These expectations had been heightened when, before his appointment in March, Wang had private meetings with the US’ ambassador to China, Terry Branstad, and former Trump adviser Steve Bannon. He has also held closed-door meetings with US executives in recent months, sources in the US business community say.

But aside from the occasional public meeting with US visitors – most recently in mid-May when he met US business executives in Beijing – and the odd appearance elsewhere, including at a forum in Russia in late May, Wang has kept a low profile.

The week before last, for example, the only news he appeared to make was when he met Bangladesh’s foreign minister and when he was appointed honorary president of the Chinese Red Cross.

For some China watchers his absence is a bad omen for the state of Sino-US relations despite Trump’s continued insistence that Xi is a close friend. If there was going to be a breakthrough in the trade row any time soon then they would expect Wang to be taking a more prominent role.

“Wang Qishan would be crazy to get on a plane until there were far greater assurances there is a deal to be had and the deal would stick,” said Scott Kennedy, deputy director of the Freeman Chair in China Studies at the Centre for Strategic and International Studies in Washington.

One source with knowledge of Wang’s meetings with US business leaders said the vice-president is only going to get involved when “he can have a clear view of how he can negotiate a solid outcome”.

When there is something to be negotiated, Wang will probably insert himself in some way, they said.

Neither the foreign ministry nor the cabinet spokesman’s office responded to a request for comment on Wang and his lack of known role so far in the US trade dispute. There is no public contact information for the vice-president’s office.

The last round of trade talks with Washington, led for China by Vice-Premier Liu He, failed to head off a US decision to impose punitive tariffs on $34 billion of Chinese imports on Friday, with China retaliating with its own increased tariffs on $34 billion of US imports to China.

Wang’s diplomacy has been low-key and behind the scenes, and there is no sign he has lost his status as a key decision-maker and political player, diplomats say.

A smoker who is 70 this month, Wang is more senior than both the Chinese government’s most senior diplomat, State Councillor Wang Yi, and Politburo member Yang Jiechi, who heads the Communist Party’s foreign affairs commission.

Unlike the urbane, Harvard-educated Liu, Wang does not speak English, though he has a penchant for no-nonsense, direct talk behind closed doors, those who have seen him in action say.

A senior Western diplomat said Beijing appeared to be reluctant for Wang to get involved after Liu had the rug pulled from under him by Trump reneging on a previously agreed “consensus” to resolve the trade spat in May.

Wang is extremely close to President Xi Jinping and reports directly to him, meaning that if a similar thing had happened to Wang it would be seen as a personal snub to Xi, the diplomat said.

“You can embarrass the vice-premier but not the vice-president,” the diplomat said, speaking on condition of anonymity.

Beijing has struggled to work out what Washington really wants, especially given that the US trade negotiating team has been split between those who tend to favour free trade and those who are more protectionist, a source with ties to the Chinese leadership told Reuters. This has led to confusing and sometimes contradictory statements from different officials.

“It’s reneging on one’s words,” said the source, quoting a saying – attributed to ancient Chinese philosopher Mencius – that state media has increasingly used to refer to the US administration’s struggle to give a single unified message.