Can Constitutional Rights Be Enforced Between Private Parties in Japan? The Doctrine of "Private Sphere Applicability"

The Constitution of Japan, like most modern constitutions, primarily serves to define and limit the power of the state vis-à-vis individuals, guaranteeing fundamental human rights against governmental infringement. This is often referred to as the "vertical effect" of constitutional rights. However, a significant and complex question in Japanese constitutional law is whether, and to what extent, these constitutional rights also govern relationships and disputes between private parties—individuals, corporations, and other non-state actors. This concept is known as the "private sphere applicability" or "horizontal effect" of constitutional rights (私人間効力 - shijinkan kōryoku). Understanding this doctrine is crucial as it can profoundly shape legal obligations and liabilities in various private interactions, including those in the business and employment spheres.

The Traditional Paradigm: Constitutional Rights as Vertical Constraints

The orthodox understanding is that constitutional rights are primarily designed to protect individuals from abuses of power by the state and its organs. The Bill of Rights (Chapter III of the Constitution) is largely framed as a set of limitations on governmental authority. This vertical application is the most direct and uncontroversial way constitutional rights operate. However, modern societies are characterized by powerful private entities and complex interpersonal relationships where significant infringements on individual dignity and freedom can occur, even without direct state involvement. This reality has led to the development of theories exploring the extension of constitutional values into the private sphere.

Theories on Horizontal Application in Japan

Japanese constitutional law has grappled with how, if at all, to apply constitutional norms to private relationships. Three main theoretical approaches have emerged:

1. No Application Theory (無適用説 - mutekiyōsetsu or 非適用説 - hitekikyōsetsu):
   This theory posits that constitutional human rights provisions do not, as a rule, apply either directly or indirectly to relationships between private parties. Private law (such as the Civil Code and commercial law) is considered the exclusive domain for regulating these interactions. Proponents argue that constitutional rights are fundamentally about limiting state power, and extending them to private actors would unduly restrict private autonomy and freedom of contract.
   However, even within this school of thought, there's often an acknowledgment that "supra-positive law human rights" (超実定法的な人権 - chōjitteihōteki na jinken), akin to natural rights, or fundamental societal values reflected in the Constitution, might still influence the interpretation of general clauses within private law, such as Article 90 of the Civil Code concerning "public order and morals" (kōjo ryōzoku). Notably, some prominent scholars, like Professor Kazuyuki Takahashi, have argued that the Supreme Court's landmark Mitsubishi Jushi case, often cited as an example of indirect application, should actually be understood through the lens of the no-application theory, with private law principles being the primary drivers of the decision.
2. Direct Application Theory (直接適用説 - chokusetsu tekiyōsetsu):
   A less common view in Japan is that constitutional rights provisions directly bind private parties in the same way they bind the state. This would mean, for example, that a private employer would be directly subject to constitutional prohibitions against discrimination. While appealing for its straightforward protection of rights, this theory faces challenges in reconciling with the principle of private autonomy and the detailed, often differing, schemes of private law.
3. Indirect Application Theory (間接適用説 - kansetsu tekiyōsetsu):
   This is the prevailing and most influential theory in both academic discourse and judicial practice in Japan. It holds that constitutional rights do not directly apply to private relationships, but their values and principles indirectly influence these relationships through the interpretation and application of existing private law statutes, particularly their general clauses or "open-textured" provisions.
   Key private law provisions often cited as conduits for this indirect effect include:Under this theory, when a court interprets what constitutes "public order and morals" or assesses the legality of an action under tort law, it should do so in a manner that is consistent with the fundamental values enshrined in the Constitution.
   • Article 1, Paragraph 3 of the Civil Code (prohibition of abuse of rights).
   • Article 90 of the Civil Code (acts contrary to public order and morals are void).
   • Article 709 of the Civil Code (general tort liability).

The Landmark Mitsubishi Jushi Employment Discrimination Case

The leading Supreme Court precedent often associated with the indirect application theory is the Mitsubishi Jushi Employment Discrimination Case (Supreme Court, Grand Bench, December 12, 1973 (Shōwa 48)).
In this case, a company provisionally hired an individual but later refused to finalize his employment after discovering his past involvement in radical student activism during his university years, a fact he had not disclosed during the hiring process. The individual sued, claiming that the refusal based on his political thoughts and beliefs violated his freedom of thought and conscience (Constitution Article 19) and the prohibition against discrimination based on creed (Constitution Article 14).

The Supreme Court, while ultimately ruling in favor of the company, laid down an important principle. It acknowledged a company's freedom of contract, including the freedom to hire and to investigate the suitability of prospective employees. However, it also stated that this freedom is not absolute. If the exercise of such private autonomy—for example, a decision by an employer that significantly disadvantages an employee based on their thoughts, beliefs, or creed—"exceeds socially permissible limits" (社会的に許容される限度を超える - shakaiteki ni kyoyō sareru gendo o koeru), then it may be deemed contrary to public order and morals (Civil Code Article 90) and thus null and void. The Court explicitly mentioned that fundamental freedoms and equality, as basic principles of the legal order, should be respected as much as possible even in private relationships.

Despite this articulation of principle, the Court found that the company's actions in this specific instance did not exceed such limits. It reasoned that companies have a legitimate interest in assessing the character and suitability of employees for maintaining their business operations and that individuals, when seeking employment, have a certain obligation of good faith, which could include disclosing information relevant to their suitability. The Court also suggested that the protection afforded to freedom of thought and belief against state action does not automatically translate with the same force into the private employment relationship.

