One rising Chinese provincial leader lauded Xi Jinping as the Communist Party’s “greatest guarantee.” The party chief of a big coastal city urged officials to revere Mr. Xi’s “noble bearing as a leader and personal charisma.” A top general said Mr. Xi had faced down “grave political risks” to achieve the “revolutionary reinvention” of China’s military.

The orchestrated adulation that has carried Mr. Xi into 2022 adds to the growing certainty that he will secure another term in power at a Communist Party congress late in the year. In an era of global upheaval and opportunity, scores of senior officials have said, China needs a resolute, powerful central leader — that is, Mr. Xi — to ensure its ascent as a superpower.

But one great uncertainty looms over China, and it is of Mr. Xi’s own design: Nobody, except maybe a tight-lipped circle of senior officials, knows how long he wants to stay in power, or when and how he will appoint a political heir. Mr. Xi seems to like it that way.

“Xi’s political genius is the strategic use of uncertainty; he likes to keep everyone off balance,” said Christopher K. Johnson, the president of the China Strategies Group and a former Central Intelligence Agency analyst of Chinese politics.

At the congress, Mr. Xi is highly likely to keep his key post as Communist Party general secretary for five more years, bucking the previous assumption that Chinese leaders were settling into a pattern of decade-long reigns. Chinese legislators abolished a term limit on the presidency in 2018, clearing the way for Mr. Xi, 68, to hold onto all his major posts indefinitely: president, party leader and military chairman.

But for how many years? And who would take over after him? The dilemmas of when and how to signal a plan to step away from formal office and confirm an heir could test Mr. Xi’s redoubtable political skills.

Keeping everyone guessing could help reinforce loyalty to him, and give him more time to judge potential successors. Yet holding off from designating one could magnify anxiety, even rifts, in China’s elite.

“To pick an heir would make Xi a lame duck to some extent,” Guoguang Wu, a professor at the University of Victoria in Canada who served as an adviser to Zhao Ziyang, the Chinese leader ousted in 1989, wrote by email. “But it would also reduce the pressure Xi has to confront in seeking his third term.”

Confidence, Mr. Xi has said, is key to protecting party power, and he wants no surprises to upset a triumphant buildup to the congress.

Setting economic priorities for 2022, China’s leaders repeated “stability” seven times. Beijing is not wavering from its “zero Covid” strategy, while other countries have buckled. This year, too, China’s Winter Olympics, so far untroubled by protest, and planned launch of a space station will bathe Mr. Xi in the aura of a statesman.

But the blaze of propaganda will shed few clues about internal deliberations building up to the congress. Secrecy around elite politics is ingrained in Communist Party leaders, and it has deepened under Mr. Xi. They see themselves as guarding China’s rise and one-party power in an often hostile world.

Mr. Xi’s power games may only come into broad focus when a new leadership files out on the red carpet of the Great Hall of the People in Beijing at the end of the congress, which is likely to convene in November.

Given his desire to keep his options open, Mr. Xi is likely to hold off even then from specifically signaling a successor who would be brought into the Politburo Standing Committee, the party’s innermost circle of power, several experts said.

Mr. Xi and the premier, Li Keqiang, vaulted into the Standing Committee in 2007, confirming them as the two leaders-in-waiting at the time.

Instead of making a similar move, Mr. Xi is more likely to bring a cohort of next-generation officials into the full 25-member Politburo — the tier below the Politburo Standing Committee — creating a reserve bench whose loyalty and mettle would be tested in the years to come.

“The action will probably be in the Politburo,” said Mr. Johnson, the former C.I.A. analyst. “Doing anything that would signal a successor now seems unlikely.”

China’s history of botched succession plans stands as a warning to Mr. Xi. Mao Zedong and Deng Xiaoping both had an unhappy record of choosing, then turning on, political heirs.

Mr. Xi became top leader in 2012 after a year of lurid strife in ruling circles. He has argued that the fall of the Soviet Union resulted from installing weak, unworthy leaders who betrayed the Communist cause.

“Whether a political party and a country can constantly nurture outstanding leadership talent to a great extent determines whether it rises or falls,” Chen Xi, the party’s head of organizational affairs, wrote late last year in People’s Daily, the party’s newspaper.

Mr. Xi has already sought to prevent undercurrents of discontent from converging into opposition before the congress.

In November, he oversaw a resolution on Communist Party history that gave a glowing affirmation of his years in power. Praise in such a weighty document will help deter pushback, and Mr. Xi has used it to demand “absolute loyalty” to the party from members. A recent video series, parading officials felled for corruption and abuses of power, reinforced the warning.

“All the machinery of coercion is in his hands,” Lance Gore, a senior research fellow at the East Asian Institute of the National University of Singapore, said of Mr. Xi. “He’s offended a lot of people, but nobody is in a position to contend with him, openly or even covertly.”

Even so, Mr. Xi does not have carte blanche over the next leadership lineup. Other officials could press on his policy missteps to quietly seek more say, Mr. Johnson said. And Mr. Xi’s own interests may also lie in showing some give and take, so different groupings feel they have a seat at the top table.

“It’s not necessarily winner-takes-all,” said Timothy Cheek, a historian of the Chinese Communist Party at the University of British Columbia. “He’s leaving room so that other people are somewhat accommodated.”

Even if politics goes smoothly, who retires and who rises presents Mr. Xi with tricky trade-offs.

At the last party congress in 2017, leaders did not pick a successor to Mr. Xi, upending the ladder-like handover of power that had been taking shape in previous decades. Some of Mr. Xi’s protégés may now be too old to stay in the race, while promising younger officials remain untested, and generally unknown.

Under an informal age ceiling for senior party posts, two of the seven members of the Politburo Standing Committee — the top tier of power — are likely to retire: Vice Premier Han Zheng and the head of the Chinese legislature, Li Zhanshu. That unspoken rule says that members who are 68 or older should step down when a congress comes around. Mr. Xi could also engineer more retirements, including of the premier, Li Keqiang, or expand the size of the Standing Committee, which is not fixed by rule.

Possible recruits into the top body include Chen Min’er, Hu Chunhua, and Ding Xuexiang. All are Politburo members young enough to serve 10 years in the Standing Committee under the age rules. So far, though, none has received a telltale pre-congress move that suggests Mr. Xi has special plans for him, such as a high-profile transfer or a propaganda push.

Party insiders once described Mr. Chen as a favorite and possible heir of Mr. Xi. But Mr. Chen already seems too old to win elite approval, said Bo Zhiyue, a consultant in New Zealand who studies Chinese elite politics. Mr. Chen will be 67 in 2027, a year when Mr. Xi could step down at a party congress. Mr. Xi was 59 when he became leader at a congress in 2012.

Mr. Xi “has to bring in new people, but he doesn’t want any of them labeled as his successor,” Mr. Bo said. “There’s the big dilemma for Xi Jinping — how to promote them but not too far and limit his options.”

There is likely to be much more turnover in the full Politburo, the second-highest rung of power. Retirements there could create 11 vacancies, which Mr. Xi could use to promote a cohort of loyal officials in their 50s or early 60s, many now provincial leaders.

But if Mr. Xi stays at the top for another decade or longer, they may also be passed over for even younger potential successors now working in obscurity in ministries and local administrations.

“If Xi stays healthy and avoids policy disasters, he could remain a capable national leader and a formidable political operator for another couple of decades,” said Neil Thomas, who analyses Chinese politics for the Eurasia Group.