At the end of November last year, a high-ranking official at the Foreign Ministry looked deeply worried.

Earlier that month, Beijing and Washington were bashing each other over trade, which left the member states of the Asia-Pacific Economic Cooperation forum unable to issue a joint statement after their summit for the first time since the group was established in 1993.

The diplomat was worried the same battle could occur during the Group of 20 meetings chaired by Japan this year, including the two-day leaders summit in the city of Osaka starting June 28.