In Puccini’s opera, Madam Butterfly, the Coro a bocca chiusa (Humming Chorus) is performed by an off-stage chorus which hums a wordless, melancholy tune whilst Butterfly, her made Suzuki, and her child begin the long wait for her husband, Pinkerton, to return after many years away. As night falls, Suzuki and the child are soon asleep, but Butterfly keeps her vigil. This arrangement features four flugel horns, each of which plays into the bell of a tuba whilst the tuba player moves their valves – creating a unique humming sound. Puccini actually wrote five versions of the opera. After a disastrous premiere in early 1904, Puccini withdrew the opera and substantially rewrote it creating a very successful second version. However, he continued to tinker with the orchestration, not being satisfied until the fifth and final version dating from 1907.