Josaku (stockades) called Nutari no Ki and Iwafune no Ki were built in Koshi Province to defend against the northern Emishi people, manned by Sakuko (immigrants from the Kanto and Hokuriku regions who were forced to work for the government).
北の蝦夷に対しては、渟足柵、磐舟柵を越国に築き、柵戸を置いて備えた。