In his latest book, The Half Known Life, Pico Iyer asks what kind of paradise can be found in a world of unceasing conflict. In the “Notes from an author” slot in the March issue of National  Geographic Traveller (UK), he recalls the time he has spent at Koyasan, centre of the esoteric Buddhist order known as Shingon and “the single most powerful spot I’ve discovered in 35 years living in Japan”.