What Happens if the Tortfeasor Lacks Legal Capacity in Japan?

Japanese Attorney at Law - Bengoshi L.L.

• 10 min read

In Japanese tort law, while liability is generally predicated on the fault (intent or negligence) of the tortfeasor, the law also takes into account the actor's capacity to understand the nature and consequences of their actions. This gives rise to the concept of "capacity to bear responsibility" (責任能力 - sekinin nōryoku). If a person who causes harm is found to lack this capacity, the legal consequences can shift significantly, often implicating those who have a duty to supervise them.

"Lack of Capacity": A Defense, Not an Element of the Tort

It is crucial to understand that in Japanese tort law, the "capacity to bear responsibility" is not an element that the plaintiff (victim) must prove to establish a tort. Rather, a lack of capacity is a defense (権利障害規定 - kenri shōgai kitei) that can be asserted by the alleged tortfeasor or on their behalf. The burden of proving that the tortfeasor lacked the requisite capacity at the time of the act lies with the defendant. If this defense is successfully established, the tortfeasor themselves may be shielded from liability.

Meaning of "Capacity to Bear Responsibility" (Sekinin Nōryoku)

The Japanese Civil Code, in Articles 712 and 713, refers to this as having "sufficient intelligence to appreciate the responsibility for one's own acts" (自己の行為の責任を弁識するに足りる知能 - jiko no kōi no sekinin o benshiki suru ni tariru chinō).

Distinction from the Capacity for Negligence

It's important to distinguish "capacity to bear responsibility" from the mental capacity required to be found negligent. Early legal theories sometimes conflated these concepts, suggesting that sekinin nōryoku was the ability to foresee harm and take steps to avoid it (i.e., the capacity to act negligently). However, this view is now largely rejected because the elements of foreseeability and avoidability are already integral parts of the negligence assessment itself.

The modern prevailing view is that sekinin nōryoku is a distinct concept. It is rooted in a policy consideration: to protect individuals who are unable to understand the meaning of legal commands and prohibitions (and thus the wrongfulness of their actions) from the burden of damage compensation. The underlying rationales for this protection include:

  • A communitarian perspective, suggesting that society should exempt those who genuinely cannot comprehend or conform to its rules of conduct.
  • A personality development perspective, which posits that individuals whose personalities are still developing (minors) or whose capacity for understanding is impaired (due to mental disability) cannot fairly be blamed or held to the same standards of responsibility as fully capable adults.

Therefore, sekinin nōryoku is generally defined as the intellectual ability to judge the rightness or wrongness of one's own actions or to recognize their illegality (善悪の判断能力・違法性認識能力 - zen'aku no handan nōryoku / ihōsei ninshiki nōryoku). Unlike the assessment of negligence, which uses an objective "reasonable person" standard, the assessment of sekinin nōryoku is individualized, focusing on the specific actor's actual mental capacity at the time of the act. This capacity can also vary depending on the nature and complexity of the act in question. While there's no absolute age threshold, a general (though not definitive) benchmark often cited is the level of intelligence typically expected of a 12-year-old, around the age of elementary school graduation in Japan.

Categories of Individuals Who May Lack Capacity

Japanese law identifies two primary categories of individuals who may lack the capacity to bear responsibility for their torts:

  1. Minors Lacking Sufficient Intelligence (Civil Code Art. 712):
    A minor is not liable for damages caused by their tortious act if they did not possess sufficient intelligence to appreciate the responsibility for their actions at the time of the act. There is no fixed age cutoff; the determination is made on a case-by-case basis, considering the specific minor's maturity, understanding, and the nature of the act committed. As mentioned, an intelligence level equivalent to roughly 12 years of age is often considered a guideline, but it is not a strict rule.
  2. Persons Lacking Capacity Due to Mental Disability (Civil Code Art. 713, main text):
    An individual who, due to a mental disability, lacked the capacity to appreciate the responsibility for their actions at the time they caused harm to another is not liable for damages.
    • Exception: Self-Induced Incapacity (Art. 713, proviso): This defense is unavailable if the person intentionally or negligently brought about their own temporary state of incapacity. This provision, often referred to as addressing "acts free in their cause" (原因において自由な行為 - gen'in ni oite jiyū na kōi), typically applies to situations like voluntary intoxication through alcohol or drug use leading to a tortious act. If the defendant raises lack of capacity due to mental disability, the plaintiff may then counter-argue (as a re-rebuttal) that this state of incapacity was self-induced through the defendant's own fault.

Liability of Supervisors of Persons Lacking Capacity (Civil Code Art. 714)

When a tort is committed by someone found to lack sekinin nōryoku, the legal focus often shifts to those responsible for their supervision. Article 714 of the Civil Code governs the liability of such supervisors.

