July 1 marked 20 years since Britain handed Hong Kong back to China, under special arrangements to protect the city's distinctiveness and autonomy. In 30 more years, Hong Kong will fully revert to the mainland.
Much could happen between now and 2047, and the tea leaves are already out there waiting to be read: There are many old - even ancient - historical precedents showing how the Chinese central authorities first manage rebellious peoples on the periphery before eventually subjugating them.
After pro-democracy protests in Hong Kong in 2014 and the election of several separatists to the local legislature, the authorities in Beijing have become increasingly assertive.
Mr Zhang Dejiang, chairman of the Standing Committee of the National People's Congress in Beijing, has called Hong Kongers who advocate self-determination - a political right sanctioned by a 1966 United Nations convention - "treasonous", and said they must be "resolutely attacked" and "struggled against".
He also asked the city's new administration to implement a controversial security provision from its constitutional document, the Basic Law. Hong Kong's new leader, Mrs Carrie Lam, has said that "patriotic education" should be taught as early as in nursery school.
Running through these provocative political messages is the notion, fairly novel, that Hong Kongers have been misinterpreting the "one country, two systems" principle that governs the city's relationship with mainland China. To set them straight, in June 2014, China's State Council Information Office issued a news statement pointing out that, in fact, Beijing had "full rights to rule over all aspects of Hong Kong".
The concept of sovereignty and national boundaries in imperial China was never as cut and dried as the norm established in the West with the 1648 Peace of Westphalia.
The roughly 2,500-year-old Book Of Documents, one of Confucianism's defining texts, describes a sovereignty system with the emperor's compound in the middle and, around it, five concentric rings. The farther from the centre, the less the centre's control and one's obligations to it.
The model was fluid, though. The empire's outer boundaries expanded and contracted with the ability of China's dynasties to project military might and exercise effective rule from the centre to the periphery, and beyond.
The implications are rich for understanding China's intentions today - in the South China Sea, with its massive "One Belt, One Road" regional infrastructure initiative and, above all, in Hong Kong.
Lingnan, the southern region that includes the city today, was brought into China's sphere of control by the first emperor of the Qin Dynasty, in the third century BC, after a series of brutal military campaigns. But barbarians aren't easy to rule. So from the seventh century through to the 10th century, emperors of the Tang Dynasty thought it best to administer these lands by relying on a somewhat informal quid pro quo: The elders of minority tribes, in exchange for bowing to the authority of the Chinese, would get their support to play local rulers. Jimi, this was called, or the tethering of livestock.
The arrangement was formalised during the 14th century, under the Yuan Dynasty. In the south-western part of modern China, tribal elders were granted the new title of tusi, literally earth lords - an official and heritable status recognised by the Chinese bureaucracy. It came with the obligation to obey the emperor and pay him tribute. But localities where tusi ruled were allowed to retain their distinct, traditional sociopolitical structures.
This, in effect, was the prototype for Deng Xiaoping's "one country, two systems" principle. Although the title of chief executive, the highest office in Hong Kong today, is not heritable, Mr Leung Chun Ying, the city's erstwhile leader, was a modern-day tusi.
Over the centuries, as the imperial centre grew more powerful and expanded its direct rule, it started replacing local tusi with its own officials, known as liuguan, or movable officers. The replacement process often was protracted, and many tusi wound up sharing power with liuguan, playing first fiddle for a time, and then second. The formal tusi system ended in the early 18th century, after a bloody campaign of subjugation under Emperor Yongzheng. Yet vestiges of the practice long remained, and some still remain today.
Mr Tung Chee Hwa, Hong Kong's first chief executive after the 1997 handover, was a tusi who acted like a liuguan. In a bid to please Beijing, in 2002 he attempted to pass draconian legislation that would have curtailed freedom of speech and association, among other things. But he was forced to back down when half a million Hong Kongers - out of a population of about seven million then - marched against the proposal.
Seeing this, the Chinese government concluded that "Hong Kongers' hearts had not yet returned to the motherland", and then set out to help them along. By 2008, the Central Liaison Office, Beijing's outpost in Hong Kong, had established what it called a "second governing team", comprising party cadres from the mainland. Pro-Beijing candidates have since been spotted heading for the Central Liaison Office after winning elections in Hong Kong, presumably to say thank you. Tusi playing second fiddle to liuguan.
Hong Kong has become inundated with Chinese money in recent years, and many powerful officials in Beijing have family members who live, work, invest and accumulate wealth here. These factors mitigate against the probability of a bloodbath occurring, even as 2047, the year that Hong Kong reverts to China, draws near. There are unmistakable signs that, instead, more power will simply be transferred from the Hong Kong government to the Central Liaison Office.
A recent political public relations event in Beijing offered some clues.
On June 26, Mr Leung, the then Chief Executive, and his successor-to-be, Mrs Lam, attended an exhibition highlighting Hong Kong's achievements since the handover. Chinese President Xi Jinping was present and, of course, the centre of attention.
The footage from China's main state TV broadcaster, CCTV, reveals an event obviously staged. It shows Mr Xi conversing at length with Mr Leung, and Mr Leung basking in the Great Leader's attention.
Considering that Mr Leung was unceremoniously denied a second term because he could not maintain in Hong Kong even the modicum of social harmony that Beijing demands, there was only one possible interpretation for the cordial, if stilted, exchange between the two men. The expression for this in Hong Kong Cantonese slang is: "One gulp of sugar, one gulp of sh**." Placate the punished, or the punished may become vengeful.
Meanwhile, Mr Xi gave Mrs Lam the cold shoulder. He appears not to have made eye contact or spoken to her - this, even though Beijing had endorsed her as Hong Kong's next leader, over another far more popular candidate.
The message to Mrs Lam was crude, crass and clear: See who is the boss? To the people of Hong Kong, it was ominous: Soon, there will be no tusi any more.
•Yi-Zheng Lian is a commentator on Hong Kong and Asian affairs.
A version of this article appeared in the print edition of The Straits Times on July 18, 2017, with the headline 'Ways of Chinese empire, then and now'. Print Edition | Subscribe
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