The scope of my research is the Civil Law, but that is not all that I study. I look at its relationship with the Constitution and administrative laws and compare it with other academic fields—such as political studies, economics, management studies, sociology, and public administration—to think about ways of harmonizing these different perspectives so that society can run smoothly.

A representative example is the case of Isahaya Bay’s reclamation/floodgates. A large dike was built in 1997 across a part of this bay, which spans the prefectures of Nagasaki and Saga. The purpose was to control floods and create farmland, but the dike changed Isahaya Bay’s tidal streams and caused enormous impact on the tidal flats’ ecosystems.

The damage to the fishing industry was severe, and the industry’s stakeholders immediately advocated the opening of the dike’s floodgates to allow fish to return, filing a lawsuit. When the Fukuoka High Court passed a judgement in 2010 recognizing the opening of the floodgates, agricultural stakeholders filed for an injunction on the opening of the floodgates, stating that there will be salt damage on farmlands. In 2017, the Nagasaki District Court passed a judgement recognizing this injunction.

Is the case of the opening and closing of the Isahaya Bay floodgates a contradiction?

In other words, the judgement on one side states that the floodgates should be opened, while that on the other side says they must not. Although the two judgements are not contradictory from a legal theory perspective, they are clearly contradictory when seen from a social perspective. When confronting such issues, besides a legal standpoint, knowledge from other academic fields will become extremely important.

For example, were there issues when forming a consensus beforehand? Being a large-scale public works project, there should have been a consensus with fishing industry stakeholders beforehand. Political studies and public administration knowledge will be necessary for studying from this perspective. Alternatively, to confirm the state of damage caused by the dike at Isahaya Bay, we will probably need information from sociology and natural sciences related to the environment.

When bringing together all kinds of knowledge, it is the Civil Law that serves as the foundation. We consider whether there are any contradictions by comparing with past dispute resolution cases and legal systems, and harmonize by incorporating knowledge from legal studies and various other academic fields. In a way, I feel that legal scholars play a role similar to the conductor of an orchestra.

Laws exist to accept and harmonize different understandings of what is right

The lawsuit for Isahaya Bay’s reclamation/floodgates reached a judgement of the Supreme Court  in 2024 to keep the floodgates closed. However, the parties remain in conflict, and the region continues to face the issue of how to regain its fishing volume. I intend to continue my research and think about the approaches that can be taken in other academic fields to study a way for resolving this conflict.

Every human being has their own narrative with its own sense of what is right. Laws are often said to be cold-hearted. That is because resolving issues according to the law inevitably results in certain portions being left out. Even so, conflicts cannot be resolved by accommodating everyone’s sense of justice. Knowledge from non-legal fields is essential for us to know what to keep and what to leave out.

Even without achieving a perfect 100-point answer, we should be able to feel happy with 60 or 70 points. I think laws exist so that, besides our own version of what’s right, we can live life while accepting and harmonizing others’ perspectives on rightness.

The book I recommend

“Yoru no Semi”(Night Cicadas)
by Kaoru Kitamura, Tokyo Sogensha

I read this book when I was a graduate student and was drawn to the fun of unravelling the small mysteries in everyday life. Even seemingly mundane issues have important significance for the parties involved. It makes me realize that the role of legal studies is to confront such issues.

Interviewed: June 2025