Ten thousand years ago the Jomon-jin inhabited the Japanese Archipelago. About 2,500 years ago the Yayoi-jin came from the Chinese continent. The two cultures mixed in the archipelago and the amalgamation of local Ko-Shinto (ancient Shinto) and the imported traditions, strongly influenced by Chinese Taoism and Korean animism, resulted in the earliest Japanese Shinto sometimes called "Pure Shinto". The Ezo people (who were pure Jomon-jin) were displaced to the North (Hokkaidō) and the South (Ryukyu). Ko-Shinto kept its identity as a belief system in the North where the Ainu kept their racial identity and also in the South, as was detailed in the 1605 anthropological work Ryukyu shinto-ki ("Account of Local Religion [Shinto] in Ryukyu"). "Pure Shinto" was influenced later by Buddhism and Confucianism and over time developed into today's Shinto. Some kokugakushu ("nativists") have tried to recover the Shinto religion, as practiced originally, from fragmentary texts and isolated popular religious practices.
Ko-Shinto has much in common with Shinto. Nature and mankind are closely interlaced and God is a function or the totality of Nature which expresses in the spiritual entities called Kamuy or Kamui (Shiji in the Ryukyu) by Ko-Shinto and Kami by Shinto. As in Shinto, there is not total homogeneity of belief, ritual and tradition, but diverse interpretations of the basic belief.
Modern Ainu belief is not always Ko-shinto, some modern conceptions are not original with the Ainu. Some rituals and traditions in use by today's Ainu have a foreign tinge to the old Ko-shinto traditions. An example is the sometimes mentioned Ainu prohibition prayer by women, which doesn't exist in the original Ko-shinto or in Uepeker, the tales with experiences of those who lived in olden times. In original Ko-shinto women are given preponderant place as shamanesses.
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 Koshinto literally means the "Ancient Way of the Gods" or "Way of the Ancient Gods".
Ko-Shinto believes that Nature's expressions and things, like trees, mountains, rivers and animals or even stones are, or are inhabited by, spiritual beings. Shinto inherited this view but combined it with Buddhism, and while in Ko-shinto there is no representation of Kamui (spirits) because they are intangible, in Shinto some Kami are represented by Buddhist-like figures. Some Shinto practices, such as Yamabushi (Shugendo) are very similar to some Ko-Shinto rituals.
In Ko-Shinto everything has a soul, nature itself has it. One must respect the spirit of the universe and worship nature itself in all its expressions. One should also worship Life in oneself as the expression of Nature. One of the main ways of life in Ko-Shinto is to live in harmony with Nature and all its beings and manifestations which include also the spiritual beings that we cannot see and who inhabit trees, mountains, rivers and other things. Death is simply to become a spirit, to just change form. Unusual characteristics in a tree, a rock, a waterfall, certain animals, and outstanding people are taken as an indication of a powerful Kamui (or Shiji in the Ryukyu).
Kagura, also called kamukura or kamikura, are dances adopted by Ko-Shinto for representing fables or for interacting with some Kamui deeds. The shishi kagura (Lion Dance) is the most often performed.
Musubi (the mystical power of becoming or of creation) has fundamental importance in the Kamui concept and in the Ko-shinto view of the world.
There is also a belief in utopian places as the Ryukyuan's Nirai Kanai or the Ainu's Kamuy Moshiri.
Ascetic discipline (shugyo or shugyō) has been undertaken in the mountains for centuries. It usually includes cold water ablutions at the base of a waterfall. It is considered profoundly transformative for the soul but the practitioner is warned of the danger of becoming possessed by one of the spirits believed to inhabit the mountains. This practice and kotodama (words with a magical effect on the world), as well as the purification rites of misogi, have been transmitted also to some Shinto sects as the Yamabushi and were practiced by some martial arts founders as Morihei Ueshiba of Aikido and Ryushin Yakushimaru of Kukishin Ryu.
Ko-shinto places importance on purifying soul and body. One can purify the body by bathing under a waterfall or pouring water on oneself or through kokyu-ho (breathing power practice) and kotodama-ho or "magic chanting practice".
Ko-Shinto shrines are simple stones, stone circles or wooden small housings and altars for the worship of the Kamui of the dead ancestors. Nature's Kamui can be worshiped where they live, in forests, rivers and mountains. Ritual is a personal and sometimes community activity, usually carried on in open spaces. Temples are reserved only for the transmission of traditions or some more reserved practices as purification, some kinds of meditation, offers and sometimes body training. Festivals and ceremonies are mostly connected with the seasons, harvest and special ages when rituals of passage can be done.
Pottery for the exclusive use of ritual is a normal practice and way of expression. There is a traditional prominence of shamanesses over shamans, with the divination and spirit possession abilities most often considered capacities of the female gender.
Stone representations of Shishi (Shiisaa in the Ryukyu) called by some komainu ("Korean dogs") or karajishi ("Chinese lions") are traditional guardians in Ko-shinto.