China's president-in-waiting Xi Jinping has not been seen in public for more than a week, prompting a wave of speculation on the reason for his absence.
Mr Xi cancelled meetings with visiting foreign dignitaries including US Secretary of State Hillary Clinton and Singapore prime minister Lee Hsien Loong.
Mr Xi's whereabouts during this sudden absence from the spotlight may never be known. One thing, however, is certain: China may now be a lynchpin of the global economy and a force in international diplomacy, but the lives of its leaders remain an utter mystery to its 1.3 billion people, its politics an unfathomable black hole.
So when the presumptive head of that opaque leadership disappears from public view, rumour mills naturally go into a frenzy.
"There is a long-standing practice of not reporting on illnesses or troubles within the elites," said Scott Kennedy, director of Indiana University's Research Centre for Chinese Politics and Business in Beijing. "The sense is that giving out such information would only fuel further speculation."
Adding grist to the mill, a scheduled photo session with visiting Danish Prime Minister Helle Thorning-Schmidt, which the media were asked to cover, was taken off the programme.
The Foreign Ministry claimed the Xi-Thorning-Schmidt meeting was never intended to take place.
"As I said last week, China's state councillors will meet the Danish prime minister," Foreign Ministry spokesman said. When asked about the rumours of an injury, he said "we have told everybody everything," and refused to elaborate.
Most online speculation about the portly 59-year-old Mr Xi has centred on a back problem, possibly incurred when he took a dip last week in the swimming pool inside the Zhongnanhai leadership compound. Another rumour has the back being hurt in a soccer game.
This year, China has seen an unusual amount of political intrigue, with the spectacular downfall of Politburo member Bo exposing divisions within the leadership and prompting rumours of nefarious activity ranging from the wiretapping of top leaders to an attempted coup.
The sudden transfer of a key secretary to president Hu Jintao earlier this month also spawned conjecture about a Ferrari crash involving the aide's son and an ensuing attempted cover-up.
The tension and uncertainty are heightened by the timing ahead of a generational shift to a new leadership that is to be headed by Mr Xi.
Mr Xi is expected to first assume Mr Hu's mantle as Communist leader at a party congress held once every five years. Yet the dates for the meeting, expected in the second half of October, have yet to be announced, prompting talk that at least some of the seats on the nine-member Standing Committee remain up for grabs.
Wang Xiangwei, editor-in-chief of Hong Kong's South China Morning Post and a long-time state media insider, wrote that Chinese leaders' meetings are planned well in advance and cancellations are extremely rare.
"Baring Mr Xi himself offering a very unlikely explanation today about his cancelled meetings last week, the outside world may never know the exact reason, and the rumours are unlikely to fade away," he wrote.