US brinkmanship over Pyongyang’s nuclear ambitions has opened a policy debate in China, which is slowly coming to view its fellow Communist neighbour’s atomic tests and missile launches as a threat to its own security.

Beijing’s state media increasingly emphasises the need for a “denuclearised” Korean peninsula, a shift in tone from its past focus on “peace and stability”. Meanwhile, Chinese strategists quietly worry that a nuclear-armed Pyongyang will provide fodder for factions in Tokyo that want similar weapons for Japan.

In the past, China’s diplomats focused on bringing Washington to the table with the North Koreans, in the face of implacable political divisions in the American capital. While Tokyo and Seoul worried about a North Korean missile landing on their territory, Beijing had deemed the risk of a collapsed state on its borders as the greatest threat.