This essay examines Kenzō Tange's visionary urban scheme, A Plan for Tokyo, 1960: Toward a Structural Reorganization (1961), in terms of its mobility rather than its much-discussed monumentality. The existing studies of this plan was too im-mersed in its unprecedented megalomaniac scale to pay sufficient attention to the fact that it was a complex design for urban mobility. While the issues of scale and speed might seem to be separate, in fact they are inextricably interconnected since the increasing speed and mobility brought about by new technology would make the existing human scale ob-solete and required the new scale of the machine. In this essay, I would like to revisit Tange's plan for Tokyo Bay as a highly nuanced plan for urban mobility. First, this essay defines A Plan for Tokyo, 1960 as a model city for an automobile society against the backdrop of Japan's rapid motorisation. Tange's unrealised urban scheme was driven by the architect's firm belief in mobility as a fundamental factor influencing the development of postwar Japanese economy and his strong ambition to provide a proper urban infrastructure for the efficient circulation of traffic. The essay then traces how Tange's interest in the visible network of transportation evolved into his preoccupation with the invisible networks of information flow by focusing on his Tokaido Megalopolis (1964), a colossal city that was organically connected by the linkup of physi-cal, social, and information networks. Although Tange's ambitious design was left only on paper and had little impact on the actual development of Tokyo, its historical im-plications lie in its radical configuration of a new concept of architecture and city not as hardware but as software in preparation for the nascent information society.