Abstract. Music ensemble players discuss musical expression of the piece of music they perform, and determine how to play each note in a score such as the length and the dynamics of tone or phrases in every detail of the music. This paper introduces our system that supports the discussion about musical expressions on the web. Our system enables the users to write comments, draw symbols, and link videos on the score where they are discussing about. We also conducted an informal usability study to evaluate the usefulness of the system.