Hong Kong in China, and China in Hong Kong, have long been part of a larger story. The story did not begin with the handover in 1997.
Its roots go back to when, for Manchu Qing China, Hong Kong was a small island far away enough from the centre to be ceded without much pain.
If the British had behaved like the Portuguese who had gone earlier to Macau, there would have been no need to worry about them. The Portuguese had played by China's rules for 300 years before the British shot their way into China.
As it turned out, Hong Kong developed very differently. Beyond being an open door for foreigners to enter China, it was also one for Chinese to leave and seek better livelihoods elsewhere.
It was a market place, a haven, and, for someone like Chinese revolutionary leader Sun Yat-sen, a model of modern urban development that he wanted the cities of China to emulate.
Chinese enterprise played a big role in the colony's success but no less important was what the British introduced, laws that guaranteed property rights and protected the freedoms that its Chinese population could not get in China.
All that began to change after the end of World War II. The retreat of the old empires led to Hong Kong and China being caught in a fierce global struggle between capitalism and communism.
The victory of the Chinese Communist Party moved the country's ideological frontiers from its borders with the Soviet Union that Nationalist China had hoped to defend, to the long coastline of the East and South China seas.
Here, the United States Navy took over from the British and, for at least 40 years, Hong Kong unwittingly became the Berlin of the East, that is, the front-line between Western and communist power.
Thus the Hong Kong people's involvement in Chinese politics became more intense and tangled than ever before.
The communist government in China knew that the city was being used as an observation centre by the West in the Cold War.
But the city was also China's window on the outside world. The colony provided access to foreign knowledge and technology, and also enabled China to seek the resources and markets it needed.
Today, as the street protests by students continue, new actors are playing on the old streets where earlier demonstrations were held. But there are significant differences in the background.
The most important is that Beijing does not need Hong Kong the way it did from 1949 to 1997, and it is burdened by problems of governance in China that it did not have a decade ago.
No less important, however, is that London and its North American and European allies are wearied by unending conflicts all over the Eurasian continent. There is thus an air of helplessness that seems to be sapping hopes of Hong Kong converging peacefully with China.
Chinese leaders have observed the changing population of Hong Kong with keen interest. Those who arrived in Hong Kong early prospered by acting as a bridge between China and the outside world. Those who came later included many who fled their homes in China for livelihood or political reasons. Among them were those who nurtured dreams of more perfect worlds far away. Yet others remained and learnt to serve different masters in the city and in China as well.
Hong Kong had always been a restless city that attracted risk-takers no less than refugees. It has been home to people of different ideological stripes. The people prided themselves on their revolutionaries such as Sun Yat-sen and also sheltered the communist enemies of his Nationalist Party.
The people were divided between those who welcomed the departure of the British and those who regretted their leaving. They were similarly divided over how the city was to return to China.
People in China have been aware of the freedoms that Hong Kong enjoys - and indeed, many mainlanders have sought to visit, study, work or live there for that reason.
They know that several generations of young people have grown up in Hong Kong with a wide range of choices that has taught them to be pragmatic and build their lives in China's shadow. That shadow was acceptable because Hongkongers were confident that they had something to offer that would help China's economic development.
It was also something that Deng Xiaoping seemed to have acknowledged by agreeing to allow 50 years for Hong Kong to adjust to the conditions of China.
There were thus different expectations at work. Since the SinoBritish Joint Declaration was ratified in 1985, two main 50-year scenarios have emerged.
One was based on the hope that Deng's reforms in China would ultimately make the country more like Hong Kong. Those who operated in globalised economies mostly supported this scenario.
The other scenario was of a gradual convergence that would enable China and Hong Kong ultimately to share the same dream of a strong and prosperous China. No one could be sure that this would happen or what the dream would be like when the time came.
The problem is that neither scenario gave sufficient weight to what generations of the young people of Hong Kong were inheriting, notably their freedoms, their rights and their sense of social justice.
In several demonstrations during the past decade, a sense of how important that heritage was, surfaced. But the promise of popular suffrage at that time satisfied the demonstrators.
Those on the streets today say that the government is breaking the promise to allow genuine democracy in 2017. Their actions suggest there is fear that the Hong Kong heritage is no longer protected.
The young students speak as if their freedoms cannot now be left to their elders, who have their vested interests to protect and too many of whom have left to find safety elsewhere. They seem to believe that they have to act now to ensure that what they value is not lost.
As far as we can tell, the leaders in Beijing have been monitoring such thinking through their offices in Hong Kong ever since the 1997 handover. They have affirmed that they are standing by the Basic Law, Hong Kong's mini-Constitution that promises direct elections for the chief executive.
They know that the Hong Kong people today are different from those in China but seem to think that the differences will lessen in time.
Therefore, they insist that they are committed to wait the promised 50 years before Hong Kong truly becomes part of China.
They also seem to have put their trust in local elites in Hong Kong to help smoothen that path but have made it clear to the Hong Kong government that any change would have to suit the interests of China as a whole.
From official statements, it would seem that they are still hopeful that the majority of Hong Kong's people will recognise the national imperative.
There is a test of wills today between the Hong Kong government and the protesters. Beijing appears to be adopting a wait-and-see approach, trying to stay out of direct involvement and concentrating on keeping outside interests and forces from intervening.
They may be hoping that, if only the West would behave as the Portuguese did when they left Macau in 1999, they would have less to worry about and there would be a better chance of a peaceful outcome.
The writer is chairman of the East Asian Institute and a professor at the National University of Singapore.