This paper examines how design tools can be realistically used by local governments in Japan. First, we provide an overview of policymaking in Japanese local governments with particular attention paid to citizen collaboration. Next, we visualize the annual policymaking and budgeting process of Nagahama City, a medium-sized local government, using publicly accessible information and interviews with city officials. From this, we identify the following three challenges to citizen collaboration in real policymaking: 1) the limited opportunity, time, and budget for citizen participation, 2) the difficulty in reflecting policy evaluations, and 3) the difficulty in prioritizing or discarding policies. Finally, this paper examines and evaluates the relationship between policymaking and citizen participation from the perspective of the range of citizen participation in policy generation. For future discussions about more effective applications of design tools in policymaking, we argue for the following: 1) discussions among citizens using visualizations during policy making, and 2) policymaking from a citizen-centered perspective by enhancing the capacities of civil servants.