This is Amanoiwato shrine which passes along the myth of Amaiwato.
According to the Records of Ancient Matters (Kojiki) and the Chronicles of Japan ( Nihonichi Shoki) :
Amaterasu Omikami (a sun goddess) got upset at her younger brother, Susanoono Mikoto’s violent behavior.
So she went and hid inside a cave ( Amaiwato), making the world become dark and a lot of bad stuff happen.
Myriads gods gathered and talked about how to get her to come out from the cave.
They had a banquet party to tempt her to come out.
Amanouzumenomikoto, who is a good dancer, danced and everybody laughed, then when Amaterasu Omikami got interested and peeked it, Tajikaraonomikoto (who is strong) opened the door of the cave and forced her out.
Then light returned to the world.
That is the story…
If you walk about 10 minutes from Amanoiwato shrine, there is Amanoyasukawara, the place where the gods held their discussion.
Takachiho is the original place of Japanese myth.