Who Bears the Burden of Proof in Japanese Civil Litigation, and What Happens if Evidence is Tampered With?

In any adjudicative process, two fundamental questions shape the outcome of factual disputes: first, which party is responsible for convincing the court of a particular fact, and second, what happens if a party unfairly interferes with the evidence-gathering process? In Japanese civil litigation, these issues are addressed through the doctrines of "burden of proof" (shōmei sekinin) and "obstruction of proof" or "spoliation of evidence" (shōmei bōgai). A clear understanding of these principles is essential for litigants to effectively prepare their cases and navigate the evidentiary landscape of Japanese courts.

Part 1: The Burden of Proof (Shōmei Sekinin) in Japanese Civil Litigation

The concept of burden of proof is central to how facts are established and decisions are rendered in Japanese civil courts.

Defining the Burden of Proof

In the Japanese context, the "burden of proof" primarily refers to the risk of non-persuasion. After all evidence has been presented and considered by the court, if a material fact remains in a state of ambiguity where its truth or falsity cannot be determined with the requisite degree of certainty (a state known as non liquet, or 真偽不明 - shingi fumei in Japanese), the party who bears the burden of proof with respect to that fact will suffer an adverse finding on that fact. This, in turn, usually leads to an unfavorable outcome regarding the legal claim or defense that depends on that fact.

It is useful to distinguish between:

• Objective Burden of Proof (客観的証明責任 - kyakkanteki shōmei sekinin): This is the burden described above – the ultimate risk of non-persuasion that determines the outcome if a fact remains unproven. It comes into play at the final stage of judgment.
• Subjective Burden of Proof / Burden of Production (主観的証明責任 / 証拠提出責任 - shukanteki shōmei sekinin / shōko teishutsu sekinin): This refers to the practical necessity for a party to come forward with evidence during the trial to support their allegations and to prevent the court from forming an adverse initial impression, or to counter evidence presented by the opponent. This burden can shift back and forth between parties as evidence is presented.

While the subjective burden of production is a dynamic aspect of trial practice, the objective burden of proof for each material fact is fixed from the outset and allocated based on established principles.

Allocating the Burden of Proof: The "Legal Requirement Classification Theory"

The predominant principle for allocating the objective burden of proof in Japan is the "Legal Requirement Classification Theory" (法律要件分類説 - hōritsu yōken bunrui setsu). This theory, widely accepted by courts and scholars, categorizes statutory provisions based on their function in relation to a legal right and assigns the burden of proof for the facts falling under these categories accordingly:

1. Right-Establishing Provisions (権利根拠規定 - kenri konkyo kitei): These are provisions that set out the factual elements necessary for a legal right to come into existence. The party asserting the existence of the right (typically the plaintiff) bears the burden of proving the facts that satisfy these provisions. For example, in a lawsuit seeking repayment of a loan, the plaintiff (lender) must prove the facts establishing the loan agreement (e.g., offer, acceptance, consensus on principal and interest) and the disbursement of the loan funds.
2. Right-Impeding Provisions (権利障害規定 - kenri shōgai kitei): These provisions stipulate facts that prevent a legal right from arising in the first place, even if the facts for establishing the right are present. The party who relies on such an impediment to defeat the asserted right (typically the defendant) bears the burden of proving these facts. For instance, if a contract is claimed, but the defendant alleges it is void due to a fundamental mistake (under Article 95, main text, of the Civil Code), the defendant bears the burden of proving the elements of that mistake. However, if the plaintiff then counters that the defendant's mistake was due to the defendant's own gross negligence (Article 95, proviso, of the Civil Code, which negates the voidness due to mistake), the plaintiff bears the burden of proving that gross negligence, as this fact impedes the "mistake" impediment.
3. Right-Extinguishing Provisions (権利消滅規定 - kenri shōmetsu kitei): These provisions outline facts that terminate or extinguish a legal right that has already validly arisen. The party asserting that the right has been extinguished (again, usually the defendant) bears the burden of proving these facts. A classic example is the defense of payment (bensai) in a debt recovery action; the defendant must prove they have paid the debt.

The textual structure of statutes often provides clues for this classification. For example, the main clause of an article might set out right-establishing facts, while a proviso or a subsequent paragraph might introduce right-impeding or right-extinguishing facts.

Modifications and Nuances in Allocation

While the Legal Requirement Classification Theory provides the primary framework, its application is not always mechanical.

