Unless you know Japanese traditional music well, you might think every piece sounds just about the same. This is especially so when the performers, dressed in traditional clothes, play instruments like the shamisen and shakuhachi. Actually, though, experts classify Japanese traditional music into 50 or even 80 different genres.

Only a very few genres are purely instrumental—the vast majority are songs with instrumental accompaniment. All vocal music has only one melodic line, even when there is more than one singer. Most songs are accompanied by only one type of instrument.

Traditional Japanese music is classified according to the articulation of the singer, the type of instrument, and the timbre (tone color) of the voice and the instrument. For example, gidayu-bushi bunraku narratives, tokiwazu-bushi songs from Kabuki and naga-uta lyrical songs are all sung to the accompaniment of the shamisen, but we place them in different genres when the timbres of the voice or instrument are different. In other words, each genre has its own vocal and instrumental timbre.

Even so, there is very little difference in timbre between one genre and the next. This is true for both voice and instruments. In many cases, only an expert can tell what genre is being performed. Nevertheless, musicians consider these slight differences to be important, and make sure that one timbre does not mix or merge with another. This is one reason why the genres have been classified in such detail. And this preoccupation with slight differences in timbre is strongly reflected in the shape of the instruments and the style of the performance.

Traditional Japanese musical instruments, like the instruments of other countries, can be grouped broadly into three types: percussion, wind and string.

One small percussion instrument is the kotsuzumi drum. Most Japanese drums are beaten with two sticks, but the kotsuzumi is struck by the fingers. To maintain exactly the right timbre, drummers listen carefully to the sound and adjust the tension of the laces that fasten the hide to the drum barrels. They sometimes even have to blow on the hide to keep it at the humidity they need for a specific timbre.

One wind instrument is the shino-bue bamboo flute. When accompanying a singer in a Kabuki play, the flutist will choose one of 12 shino-bue to achieve the desired register (musical range). In local festivals, 2 or 3 shino-bue are used for the same reason. These examples show how hard musicians strive to produce the timbre demanded by the music.