Odd Arne Westad is a professor of history at Yale University and has a distinguished record of publication on East Asian history and politics and the Cold War. This new work is based on the Edwin O Reischauer Lectures that he gave at Harvard in 2017. Such lectures generally fall into two categories. They either present a piece of ground-breaking research in an accessible form or, as Westad does here, provide a valuable and wide-ranging assessment of a particular subject.

The China-Korea relationship has puzzled the West since at least the 18th century. While Korea seemed to be a separate political entity from China, those wishing to trade or have another form of involvement with the country soon came up against an obstacle. Koreans insisted that they could not do things without Chinese permission, while still maintaining that Korea was an independent country. Westerners, convinced that their system of fully independent states, developed after the 1648 Peace of Westphalia, was the norm, failed to see in the Chinese approach characteristics that had once prevailed in Europe. Westad hints at this but does not explore it in detail. He also hints at, but again does not examine, the long-standing special relationship between China and Korea in the 1,300 years before the Ming dynasty came to power in the former in 1368 and the Chosun dynasty in the latter in 1392. During that time, Chinese dynasties had been closely, if spasmodically, involved with Korea as the disparate kingdoms on the peninsula slowly coalesced into one unified entity. Sometimes, the relationship had been a peaceful one. From China came a writing system that has faded from use only in the last seventy years. Korean government, architecture, city layout and religion all had their origins in China. In time, of course, they were modified and changed to become something recognisably different, but even today Chinese links can be discerned in both Koreas.

Not all interactions were peaceful. The Yuan dynasty that ruled China from 1271 to 1368 and its predecessor, the Mongol empire of Kublai Khan, treated Korea very harshly and effectively imposed subjugation on the country. The Koreans welcomed the overthrow of the Yuan and its replacement by the Ming. But the experience of the Mongol period also led them to seek ways to accommodate their large neighbour. This approach was known as sadae (‘looking up to the great’).