Burden of Proof in Japanese Civil Cases: Who Needs to Prove What, and Are There Any Shifts?

Japanese Attorney at Law - Bengoshi L.L.

• 9 min read

In any legal contest, the question of who needs to prove which facts is fundamental to the outcome. This concept, known as the "burden of proof," dictates which party bears the risk if a crucial fact remains unproven. In Japanese civil litigation, this is referred to as shōmei sekinin (証明責任) or risshō sekinin (立証責任). Understanding how this burden is allocated, the standard to which facts must be proven, and the circumstances under which the burden might shift or be alleviated is critical for any party involved in civil proceedings in Japan.

This article examines the principles governing the burden of proof in Japanese civil cases, including its allocation, potential modifications, and its impact on litigation strategy.

I. Defining the Burden of Proof (Shōmei Sekinin) in the Japanese Context

The burden of proof in Japanese civil procedure has two interrelated aspects:

A. The Dual Nature: Objective and Subjective Burden

  1. Objective Burden of Proof (客観的証明責任 - kyakkanteki shōmei sekinin): This is the core concept, often simply called shōmei sekinin. It refers to the risk or disadvantage that a party bears if, after all evidence has been presented and considered by the court, a particular fact remains in a state of non liquet (真偽不明 - shin'i fumei), meaning its truth or falsehood cannot be determined to the required standard. The party with the objective burden on that fact will have that fact treated as if it does not exist, leading to an unfavorable outcome on the issue dependent on that fact.
  2. Subjective Burden of Proof (主観的証明責任 - shukanteki shōmei sekinin) / Burden of Production (行動責任 - kōdō sekinin): This refers to the practical obligation on a party to introduce sufficient evidence to the court to support their factual allegations. If a party fails to produce any, or enough, credible evidence on a point for which they bear the objective burden, they risk the court not being persuaded, thus failing to meet their objective burden.

While distinct, the subjective burden is essentially the procedural activity undertaken to satisfy the objective burden.

B. The Consequence of Non Liquet

If, at the close of evidence and arguments, the court finds itself unable to definitively determine whether a material fact exists or not (i.e., the matter is non liquet), the case is decided against the party who bears the objective burden of proving that particular fact. This underscores the critical importance of correctly identifying who bears the burden for each essential element of a claim or defense.

II. Allocation of the Burden of Proof: The Normative Theory

The primary principle for allocating the burden of proof in Japanese civil litigation is a doctrine known as the "Hōritsu Yōken Bunrui Setsu" (法律要件分類説 – often translated as the "normative classification theory" or "legal requirement classification theory"). This theory is widely accepted by scholars and forms the basis of court practice.

A. The Prevailing Doctrine: Hōritsu Yōken Bunrui Setsu

This theory posits that the allocation of the burden of proof is determined by the structure of the substantive laws governing the dispute. Specifically:

  • A party asserting a particular legal right (e.g., a contractual right, a right to damages in tort) bears the burden of proving all the factual elements that constitute the "right-creating norms" (権利根拠規範 - kenri konkyo kihan) for that right, as stipulated in the relevant statutes.
  • Conversely, the opposing party bears the burden of proving any facts that fall under "right-hindering norms" (権利障害規範 - kenri shōgai kihan, e.g., duress in contract formation), "right-extinguishing norms" (権利消滅規範 - kenri shōmetsu kihan, e.g., payment of a debt, statute of limitations), or "right-suppressing norms" (権利阻止規範 - kenri soshi kihan, e.g., a defense of abuse of rights).

Essentially, "he who asserts must prove" the factual basis for the legal rule that benefits him.

