The Japanese central government developed in 2010 a five year experimental programme of “smart” demonstrators called “smart communities”. The irruption of “smart” in Japanese urban development is, however, not a sudden revolution, but has been produced by a slow transformation of relations of power within urban growth machines around the stakeholders involved in urban planning. This paper formulates the hypothesis that this radical shift of power in social, economic and political relations is the result of an upstream shift in the control of urban information systems by actors of the digital economy. Using a political economy approach, the paper begins with a description of the specificities of Japanese “smart communities” in terms of technology, urban planning, and politics. It then interrogates the transformation of actor power relations, before concluding with a critical analysis of the new models of urban society that actors of the “smart” economy are creating in Japan.