Musical harmony is considered to be one of the most and technically difficult parts of music. It is y taught formally via abstract, domain-specific concepts, principles, rules and heuristics. By contrast, when harmony is represented using an existing interactive desktop tool, Harmony Space, a new, parsimonious, but equivalently expressive, unified level of description This focuses not on abstract concepts, but on concrete locations, objects, areas and trajectories. This paper presents a design study of a prototype version of Harmony Space driven by whole body navigation, and characterizes the new opportunities presented for the principled manipulation of chord sequences and bass lines. These include: deeper engagement and directness; rich physical cues for memory and reflection, embodied engagement with rhythmic time constraints; hands which are free for other simultaneous activities (such as playing a traditional instrument); and qualitatively new possibilities for collaborative use....