It was not always thus. Under Japanese colonial rule northern Korea was developed as the industrial hub, with the southern part regarded as a agrarian backwater, and when the North designed its national emblem in the 1940s it gave pride of place to the Suphung hydroelectric dam on the Yalu river.

“Back then, they had the best generation capacities in east Asia, probably better than in Japan, definitely better than anywhere else,” said Andrei Lankov of Korea Risk Group.