It seems fair to say that Japanese popular music has reached its present state of prosperity through the reception, absorption, and further development of music imported from abroad. For this reason, in order to study Japanese popular music it is fi rst of all helpful to keep in mind how such imported music, in particular popular music, has been diff used widely around the world. 1

By focusing on the media and forms of mediation that have strongly infl uenced the diff usion of music, we can think of the following historical periods (Tōya 2008: 117-18):

1. Th e period dominated by staff notation. 2. Th e period dominated by U.S. military bases. 3. Th e period dominated by mass media. 4. Th e period dominated by multimedia.