Tort Law in Japan

Overview and Sources

Japanese tort law is governed principally by Book V of the Civil Code (Minpo), Articles 709 through 724. The Civil Code was enacted in 1896 and drew heavily from the French Civil Code and the first draft of the German Civil Code, but its tort provisions have since developed a distinct doctrinal character through decades of judicial interpretation and statutory supplementation. Article 709, the general tort provision, provides that “[a] person who has intentionally or negligently infringed the rights or legally protected interests of another shall be liable for damages arising from such infringement.” This formulation, amended in 2004, expanded the scope of protection from “rights” to include “legally protected interests,” thereby codifying the expansive interpretation that the Supreme Court had already adopted in practice.

The tort system coexists with contractual liability (keiyaku sekinin) and unjust enrichment (futō ritoku), and the boundary between tort and contract is not always rigid. Japanese courts permit the elective concurrence of claims (kyōsoku), allowing a plaintiff to plead in tort even where a contractual relationship exists between the parties, subject to the limitation that the tort claim cannot circumvent a shorter contractual limitation period.

Elements of Tort under Article 709

To establish liability under Article 709, the plaintiff must prove (i) intentional or negligent conduct by the defendant, (ii) infringement of the plaintiff’s rights or legally protected interests, (iii) causation between the conduct and the harm, and (iv) the fact and amount of damage.

Duty of Care and the Standard of Negligence

Japanese law adopts the objective standard of the “good manager” (zenki kanrishā), derived from Article 400 of the Civil Code. The court asks whether the defendant failed to exercise the degree of care expected of a reasonable person in the same position. Negligence is established by reference to two criteria: foreseeability (yoken kanōsei) and avoidability of harm (kekka kaihi kanōsei). The Supreme Court has consistently held that a duty of care arises where a reasonable person could have foreseen the risk of harm and could have taken effective measures to prevent it. In professional contexts, the standard is calibrated to the level of expertise expected of a qualified practitioner; thus, a physician must exercise the care expected of a reasonably competent physician in the same speciality.

Causation

Causation in Japanese tort law operates on two levels: factual causation (jijitsuteki inga kankei) and legal causation (hōteki inga kankei, equivalent to proximate cause). The courts apply a probability standard rather than a scientific certainty threshold. The landmark Itai-itai disease case (Toyama Itai-itai Case, Toyama District Court, 1971) held that epidemiological evidence establishing a statistical correlation between cadmium exposure and the disease was sufficient to prove causation in a tort action. Similarly, in the Minamata disease litigation (Minamata-byō cases, Kumamoto District Court, 1973), the court accepted epidemiological proof of causation between methylmercury discharge and neurological injury.

Where multiple factors contribute to harm, Japanese courts have developed the proportionate share approach (wariai sekinin). In the Kawasaki City Case (Supreme Court, 2004), the court apportioned liability for noise and air pollution among multiple railroad operators on the basis of each operator’s relative contribution to the harm, rejecting the all-or-nothing model of but-for causation.

Damages

The Civil Code provides for compensatory damages covering actual loss (jissai songai), lost profits (shitsueki rieki), and non-pecuniary damages (isharyō). The calculation of lost profits requires proof of the probability that the profit would have been realized but for the tort. Non-pecuniary damages for pain and suffering (isharyō) are calculated according to standardized schedules, with amounts varying by the nature and severity of the injury. Japanese courts typically award damages as a lump sum (sokubaku), rather than periodic payments, and the discount rate for future losses is prescribed by statute.

Special Types of Torts

Product Liability

The Product Liability Act (Seizōbutsu Sekinin Hō, Law No. 85 of 1994), effective from 1995, introduced a strict liability regime for manufacturers of defective products. The Act defines a defect (kekkan) as a lack of safety that a product ought ordinarily to provide, taking into account the nature of the product, its ordinarily foreseeable use, and the time of delivery. The plaintiff need not prove negligence, but must prove the existence of the defect, the damage, and the causal link. Defenses include the development risk defense (where the defect could not have been discovered given the state of scientific knowledge at the time of delivery) and the component manufacturer defense (where the defect arose from the design specifications provided by the assembler). The limitation period is three years from the date on which the claimant learned of the damage and the identity of the liable party, and 20 years from the delivery of the product.

