BEIJING, Sept 12 (Reuters) Being next in line in China can be hazardous to your health.
After more than five decades of sometimes bloody generational change, China's Communist rulers only managed their first smooth leadership transition five years ago when Hu Jintao took over the Party.
And, as they prepare for a mid-October meeting at which Hu's own heir may emerge, a look at the history books highlights the potential risks facing his own chosen successor.
Mao Zedong's first chosen heir fell from grace and died in prison. Another was killed in a mysterious plane crash and accused of plotting to assassinate the chairman.
The last was ousted by Deng Xiaoping after only a few years in power.
Of Deng's three successors, the first was purged, another died after 16 years under house arrest. His last, Jiang Zemin, was plucked from obscurity after the Tiananmen Square massacre and went on to lead the country for 13 years before yielding the top party, government and military jobs to Hu.
Now it may be Hu's turn.
Five years into his mandate, he has dismantled many of his predecessor's legacies, toppled a powerful Jiang ally, trumpeted his own political doctrine and promoted his men to key positions.
Whether Hu can name a protege as fifth-generation successor -- after Mao, Deng, Jiang and Hu himself -- at the October congress will be a barometer of his influence, analysts said.
''Deng could point to a deer and call it a horse,'' a source with ties to the leadership said, noting that Deng in 1992 chose Hu to parachute into the party's top echelons as 49-year-old heir to Jiang, then the party chief.
LACKING CLOUT Mao and Deng derived their political legitimacy from the 1949 revolution and were able to appoint heirs.
But like Jiang before him, Hu lacks the power of either Mao or Deng, and either must produce a mechanism to institutionalise selection of successors or strike a deal with his predecessor, who still yields lingering power from retirement.
''If Mao wanted someone dead, that person had to die. If Deng wanted someone to step down, that person had to step down.
If Hu wants to name a successor, he needs to do a deal with Jiang,'' a second source with leadership ties told Reuters.
Hu protege Li Keqiang, 52, party boss of the northeastern rustbelt province of Liaoning, is front-runner to join the all-powerful Politburo Standing Committee at next month's congress.
Other rising stars include Shanghai Party boss Xi Jinping, 54, and another Hu protege, Li Yuanchao, 56, Party boss of the wealthy eastern province of Jiangsu.
Both Xi and Li Yuanchao are ''princelings'' -- the privileged sons and daughters of incumbent, retired or late leaders. Xi's father was a Politburo member while Li Yuanchao's father was a former vice-mayor of Shanghai.
But Xi may not make it to the Standing Committee this year because he only took over recently as Shanghai Party boss. Li Yuanchao's problem is he is only an alternate member of the Party's Central Committee.
But at the least, Xi, Li Yuanchao and other fifth-generation candidates will join the Politburo, ranked one notch below the Standing Committee and one above the Central Committee.
While Hu managed to wait quietly in the wings for a decade before becoming Party chief, even if he does make Li Keqiang heir apparent, there is no guarantee the latter will survive politically.
Since imperial times, heirs apparent and young emperors with regents looking over their shoulders have often found themselves in precarious situations.
Guang Xu (1871-1908), the reform-minded emperor of China's last dynasty, the Qing, was imprisoned by his own aunt, the Empress Dowager Cixi, for introducing the ''Hundred Days Reform'' movement in 1898.
Deng sacked not one but two heirs apparent -- Zhao Ziyang and Hu Qili -- after he sent in troops to crush student-led demonstrations for democracy centred on Beijing's Tiananmen Square on June 4, 1989.
''In China, it's difficult to be a crown prince,'' said political commentator Wu Ke. ''If the crown prince performs well, the emperor could be unhappy. If the crown prince does not show his abilities, he'll be out.'' REUTERS NC VC0852