Channels radiate out from all directions of Mt. Futago on the upturned bowl-shaped Kunisaki Peninsula, and in ancient times settlements known as "Rokugo" (lit. Six Townships) were formed along each of these channels, of which Tashibu Township was the settlement on the west of the peninsula.
椀を伏せたような形をした国東半島には、両子山を中心として四方へと谷筋が走り、古代にはこの谷筋に沿って六郷と呼ばれる6つの集落が形成され、そのうち半島の西側にあたるこの地には田染郷があった。