In this paper, the authors introduce an interactive device, “POWDER BOX”for use by novices in musical sessions. “POWDER BOX” is equipped withsensor-based replaceable interfaces, which enable participants to discover andselect their favorite playing styles of musical instruments during a musicalsession. In addition, it has a wireless communication function thatsynchronizes musical scale and BPM between multiple devices. To date, various kinds of “inventive” electronic musical instruments havebeen created in the field of Computer Music field. The authors are interestedin formations of musical sessions, aiming for a balance between simpleinteraction and musical expression. This study focuses on the development ofperformance playing styles.Musicians occasionally change their playing styles (e.g., guitar pluckingstyle) during a musical session. Generally, it is difficult for nonmusicians toachieve this kind of smooth changing depends on levels of their skillacquisition. However, it is essentially important for enjoying musical sessionswhether people could acquire these skills. Here, the authors attempted to develop the device that supports nonmusicians toconquer this point using replaceable interfaces. The authors expected thatchanging interfaces would bring similar effect as changing playing style by theskillful player. This research aims to establish an environment in whichnonmusicians and musicians share their individual musical ideas easily. Here,the interaction design and configuration of the “POWDER BOX” is presented.