You may have heard the difference between civil law and common law explained like this: "Japan places importance on what is written in the law, whereas the United States places importance on judicial precedents." However, common law countries also have a vast amount of statutory law, and in Japan, Supreme Court precedents are extremely important in actual practice. It cannot be understood through a binary choice between statutes or precedents.

In terms of the basic framework of its modern law, Japan is classified under the civil law system. Layered on top of this are the post-war influences of American law and uniquely Japanese systems and practices.Why did that happen? Tracing back to the nation-building of the Meiji era reveals the shape of the laws we use today.

What is the difference between civil law and common law?

The "continent" referred to here mainly means the European continent. Represented by France and Germany, civil law is a legal tradition that has built its systems around systematic codes such as civil codes. Common law originates from the common law developed in England and is characterized by the formation of legal principles through court cases and the treatment of precedents.

This is a typical image for understanding. There are differences depending on each country, region, and legal field, and "not everything is the same in common law" either. In the explanation of common law, common law forms a pair with civil law It refers to civil law as a legal system, which must be distinguished from instances where it is used in the sense of "civil law versus criminal law."UK Ministry of Justice institutional guideAlso, as a system of England and Wales, it explains the relationship between case law and parliamentary statutes.

The reason Japan rushed to establish modern laws lay in treaty revision.

For the Meiji government, the development of laws was not limited to creating domestic rules; it was also tied to the challenge of revising treaties that granted consular jurisdiction and other rights to foreigners, thereby restoring the nation's international standing.

the codification of law and the establishment of constitutional government required by various nations as conditions for treaty revision progressed,National Archives commentaryBut that can also be confirmed. It was necessary to establish a system that would function as a modern state, not merely as an academic choice of "whose laws you prefer."

Given this background, it is understandable that developing institutions by referencing systematic codes was a strong option for Japan at the time. However, the reception of civil law cannot be fully explained solely by the single reason that codes were convenient.

I didn't choose German law from the beginning.

Japanese modern law was initially greatly influenced by French law. The government invited French jurists such as Boissonade to proceed with drafting codes. However, the old civil code, which was strongly influenced by French law, ultimately never went into effect after debates and postponements regarding its implementation.

The system of the current Civil Code, which was compiled afterward, adopts a structure that includes "General Provisions" referencing the first draft of the German Civil Code. Meanwhile, French law's influence through the former Civil Code also remained in its contents. Therefore, the understanding that "the Japanese Civil Code is a translation of the German Civil Code" is not accurate either.National Diet Library "Enactment of the Civil Code", summarizes the differences between this system and its contents.

Constitutions and judicial systems were not created through the exact same channels as the civil law either. If we view Japan as a whole as a copy of a single country's laws without looking at the reception process for each legal field, we will misread history.

Did postwar Japan change into a common law country?

After World War II, the Japanese legal system was heavily influenced by American law. Significant changes occurred, such as constitutional review by the courts, the system of judicial administration, and procedures emphasizing the litigation activities of the parties.

However, existing legal systems, including the Civil Code and the Commercial Code, were not entirely replaced by Anglo-American law.Explanation of the judicial system history of the courtalso view Japan's legal system as one that has developed its own unique legal culture while being influenced by both civil law and American law.

To the question "Is Japan a civil law country?", the answer is generally "yes." However, to the question "Are all Japanese laws built solely on civil law concepts?", the answer would be "no."

Saying "You don't need to read judicial precedents in Japan" is a major misconception.

Even with the same legal provision, it is sometimes impossible to tell from the text alone to what extent and to what factual circumstances it will apply. This is where judicial precedents become important. How to understand the words used in a legal provision and which facts are given greater weight—examining case law is also the process of learning those specific judgments.

Although civil law and common law differ in the institutional standing of precedents, it does not mean that precedents are meaningless in Japan. Conversely, even in common law, one cannot make a decision based solely on similar precedents without checking the relevant statutes.In both legal systems, it is necessary to read the applicable laws and regulations together with judicial precedents that embody their interpretation and application.

In taxation, you cannot reach a conclusion based solely on the classification of the legal system.

Article 84 of the Constitution of Japan requires that no new taxes shall be imposed or existing ones modified except by law or under such conditions as the law may prescribe. In tax matters, the starting point is to first confirm the basis for taxation and which requirements must be met in order for a tax to be levied. The basis isarticles of the Constitution of JapanExactly.

However, that does not mean we can draw a contrast by saying that common law countries determine taxes solely through case law. Understanding the classification of legal systems and examining the legal basis of individual tax systems are two different tasks.

For example, conclusions such as "Japan doesn't have a days-based standard for determining residency because it's a civil law country" or "foreign-source income isn't taxed because it's a common law country" cannot be drawn from this classification alone. The definition of a resident, the scope of taxable income, exceptions, and tax treaties must be checked for each country and system.

In international transactions, don't assume that the same words mean the same system.

When dealing with overseas contracts or company establishment, confirming the actual rights and obligations is more important than guessing which legal system the counterpart country belongs to. Even if the same English is used, it does not necessarily mean the terms have the same meaning and scope as under Japanese law. It is necessary to verify one by one the law applicable to the contract, the place to resolve disputes, and the legal treatment of the corporation and assets.

Common sense acquired in Japan cannot always be directly applied overseas. At the same time, it is dangerous to dismiss all differences simply by saying, "It's common law." The classification into civil law and common law is merely a starting point for understanding the background of legal systems. Beyond that, one must return to statutory provisions, case law, contracts, and specific facts to think things through. This mindset is equally important in international taxation.