General Principle (Art. 714(1), main text):
If a person lacking capacity to bear responsibility (e.g., a minor or an individual with a severe mental disability) inflicts damage on another, the person who is legally obligated to supervise them (監督義務者 - kantoku gimu sha) is liable to compensate the victim for those damages. This liability also extends to a person who supervises the individual lacking capacity in place of the legally obligated supervisor (代理監督者 - dairi kantoku sha).

Nature and Rationale of Supervisor's Liability:
This liability is considered to be for the supervisor's own negligence in performing their supervisory duties (監督過失 - kantoku kashitsu), rather than a vicarious liability for the act of the person lacking capacity. The rationale is often linked to the special nature of relationships like parent-child or guardian-ward, where the supervisor has a status-based duty to care for, educate, and control the conduct of the person under their supervision to prevent harm to others.
Crucially, Article 714(1) effectively shifts the burden of proof regarding supervisory negligence to the supervisor. While the supervisor's liability is fault-based (their own negligence), they are presumed negligent unless they can prove otherwise. This is traditionally termed "intermediate liability" (中間責任 - chūkan sekinin).

Elements a Plaintiff Must Prove for Supervisor Liability (請求原因 - Seikyū Gen'in):
To hold a supervisor liable under Article 714(1), the plaintiff typically needs to establish:

  1. Infringement of the plaintiff's right.
  2. A tortious act by the person lacking capacity (A), including A's intent or negligence concerning their act (even if A isn't liable, the act itself must meet tort criteria).
  3. The occurrence of damages (and their amount).
  4. A causal link between A's act and the infringement/damages.
  5. That A lacked the capacity to bear responsibility at the time of the act.
  6. That the defendant (Y) was the person legally obligated to supervise A at the time of the act.

Supervisor's Defenses (Art. 714(1), proviso - 抗弁 - Kōben):
The supervisor can avoid liability if they can prove either of the following:

  1. That they did not neglect their duty of supervision (監督義務を怠らなかったこと - kantoku gimu o okotaranakatta koto). The supervisory duty here is generally interpreted as a comprehensive one aimed at preventing harm, making this defense very challenging to establish in practice.
  2. That the damage would have occurred even if they had fulfilled their duty of supervision (監督義務を怠らなくても損害が生じたであろうこと - kantoku gimu o okotaranakute mo songai ga shōjita dearō koto), essentially arguing a lack of causation between any alleged supervisory lapse and the harm. This too is a difficult burden given the broad nature of the duty.

The scope of the supervisory duty under Article 714 and when a supervisor can be said to have fulfilled it has been subject to evolving interpretation.

  • Traditional View: Often linked the supervisory duty directly to status-based obligations, such as the parental duty of care and education (Civil Code Art. 820) or a legal guardian's duty concerning the personal affairs of an adult ward (Civil Code Art. 858). This tended to imply a very broad and encompassing duty, making successful defenses rare.
  • Recent Judicial Trend: While still acknowledging the relationship-based context, recent court decisions have tended to analyze the supervisory duty under Article 714 in a manner more akin to the general duty of care seen in Article 709 (the general tort provision), focusing on the duty to take reasonable steps to prevent foreseeable harm. However, it remains a comprehensive duty reflecting the specific supervisory relationship.

Two important Supreme Court cases illustrate the modern application:

