in his task by the prestige he enjoys as the last of a generation of Communists who survived the historic Long March of 1934-35, China's civil war and its first three decades of nationhood. He is known to have a keen mind and close friendships among younger communist leaders, whom he met when he was a China's youth leader during the 1950s and 1960s.

But Hu's most valued asset, at least for the short run, is his intimate relationship with Deng Xiaopong, China's foremost leader. It was Deng who muscled through the appointment of his protege and longstanding bridge partner, against the opposition of suspicious old-line military officers and party bureauacrats.

Like his mentor, Hu, 65, is a pragmatic politician who helped fashion the programs that have governed China since he and Deng returned from their Cultural Revolution ignominy in 1977: opening China to the West, injecting capitalist incentives into a stagnant economy, reforming the bloated and conservative Communist Party, and taking politics out of science.

As Deng's choice for party secretary general and a top official of the new disciplinary committee 30 months ago, Hu has acted as a broom, trying to sweep out the leftover radical associates of Mao Tse-tung who continue to occupy important positions in the bureaucracy and take every opportunity to resist the new reforms.

He acted in two other jobs that created controversy but gained him the respect of party leaders. As head of the party's organization work, he investigated Cultural Revolution cases and boldly rehabilitated its victims. As head of the propaganda department, he focused media attention on cases of party corruption and the need to reform the party structure.

Hu also has served as the leadership's most acid critic of the decade-long Cultural Revolution, calling it "a catastrophe" without a single redeeming quality. Even before the official press began questioning Mao's role in the calamitous campaign, Hu blamed "the great helmsman" for the "majority of ultraleftist mistakes."

This has gained him wide popularity among the party intellectuals and scientists who, like Deng and Hu, suffered grievously during the radical decade. They regard Hu as an ally who possesses the leadership's most tolerant view on freedom of expression.

But these qualities alienate still-powerful leftists in the military and party who feel threatened by Hu's slashing attacks against them and their hero, Mao. They believe that the reforms Hu is trying to implement run contrary to socialist ideals and will weaken the authority of the Communist Party.

"There is a liberal streak in Hu that turns on the risk-takers in the party, the intellectuals, the people in the media and the experts" of the professional class, said a Western diplomat who has closely watched Hu's career. "But the part of his personality that appeals to the thinking man scares the hell out of the conservatives."

With Deng behind him, the new chairman is expected to have the authority to offset the conservatives' influence. Once his patron departs, however, it is uncertain whether Hu will have sufficient political connections and levers of power to control a party still fractured by the Cultural Revolution.

As Deng's alter ego for the last 40 years, Hu never built the kind of power base that has propelled other Chinese to leadership positions.

"Without Deng," concluded an Asian diplomat, "Hu cananot operate. Deng is the one who holds it together for his junior partner."

The partnership began not long after Hu left his native Hunan Province at the age of 14 to become a "litle red devil," or child soldier fighting for commnist forces. Since the two men fought side by side against the Japanese in the arid Taihang Mountains of northwest China, Hu has shared his senior partner's political ups and downs.

When Deng was party boss of southwest China after the communist takeover in 1949, Hu was posted in Deng's native southwest province of Sichuan. In 1952, Hu followed Deng to Peking, where he began his long career as head of the Communist Youth League, which was the main avenue of entry into the party for most of the second generation of communist leaders.

The two men disappeared in 1966 after Red Guards brutally criticized them for, among other things, directing private railway cars and special airplanes to ferry bridge partners around the coucntry, where they allegedly would pursue their obsession with card games during working hours.

Hu has said that he spent two years of his political exile living in a rural cow shed, forced to clean cattle. The rest of the Cultural Revolution was spent at cadre reeduccation schools and under house arrest, he told Yugoslav journalists in a rare interview last year.

When Deng briefly regained power in 1973, he assigned his old friend to restore morale at the battered Academy of Sciences. And when Deng was purged a second time in 1976, Hu also vanished, remaining out of sight until his mentor again reappeared in 1977 and quickly had his favorite lieutenant placed on the Central Committee of the Communist Party.

Hu has operated in Deng's shadow for so long that his own style and capabilities have been obscured by his more famous friend. Even his appearance resembles Deng's. A tiny, thin man who seems smaller than Deng, Hu wears his close-cropped hair over a high forehead.

Hu nonetheless is known as an independent thinker who dares to be irreverent among China's pious politicians. This was evident as far back as 25 years ago when he frequently questioned Mao's growing cult before such skepticism was fashionable. In 1955, for example, he lectured a group of young people who were dedicating a reservoir they had just built in Anjui Province with the standard slogan, "Boundless life to Chairman Mao."

"Well! Ten thousand years! They said it is rather rare to live to 70," said Hu, then a little-known youth leader. "You workers have sweated away with hardly a break, so we can wish you a life of 10,000 years. I Hu Yaobang, am an X-grade official. May I not be wished a life of 10,000 years?"

According to the few foreigners who have met him, Hu is energetic, witty and usually open for a Chinese official. Although he received little formal education during his youth as a communist liberation fighter, he is said to draw heavily from Chinese classics in making a point.

His sharp wit is legendary among China's intellectuals, who have circulated a story about how Hu allayed their fears of another literary crackdown early this year. Their concerns were aroused when the military writer Huang Gang, whose name literally means "Yellow Steel," harshly criticized the famous playwright Bai Hua, whose pen name means "White Birch."

When several old members of China's official writers' union went to express their worries to Hu, he reputedly responded by saying: "With the passage of time, Huang Gang will turn to rust while Bai Hua will grow up straight."