As I write, North Korea and Japan – two states that could hardly hate each other more – are talking in Beijing. This week China’s president will meet his best Korean friend – in Seoul, not Pyongyang. Both events show how drastically the peninsula’s geopolitics have changed. Gone are the old frozen Cold War dichotomies. Everything is more fluid now. Anything goes.

To see how radically things have changed in the last 25 years, let’s take a short ride back on a time machine. In the 1980s I introduced a course that I called Modern Korean Societies (note the plural: daring at the time) at Leeds University. One lecture that pretty much wrote itself – at least in outline – was the one covering the peninsula’s then-current international relations.