During the 48th year of Sujin's reign (50 BC), he summoned two of his sons saying that he loved them equally and could not make up his mind which to make his heir. He then asked his sons to describe the dreams they had recently, so he could divine their lot by interpreting them. The elder son's name was , and explained to his father that he dreamt of climbing Mt. Mimoro (Mount Miwa). While facing east, he said that he thrust his spear eight times and then waved his sword eight times skywards. The younger prince, whose name was dreamt of climbing Mimoro and spanning ropes on four sides. He went on to say how he chased the sparrows that ate the millet. Sujin accordingly chose his younger son Ikume to become the next Crown prince, while his older son Toyoki was chosen to govern the east. Toyoki ultimately became the ancestor of the Kamitsuke and Shimotsuke clans.