Wikipedia
refers to the original animism of Jōmon period Japan which is a basis of modern Shinto practices. The search for traces of Koshintō began with Restoration Shinto in the Edo period. Some movements which claim to have discovered this primeval way of thought are Oomoto, Izumo-taishakyo, and Shinrikyō.
The Japanese word means "ancient or old"; from Chinese Shen, means "spiritual force or spirit" often loosely translated as "deity" or "god"; and from Chinese Tao, means "The Way". Thus Koshintō literally means the "Ancient Way of the Gods". The term Shinto itself originated in the 6th century CE (to distinguish it from continental ideas such as Buddhism and Taoism then being introduced), so paradoxically, the reconstructed Koshintō predates any use of the word Shinto.