Key Points

- It is the journey of gods descending from the Heavens to Japan to live and rule amongst mankind. 

- During this time the kami on earth will lose their immortality and most of thier godly powers

 - Completion of the journey signals the end to The Age of the Gods and the start of The Imperial House of Japan Dynasty

Brief Bio 

In Japanese mythology, the "Three Generations of Hyuga" (日向三代, Hyūga Sandai) refers to a period of three generations of deities who lived in the Hyuga region of Japan, following the descent of Ninigi-no-Mikoto (瓊瓊杵尊) from heaven. It is the journey of the gods descending from the Heavens to Japan to live and rule amongst mankind. 

The journey begins when Amaterasu commands Ninigi to leave the heavens and ends with Jimmu establishing the Imperial House of Japan. During this time the kami on Japan will lose their immortality and most of the godly powers.  The completion of The Three Generations of Hyuga signals the end to The Age of the Gods. 

This period is situated between the Tenson kōrin (天孫降臨), the descent of Ninigi, and the Eastern Expedition of Emperor Jimmu.

Timeline: 

Amaterasu (Commands her grandson Ninigi to descend to Japan)

Ninigi-no-Mikoto (Leaves the Heavens as many kami follow, Fathers Hoori) 

Hoori (Fathers Ugayafukiaezu)

Ugayafukiaezu (Fathers Jimmu)

Jimmu (Ascends to the Throne and Establishes the Imperial House of Japan)

Imperial House of Japan (Japan's Imperial Dynasty that continues to today)