According to the "Kojiki" (the Record of Ancient Matters), Amaterasu Omikami said to her grandchild, Ninigi-no Mikoto: 'Ashihara no nakatsukuni is a country which you should rule.'
『古事記』には天照大神が孫の瓊瓊杵尊に「この豊葦原水穂国は、汝の知らさむ国なり」とある。