Around the end of the 7th century, the government office of the Koza District in Sagami Province (Koza-gunke) was established on a small hill in Shimoterao, and a temple (ruins of Shichido Garan) was also built to the southwest of it. A kawazu (landing place) and a ritual site have also been detected in the vicinity. The area including these ruins were designated as a National Historic Site in 2015 because it provides an overall picture of ancient local government office and is valuable for confirming the process from its establishment to its abolition.