After his father, Kōnin, became emperor, Kammu's half-brother Prince Osabe was appointed to the rank of crown prince; but instead of his half-brother, it was Kammu who was later named to succeed their father.
After his father, Kōnin, became emperor, Kammu's half-brother Prince Osabe was appointed to the rank of crown prince. His mother Princess Inoe was a daughter of Emperor Shōmu; but instead of his half-brother, it was Kammu who was later named to succeed their father.