This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
The Kojiki traces a five generation line from the sun goddess Amaterasu down to Emperor Jimmu, a documented mythic genealogy distinct from a king list that begins with Jimmu himself and claims no divine ancestor. Amaterasu sends her grandson Ninigi down from heaven to rule the earth, a documented act of descent distinct from a ruler who arises from within the earthly realm alone.
Ninigi's son Hoori marries Toyotama-hime, daughter of the sea god Watatsumi, a documented divine marriage distinct from a purely human lineage from that point forward, and their son Ugayafukiaezu is raised by Toyotama-hime's sister Tamayori-hime, whom he later marries and who becomes Jimmu's own mother, a documented continuation of the same divine line distinct from a break introduced at any later generation.
That this five generation chain running from Amaterasu through Ninigi, Hoori, Ugayafukiaezu and Tamayori-hime ends specifically at Jimmu, traditionally reckoned Japan's first emperor, is documented as the mythic charter by which the imperial house has claimed descent from the gods, marks Emperor Jimmu's place in the Kojiki as a documented case where a genealogy is told for the express purpose of arriving at the ruler it was written to legitimate.