Mount Kusatsu-Shirane. Viewed from the SE. Mount Kusatsu-Shirane (草津白根山, Kusatsu Shirane-san) is a 2160-meter active volcano in Kusatsu, Gunma, Japan. It is called Kusatsu Shirane to differentiate it from the Mount Nikkō-Shirane on the other side of Gunma Prefecture. The summit of Kusatsu-Shirane volcano, located immediately north of Asama volcano, consists of a series of overlapping pyroclastic cones and three crater lakes.