He pointed to a history that includes US journalist Edgar Snow's engagement with China, Ping-Pong Diplomacy, and the North American redwood brought to Hangzhou during former president Richard Nixon's 1972 visit.

For Liu, the value of people-to-people ties lies partly in its resilience. Such relationships can endure even during periods of tension.

"The motivation comes from the need for exchange," he said.

That need can take many forms, including curiosity about another society and culture. It also has a human dimension — the goodwill, trust and emotional connections that develop when people meet one another directly, he said.

That is also why Liu places particular importance on exchanges among young people, as they often share a wide range of common interests.

"Unlike formal diplomatic or policy discussions, their interactions often begin with everyday subjects, and can therefore create personal experiences that endure," he said.