Japan's mythological origins could have come from the pen of J.R.R. Tolkien. According to the oldest written records, the Kojiki and the Nihon-shoki , the god Izanagi-no-Mikoto and goddess Izanami-no-Mikoto leant down from the Floating Bridge of Heaven and stirred the ocean with a jewelled spear. Drops of brine falling from the spear created the first island of Japan, Onogoro-jima, where the couple gave birth to an "eight-island country", complete with kami . Amaterasu , the sun goddess and ultimate ancestress of the imperial family, was created out of a bronze mirror held in Izanagi's left hand and sent to rule the heavens. Her younger brother, Susanoo , was put in charge of the earth. Unhappy with this situation, he started causing turmoil in the heavens, and so upset Amaterasu that she hid herself in a celestial cave, plunging the world into darkness.

The other gods banished Susanoo to the underworld. Then, in an effort to coax Amaterasu out of the cave, they performed a comical dance involving a spear. Upon hearing the somewhat ribald laughter, Amaterasu's curiosity got the better of her and she poked her head out to see the fun. Enticed out a little further by a beautiful jewel, Amaterasu was then captivated by a bronze mirror. While she was preoccupied, the gods quickly sealed the cave entrance and sunlight returned to the world.

In time, Amaterasu's grandson, Ninigi , was sent down to rule Japan. She gave him three gifts which were to be his imperial regalia : a bronze mirror, a sword and a curved jewel. Here myth finally merges into proto-history, when Jimmu , said to be Ninigi's great grandson, became the first emperor of Japan on the first day of spring 660 BC.