In 2017, I developed a computer application entitled "Sanka Play," which enables audience members to participate in improvisational performances by making real-time requests to performers. In most cases of free improvisation, the audience atmosphere influences performers. While audience--performer interaction is generally nonverbal, Sanka Play allows timeous written verbal interaction. This study determines the positive pedagogical possibilities of using Sanka Play for elementary school music classes. It was expected that using Sanka Play for group improvisation activities in music classes would encourage various styles of expression among the students. Sanka Play was used in two fifth grade (age 10-11 years) music classes in a Japanese elementary school. Observation of class videos revealed that the application induced students to use various modes of expression, such as music, dance, theatrical acting, and even karate. Furthermore, various requests the students made not only improved performance in general but also helped highlight particular strengths in each student's performing ability. The observations reveal Sanka Play's pedagogical usefulness and several factors that teachers should consider when using the application. This research illustrates the possibilities of employing a new teaching approach to encourage students to creatively use their inherent expressive abilities.