Traditionally, East Asians have tended to hold a strong national, or state-centric, view. In the modern university system established in the Meiji period in Japan, Japanese history was defined as National History, and strictly differentiated from Asian history, as National (i.e. Japanese) literature was differentiated from Chinese literature. Imperial Japan used the theory of expansionism to justify its hegemony in Asia, but that theory collapsed with the close of World War II. Political complications, furthermore, made it difficult for Japanese historians to have contacts with their fellow Asian scholars. Under these circumstances the tradition of National History was reinforced among the academic circle of Japanese historians. Predominant in this version of Japanese history was the image of early modern Japan as a self-contained, “mono-ethnic” state, in “sea-locked isolation”, and the Tokugawa bakufu's sakoku (national seclusion) policy was the symbol of that isolation. Internationally renowned studies on Japan's foreign relations by scholars such as Kobata Atsushi and Iwao Seiichi did not attract much attention in Japan.