Traditions and customs
"Place names with 'to' in them, from one to nine [Hachinohe and Kunohe edition]...
The place names containing the character "to" (door) in the area formerly known as Nukanobu County, which stretches from Aomori Prefecture to Iwate Prefecture, are thought to have lined up from south to north along the Oshu Kaido road up to Shichinohe.
DaiwaConsilio