The term Shinto covers a many-hued array of Japanese religious traditions. In the Japan of today, these are represented by a considerable number of organized religious groups, an even larger number of more or less organized local shrine cults, and an ill-defined body of unorganized beliefs and practices that do not involve religious professionals. To the outside observer Shinto appears less as a distinct religion, than as an extremely fluid body of religious phenomena linked, at best, by a family resemblance.
What defines these disparate phenomena as aspects of Shinto, is not so much shared beliefs, ideas or moral attitudes, but rather a common set of physical symbols and ritual patterns. There is no scripture, no set of dogmas, nor even a shared pantheon that could warrant the lumping together of Shinto’s multifarious traditions under one label. Rather, practices are identified as some form of Shinto by such markers as the torii gate and shimenawa straw ropes, used to demarcate sacred spaces or objects; by branches of the evergreen sakaki tree, used as offerings or for purification; by shrine buildings with readily identifiable characteristics that set them apart from both Buddhist temples and the churches of established and new religions; and by the use of mirrors to signal the presence of the kami or deities.
From Shinto, A Short History, Inoue Nobutaka (editor) -- available on Net Library