Or takama-no-hara. The Plain of High Heaven. The other world from which the heavenly kami, amatsu-kami descend. It is the upper realm in a 'vertical' cosmology comprising high heaven, this human world and yomi, the lower realm of the dead. Takama-ga-hara is sacred but otherwise not much different from the physical world. It contains rice fields, houses, earth floors, animals and the cave in which Amaterasu hides herself. The notion widespread since the Meiji era that the emperor was descended from the kami of takama-ga-hara derived from the rediscovered 'classic' mythologies of the Kojiki and the Nihongi (see Kokugaku, Kokka Shinto), whereas the traditional cosmology of shrine worship overwhelmingly refers to kami who live in this world or come from mountains (yama-no-kami), over the horizon or under the sea (tokoyo, marebito, ryugu).
A Popular Dictionary of Shinto. Brian Bocking.