Who Bears the "Burden of Proof" in Japanese Civil Litigation?

In any legal dispute, facts are paramount. But what happens when, after all evidence is presented, a crucial fact remains uncertain or unproven in the eyes of the court? This is where the "Burden of Proof," known in Japanese as Shōmei sekinin (証明責任), comes into play. It is a fundamental principle of civil procedure that determines which party will suffer the adverse consequences if a material fact is not proven to the required standard. Understanding how this burden is allocated and discharged is critical for any business involved in or contemplating litigation in Japan, as it directly influences case strategy, evidence gathering, and the ultimate outcome.

I. Understanding "Burden of Proof" (Shōmei sekinin) in Japanese Civil Litigation

A. Definition: The Risk of Non-Persuasion

The "Burden of Proof" in its core sense refers to the risk a party bears if a material fact relevant to their claim or defense remains in a state of non liquet (真偽不明 - shingi fumei, meaning "it is not clear" or "uncertain") after the court has considered all the evidence and arguments. If the judge, despite evaluating everything under the Principle of Free Evaluation of Evidence (Jiyū shinshō-shugi 自由心証主義), cannot reach the required level of conviction (typically a "high degree of probability") about the existence or non-existence of a fact, the party who carries the burden of proof for that fact will be treated as if that fact has not been established, usually to their detriment.

B. Objective Burden of Proof vs. Subjective Burden of Proof

It's useful to distinguish two aspects of the burden of proof:

1. Objective Burden of Proof (Risk of Non-Persuasion - 客観的証明責任 Kyakkan-teki shōmei sekinin): This is the true burden of proof as described above. It is a legal rule that allocates the risk of uncertainty. It becomes decisive at the judgment stage when the court makes its final factual determinations. This article primarily focuses on this objective burden.
2. Subjective Burden of Proof (Burden of Adducing Evidence - 主観的証明責任 Shukan-teki shōmei sekinin): This refers to the practical necessity for a party to present evidence during the trial to persuade the court of its factual allegations and to avoid an unfavorable ruling. This is more a reflection of the dynamics of the adversarial process (Principle of Party Presentation - Benron-shugi 弁論主義) than a fixed legal rule of allocation. As evidence is presented, this "burden" can shift back and forth between parties.

C. Why is the Burden of Proof Necessary?

The allocation of the burden of proof is essential because:

• It allows courts to reach a decision even when factual certainty is unattainable. Without it, cases where facts remain unclear would be perpetually unresolved.
• It provides a framework for parties to understand what they need to prove to succeed.
• It promotes fairness by generally placing the burden on the party asserting a particular state of affairs or seeking to benefit from a legal rule.

II. Allocation of the Burden of Proof: The Prevailing Theory (Hōritsu yōken bunrui setsu - 法律要件分類説)

The primary principle for allocating the objective burden of proof in Japanese civil litigation is known as the "Legal Requirement Classification Theory" (Hōritsu yōken bunrui setsu 法律要件分類説).

A. The "Legal Requirement Classification Theory"

This theory, widely accepted by courts and scholars in Japan, essentially states that each party bears the burden of proving the facts that constitute the elements (legal requirements) of any statutory provision or legal rule upon which they rely to support their claim or defense.

More specifically:

