Kojiki or Hurukotohumi is the oldest known historical book about the ancient history of Japan. Literally, it means "records of past things". According to the preface, the book was presented by O no Yasumaro based on the story memorized by Hieda no Are in 712 under the order of the Imperial Court. Nihonshoki followed the book. Kojiki contains from the start of the world as they were constructed by deities to the era of Empress Suiko and contain various myths and legends. It also contains various songs.

The Nihongi continues where the Kojiki finishes, cataloguing the descent of the Yamato rulers of Japan from the Gods, to the date of 697 AD. In this sense, the Nihongi, as with the Kojiki, represents a mixture of an open political agenda with a sometimes mixed groups of folkloric tales and mythological happenings. The Nihongi itself was completed around 720 AD, and played an important role in the reshaping of Japan by the Yamato rulers, not least in the naming of the country as Nippon.

Indigenous religion of Japan, based on the worship of spirits known as kami.

The term Shinto ("way of the kami") came into use to distinguish indigenous Japanese beliefs from Buddhism, which had been introduced into Japan in the 6th century AD. Shinto has no founder and no official scripture, though its mythology is collected in the Kojiki ("Records of Ancient Matters") and Nihon shoki ("Chronicles of Japan"), written in the 8th century

At its core are beliefs in the mysterious creating and harmonizing power of kami. According to Shinto myths, in the beginning a certain number of kami simply emerged, and a pair of kami, Izanagi and Izanami, gave birth to the Japanese islands, as well as to the kami who became ancestors of the various clans.

The Japanese imperial family claims descent from Izanagi's daughter, the sun goddess Amaterasu. All kami are said to cooperate with one another, and life lived in accordance with their will is believed to produce a mystical power that gains their protection, cooperation, and approval.

Through veneration and observation of prescribed rituals at shrines (e.g., ritual purity), practitioners of Shinto can come to understand and live in accordance with divine will.

Izanagi

In Japanese Shinto-mythology, the primordial sky, the god of all that is light and heavenly. Izanagi ("the male who invites") and his wife and sister Izanami ("the female who invites") were given the task of creating the world.

Standing on Ama-no-ukihashi (the floating bridge of the heavens), they plunged a jewel crested spear into the ocean. When they pulled it free, the water that dripped from the spear coagulated and formed the first island of the Japanese archipelago. Here the first gods and humans were born.

Izanami

In Japanese Shinto-mythology, a primordial goddess and personification of the Earth and darkness. Izanami ("the female who invites") is the wife and sister of Izanagi.

Together they created Onogoro, the first island of the Japanese archipelago. She died gaving birth to the fire god Kagutsuchi and since then she rules over the underworld.

A torii is a traditional Japanese gate commonly found at the entry to a Shinto shrine. It has two upright supports and two crossbars on the top, and is frequently painted vermilion.

The origin of the torii is said to come from an old Japanese legend, when the sun goddess became extremely annoyed with her prankster brother. She hid herself in a cave and sealed the entrance with a rock, causing an eclipse. The people were afraid that if the sun never returned, they all would die.

So, per the advice of a token wise old man, they built a large bird perch out of wood and placed all the town's roosters on this perch. They all started to crow noisily, causing the curious sun goddess to peek out of her cave. Having opened the door a crack, a large sumo wrestler from the town ran up and pushed the rock away, letting the sun out and thus the world was saved.

That bird perch was the first torii gate. From then on, the torii became a symbol of prosperity and good fortune, and spread all over Japan.

Info from http://en.wikipedia.org/wiki/Torii