"Azuma-reijin-so" (Aconitum pterocaule) belongs to Ranunculaceae (the Buttercup family). It is a perennial herb that is distributed from the Chubu regions to the Kanto region in Honshu, Japan. It grows in forests in mountainous areas, and grows erect or as a vine, reaching 80 to 100 cm in height. From August to October, it produces gross inflorescences and produces pale reddish-purple flowers. The Japanese name comes from the shape of the flower, which resembles the crown worn by a "Reijin". The word "Reijin" refers to the musicians who perform gagaku (ancient Japanese court music).