B. Practical Examples

  • Contract Claims:
    • The plaintiff (creditor) must prove: (1) the formation and existence of a valid contract, (2) the relevant terms of the contract, (3) that any conditions for the defendant's performance have been met (e.g., plaintiff's own performance if it's a prerequisite), and (4) the defendant's breach (e.g., non-payment by the due date, failure to deliver goods).
    • The defendant (debtor) must prove affirmative defenses such as: (1) payment of the debt, (2) expiration of the statute of limitations, (3) facts rendering the contract void or voidable (e.g., mistake, fraud, duress), (4) valid termination of the contract.
  • Tort Claims (不法行為 - fuhō kōi) (Article 709 CCP et seq.):
    • The plaintiff (victim) generally bears the burden of proving: (1) the defendant's intentional act or negligence (故意・過失 - koi, kashitsu), (2) the infringement of the plaintiff's legally protected right or interest, (3) the occurrence of damages, (4) a causal link (因果関係 - inga kankei) between the defendant's act and the damages, and (5) the illegality of the act (違法性 - ihōsei, though this is often presumed if the other elements are present, with the defendant needing to prove justification).
    • The defendant (tortfeasor) must prove justifications such as self-defense (正当防衛 - seitō bōei) or necessity (緊急避難 - kinkyū hinan).

C. Pleading and Proof

Generally, the allocation of the burden of proof aligns with the burden of pleading (主張責任 - shuchō sekinin). A party must plead the material facts for which they bear the burden of proof. If a party fails to plead a crucial fact for which they have the burden, the court cannot find in their favor on that point, even if evidence supporting it coincidentally emerges, due to the principle of party presentation (benron-shugi).

III. Shifting or Alleviating the Burden of Proof

While the hōritsu yōken bunrui setsu provides the default allocation, Japanese law recognizes situations where this burden can be modified, effectively shifting it or making it easier for one party to meet.

A. Statutory Reversals or Modifications

Certain statutes explicitly alter the burden of proof or establish presumptions that have a similar effect:

  • Product Liability Act (製造物責任法 - Seizōbutsu Sekinin Hō): Article 4 creates a presumption of defect under certain circumstances. If a product causes harm and (1) the damage normally would not occur unless there was a defect in the product, and (2) the damage occurred while the product was used in its ordinary manner, the product is presumed to have been defective at the time of delivery, and the damage is presumed to have been caused by such defect. The manufacturer can rebut these presumptions.
  • Labor Law: In cases of allegedly unfair dismissal, while the employee formally pleads the existence of an employment contract and its termination, court practice, reinforced by provisions like Article 16 of the Labor Contract Act (regarding dismissal lacking objectively reasonable grounds and social acceptability), places a substantial burden on the employer to justify the dismissal.
  • Specific Statutory Presumptions: For example, Article 228, Paragraph 4 of the CCP states that a private document is presumed to be authentically made if it bears the seal or signature of the purported maker or their agent. This is a rebuttable presumption concerning the document's origin, not its content's truthfulness.

B. Judicial Doctrines and Interpretations

Courts have also developed doctrines, particularly in areas with inherent informational imbalances, to alleviate a party's burden:

  • Presumptions of Fact (事実上の推定 - jijitsujō no suitei): These are not legal rules but inferences drawn by the court based on established indirect facts and common experience rules (経験則 - keikensoku). For instance, proof that a letter was properly addressed, stamped, and mailed may lead to a factual presumption that it was delivered. This does not shift the ultimate burden of persuasion on the fact of delivery but shifts the burden of production to the other party to show non-delivery.
  • "Ichidan no Suitei" (一応の推定 - often translated as "prima facie presumption" or "initial presumption"): This doctrine is particularly significant in cases like medical malpractice or pollution disputes, where the plaintiff often has limited access to crucial evidence primarily held by the defendant. If the plaintiff can establish a certain set of preliminary facts that create a strong inference of, for example, negligence or causation, the court may recognize an "initial presumption." This effectively requires the defendant to come forward with evidence to rebut this inference. If the defendant fails to do so persuasively, the court may find the presumed fact to be true.
    • Medical Malpractice: If a patient undergoes a medical procedure under the exclusive control of medical professionals and suffers an adverse outcome that would not ordinarily occur in the absence of negligence, and other potential causes are reasonably excluded by the plaintiff, a court might infer negligence unless the medical institution provides a convincing alternative explanation.
    • Pollution Cases: In historical pollution cases, where direct proof of causation was difficult, courts sometimes accepted proof of a high statistical correlation between the defendant's emissions and the occurrence of specific diseases in an area, along with other circumstantial evidence, to establish a prima facie case of causation, shifting the onus to the polluter to disprove it. The Yokkaichi Asthma litigation (Tsu District Court, Yokkaichi Branch, Judgment of July 24, 1972) is a classic example where epidemiological evidence played a key role.
  • Res Ipsa Loquitur-like Inferences: While the Latin term is not commonly used, the reasoning behind ichidan no suitei in certain contexts (like things under the defendant's exclusive control that cause injury in a way that ordinarily implies negligence) is analogous to the res ipsa loquitur doctrine in common law.