• Facts Giving Rise to a Right (Kenri hassei jijitsu 権利発生事実): The party asserting a right (typically the plaintiff) bears the burden of proving all the facts that are necessary under substantive law for that right to come into existence.
  • Example: In a breach of contract claim seeking payment, the plaintiff must prove: (1) the existence of a valid contract, (2) the terms of the contract (including the payment obligation), (3) their own performance if it was a condition precedent to the defendant's duty to pay, and (4) that the payment is due.
• Facts Hindering the Arising of a Right (Kenri shōgai jijitsu 権利障害事実): The party arguing that a right, despite the apparent fulfillment of its generating facts, never actually came into effect (e.g., due to invalidity from the outset) must prove the facts supporting this assertion.
  • Example: A defendant arguing a contract is void due to mistake or duress at the time of formation bears the burden of proving the elements of mistake or duress.
• Facts Extinguishing a Right (Kenri shōmetsu jijitsu 権利消滅事実): The party asserting that an existing right has been extinguished or is no longer enforceable bears the burden of proving the facts that led to such extinguishment.
  • Example: A defendant to a debt claim who asserts they have already paid the debt bears the burden of proving payment. A defendant claiming the statute of limitations has expired must prove the facts supporting that defense.
• Facts Preventing the Effect of a Right (Kenriそ止事実 - Kenri soshi jijitsu - less common term, often covered by hindering or extinguishing): Facts that temporarily or permanently prevent the effect of an established right.

B. Examples in Business Litigation:

• Breach of Contract:
  • Plaintiff (Claimant): Proves contract formation, relevant terms, their own performance (if required first), defendant's breach (e.g., non-payment, non-delivery, defective performance), and resulting damages.
  • Defendant: Proves affirmative defenses like payment, waiver, contractual exclusion of liability, force majeure (if applicable), or that the plaintiff failed to mitigate damages.
• Tort (e.g., Intellectual Property Infringement, Unfair Competition):
  • Plaintiff: Proves the existence of their right (e.g., valid patent, trademark, copyright, trade secret), the defendant's infringing act, the defendant's intention or negligence (though for some IP rights like patent infringement, negligence is presumed or not required for injunctive relief), causation between the act and the harm, and the damages suffered.
  • Defendant: Proves defenses such as license, invalidity of the IP right, independent creation (for copyright), or lack of causation.
• Product Liability:
  • Plaintiff: Proves a defect in the product, injury or damage, and a causal link between the defect and the injury/damage (Product Liability Act, Art. 3). The Act has provisions that can alleviate the plaintiff's burden regarding proving "defect" compared to general tort law.

C. Rationale of the Theory
This allocation principle is generally considered to be based on fairness (the party seeking to change the status quo or benefit from a rule should prove its elements), predictability, and an interpretation of legislative intent behind substantive laws.

III. Standard of Proof (Shōmei-do - 証明度): How Certain Must the Judge Be?

A. "High Degree of Probability" (Kōdo no gaizen-sei - 高度の蓋然性)
The general standard of proof required in Japanese civil cases for a party to discharge their burden is that the judge must be convinced to a "high degree of probability" that the alleged fact is true. This means more than a mere possibility or suspicion; it requires a strong conviction based on the evidence.

B. Comparison to Other Standards (Conceptual)

• Not Mere "Preponderance of Evidence": While a direct equivalence is difficult, kōdo no gaizen-sei is generally understood as a more demanding standard than the simple "more likely than not" (greater than 50% probability) often associated with the "preponderance of the evidence" standard in some common law systems. It requires a level of confidence that makes the fact's existence substantially probable.
• Not "Beyond a Reasonable Doubt": It is, however, a less stringent standard than the "beyond a reasonable doubt" required in criminal prosecutions. Absolute certainty is not demanded.

IV. Mechanisms Affecting the Burden of Proof: Presumptions and Prima Facie Evidence

While the ultimate burden of proof generally does not shift, certain legal mechanisms can assist a party in meeting their burden or can place a practical burden on the opposing party to adduce counter-evidence.

A. Legal Presumptions (Hōritsu-jō no suitei - 法律上の推定)
These are rules explicitly stated in statutes that direct a court to presume a certain fact (the "presumed fact") to be true if another fact or set of facts (the "basic facts" or "predicate facts") is proven, unless and until the opposing party adduces evidence to rebut the presumption.

• Effect: A legal presumption effectively shifts the burden of proving the non-existence of the presumed fact to the party against whom the presumption operates. If they fail to rebut it, the presumed fact is established.
• Examples:
  • Article 772 of the Civil Code presumes a child conceived by a wife during marriage to be the child of her husband (presumption of legitimacy).
  • In some specific torts, negligence might be legally presumed once certain conditions are met, shifting the burden to the defendant to prove they were not negligent.

