Aso Atrio, consisting of the volcano, the alluvial plain, the alluvial fan, the talus, the terrace and the plateau, has the very complicated natural features, the whole of which orginates in the volcano-actions.
Through the study of the process of reclamations, I made it clear what a regional system the modes of production and the enlargement of the residence did bring about.
The reclamation on Aso Atrio, which were, to begin with, set about at the foot of the somma wall and the central corn both in the southrn valley and the northern one and secondly spread to the central region, left the terrace region in the southern valley and the fans in the eastern regions of both valleys undeveloped till rather later times.
The farming methods in the process of reclamation on Aso Atrio came into being by the combination of the farming and the stock farming.
And the regional unity had the combination of the arable land and the meadow on its basis, too.
The administrative unit accordingly had often changed since olden times, but it had always included the arable land on the atrio, the central corn, the pasture and the meadow on the somma wall. The changing process of administrative division will explain that of the regional unity distinctly.
