Shrine Shinto is the ordinary public practice of Shinto: the network of shrines where the kami are enshrined and served, the festivals, the rites of passage, and the visits that a very large proportion of Japanese people make without regarding themselves as belonging to a religion.
It has no founder, no scripture in the revealed sense, no creed and no conversion. The Kojiki of 712 and the Nihon Shoki of 720 record the mythology, and the Engishiki of the tenth century records the ritual procedure, but none of these functions as scripture does elsewhere. What a shrine offers is not doctrine but access: purification, offering, petition, and the observance of the year.
Its modern institutional form, however, is not ancient. It was made in the nineteenth century. The shinbutsu bunri order of 1868 separated kami from buddhas, tearing apart an amalgamation of Shinto and Buddhist practice that had been the ordinary condition of Japanese religion for a thousand years, and stripping Buddhist imagery, clergy and buildings out of the shrines.
Then came a definition with consequences. From 1882 the state classified shrine practice as not a religion, a suprareligious national observance, while classifying the organised Shinto sects as religions. That allowed the government to require shrine attendance of everyone, Christians and Buddhists included, without formally infringing the religious freedom its constitution granted. It is among the most consequential definitional manoeuvres any modern state has performed on a religion.