Word War second left Japan crippled,affecting its economy, governance, demography, settlements,social well-being, and others. However, Japan used this asan opportunity to restructure itself to become aprogressive, balanced, and well-rounded country. Spatial orterritorial development is critical to national economictransformation. It is supported by and simultaneouslyimpacts economic, social, demographic, institutional, andadministrative reforms. Based on lessons from a wide rangeof international experiences, three key agendas arise as keyto effective territorial development: (a) concentration:create generic capital for an uncertain future economy, (b)connectivity: connect markets nationally andinternationally, and (c) convergence: ensure decent livingstandards everywhere. Japan has followed a virtuous path ofquite intense concentration, with early investment in strongconnectivity between places, and in high living standardsand human capital investments everywhere. At present, Japanis entering an era of substantial decline and aging of thepopulation, which requires reexamining of all the plans andpolicies for reconstructing the society. Looking forward,Japan’s declining, and aging population, in fact raises theimportance of allowing concentration in a few dynamic,high-amenity, places that can be serviced efficiently,rather than trying to spread a dwindling population acrossthe country.