Chinese micro-bloggers and overseas websites have come up with all kinds of creative speculation as to why President-in-waiting Xi has gone unseen for more than a week. (Li Tao/AP)

When Lin Biao, China’s then heir apparent, died in an air crash more than 40 years ago, it took the Communist Party two months to inform the public.

This week’s unexplained disappearance of Xi Jinping, China’s leader-in-waiting, who has not been seen in public for 11 days, shows that, despite the country’s economic transformation, when it comes to its leaders, Beijing is as secretive now as it was in 1971, when Lin Biao died and Mao Zedong was still in power.

According to Beijing’s official version, Lin had been plotting a coup against Mao and decided to flee to the Soviet Union with his family after learning that he had been found out. His flight crashed in Mongolia, killing everyone on board. While Russian forensic evidence confirmed that he died in the crash, foreign historians continue to doubt Beijing’s explanation of a coup.

More recent cases involving senior party leaders have been handled in a similar fashion. It was not until July this year that the People’s Daily, the party’s mouthpiece, confirmed that Li Peng, at the time China’s prime minister, had been in a hospital in 1993.

Li disappeared from public view for several months that year, cancelling trips abroad and meetings with visitors. The foreign ministry had said he had a cold and was recovering. It is by now widely believed that Li had suffered a heart attack.

Keeping things secret today is much more difficult as the spread of social media has robbed the party of the power to control information.

Xi cancelled meetings with Secretary of State Hillary Rodham Clinton, Singaporean Prime Minister Lee Hsien Loong and a Russian delegation last week. He also appeared to cancel a meeting with Helle Thorning-Schmidt, the Danish prime minister, on Monday, although she herself later said no meeting had been planned.

An official account did not list Xi among the participants of a meeting held last Friday by the central military commission, of which he is vice chairman.

There have been no public appearances, news pictures or new mentions of Xi in the state media since Sept. 1, when he gave a speech at the central party school.

Although Xi’s absence from the public eye so far has not lasted as long as those of some past Chinese leaders, politicians who have disappeared previously still sent signals by publishing articles in official media or sending congratulatory messages on major occasions.

The mystery surrounding Xi has triggered a flurry of rumors on Sina Weibo, the country’s leading Twitter-like microblog, especially as it comes amid preparations for the complex once-in-a-decade leadership transition in which Xi is supposed to star.

Internet users passed round suggestions that Xi and He Guoqiang, another senior leader who was also missing from public view, had both been involved in car crashes. Another rumor was that they had both been victims of assassination attempts.

On Wednesday night, He resurfaced, appearing on state television during a visit to state publishers to promote officially-approved books. His last appearance before Wednesday had been an anti-corruption speech on Aug. 29.

“In my recent meetings with senior government officials and advisers in Beijing, many of them said they felt that the party is losing control over the discourse and just isn’t able manage the message like it could before Weibo came along,” said one well-connected Chinese economist.

Posts referring to Xi and He have been quickly deleted on Chinese microblogs, while searches for their names have been censored. And yet Internet users quickly found other ways of discussing the issue. One Weibo user posted a picture showing Yuan Shikai, the early 20th century Chinese ruler who had himself elevated to emperor but was toppled after 83 days, next to Xi Jinping.

The post joked that while one had been on the throne for just a matter of days, the other might never make it there because he has gone missing.

— Financial Times

Anderlini reported from Tianjin. Additional reporting by Gu Yu and Zhao Tianqi.