Emperor Kōnin
Kammu's personal name ("imina") was . He was the eldest son of Prince Shirakabe (later known as Emperor Kōnin), and was born prior to Shirakabe's ascension to the throne. According to the , Yamabe's mother, Yamato no Niigasa (later called Takano no Niigasa), was a 10th generation descendant of Muryeong of Baekje.