Bit by bit, Donald Trump’s China policy has come into a sharper focus and he is set to propel the Sino-US relationship, arguably one of the world’s most important bilateral ties, down a slippery road onto more treacherous terrain.

Even weeks before he assumes the presidency next month, Trump, true to his unpredictable and unorthodox nature, already signalled his intention to shake up the one-China principle, which has underpinned the bilateral relationship for more than four decades, by intending to use Taiwan as leverage in broader negotiations with China.

WATCH: China warns Trump on Taiwan comments

It started with a phone call early this month with the Taiwanese president Tsai Ing-wen and was followed by his interview last Sunday where he said the United States was not bound by the one-China policy unless “we make a deal with China having to do with other things, including trade”. Later in the interview he appeared to outline other contentious issues on which he wanted to bargain with China, including the yuan, China’s high taxes on American goods, its activity in the South China Sea, and its failure to curtail North Korea’s nuclear proliferation.

Given the fact that the Taiwan issue is one of China’s core interests, the so-called red line which must be not crossed in its foreign affairs dealings, the initial reaction from Beijing has been remarkably measured. Immediately after the shock phone call occurred, Foreign Minister Wang Yi (王毅) labelled it merely “a little trick” by Taiwan which would not change the one-China consensus in the international community.

Maybe the Chinese leadership has taken the advice from Henry Kissinger, long seen as a conduit for Beijing in managing the bilateral ties. Kissinger, who helped craft the one-China policy in the 1970s when he was the US secretary of state, praised the mainland leadership for “the calm reaction, which suggests a determination to see whether a calm dialogue can be developed”.

But in diplomacy, the timing of events can be very telling. Many Chinese observers could not help but notice that Trump spoke with Tsai on the same day when Kissinger was in Beijing meeting President Xi Jinping (習近平) in a trip meant to reassure the Chinese side after Trump’s blistering campaign, which often singled out China.

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Coincidentally, on the same day as the US TV network Fox News aired the interview with Trump in which he intended to turn the long-standing US policy on China on its head, Kissinger was speaking in Oslo, urging patience on the coming Trump administration, saying that his personality had “no precedent” in modern US history and he should be given a chance to put forward his vision. While he listed the worsening of relations between the US and China as one of the biggest challenges during Trump’s presidency, he also cautioned against judging him on his campaign rhetoric.

But the truth of the matter is that Trump’s phone call and the interview occurred after his campaign had ended and he had become the president-elect, whose comments should carry much more weight.

Indeed, the ensuing developments have indicated that Trump’s double-act on targeting China was not due to inexperience or recklessness as some of the Chinese media have previously speculated but appeared to be well thought out to test China’s bottom lines.

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More significantly, they could signal a shift in its policy towards China. Although Trump said he knew about the call request from Tsai just one or two hours in advance, US media reports suggested that lobbyists for Taiwan spent months laying the groundwork for the call and Trump and his aides were fully aware of the nuances surrounding the sensitivities of the one-China principle.

Following Trump’s interview, the Chinese media started to react more strongly by saying that the one-China principle was non-negotiable and Xinhua said in a commentary on Tuesday that any deviation from the policy would be a deal breaker.

For many Chinese observers, the initial assessments that Trump would retreat from Asia based on his campaign rhetoric appear to be misplaced. So was the short burst of optimism when Trump announced that he would tap Iowa Governor Terry Branstad as the next ambassador to China just a few days before Trump’s shock interview was aired. Official media had hailed Branstad as an old friend of Xi and his appointment as a positive signal.

WATCH: Trump questions continuing one-China policy

But some still believe that the Trump administration will become more moderate in dealing with China after the initial period of turbulence in bilateral ties – as seen with previous US administrations.

Trump’s top choices for his foreign policy team should serve as another warning.

The relations between Washington and Moscow are set to warm significantly during Trump’s presidency after he named Rex Tillerson, the chief executive of Exxon Mobil as his choice for secretary of state, and Michael Flynn as his national security advisor, both of whom have pro-Russia views.

Such a scenario could bring more undercurrents to the Sino-US relations in the realignment of great power relations.

Wang Xiangwei is the former editor-in-chief of the South China Morning Post. he is now based in Beijing as editorial adviser to the paper