Changes in the International Situation of East Asia in the 5th Century and Immigration

The ancient Korean Peninsula is functioned as an important bridge that connects China and the Japanese archipelago. As a result, there are lots of Chinese cultures and systems that were spread to Japan through the Korean Peninsula. Such cultural and institutional transmission was just achieved by means of population migration, that is, immigration. During the 4th to 5th centuries, a period of turmoil in China (Wei-Jin-Northern and Southern Dynasties Civilization), many Han Chinese migrated to Japan via the Korean Peninsula, and they contributed to the formation of ancient Japanese states and the strengthening of royal authority. In particular, their role was prominent in diplomacy between the Wa kingdom and China during the era of the “Five Kings of Wa” (倭五王). However, research by earlier scholars has revealed that most of these people were originally from the Korean Peninsula. In the paper, it emphasizes that diplomacy between countries is not merely simple communication but requires the establishment of a system. Based on the fact that such a system can be constructed by individuals with a deep understanding of international affairs and diplomacy, the paper explores the impact of the political chaos in East Asia and the resulting large-scale migration from the 4th to the 5th century on the formation of the ancient Japanese state as well as the development of its monarchy.