BEIJING (Reuters) - China's new Communist Party chief Hu Jintao was anointed heir apparent 10 years ago when he was catapulted to a leadership post at the age of just 49.

But when Hu finally took China's top job at the 16th party congress last week, there were no clues as to who might replace him in the next leadership succession, analysts said on Tuesday.

They had expected at least one promising person in his forties to be moved into the party's highest echelons like Hu when he joined the seven-man Politburo Standing Committee in 1992.

But last week, nobody under 50 made it onto the new 24-man Politburo -- let alone the expanded nine-man Standing Committee.

"I was surprised not to see a single candidate from the next generation join the Politburo," said one Western diplomat. "I guess the next succession is still up for grabs."

Hu, 59, is now officially head of the "fourth generation" of leaders after Chairman Mao Zedong, Deng Xiaoping and Jiang Zemin, who stepped down as party chief last week.

So who and where are the "fifth generation?"

"There is a lot of talent among the young provincial leaders, but talent is not everything," said one veteran Chinese reporter.

"Their future depends on what happens in Beijing, who becomes more powerful. There is no clear fifth generation leader yet."

DYNAMIC TRIO

Frontrunners are the three youngest provincial governors -- Xi Jinping, 49, Li Keqiang, 47, and Zhao Leji, 45, analysts said.

Xi, recently promoted to governor of the eastern province of Zhejiang, was made a full member of the Central Committee at the congress, having previously been an alternate member.

Li, governor of the central province of Henan, one of China's poorest and most crowded, kept his seat on the Central Committee.

Zhao, who governs his native province of Qinghai in the northwest, leapt on to the new Central Committee as a full member, having not been even an alternate member before.

"Zhao Leji is the most promising candidate," said one Chinese political scientist. "But his promotion does not guarantee anything. It will be worked out over the next few years and maybe we'll see a clear sign at the next congress.

At the 17th congress in 2007, one of the current Standing Committee will be due for retirement -- Luo Gan, now 67.

But come the congress in 2012 -- assuming they are still held every five years -- at least six more will have to retire.

"You can't just look at this congress," said one Chinese source with close party links. "You have to look at the next one, and then the one after that. They are preparing for those."

"What corporation doesn't have it's future mapped out for the next 10 or 20 years?"

GENERATIONAL SHIFT

With that in mind, China watchers are already studying the backgrounds of rising fifth generation stars like Xi, Li and Zhao to assess their views on political and economic reforms. Mao and Deng's generations were characterized by the early years of war and revolution, Jiang's peers by the Soviet-inspired industrial drive of the 1950s.

Hu's conservative outlook was molded by the chaos of the 1966-76 Cultural Revolution, analysts said.

The fifth generation, by contrast, entered society after Deng launched market-oriented reforms in the late 1970s.

Xi, for example, graduated from Tsinghua University in 1979 and went straight into a job in the cabinet bureaucracy.

While the third and fourth generations are dominated by engineers, the fifth includes graduates in law, business and social sciences, analysts said.

Li graduated with a doctorate in economics from Peking University in 1982. Zhao studied philosophy there from 1977-1980.

Their futures are by no means certain, analysts said.

Xi may be hampered by his "princeling" status -- he is the son of a former party bigwig. Li's tenure in Henan has been blotted by two deadly fires and a scandal in which thousands were infected with HIV by selling plasma to illegal blood banks.

Zhao has hardly ever worked outside Qinghai.