  1. The "Soccer Goal Case" (Supreme Court, April 9, 2015, Minshu 69-3-455):
    An 11-year-old boy (deemed to lack sekinin nōryoku) was practicing free kicks at a soccer goal in an elementary schoolyard open to children after school. A kicked ball went over the goal, over a nearby gate, and onto a road, causing an 85-year-old motorcyclist to swerve, fall, and sustain fatal injuries. The Supreme Court held the boy's parents were not liable under Article 714.
    The Court reasoned that the boy's act (kicking a soccer ball towards a goal in a schoolyard) was a normal and generally not inherently dangerous activity. Unless there were special circumstances making this specific act foreseeably dangerous to others outside the schoolyard (which were not found), parents who provide ordinary upbringing and general guidance on safe behavior cannot be said to have breached their supervisory duty just because an unexpected accident occurs from such an ordinary activity. The parents' duty regarding a child's actions not under their direct, immediate observation is necessarily somewhat general.
  2. The "JR Tokai Case" (Supreme Court, March 1, 2016, Kin'yū Hōmu Jijō 1488-10):
    A 91-year-old man with severe Alzheimer's disease (requiring a high level of nursing care, certified as Yōkaigo 4) wandered from his home, entered a railway station, went onto the tracks, and was fatally struck by a train. The railway company sued the man's elderly wife (85, also requiring some care) and his adult son (who lived and worked in a different city, visiting on weekends) for damages under Article 714. The Supreme Court found neither the wife nor the son liable.
    The Court's reasoning included several key points:
    • Simply being a spouse, with general marital duties of cohabitation, cooperation, and support (Civil Code Art. 752), does not automatically make one a "person legally obligated to supervise" under Article 714(1) with a duty to prevent harm to third parties. These marital duties are primarily internal to the spousal relationship.
    • Similarly, an adult child does not, by virtue of that relationship alone, have a legal supervisory obligation over an elderly parent in this context.
    • The Court did, however, acknowledge the possibility of liability for "persons equivalent to legal supervisors" (法定の監督義務者に準ずべき者 - hōtei no kantoku gimu sha ni junzu beki mono). A person who is not a formal legal supervisor might still be held liable by analogy under Article 714(1) if, considering all circumstances (their own situation, the nature of their relationship with the person lacking capacity, their daily contact, their involvement in care and property management, the supervised person's condition and behavior, and the actual supervision provided), they are found to be actually supervising the person lacking capacity to an extent that goes beyond mere factual oversight, or if it is equitable to hold them responsible because supervision was possible and easy for them. In this case, neither the elderly wife (who was herself frail and reliant on assistance from her daughter-in-law) nor the son (who lived far away and was not involved in daily care) met this high threshold.
  • Legal Supervisors: For minors, this typically includes those with parental authority (親権者 - shinkensha), legal guardians, or, in their absence, heads of child welfare institutions where the minor resides. For adult wards under guardianship, the Supreme Court in the JR Tokai case clarified that an adult guardian's duties (e.g., under Civil Code Art. 858 regarding personal affairs) primarily relate to legal and property matters and do not automatically entail a duty to physically supervise daily conduct to prevent harm to third parties for the purposes of Article 714. Similarly, statutory "protectors" of individuals with mental disabilities under mental health laws are generally not considered to have an Article 714 supervisory duty to prevent harm to others.
  • Proxy Supervisors (代理監督者 - Dairi Kantoku Sha) (Art. 714(2)): These are individuals or entities that supervise a person lacking capacity on behalf of the legally obligated supervisor. Examples often include staff at childcare facilities, teachers in schools, or doctors and staff in psychiatric hospitals for inpatients. In organizational settings, liability as a proxy supervisor often attaches to the head of the organization or those with delegated command authority over the relevant operations, rather than just frontline employees (who might face liability under general tort principles, Art. 709, for their own negligence).

Liability of Guardians/Parents if the Tortfeasor Has Capacity

If the person committing the tort (e.g., a 16-year-old who is generally deemed to have sekinin nōryoku) does possess the capacity to bear responsibility, then Article 714 does not apply. The primary claim for the victim is against the tortfeasor directly, under the general tort provision of Article 709.

However, this does not mean guardians or parents are always free from liability. They can still be held liable under Article 709 for their own distinct negligence in supervision, if such negligence can be proven and is causally linked to the harm caused by the (capable) minor's tort. This was affirmed by the Supreme Court on March 22, 1974 (Minshu 28-2-347).
Key distinctions from Article 714 liability:

  • The liability is for the guardian's/parent's own tort (negligent supervision), not a substituted liability for the minor's act.
  • The plaintiff bears the full burden of proving the guardian's/parent's negligence. This involves demonstrating specific facts supporting an evaluation that the guardian breached a specific duty of supervision relevant to preventing the specific type of harm that occurred. General allegations of poor upbringing are insufficient.
  • The plaintiff must also prove an adequate causal link between the guardian's/parent's specific supervisory negligence and the resulting harm.

In practice, establishing such liability against parents/guardians for the torts of their capable children is challenging and typically limited to situations where the child has a known history of delinquency or dangerous behavior that the parents demonstrably failed to address with appropriate supervision, leading to foreseeable harm (e.g., parental liability was denied by the Supreme Court on February 24, 2006, Hanrei Times 1206-177, concerning a crime committed by a 19-year-old who was on parole).

Conclusion

Japanese tort law provides a clear, albeit nuanced, framework when the tortfeasor's capacity to bear responsibility is in question. Individuals lacking this capacity (typically certain minors or those with severe mental disabilities) are generally exempt from personal liability. However, liability often shifts to their legal supervisors under Article 714 of the Civil Code, who are then liable for their own (presumed) negligence in supervision unless they can meet a high burden of proof to show otherwise. Recent Supreme Court jurisprudence has refined the understanding of who qualifies as a supervisor, particularly for adults with diminished capacity, emphasizing actual supervisory roles and equitable considerations rather than mere familial or formal guardianship status. If the tortfeasor does possess capacity, their supervisors are not liable under Article 714, but may still face liability under general tort principles (Article 709) if their own specific negligence in supervision can be proven to have caused the harm.