Results of Excavations at the Akita Castle Site

Abstract

The Akita Castle Site, located in Akita City, Akita Prefecture, is the northernmost fortified government office site of ancient Japan.
First built by the Ritsuryo state as Dewa no saku in the year 733, the name was later changed to Akita Castle. From the first half of the eighth century, and continuing into the tenth, it served as the military and governmental base of Dewa province for the control and governance of the Emishi and of immigrants to the region. It is thought that in the Nara period a Dewa provincial headquarters was established, and in recent years its role as a base for diplomacy and exchange with the country of Bohai on the continent, across the Sea of Japan, has been the subject of attention.
The Akita Castle Site has been under continuous investigation by the Board of Education of Akita City since 1972, and the locations and changes over time of its external fortifications, as well as those of central facilities such as administrative headquarters and various governmental offices, have been confirmed, and thus the manner in which both the internal and external portions of the site were used is gradually becoming clear.
In the excavations of recent years, with regard to diplomatic exchange, administration, and military affairs, there have been important discoveries concerning the special characteristics of the Akita Castle Site and the role it played as a fortified government office.
The remains of a toilet, together with the structure housing it and superb facilities for flushing, were discovered in Excavation No. 63, in the Unoki precinct. From an analysis of the eggs of intestinal parasites found in the toilet remains, the possibility has been pointed out that it was used by a visitor from the continent, for whom pork was a regular item in the diet, focusing attention on the connections of this find with the role played by Akita Castle as a base for diplomacy, and with the envoys from Bohai who came to Dewa during the Nara period.
In Excavation No. 72, administrative documents that had become permeated with lacquer were recovered in unprecedented amounts. These were death and family registers, and tax registers, etc., kept for the purpose of controlling residents who consisted of immigrants, Emishi, and others, and for governing them in accordance with Ritsuryo law, making this a highly valuable discovery for learning about the regional administrative system, and the composition and lifeways of the residents, for a region having a fortified government office under the ancient Ritsuryo state order. Also recovered in Excavation No. 72 were nonferrous lamellar plates for body armor, dating from the first half of the ninth century. As no other examples, excavated or otherwise, of nonferrous lamellar armor are known for the first half of the Heian period, this is a significant discovery for studying changes in ancient Japanese armor. The discoveries of lacquer-permeated documents and lamellar armor are suggestive of the role played by Akita Castle as a pivotal administrative and military institution in the Heian period.
In future investigations of the Akita Castle Site, in addition to continuing to pursue the administrative and military roles constituting its basic functions as a fortified government office, it is also necessary to continue throwing light on its particular characteristics as the northernmost of such facilities in Japan.