On the afternoon of March 22, the 22nd lecture of the "Interdisciplinary Salon of Law" sponsored by the china institute for social-legal studies of Shanghai Jiao Tong University was successfully held in Room 206 on the fourth floor of the North Fourth Floor of Xuhui Campus of Shanghai Jiao Tong University. The theme of this salon is "The Problem of Unclaimed Land in Japan," and Narufumi Kadomatsu, a professor at the Graduate School of Law at Kobe University, will be the keynote speaker. Zheng Zhihua, associate researcher of the Center for Japanese Studies of Shanghai Jiao Tong University, presided over the salon, and Gu Zhuxuan, professor of Shanghai Jiao Tong University Kaiyuan Law School, and Zhu Qiaochu, assistant researcher of the Center for Japanese Studies of Shanghai Jiao Tong University, served as discussants. Lin Yan, professor of Kaiyuan Law School of Shanghai Jiao Tong University, Tan Jun, assistant researcher of the Institute of Chinese Law and Society of Shanghai Jiao Tong University, Jing Shiyuan, postdoctoral fellow of the Institute of Chinese Law and Society of Shanghai Jiao Tong University, and other teachers and students attended the salon.

Associate Researcher Zheng Zhihua first welcomed the visit of Professor Narufumi Kadomatsu. He introduced the academic background, main research areas, representative academic achievements, and the theme of this salon, as well as the guests attending the meeting. He pointed out that Professor Kadomatsu's research in the field of land law is highly forward-looking and of practical significance, and said that he is very much looking forward to Professor Kadomatsu's wonderful lecture. 

Professor Narufumi Kadomatsu first introduced the background of this lecture, that is, the phenomenon of "shrinking society" in Japan. Since 2010, Japan's population has declined across the board, leading to a shrinking economy and shrinking housing space. Professor Narufumi Kadomatsu then introduced the current situation of the problem of land with unknown owners in Japan and analyzed the causes of the problem. He pointed out that since 2010, the issue of land with unknown owners has become a hot topic in Japan. These unidentified landowners have hindered post-tsunami recovery efforts, with a range of impacts on the construction of public facilities, the reduction of forest area, and the management of abandoned farmland. With the decline in land values and the shattering of the "land myth", the demand for and interest in land in Japanese society has been hit. However, according to Japanese law, the change of property rights is based on the doctrine of expression of intent, and land registration is not a prerequisite for obtaining land ownership, but plays a role against third parties, and land registration is not a legal obligation in principle, and there are large transaction costs and registration costs at the time of inheritance, which indirectly leads to the problem of land with unknown owners. 

In this vein, Professor Narufumi Kadomatsu introduced the theory of anti-commons and the provisions of the Japanese Civil Code on joint ownership, and pointed out that it is necessary to think about measures to deal with practical problems and measures to prevent future problems, measures to address negative externalities, and measures aimed at optimal use, and to be rigorous in what constitutes "optimal use". At the same time, he said that "territory" has become a key factor in the issue of land with unknown owners. After analyzing the causes and consequences of the problem of land with unknown owners in Japan, Professor Narufumi Kadomatsu introduced Japan's countermeasures to this problem: through a series of legislation and amendments, measures to prevent the occurrence of land with unknown owners and measures to help promote the use of land with unknown owners have been formulated.

Finally, Professor Narufumi Kadomatsu concluded by pointing out that the normative legitimacy of the "Regional Welfare Progress Project" lies in the fact that it can benefit the local community, and that the actual result of the implementation of the "Regional Welfare Progress Project" is not only to obtain the right to use land where the owner is unknown, but also to revitalize the community in the process of implementation. In a society with a shrinking population, the role of geography is being re-examined, and we should consider the challenges facing the legal system.

In the discussion session, Professor Gu Zhuxuan discussed the adjustment of rules in Japan to the issue of land with unknown owners from the perspective of civil law. Promote the effective use of land and achieve a balance between the protection of ownership rights and the public interest through the establishment of a property management system, the improvement of the provisions on the disposition and division of adjacent relationships and common property, and the revision of the inheritance law. In particular, he pointed out that the major changes in the basic concept of Japan's property law deserve in-depth consideration.