It was considered that it was not so large area mainly located in Asuka Basin and the east of the Asuka-gawa River (its flatland was equivalent to the area, 1.6 kilometers from the north to south, 0.8 Kilometers from east to west) (by Toshio KISHI, and so on).
飛鳥盆地を中心として飛鳥川の東側に当たるあまり広くないところ（平地に限れば南北1.6キロ、東西0.8キロほど）と考えられていた（岸俊男など）。