It would be perfectly possible for a foreigner to live in Heisei Japan for quite some time without ever becoming aware that Japan has an original music of its own, so low is the profile of "hogaku" (Japanese-style music) today. Foreigners who do come into listening range of hogaku sometimes react very strongly for or against it. Hogaku is Different with a capital D; it is the Other made music.
Anyone who studies Japanese history or literature, however, must be aware of how large Japanese music's impact was on events in every age, and this impels us to deal with it directly, to try to understand what the music meant to the listener, and what it can tell us about Japan.
It is hard to get a grip on. The instruments and performance styles are radically different from Western ones; the newcomer may be dismayed by a welter of Japanese terminology. William Malm's great "Japanese Music and Musical Instruments" explains it all in detail, though after 44 years it is becoming a little outdated.