German architectural photographer Dieter Leistner has experienced something few can lay claim to. Since the 1940s Korea has been divided as Germany once was, and North Korea – an oppressive and famously secretive place under single party socialist rule – remains one of the world’s least documented countries. Fascinated by the parallels with the history of his own country, Leistner received official sanction to enter Pyongyang with his camera, and later the booming South Korean capital Seoul, and his discoveries and comparisons are gathered together in the 190-page book Korea – Korea from publishers Gestalten.

The book, as well as depicting the stark differences between the two countries once united but now so clearly divided, contains excerpts from diaries by Philipp Sturm, who grew up in East Germany and took the trip to Pyongyang with Leistner, and Hehn-Chu Ahn, a German of Korean descent who has been a regular visitor to Seoul since childhood. Korea – Korea is both a rare chance to glimpse behind an iron curtain still very much drawn tightly closed, and a poignant investigation of the effects of human segregation. No prizes for guessing which Korea is which in these images…