DURING THE nineteenth century China and Japan faced an external challenge to their territory and society that put them in danger to an extent unknown to either country since the days of Genghis and Khubilai Khan. In the thirteenth century China had been conquered by the Mongols, but had to some extent civilized them, while Japan had successfully resisted them. In the nineteenth century, too, the response and experience of the two countries differed. This time the barbarian was in important respects more alien and more powerful than his nomad predecessors: he was the representative of political structures that were compact and capitalist, not tribal or feudal; he was the agent of an economy that was industrial and commercial, not pastoral or agrarian; he was the exponent of ideas that were nationalist and 'scientific,' not universalist and ethical. For these reasons, the threat he posed was more fundamental than the merely military one. It implied the destruction of a society, not just the conquest of a land. Also for these reasons, he had at his command military and economic weapons more powerful than the world had ever known before. He could be opposed, certainly. But he could not be ignored.