Primitive Shinto embraced cults of exceedingly diverse origins, including animism, shamanism, fertility cults, and the worship of nature, ancestors, and heroes. In the course of time the distinctions between these various cults tended to disappear. The Sun Goddess, for instance, because the chief deity not only of nature worshipers, but also of ancestor worship as well. She was also considered to be the dispenser of fertility and of the fortunes of the nation. Similarly, an object of animistic worship could assume the role of a fertility god or a shamanistic deity, or even pose as the ancestor of the land on which a community lived.....
The oldest center of Shinto worship was that of the Izumo Shrine on the Japan Sea coast, and thus close to the Korean peninsula, by way of which continental civilization had reached Japan. .... The shrine at Ise, that of the Sun Goddess, came to be the most important, and it was there that various symbols of the imperial power were displayed.
The buildings of the shrines were architecturally very simple. They consisted generally of a single room (although it was sometimes partitions), raised from the ground and entered by steps at the side or front. It was invariably of wood, with whole tree-trunks used for beams. A mirror or a sword might be enshrined within, but often the building served merely as a place where the kami, visible or invisible, might be worshiped.
Outside the main building of the shrine two other architectural features usually may be found, a gateway called a torii, and a water basin where the mouth and hands of worshipers may be washed. The characteristic Japanese insistence on cleanliness finds its expression in many forms. Two important acts of worship at Shinto shrines, the harai and the misogi, both reflect this tendency. The former apparently originated in the airing of the cave or pit dwellings of prehistoric times, and came to refer to both the sweeping out of a house and the special rites of chasing out evil spirits; the latter refers to the washing of the body, an act of increasingly spiritual significance. In addition to these formal acts of religion, there were formulas, prayers, and ritual practices associated with almost all human activities (but especially in the arts and crafts), whereby divine power was invoked to assure success.
Worship at a Shinto shrine consisted of "attendance" and "offering." "Attendance" meant not only being present and giving one's attention to the object of worship, but often also performing ceremonial dances or joining in processions, which have always been an important part of Shinto ritual. The offerings usually consisted of the first-born of a household, the first fruits of the season or the first catch from the water, but might also include booty of war, such as the heads of enemies. The shrine was in the charge of a medium who transmitted messages both from the kami and from the political rulers. The mediums were assisted by supplicators, the general term for officers of the shrine, and by ablutioners. Some of the texts of the prayers and rituals of this early time have been preserved. The following is part of a prayer for the harvest festival:
More especially do I humbly declare in the mighty presence of the Great-Heaven-Shining Deity who dwells in Ise. Because the Great Deity has bestowed on him [the sovereign] the lands of the four quarters over which her glance extends as far as where the walls of Heaven rise, as far as where the bounds of Earth stand up, as far as the blue sky extends, as far as where the white clouds settle down; by the blue sea-plain, as far as the prows of ships can reach without letting dry their poles and oars; by land, as far as the hoofs of horses can go, with tightened baggage-cords, treading their way among rock-beds and tree-roots where the long roads extend, continuously widening the narrow regions and making the steep regions level, in drawing together, as it were, the distant regions by throwing over them [a net of] many ropes - therefore let the first-fruits for the Sovern Deity be piled up in her mighty presence like a range of hills, leaving the remainder for him [the sovereign] tranquilly to partake of.
The texts of these ancient prayer are often beautiful, with a simplicity that is characteristic of Shinto. The above example indicates moreover that at the time of its composition the cult of the Sun Goddess of Ise was closely associated with the imperial house and had already come to dominate the various other beliefs. It was, in fact, just when Shinto was first assuming the features of a more homogeneous and developed religion that the arrival of Buddhism caused it to be relegated to a position of minor importance for many centuries.
Film: Shinto: Nature, God, and Man in Japan (F-976)