Medical Malpractice

Medical malpractice in Japan is litigated under Article 709 as a negligence tort, supplemented by principles of informed consent. The Supreme Court, in Kōno v. Kosei Iryō Dan (Supreme Court, 2000), held that a physician’s failure to obtain informed consent before treatment infringes the patient’s right to self-determination and sounds in damages. The physician bears the duty to disclose the diagnosis, the proposed treatment, the risks and benefits, and available alternatives. The standard of disclosure is measured by what a reasonable physician in the same speciality would disclose, but the Supreme Court has moved toward a patient-oriented standard in recent decisions.

Hospitals may be held liable under Article 715 CC for the negligent acts of their employees acting in the course of employment. The Supreme Court has also recognized the theory of apparent authority (hyōken dairi), holding a hospital vicariously liable for the negligence of independent-contractor physicians where the hospital held itself out as providing medical treatment.

Environmental Torts

Japanese environmental tort law is characterized by a combination of Civil Code principles and special statutes imposing strict liability. The Air Pollution Control Act and the Water Pollution Control Act impose strict liability on industrial operators for harm caused by specified pollutants, reversing the burden of proof on causation and negligence. In the Four Major Pollution Cases — the Itai-itai disease, Minamata disease, Niigata Minamata disease, and Yokkaichi asthma cases — Japanese courts developed the theory of joint tortfeasor liability under Article 719 CC to hold multiple polluters jointly and severally liable for environmental harm, even where each defendant’s individual contribution could not be isolated. Article 719(1) provides that where damage arises from the tortious acts of two or more persons, each is jointly and severally liable; the court may apportion liability but each defendant remains liable to the plaintiff for the full amount.

Defamation

Defamation (meiyo kison) is actionable under Articles 709, 710, and 723 CC. Article 723 provides a distinctive remedy: in addition to damages, the court may order the defendant to publish a retraction (tekkai kōkoku) in a manner equivalent to the original defamatory publication. The defense of truth applies only where the statement is both true and made in the public interest (kōkyō no rieki). The Supreme Court, in Gunma Jinken Case (Supreme Court, 1966), established that even false defamatory statements may be immune from liability where the defendant reasonably believed the statements to be true and made them for a public purpose. More recently, the court has recognized the public figure doctrine, affording defamation defendants greater leeway in reporting on the conduct of politicians and government officials.

Vicarious Liability

Article 715 CC imposes vicarious liability (shiyōsha sekinin) on employers for torts committed by their employees in the course of employment. The employer may seek indemnity from the employee only where the employee acted intentionally or with gross negligence. The same provision applies to principals for the acts of their agents. Courts interpret the “course of employment” requirement broadly, holding employers liable for acts that are objectively related to the employee’s duties, even where the employee acted for personal motives.

Strict Liability for Vehicle Accidents

The Automobile Liability Security Act (Jidōsha Songai Baishō Sekinin Hoken Hō, Law No. 97 of 1955) imposes a regime of near-strict liability on vehicle operators for personal injury or death caused by the operation of an automobile. The defendant may avoid liability only by proving (i) that the accident resulted from external circumstances beyond the control of the operator and the vehicle, (ii) that the operator was not negligent, and (iii) that the injured party or a third party was negligent. In practice, these defenses are extremely difficult to establish, and the Act operates as a strict liability scheme combined with mandatory liability insurance.

Limitation Period

Article 724 CC establishes a dual limitation framework: the tort claim is extinguished three years from the date on which the injured party learned of the damage and the identity of the tortfeasor; in any event, the claim is extinguished 20 years from the tortious act. The 1994 Product Liability Act extended the limitation period for product claims to five years from knowledge, with a 20-year long-stop. The Supreme Court has interpreted the knowledge requirement strictly, holding that the period begins to run when the claimant has actual knowledge of the damage and the identity of the tortfeasor, not when the claimant discovers the legal basis for the claim.