By Catherine Wong From South China Morning Post

• Issues such as the trade war may ultimately hinge on how well the Chinese and American leaders get on during their talks in Argentina this weekend
• The volatile US president has blown hot and cold towards his Chinese counterpart, but the meeting in Buenos Aires offers a chance for a reset

As the leaders of China and the United States prepare for their much-anticipated meeting in Argentina over the weekend, the South China Morning Post looks at the increasingly strained ties between the two nations. This first part looks at the personal relationship between Chinese President Xi Jinping and his US counterpart Donald Trump.

Chinese and American officials may have spent weeks preparing for the high-stakes summit between Xi Jinping and Donald Trump this weekend, but any hopes of resolving the current trade war may ultimately hinge on their personal chemistry.

Their encounter in Buenos Aires on the sidelines of the G20 summit will be the first face-to-face meeting between the two leaders in nearly a year – and the first since Trump started the trade war over the summer.

Given the stakes involved, observers will be closely watching for any clue as to how things are going, down to the two leaders’ demeanour and body language.

“In the history of China-US relations, it has always been determined by the top leaders,” said Ni Feng, a specialist on Sino-US relations at the Chinese Academy of Social Sciences.

“For example, the decision to establish diplomatic relations [in the 1970s] was decided and known only to a few people.”

Adding to the uncertainty is Trump’s volatile and impulsive approach to the presidency, which has resulted in some major swings in his relationship with Xi.

While campaigning for the presidency, he lashed out at China, which he branded a currency manipulator.

But after coming to power his affinity for autocratic rulers, such as Vladimir Putin of Russia or Saudi Crown Prince Mohammed bin Salman, appeared to come to the fore.

He gushed about his “great chemistry” with Xi and heaped praise on him – highlighting everything from Xi’s role in the North Korea nuclear crisis to the scrapping of presidential term limits.

A few months after taking office, Trump rolled out the red carpet for his Chinese counterpart, welcoming him to his private resort of Mar-a-Lago in Florida, where they discussed Syrian air strikes over slices of chocolate cake.

Seven months later China reciprocated with a “state visit-plus” to Beijing, shutting down the Forbidden City for Trump and his wife Melania.

Xi and his wife Peng Liyuan drank tea with their American counterparts inside the Bao Yun Lou, or Hall of Embodied Treasures, a storehouse for cultural treasures inside the former imperial palace complex.

The hall was built with funds remitted by the US government in the early years of the 20th century, so that the Chinese people could benefit from the compensation Beijing was forced to pay Western powers after the Boxer Rebellion, giving the venue an extra layer of symbolism.

Later in the visit, Trump boasted that a dinner held in his honour – the first for a foreign leader inside the Forbidden City since 1949 – had gone on for two hours, rather than the planned 25 minutes.

The visit also resulted in a number of deals between the two sides, including a Chinese agreement to buy more natural gas from the US, and things appeared calm for the next few months.

But gradually Trump revived his complaints, first made during the 2016 election campaign, about the trade gap between the two countries and what he characterised as China’s unfair trade practices.

In July he fired the first salvo in the current trade war, by slapping tariffs on US$50 billion worth of Chinese imports – a move that triggered immediate retaliation – and the dispute has since escalated further.

The two sides have also adopted an increasingly antagonistic stance towards each other on issues such as Taiwan and the South China Sea, while Trump has accused Beijing of trying to undermine him by interfering in the US midterm elections.

Leow Chee Seng, chief consultant at the behaviour research firm Humanology, said that several incidents during Trump’s Beijing trip may offer some insights into the relationship between the two leaders.

At one point, when the two leaders were walking outside the Great Hall of the People to inspect an honour guard, Trump tapped the back of Xi’s back.

Leow said this could be read as a message from the US leader, saying “I am actually in control and I am in power, you need to listen to me”.

Leow also said that Trump had failed to mirror Xi’s non-verbal communications as the Chinese leader made his introductory remarks, which may mean that “the message is heard but it might not reach the heart and mind of the listener”.

As preparations continue for this weekend’s meetings, Chinese officials have stressed the importance of treating both sides equally.

Beijing may also offer concessions as a way to resolving the dispute and the South China Morning Post has previously reported that China has offered to buy more natural gas and improve protections for intellectual property rights.

The approach the White House will take is rather less certain, with the administration reportedly split between those who favour a tougher stance, such as US Trade Representative Robert Lighthizer and trade adviser Peter Navarro, and more dovish figures such as Treasury Secretary Steven Mnuchin.