Kim Jong Un normally inspires either fear or ridicule in the outside world. But could there be much more to the corpulent North Korean dictator than a predilection for murdering relatives and testing nuclear weapons? Might he be a secret reformer who is actually intent on disarmament and peace?

In their different ways both Donald Trump and Moon Jae-in — the presidents of the US and South Korea— are making big bets on the idea that Mr Kim is indeed a reformist. Last week, Mr Trump accepted an invitation to another summit with the North Korean leader with a friendly tweet proclaiming: “Thank you to Chairman Kim. We will both prove everyone wrong.” And this week Mr Moon is heading to Pyongyang, the North Korean capital, for a three-day summit with Mr Kim.

Mr Moon’s hypothesis (or hope) is that the sheer unpredictability of Mr Kim and Mr Trump could actually create the conditions for peace. In past decades, the politics of the Korean peninsula have been all too predictable, with repeated efforts at diplomacy failing to end the armed deadlock between North and South.