Modern Japanese culture is flooded with yokai. They can be found in all forms of entertainment such as novels, manga and movies, and appear as promotional characters for various campaigns and corporations around the country. However, when the concept of yokai first emerged, these yokai were not related to any form of entertainment. Rather, they were seen to embody supernatural forces that threatened everyday life, forces which were to be feared and awed. This attitude towards yokai developed throughout the history of Japan, and changed fundamentally during the Edo period; no longer feared, they were used as subject matter for various media of entertainment. Such use of yokai in entertainment still prevails today.
Natsuhiko Kyogoku is a popular contemporary writer of yokai related stories, and at the same time a yokai researcher. The original concept of yokai and its later development in entertainment will be discussed in terms of Kyogoku's theory of yokai as mono and koto. His conceptualisation of yokai as mono, meaning tangible thing or being, and yokai as koto, meaning abstract thing or phenomenon, allows us to further our understanding about yokai in its original context, yokai in the academic field, and yokai in entertainment.