This will be a period of testing the limits, on both sides. Thousands of Hong Kongers tested the limits yesterday, demonstrating under the slogan "Build a democratic China!" There were no arrests - as there would have been, within seconds, if such a protest march had taken place in mainland China. But it was clear from the start that change will be much more gradual, when it comes.
Mainland China, which has never administered a free-thinking society even at one remove, will undoubtedly try to see with how far it can push Hong Kongers. "One country, two systems" is the official pledge. On the economy, China is undoubtedly serious. In the much quoted phrase, China has no reason to kill the golden-egg-laying goose, by tampering with Hong Kong's money-making possibilities. On politics, however, it is still unclear whether China understands that politically free-range eggs are liable to be much tastier.
Lee Cheuk-yan, an organisers of yesterday's protest march in Hong Kong, insisted that there was a basic principle at stake. "What we've done in the past, we should be able to do in the future." New public order laws, passed by Hong Kong's new China-appointed legislature, make it more difficult to protest. And yet the official line appears to be that all will still be allowed. And yet, Tung Chee-hwa, the new Peking-approved chief executive, spoke in ambiguous terms yesterday when he talked of valuing plurality, but discouraging "open confrontation".
It would be wrong to describe Hong Kong today as a place of pessimism. There is general satisfaction at the obvious new truth: Hong Kong belongs to China, just as it always should have done. Trickier is the question of whether Hong Kong wishes to be part of the People's Republic of China - in other words, subject to the regime which currently rules China. That regime believes itself to be eternal, but may in reality have a finite lifespan.
Hong Kong is a place of nagging worries, combined with extraordinary optimism. Many Hong Kongers are grateful for what the outgoing governor, Chris Patten, did for democratic rights in Hong Kong. In many ways, however, the final departure of the Mr Patten and the removal of the last royal crests across the territory, make it easier for Hong Kongers. Now they can roll up their sleeves not just economically but also politically, knowing that the future lies in their own hands, and is not affected by anybody, benevolently or otherwise, from London.
Theoretically, the future does not just depend on Hong Kong. Yesterday, the Chinese flag was being raised on official buildings all over Hong Kong. China, it can be argued, might change Hong Kong's future with just a few tanks, if it decided that the democrats were becoming too bold - just as Moscow sought to do in Czechoslovakia in 1968 or as China itself did, when lethally crushing the Tiananmen pro-democracy movement in 1989. But the Soviet invasion rebounded on Moscow. And the chapter on the legacy of Tiananmen is by no means finished. Peking's official version is that Tiananmen Square is now forgotten by all in China. But Peking's actions in suppressing dissent make it clear that China itself knows this to be a lie.