Xiao Xiao and Lei Lei, two baby pandas residing in Tokyo’s Ueno Zoo, have a weighty diplomatic lineage. In 1972, two pandas, Kang Kang and Lan Lan, were presented to Japan by China’s rulers to celebrate the normalisation of relations between the sometime foes that year. They were probably the first pandas to set paw in Japan; the queue to see them stretched a kilometre through the zoo’s leafy grounds.

In some respects, the relationship between Asia’s two economic heavyweights has since been happily symbiotic. Japanese aid and investment helped China modernise; the growing Chinese market helped fuel Japan’s growth. In 2021, China was by far Japan’s biggest trading partner, and Japan was China’s second-largest: bilateral trade hit a 10-year high of US$391 billion (S$530 billion). Yet the disagreements over territory and history that still strained the relationship half a century ago – chiefly, over the status of the Senkaku/Diaoyu islands, and of Taiwan, and memory of Japan’s wartime aggression – are unresolved. And under President Xi Jinping, China’s aggrieved, nationalistic leader, they have been exacerbated.