A kind of vocal intonation to decorate the melody. Its use is optional; the actors will decide whether to intone the lyrics or speak with no tune, as well as how they will chant. Iro sometimes describes a section of chanting with unique intonation, falling into an intermediate category between fushi (with a tune) and kotoba (without a tune). There are various ways of chanting, depending on the play and the role, and actors use them in ways that will be effective for the scene. It is also called suteru by some schools.