Tōsandō

Tōsandō (東山道^?, literally, "eastern mountain circuit" or "eastern mountain region") is a Japanese geographical term. It means both an ancient division of the country and the main road running through it. It is part of the Gokishichidō system. It was situated along the central mountains of northern Honshu,Tōhoku region.

This term also refers to a series of roads that connected the capitals (国府, kokufu^?) of each of the provinces that made up the region.

The Tōsandō region encompasses eight ancient provinces.

After 711, Tōsandō was understood to include Musashi province.

...
Wikipedia