Recherche FFJ Research Statement Mari Uchiumi

Mari Uchiumi

Depopulation and sustainable maintenance of urban functions

Focusing on wide area cooperation and coordination in the Japanese and French urban planning systems


This research statement gives an overview of research I have conducted thus far, and describes my future research plans.

In the past, there was a time when cities expanded due to population concentration in urban areas against the backdrop of economic growth. However, today, there is a requirement for urban policies that sustain the previously formed urban functions. In Japan, in particular, due to a declining birthrate, depopulation, and an aging society, sustaining urban functions has become an issue and, as one measure to combat this, legislation is being revised to build compact cities. However, in order to realize these policies, it is said that cooperation between basic municipalities and wide area coordination (hereinafter, “wide area cooperation and coordination”) is essential. On the other hand, in France, depopulation and its elimination are not the issues. However, as for city planning legislation, from the perspective of sustainable maintenance of urban functions, systems aiming at wide-area cooperation and coordination have been strengthened. So, what is the relationship between population change in cities and wide area cooperation and coordination policies? In this research, from the viewpoint of “sustainable maintenance of urban functions”, after comparing and organizing urban policies centered on Japanese and French urban planning laws, by examining the urban policies of Japan, whose population is declining, and France, for which such is not the case, from the perspective of wide area cooperation and coordination we can clarify the relationship between depopulation and policies related to wide-area cooperation and coordination.

Decentralization of city planning

My research traverses the fields of urban engineering, administrative law and administrative science. Firstly, in 1998, based on the relationship between the Japanese national government and local governments, I analyzed ordinances related to city planning by local governments nationwide (orders voted on in municipal assemblies) to show city planning legislation role sharing, and determine role sharing between laws and ordinances (1998, doctoral dissertation: Doctor of Engineering). In Japan, the delegation of decentralization in 2000 led to the transfer of urban planning authority. So, applying the knowledge obtained from my doctoral dissertation, I considered and developed a method to deploy a local government-led urban planning system based on a combination of laws and ordinances, focusing on policy areas such as landscape and land use.

French and Japanese city planning

I stayed in France from 2009 to 2011 to compare Japanese and French urban planning. Specifically, I did a comparative study based on a case study conducted for the SCOT/PLU in France and the Japanese wide area plans and regional plans formulated by decisions of basic municipalities, and clarified the differences between the French and Japanese planning systems, land use systems, and local government decision-making. Regarding the planning system and land use system, I clarified differences such as consistency between wide area coordination plans and the principles of building restrictions.

Depopulation and urban shrinking

In Japan, depopulation and aging have been social issues since around 2010, and these have become apparent over land use as follows. First, there is a management problem that arises from the decline in community functions. Due to declines in community functions caused by depopulation, it is becoming difficult to maintain and manage regional spaces. For example, in Satoyama, located between natural forests and communities, it has become difficult to maintain ecosystems that exist on the premise of human activities. In such a situation, how to manage Satoyama is an issue. Secondly, there is the issue of maintaining infrastructure as urban sponging progresses. Currently, compact city policy is implemented; in reality however, the phenomenon is in progress in which overall city density is reduced (so-called "sponge") due to random vacant houses and small vacant lots occurring whereas the size of the city area has not been changed and city expansion is not controlled. As this kind of phenomenon progresses, municipalities still must manage and update infrastructure. This has put pressure on municipalities' administrative and financial resources, making it difficult for them to manage and update infrastructure on their own. Third is decline in transportation networks. During the high growth period, public transport networks were developed by the private sector along with the progress of motorization. However, at present, private companies that had been responsible for public transportation have withdrawn, making it no longer possible to secure local transportation. In this situation, securing means of transportation for residents in a sustainable manner has become an issue.

These challenges all represent a situation in which it is difficult to maintain urban functions sustainably. In other words, there are challenges that require coordination between basic municipalities, and those that cannot be dealt with by only one basic municipality, and, in response to this, the national government and local governments are considering measures to coordinate between cities and regions.

Future research plan

In future research plans, I will first compare Japanese and French urban planning related legislation with recent developments from the perspective of “sustainable maintenance of urban functions.” In considering this, I will add consideration of the relationship with demographics and, in particular, study urban policies between Japan and France, focusing on the relationship between urban functions and village functions, infrastructure maintenance and management, and transportation networks, which are particularly problematic in Japan's regions suffering depopulation. Next, from the viewpoint of “sustainable maintenance of urban functions”, I will clarify the actual situation of issues that require coordination between basic municipalities in Japan and France and issues that cannot be addressed by one basic municipality alone. In considering Japan, in September 2020 I plan to send a questionnaire to wide area and basic municipalities nationwide regarding this issue with the cooperation of the Ministry of Land, Infrastructure, Transport and Tourism. On the other hand, when considering France, I will select and examine cities that contrast with the trends that become apparent in the questionnaire survey in Japan. Then, using the presence or absence of depopulation as a variable, I will clarify the differences in policies and responses regarding wide area cooperation and coordination to sustainably maintain urban functions.


Mari Uchiumi, "Basic Structure of Land Use Regulations and Issues to be Considered," Quarterly Jurist No.15, pages 7-16, 2015

_____________, “Consistency Between Plans and Immediate Detailed Planning in the French Land Use System”

_____________, “Land Use Administration of Local Governments in the Age of Super Aging and Population Decline” Japan Municipal Research Center Edition, pages 230-346, 2017

Takashi Onishi Collection, “Urban Planning in the Age of Population Decline” Gakugei Shuppansha 2011

Jacquot, H. et Lebreton, J. (2001) « La refonte de la planification urbaine », Actualité juridique. Droit administratif, 57e année, n° 1.

Jacquot, H. et Priet, F. (2008) Droit de l’urbanisme, 6ème éd., Dalloz.

Ministère de logement de l’égalité des territoires (2014) Un urbanisme et un aménagement rénovés pour relancer la construction.