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Victory of Customary Law in Japan: Then Who Is Written Law For?

In one of the classes I took at Kyushu University in Japan, we ended up discussing one provision in the Japanese Civil Code that surprised me by its language. In fact, for someone familiar with Japanese culture and the societal structure, that provision can seem ordinary. But for someone coming from the jurisdictions where almost every relationship is regulated by legal norms, that provision is just extraordinary. When I first heard about the provision, I told the professor that this provision is absolutely far from the understanding of the mutual relationship between statutes and customary law in civil-law countries, including Azerbaijan. However, it seemed the provision was quite normal for the Japanese professor since he did not find it impressive or outstanding.

In this blog post, I would like to write about Article 92 of the Japanese Civil Code and compare it with similar provisions of the Civil Code of the Republic of Azerbaijan. Further, I would like to reveal how this provision that was written by the influence of the civil-law countries, particularly, of Germany and France, indeed, reflects the Japanese culture. I wish you will enjoy reading it!


As a lawyer, let us start with the provision itself:

"In cases there is any custom which is inconsistent with a provision in any law or regulation not related to public policy, if it is found that any party to a juristic act has the intention to abide by such custom, such custom shall prevail."

The double conditional in the text of the provision may complicate. Put simply; if there is a legal norm and a customary law applicable to the relationship between parties, the customary law prevails over the legal norm and applies to the relationship, if the parties intended to be bound by the customary law. However, if the said legal norm is related to the public policy, then the legal norm applies, not the customary law. Interestingly, the Japanese Civil Code declares the prevalence of the customary law over the legal norm, and this prevalence is beyond the case of the interpretation of law appearing in the direct implementation.

Traditional Japanese Wedding

The Civil Code of the Republic of Azerbaijan regulates the interaction between customary laws and legal norms as well but in a different way. The following comparison will illustrate the impact of Article 92 of the Japanese Civil Code much clearer.

According to Article 10(2) of the Civil Code of the Republic of Azerbaijan, "business customs which are contrary to the law or contract shall not be applied." In addition, under Article 11(1) of the same Code, "where civil legal relationships are not specifically regulated by civil law or by agreement of the parties and no applicable business custom exists, the norms of civil law regulating similar relationships shall apply, provided, however, that it does not contradict the essence of such relationships." It can be inferred that no customary law contradicting the statutes can apply in Azerbaijan. Whereas, the Japanese Civil Code clearly permits this. Moreover, when filling in lacunae in Azerbaijan, the business customs can only be applied if there is not any applicable legal norm or contract. In other words, the customary laws in Azerbaijan, be it related to public policy or not, always come after statutes and contracts. However, in Japan, this sequence is only relevant for the relationships related to public policy.

Here comes an interesting question; concerning the understanding in Article 92 of the Japanese Civil Code, statutes are only for public-policy-related cases, while customary laws for the rest? To understand this, we need to briefly overview the legal history of Japan until and in the 19th century.

According to Van Der Berg (2018), the preservation of the power of customary laws in the Japanese Civil Code is related to the motive of the codification in Japan started during the Meiji era (1868-1912). Unlike the European countries, the purpose of Japan in the codification was not in the first place contributing to establishing legal unity at the national level, but showing to the Western countries of that time, which was trying to capture Japan through various means, especially, disgraceful treaties that Japan has a uniform civilized legal system as well. Therefore, even though Japan chose the codification path, Japan brought the rules like Article 92 in order not to abandon customary laws as a whole that had played a pivotal role in dispute settlement in the Japanese society by that time.

Indeed, Article 92 helps many customary laws to play an important role in social relationships, because it is quite broadly interpreted and implemented in practice. Concerning the broad interpretation in practice, for example, if there is applicable customary law in one case, the Japanese judges are inclined to apply the customary law assuming the intention of the parties, even though the parties have not openly agreed thereon. This provision and its reflection in practice clearly include the customary laws in the sources of the Japanese civil law. Even if customary laws contradict civil laws, the Japanese judge is authorized by law to apply the customary law to the case. It is not possible at all to envisage the same scenario in Azerbaijan or other civil-law countries that have adopted the "ruling" of solidly written laws. Undoubtedly, we must emphasize the efforts of the judges and their interest in preferring the customary laws to the written statutory laws, in addition to the door opened by the Japanese Civil Code. Because it would hardly be possible to achieve the current impact of the provision with the gavel of the judges who would choose to be loyal to the written-law philosophy of the civil-law system and forget about the importance of the traditional Japanese legal system and the role of customary laws in the society.

Illustration: Meiji Reforms in Japan

The system preserved by the Japanese Civil Code until today corresponds to the structure of Japanese society and traditions. In traditional Japan, particularly before the Meiji era, even though the hard law was existing, they did not replace customary laws but complemented them. The customary laws, on the other hand, differed in various prefectures of Japan. However, this diversity again reflected the needs of the society because the subject of the law was considered to be families and communities, rather than individuals like in the Western countries. No doubt, the customary laws were successful in fitting the needs and disputes of the families and communities on the management of communal lands in different prefectures.

Emperor Meiji

Admittedly, it is open to discussion to what extent customary laws are preferred to the statutes, and most importantly, whether such a need is often created in the Japanese society within trade relations. Nonetheless, as I live in Japan, I somehow feel how the rules of hard law are secondary given the fact that social norms can function quite well in Japan to regulate social relationships.

In my opinion, it is difficult to deny the importance of written statutes today. But unless it is contrary to the public policy, unwritten laws - customary rules must be allowed to replace statutory rules as well. Partially because of the technology, human relationships are getting so complicated that soon the hard law may give its place to soft, flexible regulatory tools, while the role of the statutory law may evolve into more secondary, general, and less flexible rules that can intervene in the application of customary rules when needed through general principles. However, first, the societies must be educated more and more to get prepared for this change.


  1. Azərbaycan Respublikasının Mülki Məcəlləsi. Bakı, 2000.

  2. Yaponiya Mülki Məcəlləsi. 78 Nömrəli Düzəliş Aktı. 2006.

  3. Peter Van Der Berg. (2018). Politics of Codification in Meiji Japan (1868-1912): Comparative Perspective of Position of Customary Law in Japanese Civil Code. 65 Osaka University Law Review 69.


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