China has a valuable card to play as it holds trade talks with the US today

By John Liu, CNN

Hong Kong (CNN) — A new round of trade negotiations between the United States and China has started in London, with both sides trying to preserve a fragile truce brokered last month.

The fresh talks were announced last week after a long-anticipated phone call between US President Donald Trump and Chinese leader Xi Jinping, which appeared to ease tensions that erupted over the past month following a surprise agreement in Geneva.

In May, the two sides agreed to drastically roll back tariffs on each other’s goods for an initial 90-day period. The mood was upbeat. However, sentiment soured quickly over two major sticking points: China’s control over so-called rare earths minerals and its access to semiconductor technology originating from the US.

Beijing’s exports of