• Express Statutory Allocation: In some instances, statutes explicitly allocate the burden of proof for certain issues. For example, Article 3 of the Act on Securing Compensation for Automobile Accidents contains a proviso that shifts a burden to the operator/driver in certain circumstances.
• Substantive Considerations and Fairness (The "Modified" Theory): There's a recognition that strict adherence to statutory structure might sometimes lead to unfair outcomes or place an unreasonable evidentiary burden on one party. Therefore, a "Modified Legal Requirement Classification Theory" is often applied, which, while starting with the classification, also takes into account factors such as fairness between the parties, relative ease of proof, access to evidence, the typical course of events (probability), and the underlying policy of the substantive law.
  A notable example cited in legal commentaries is the treatment of quasi-loan agreements (準消費貸借契約 - jun-shōhi-taishaku keiyaku) under Article 588 of the Civil Code. Structurally, the existence of the original debt appears to be a right-establishing fact (burden on creditor). However, due to fairness considerations (e.g., the creditor might have returned the original evidence of debt upon concluding the quasi-loan), case law, such as the Supreme Court decision of February 16, 1968 (Minshu Vol. 22, No. 2, p. 217), effectively places the burden of proving the non-existence of the original debt on the debtor.
• Presumptions: Legal presumptions (e.g., presumption of negligence in certain torts) or strong factual presumptions can shift the subjective burden of production to the opposing party.

A specific application discussed in legal problems is the termination of a lease due to unauthorized subletting (Article 612(2) of the Civil Code). Japanese case law, notably a Supreme Court decision of September 25, 1953 (Minshu Vol. 7, No. 9, p. 979), has established that such termination is not permitted if there are "special circumstances where the act (of subletting) cannot be deemed a breach of trust (haishin-kōi) against the lessor". The prevailing view, supported by the Supreme Court decision of January 27, 1966 (Minshu Vol. 20, No. 1, p. 136), is that these "special circumstances negating a breach of trust" function as a right-impeding element for the lessor's right to terminate. Thus, the burden of proving these special, exculpatory circumstances falls on the lessee (tenant).

Part 2: Obstruction of Proof or Spoliation of Evidence (Shōmei Bōgai)

The integrity of the fact-finding process depends on the availability and reliability of evidence. When a party intentionally or negligently undermines this process by tampering with, destroying, or otherwise obstructing access to relevant evidence, the doctrine of shōmei bōgai comes into play.

Statutory Sanctions for Specific Obstructive Acts

The Code of Civil Procedure provides specific sanctions for certain types of non-cooperation or obstruction related to evidence:

• Failure to Comply with a Document Production Order (CCP Art. 224): If a party, having been ordered by the court to produce a document, fails to do so without justifiable reason, the court may, in its discretion, deem the opposing party's allegations concerning the description or purport of that document to be true (Art. 224(1)). If a party intentionally destroys a document they were obliged to produce, or renders it unusable to prevent its use by the opponent, the court may also deem true the opponent's allegations regarding the facts to be proven by that document (Art. 224(3)).
• Non-Cooperation in Party Examination (CCP Art. 208): If a party, without justifiable reason, fails to appear for their court-ordered examination or refuses to take an oath or make statements, the court may deem the opposing party's allegations regarding the matters of the examination to be true.
• Refusal to Provide Handwriting Samples (CCP Art. 229(4)): If a party, ordered to write characters for a handwriting comparison (to determine a document's authenticity), refuses without justifiable reason, the court may deem the proponent's assertions regarding the authenticity of the document in question as true.

Shōmei Bōgai as a General Doctrine

Beyond these specific statutory provisions, there is a broader, less codified doctrine of shōmei bōgai that addresses other forms of evidentiary misconduct. This might include, for example, the failure by a doctor to create or properly maintain legally required medical records, or the premature destruction of relevant business records before litigation is even contemplated but when it is foreseeable.

The legal basis for this general doctrine is debated:

• Experience Rule Theory: Some argue that an act of obstructing proof suggests, as a matter of common experience, that the evidence was likely unfavorable to the obstructing party. This rationale, however, is less convincing for negligent obstruction.
• Duty-Based Theories: Others posit a substantive legal duty to preserve certain evidence or a general procedural duty to cooperate in truth-finding. Establishing such broad duties without explicit statutory backing can be challenging.
• Principle of Good Faith (CCP Art. 2): The most widely accepted basis is the overarching principle of good faith and fair dealing in litigation. Parties are expected not to unfairly impede their opponent's ability to present their case, and conduct that violates this expectation can trigger consequences under the shōmei bōgai doctrine.

