Chinese foreign policy debates are seldom lively, which is just the way the ruling Communist party wants to keep them. Polemics are few, articles and lectures are full of sleep-inducing slogans and official orthodoxy.

But a curious exception to this apparently placid consensus has taken place as a debate roils China’s expert community over what to do about North Korea, its increasingly wayward, nuclear-armed neighbour.

Over the past several months, policy journals have run articles questioning the official line, while scholars at top universities have been unafraid to publish previously heretical views — in western journals, no less. They have even taken to social media to argue with each other.