From discovering the river piracy near Asuka-Mizuochi-Iseki Ruins by the Asuka-gawa River to the conclusive evidences implemented at the Empress Saimei's period,

using relations between river terraces originated by the piracy and locations of ruins on them.

Abstract

Since Japan hegemony of the Yamato sovereignty was settled, its capitals had been put in the Asuka Valley of the Nara Basin south border for almost a century. The present author restored an Asuka River replacement causing river piracy using river terraces by stereo-photographic interpretation and Empress Saimei 's Asuka-kyu Palace III-A ruins. The attached scenic garden of Asuka-kyu is found to have been located directly on the natural bed of the 2nd river terrace. The oblong-shaped inner palace is situated to the southeast, and its southwestern part is recognized to be deeply cut by the 1st river terrace. Asuka-kyu had been used by her and her son from AD656 to 667, therefore the replacement is concluded to have been implemented during that time.