ABSTRACT
This chapter shows how the Ōmiwa-no-Ason clan took an important role in diplomatic policy of ancient Japan, and how the clan engaged in the establishment of Koma County, Musashi Province. It analyzes the situation surrounding the Miwa-jinja Shrine from the late eighth century to the ninth century, and the historical background of the ranking of this shrine as Kansha in 796 and in 880, in relation with the expedition to the Tōhoku Region. The Ōmiwa-no-Ason clan and its cognate clans achieved satisfactory results in diplomatic policy against the Korean Peninsula for a half century from the middle of the seventh century. In particular, Naniwamaro was dispatched to Goguryeo and led immigrants from Goguryeo to Japan. The immigrants were thought to have lived around the strongholds of the Ōmiwa-no-Ason clan and the Miwa-no-Hikita clan. These two clans built close relationships with these people from Goguryeo.
