Depending upon the play, a combination of varied musical ensembles may participate in a performance, and each one fulfils a separate and distinct purpose. These are the debayashi, hayashi, geza and chobo.
Debayashi
The debayashi is the principal ensemble of kabuki and has as its basis the instruments of the Noh drama's hayashi ensemble: ko-tsuzumi, o-tsuzumi, taiko and nohkan (noh flute). To this are added shamisen, singers, additional tsuzumi ("ko"and "o") and a takebue. There can be as many as 10 shamisen players, 8 singers and 6 tsuzumi players. Generally there is only one performer for the taiko, and a separate player doubles on both the nohkan and takebue. The performers sit at the rear of the stage with the singers and shamisen players on a raised platform behind the other players at stage level (shitakata).
The ensemble can play tutti, or in smaller combinations, with the responsibility for solo performance passing to specific players. The principal shamisen player is responsible for coordinating the music with the dancers.
Hayashi
The hayashi ensemble of taiko, ko-tsuzumi, o-tsuzumi and nohkan, was taken from the Noh theatre. It forms the basis of the debayashi and is included within the geza.
Geza
Used to augment the action at many points throughout a kabuki play, the geza ensemble is hidden from view in a small room behind a grille stage right. It is similar to a sound effects booth although its contribution is more sophisticated than a mere selection of crude "noises off".
The music is highly organized and integrated with the music of the debayashi ensemble. It forms an aural kaleidoscopic experience constructed from a range of recognized melodies and interludes in combination with a large variety of rhythmic and melodic patterns. Melodies that make elliptical reference to related subject matter outside of the play, and the evocative use of distinctive instruments creates a sound world that supports the action on stage. The geza contains a hayashi ensemble, shamisen, a singer, and a large variety of gongs, drums, noisemakers and bird calls. In particular the o-daiko is used to great effect. More modern plays require the addition of shakuhachi, kokyuu and koto.
Frequently, the audience will associate music from the geza with particular moods or scenes. For example there are drum patterns played be the o-daiko which can suggest falling snow, and there is a particular pattern (hyuudorodoro) played by a combination of o-daiko and nohkan which is used to mark the appearance of ghosts (more). Sometimes a snatch of a folk tune played by the takebue will establish the connection with a matsuri bayashi scene. Not all of the resources of the geza are called upon during a performance!
Chobo
The ensemble that performs exclusively narrative (joururi) music, in particular the style known as gidayu bushi, became popularly known as the chobo. This combination of singer and shamisen player sits stage left on a raised platform (yamadai) and performs a style of music that was introduced directly into the kabuki tradition from the puppet theatre by the famous puppet and kabuki playright Chikamatsu Monzaemon.