B. Factual Presumptions (Jijitsu-jō no suitei - 事実上の推定)
These are not mandated by law but are inferences that a judge, in their free evaluation of evidence, may draw from proven (usually indirect) facts based on logic, common sense, and general human experience.

• Effect: A factual presumption does not shift the formal (objective) burden of proof. However, if a judge makes a strong factual inference based on the evidence presented by one party, it creates a practical need for the opposing party to introduce counter-evidence or offer a plausible alternative explanation to avoid an adverse finding.

C. Prima Facie Evidence / Anscheinsbeweis (Provisional Proof - Ichiō no suitei 一応の推定 / Hyōken shōmei 表見証明)
This concept, often discussed in contexts like medical malpractice, traffic accidents, or some product liability and pollution cases, refers to situations where direct proof of a key element (like causation or negligence) is inherently difficult for the plaintiff because evidence is largely within the defendant's control or the event is scientifically complex.

• If the plaintiff proves a certain pattern of typical facts that experience shows usually leads to the kind of harm suffered, the court may make a preliminary inference that the key element (e.g., negligence or causation) exists. This establishes prima facie proof.
• Effect: This does not formally shift the ultimate burden of proof, but it places a significant evidentiary burden on the defendant to provide a concrete and persuasive explanation or evidence to negate the inference. If the defendant fails to do so, the court may find the fact proven based on the prima facie evidence. This is often seen as a mechanism for alleviating the plaintiff's proof difficulties in specific, recognized types of cases to ensure a fair outcome.

V. Spoliation of Evidence (Shōmei bōgai - 証明妨害)

If a party intentionally destroys, conceals, or refuses to produce relevant documents or other evidence that is in their possession and which they have a duty to produce, this is termed Shōmei bōgai (obstruction of proof).

• Effect: While there isn't a direct "spoliation tort" in the same way as in some jurisdictions, Japanese courts have the discretion, under the Principle of Free Evaluation of Evidence, to draw adverse inferences against the spoliating party. The court may infer that the unavailable evidence would have been unfavorable to that party or would have supported the opponent's assertion regarding the facts that evidence would have clarified (Code of Civil Procedure, Art. 224, Para. 3 for refusal to comply with a document production order). This can significantly impact how the burden of proof plays out.

VI. Practical Implications for Businesses

• Identify Burdens Early: For each factual assertion crucial to your case (whether you are plaintiff or defendant), determine who bears the burden of proof. This will shape your entire litigation strategy.
• Proactive Evidence Management: Systematically collect, organize, and preserve all potentially relevant documents and information well before litigation is anticipated, and certainly once it commences. This is especially critical for facts where your company bears the burden.
• Aim for "High Degree of Probability": When presenting evidence, your goal is to convince the judge to this demanding standard. This means focusing on the quality, credibility, and coherence of your evidence.
• Leverage Presumptions and Prima Facie Arguments: If your case fits a pattern where legal presumptions apply or a prima facie argument can be made, strategize to establish the necessary predicate facts.
• Anticipate and Address Opponent's Burden: Understand what your opponent needs to prove and be prepared to challenge their evidence and arguments effectively.
• Document Everything: In business dealings, clear and comprehensive documentation of agreements, performance, communications, and any issues that arise can be invaluable if disputes later require proof in court.

Conclusion

The allocation and discharge of the Shōmei sekinin (Burden of Proof) are pivotal to the outcome of virtually every civil lawsuit in Japan. It dictates who bears the risk when factual uncertainty persists after all evidence has been heard. For businesses, a clear understanding of the Hōritsu yōken bunrui setsu (the principle for allocating this burden) and the "high degree of probability" standard required to satisfy it is fundamental. Combined with diligent evidence management and a strategic approach to presenting facts, this understanding allows companies to better navigate the Japanese litigation process and enhance their prospects of a favorable judgment.