Previous research has established the relevance of digital tools in participatory processes of urban planning and design. Nevertheless, the debate about the role that these information and communication technologies (ICTs) play within the participatory process, with respect to established practices and methods, and in relation to community building and public space, is still ongoing. The purpose of this paper is to present the design and development of a participation tool that attempts to combine physical and digital forms of interaction with public space and the community in the context of an essential initiation practice in Japanese participatory planning, called machi-aruki (town walking or walking tours). This tool, named the Location Hunting Game (LHG), employs location data as a medium to connect digital and physical realms, and was developed in a broader theory-driven research endeavor that explores the potential of location data in collective urban planning and governance. This article presents the concepts and objectives of LHG, the game design, the interface design, the prototyping process, the technical specifications, and a summary of the preliminary results of a trial study. The results provide insights into the potentials and limitations of the current prototype and development challenges, and conclude with future research steps.