The Mitsubishi Jushi judgment, therefore, affirmed the principle of indirect applicability—that constitutional values can permeate private law to invalidate private acts that are grossly offensive to those values—while simultaneously demonstrating a high threshold for finding such an infringement in the context of corporate hiring discretion.

Invoking the Doctrine: Explicit and Implicit Application

The manner in which indirect application is addressed by courts can vary:

• Explicit Articulation: The full doctrine of indirect application is often explicitly discussed when a plaintiff makes a direct constitutional claim against a private defendant, and the court needs to clarify the theoretical basis for considering constitutional norms in a private dispute. This is common when an asserted constitutional value (e.g., non-discrimination, freedom of conscience) appears to conflict with an established private law principle like freedom of contract.
• Implicit Application or Direct Balancing: In certain types of disputes, courts may engage in a balancing of constitutionally-inflected interests without an elaborate discussion of indirect application theory. This is often seen in:
  • Defamation vs. Freedom of Expression: Courts balance the individual's right to reputation (a private law interest with constitutional underpinnings in Article 13's respect for individuals) against the defendant's freedom of expression (Article 21). The legal framework for defamation itself (e.g., defenses of truth and public interest) is often seen as already incorporating this constitutional balance.
  • Internal Disputes within Organizations: When an organization (e.g., a labor union, professional association) takes action against a member that allegedly infringes the member's rights, courts often focus on whether the organization's action was within its legitimate purposes and followed fair procedures. While constitutional rights of the member (e.g., freedom of speech, conscience) are considered, the analysis may be framed more in terms of the limits of the organization's internal autonomy and the member's obligations, rather than a formal "indirect application" of the Constitution to the organization's rules. The Otaru Public Bath Discrimination Case (Sapporo District Court, November 11, 2002 (Heisei 14)), where a municipal bathhouse operated by a private entity refused entry to foreign nationals, saw the court consider Article 14's prohibition of racial discrimination as a standard for interpreting the illegality of the discriminatory act under private (tort) law.

The State's Duty to Protect Rights (Kihonken Hogo Gimuron)

A significant theoretical development that supports the idea of constitutional values reaching the private sphere is the "theory of the state's duty to protect fundamental rights" (基本権保護義務論 - kihonken hogo gimuron). Advanced by scholars like Professor Tsuyoshi Koyama, this theory posits that the state has not only a negative duty to refrain from violating human rights but also a positive duty to take appropriate measures to protect fundamental rights from infringement by third parties (i.e., other private actors). Indirect application of constitutional norms through the interpretation and enforcement of private law is seen as one of the primary ways the state can fulfill this protective duty. This provides a stronger theoretical grounding for judicial intervention in private disputes where fundamental rights are at stake.

The Balancing Act: Weighing Competing Private Interests

When constitutional values are deemed relevant in a private dispute through indirect application, the core judicial task becomes one of balancing the competing rights and interests of the private parties involved. This is often a highly context-specific exercise.

The Mitsubishi Jushi decision, for instance, involved balancing the company's freedom of contract and its interest in assessing employee suitability against the individual's freedom of thought and conscience and interest in non-discriminatory hiring. The Supreme Court appeared to give considerable weight to corporate autonomy in the employment context, suggesting that the standards governing state action regarding freedom of conscience cannot be identically applied to private employers.

This raises a critical question: should constitutional values, such as non-discrimination or freedom of conscience, carry the same weight and demand the same level of protection in the private sphere as they do against the state? The Mitsubishi Jushi Court indicated not necessarily, highlighting the importance of private autonomy. However, legal scholarship continues to debate this, especially in situations involving significant power imbalances (e.g., employer-employee, large corporation-consumer) or where core human dignity is profoundly affected. There is an argument that where fundamental values are severely compromised by private action, the "socially permissible limits" of private autonomy should be interpreted more stringently in light of constitutional principles.

Critiques and Future Directions

The outcome in Mitsubishi Jushi and similar cases, where private autonomy has often prevailed over individual constitutional claims, has faced criticism. Some argue that it gives insufficient protection to fundamental rights in the powerful private sector, particularly in employment, where individuals may be vulnerable.

There is ongoing discussion about whether the threshold for "exceeding socially permissible limits" should be re-evaluated, perhaps arguing for a more robust infusion of constitutional non-discrimination principles or stronger protections for freedom of conscience in private law interpretations, especially when there is no compelling justification related to the inherent requirements of a job or the core functions of a private enterprise. The balance between protecting private autonomy and ensuring that the private sphere does not become a zone devoid of constitutional values remains a central challenge. Future developments may see more explicit reliance on the state's duty to protect rights or a more refined jurisprudence on how to weigh competing constitutionally-tinged interests in private law.

Conclusion

While the primary thrust of Japan's constitutional rights is to regulate state power, the doctrine of "private sphere applicability," predominantly through indirect application, allows for the pervasive influence of constitutional values in relationships between private actors. This is chiefly achieved by courts interpreting and applying general clauses of private law (such as public order and morals, or tort principles) in a manner consistent with the fundamental rights and principles enshrined in the Constitution.

The practical effect in any given case involves a complex, fact-sensitive balancing of the competing interests of the private parties. The weight accorded to constitutional values can vary significantly depending on the nature of the rights involved, the context of the dispute, and the perceived importance of private autonomy in that particular sphere. This area of Japanese law is continuously evolving, reflecting the ongoing judicial and academic endeavor to delineate the appropriate reach of constitutional norms into the fabric of private life and commerce.