It was only a phone call between Vice-Premier Liu He and US Trade Representative Katherine Tai, but the first contact between top Chinese and American trade negotiators since Joe Biden became US president came at a pivotal moment in the bilateral relationship. “Candid” and “constructive” talks, to use Beijing’s words, did little to narrow differences in their three-year trade war. “Candid” in this sense means differences on this issue remain big but they are willing to engage each other. The biggest challenge in bilateral relations now, however, is no longer trade but technological rivalry. President Xi Jinping left no doubt about this in a speech to mark national day for science and research, in which he said unprecedented scientific and technological competition had become the main battleground of global power rivalry. There is at least bilateral consensus on that. A few days before, White House Asia-Pacific policy director Kurt Campbell told an American audience that the dominant paradigm between China and the US would now be one of competition, focusing on technology, as the period of engagement with China had “come to an end”. In that respect, trade can now be seen as the ballast or stabiliser in a stormy relationship wracked with tension and mistrust over technology, the origins of the coronavirus, the South China Sea and Hong Kong, Xinjiang and Taiwan. Maintaining trade ties can help prevent the wider relationship from collapsing. Evidence that Beijing values the trade relationship and continuity is to be found in Liu’s leadership of the Chinese side in the talks, even though Wang Wentao was appointed as the trade chief last year. Liu negotiated the “phase one” trade deal between China and the Trump administration. Thanks to an increase in US exports, China in 2020 was once again the United States’ top trade partner, even though the US trade deficit has grown. But the China-US relationship seems headed for some very testing times on more sensitive issues. If the two global rivals can continue this kind of dialogue in trade, however, that can only be positive for navigation of other rocky patches and management of their differences to ensure peaceful resolution.