Much has been written in recent years about the importance of civil society in ensuring positive outcomes for people in the development of urban space. For citizens to be involved in a meaningful way in urban planning requires the existence of a political space - created by organizations, community groups, social movements, voluntary societies - that is outside the control of government. The development of the international planning movement during the first decades of the twentieth century is an excellent example of the importance of such non-state actors in developing a competing vision of the urban future - and a set of prescriptions on how to achieve it - that was both at variance with the priorities then being pursued by national governments and which explicitly put forward the public welfare and urban quality of life as the highest values. Japanese planners, architects and municipal administrators were avid followers of international planning ideas during this period, attending many of the international congresses and attempting to adopt many of the current ideas for use in Japan. While the early years of the Taisho period saw a proliferation of social organizations in Japan and the development of an embryonic civil society, however, by the early 1930s an expansion of the role of the state, and particularly of the activities of the Home Ministry had resulted in its effective absorption of most of the political space available for independent agendas in city planning. After this period, planning thought and practice was firmly central government territory. This paper examines the role of this important watershed in the development of Japanese city planning and urban management practice.