How are onstage debayashi musicians different from offstage geza musicians in Kabuki?

In Kabuki theatre, the primary distinction between debayashi (onstage music) and geza (offstage music) lies in their visibility and functional roles within the performance.

• Debayashi (Onstage Music): These musicians are visible to the audience, typically positioned on a riser at the back of the stage or placed according to the specific scenery requirements of the play. They often perform nagauta and hayashi music, which is closely integrated with the dance and melodic narrative of the performance.1
• Geza (Offstage Music): Also known as kagebayashi (shadow hayashi), these musicians perform from a small, hidden room on stage right, viewing the drama through a bamboo curtain. Their role is to provide atmospheric support, sound effects, and mood-setting music—such as the sound of waves or specific songs—to reinforce stage action, particularly when onstage musicians are not present.2

While debayashi focuses on the primary melodic and rhythmic accompaniment of the actors and dancers, geza serves as a vital, often naturalistic, sonic backdrop that helps define the setting and emotional tone of the scene.21