Requirements for Establishing General Shōmei Bōgai

For the general doctrine of shōmei bōgai to apply, several conditions are typically considered:

1. Objective Requirements:
   • Breach of a Duty: There must have been a breach of a duty to create, preserve, or make available certain evidence. This duty can arise from statute, contract, or the general principle of good faith in litigation.
   • Causation: The obstructive act must have made it more difficult or impossible for the opposing party to prove a relevant fact, potentially leading to a state of non liquet regarding that fact. Examples from case law include a defendant destroying boundary markers crucial for the plaintiff to prove the extent of their land (Osaka High Court, January 30, 1980, Hanrei Times No. 409, p. 98 ), or a factory destroying records and equipment that could have proven its role in discharging pollutants (Niigata District Court, September 29, 1971, Kakyū Minshu Vol. 22, No. 9-10, p. 1 ).
2. Subjective Requirement:
   • Culpability: The party engaging in the obstructive conduct must have done so either intentionally or negligently. There is some debate among scholars as to whether simple negligence is sufficient, or if gross negligence or intent is required, particularly for more severe remedies.

Effects and Remedies for General Shōmei Bōgai

The consequences of establishing shōmei bōgai (where no specific statutory sanction like CCP Art. 224 applies directly) are not uniformly defined and are a subject of considerable academic discussion. Potential effects include:

• Shifting the Burden of Proof: The burden of proof regarding the fact whose ascertainment was obstructed may be shifted to the obstructing party. This was the approach taken by the Tokyo District Court on July 24, 1990 (Hanrei Jiho No. 1364, p. 57), in an insurance dispute where an insurer's agent failed to properly date a receipt for overdue premium payments, making it hard for the insured to prove payment before an accident occurred.
• Lowering the Standard of Proof: The court might allow the party whose proof was obstructed to establish the relevant fact with a lower degree of probability than usually required.
• Adverse Factual Inference / Factual Presumption: The court may, within its broad power of free evaluation of evidence (CCP Art. 247), draw an inference adverse to the obstructing party—i.e., presume that the lost or destroyed evidence would have been unfavorable to them. This was the effect seen in the boundary marker and factory pollution cases mentioned earlier.
• Truth Presumption (Shinjitsu Gisei) / Deeming the Fact True: More aggressive theories, gaining some traction, suggest that in egregious cases, the court should have the discretion to deem the obstructed party's assertion regarding the fact as true, effectively treating the fact as proven.

The choice of remedy often depends on a holistic assessment of the circumstances, including the nature of the fact in question, the importance of the lost or obstructed evidence, the degree of culpability of the obstructing party, and the impact on the overall fairness of the proceedings. The Tokyo High Court, in its decision on January 30, 1991 (Hanrei Jiho No. 1381, p. 49), which was the appeal in the insurance receipt case, suggested that the court could consider a range of effects from factual presumptions to deeming facts true, depending on the specific circumstances, including the obstructing party's level of intent or gross negligence.

Example: The Undated Insurance Premium Receipt

The scenario involving an insurer's agent failing to record the date on a receipt for overdue insurance premiums illustrates the application of shōmei bōgai. The date of payment was critical to determining whether insurance coverage was active at the time of an accident. The insurer has a legal duty (under Article 486 of the Civil Code) to issue a proper receipt upon payment. Failure to include the date could be seen as a breach of this duty, thereby obstructing the insured's ability to prove timely payment.
The Tokyo District Court (July 24, 1990) shifted the burden of proof, requiring the insurer to prove that the accident occurred before the premium was paid. On appeal, the Tokyo High Court (January 30, 1991) suggested a more flexible approach, indicating that based on the culpability (requiring intent or gross negligence for stronger effects like truth presumption), the court could draw adverse inferences or even deem the payment to have been timely. This highlights that even with similar facts, the precise legal consequence of shōmei bōgai can be subject to nuanced judicial assessment.

The Interplay and Conclusion

The allocation of the burden of proof sets the initial landscape for what each party must establish. However, the integrity of this process can be severely compromised if one party engages in conduct that obstructs the other's access to or use of relevant evidence. The doctrine of shōmei bōgai, through both specific statutory sanctions and its broader application under the good faith principle, serves as a critical tool for Japanese courts to redress such imbalances, prevent parties from benefiting from their own wrongdoing, and strive for a just outcome based on the most complete and fairly presented evidence possible. While the precise effects of general shōmei bōgai continue to be refined in case law and academic theory, the underlying message is clear: the Japanese legal system expects parties to conduct litigation honestly and fairly, and actions that undermine the evidentiary process will not be without consequence.