C. Obstruction of Proof (証明妨害 - Shōmei Bōgai)

If a party unjustifiably refuses to produce a document ordered by the court, or is found to have intentionally destroyed or hidden evidence, this can have significant consequences on the burden of proof.

  • Under CCP Article 224, Paragraph 1, if a party fails to comply with a document production order, the court may deem the opposing party's allegations concerning the contents of that document to be true.
  • More generally, if a party engages in conduct that obstructs the proof of a fact (証明妨害 - shōmei bōgai), the court may draw adverse inferences against that party, which can alleviate the evidentiary burden on the other side.

IV. The Standard of Proof: Reiteration and Context

A. "High Degree of Probability" (Kōdo no Gaizensei)

As discussed in the context of the Principle of Free Evaluation of Evidence, the standard of proof in Japanese civil cases is generally a "high degree of probability." The party bearing the burden of proof for a specific fact must convince the judge that it is highly probable that the fact is true. This standard was notably articulated by the Supreme Court in its judgment of April 25, 1975 (Minshū Vol. 29, No. 4, Page 481).

B. Application in Conjunction with Burden of Proof

This standard is applied to each contested factual element of a case. If the party bearing the burden of proof for a particular fact fails to adduce evidence that persuades the judge to this "high degree of probability," that fact will be considered not proven, and the objective burden of proof will not have been met, leading to consequences based on the non liquet rule.

V. Strategic Implications for Litigants

A clear understanding of burden of proof principles is fundamental to effective litigation strategy in Japan.

  1. Initial Case Assessment: At the outset, meticulously analyze the elements of each claim and potential defense to determine precisely who bears the burden of proof for each factual component. This analysis will drive the entire evidence-gathering and case presentation strategy.
  2. Focused Evidence Gathering: Concentrate investigative and evidentiary efforts on proving the facts for which your side bears the burden. Conversely, identify weaknesses in the opponent's ability to meet their burden on facts they must prove.
  3. Pleading with Precision: Ensure that pleadings (complaint, answer, briefs) accurately and comprehensively assert all facts for which your side intends to offer proof and bears the burden.
  4. Leveraging Presumptions: If the facts of the case allow, strategically argue for the application of statutory or factual presumptions, or the ichidan no suitei doctrine, to ease your evidentiary burden or place a greater onus on the opposing party.
  5. Rebuttal Strategy: If the opposing party successfully establishes a prima facie case or benefits from a presumption, be prepared with a robust strategy and evidence to rebut it effectively.
  6. Understanding Non Liquet Risk: Identify the key facts where proof might be challenging and therefore the risk of non liquet is high. This helps in assessing litigation risk and can inform settlement strategy.
  7. Anticipating Defenses: When framing a claim, anticipate the affirmative defenses the opponent is likely to raise and consider what evidence they would need to meet their burden of proof on those defenses.

VI. Conclusion

The allocation of the burden of proof, predominantly guided by the hōritsu yōken bunrui setsu, is a critical determinant of outcomes in Japanese civil litigation. While the principle itself provides a structured framework, the legal landscape is nuanced by statutory provisions that can shift or modify this burden, and by judicial doctrines like ichidan no suitei that respond to practical challenges in evidence gathering, particularly in cases of informational asymmetry or strong public policy considerations.

For businesses, especially those accustomed to different legal systems, a thorough grasp of these rules, from the initial allocation to potential shifts and the exacting standard of "high degree of probability," is indispensable. It informs every stage of the litigation process, from pre-suit investigation and pleading, through evidence presentation, to final arguments, and is a key factor in successfully navigating the complexities of civil disputes in Japan.