Unlike early Buddhism, which seems on the whole unconcerned with the question of evil, much of medieval Japanese Buddhism has to do with exorcizing demons. In other words, premodern Japanese Buddhism was above all a demonology.
But who were these demons, and why have they been neglected for so long by Buddhist scholarship? The Western distinction between gods and demons, with its moral connotations, is misleading. Most medieval deities were "demonic (in the Greek sense of daimon) rather than "demoniac" (in the Christian sense).
True, Buddhism did contribute to demonize these daemons, while attempting to transform most powerful among them into allies. Yet one could argue that there are no demons, only acts of demonization. Through such acts, Buddhism was perhaps yielding to its own inner demons.
A case in point is that of Vināyaka or Shōten, the Buddhist version of the Indian god Ganesa, who needed to be propitiated at the beginning of every ritual.This Janus-faced demon of obstacles, came to be identified with Kōjin (the "wild god") — a paradigmatic deity of the "third kind" (neither buddha nor kami, neither god or demon, or both).
The case of Kōjin, in turn, reveals how, while Buddhism populated the outside world with demons, it also interiorized them — finding evil (yet at the same time deliverance) at the innermost heart of human beings.
Demons of obstacles once stood in the way of Awakening and had to be ritually propitiated. Likewise, they stand today in the way of our scholarly understanding of premodern Japanese religion, and have to be paid their dues. The present paper is but a small step in that direction.