Free Evaluation of Evidence (Jiyū Shinshō) in Japan: What is the Standard of Proof in Civil Cases?

The resolution of many civil lawsuits ultimately turns on the determination of disputed facts. How judges in Japan approach this critical task of fact-finding is governed by two intertwined core principles: Jiyū Shinshō Shugi (自由心証主義), the Principle of Free Evaluation of Evidence, and Shōmei-do (証明度), the Standard of Proof. These concepts dictate the manner in which evidence is weighed and the level of certainty a court must achieve before accepting a fact as true. This article explores these principles, their underlying rationale, inherent limitations, and related doctrines such as presumptions that play a significant role in the Japanese civil justice system.

The Principle of Free Evaluation of Evidence (Jiyū Shinshō Shugi)

Article 247 of the Japanese Code of Civil Procedure (CCP) provides the statutory basis for the Principle of Free Evaluation of Evidence. It states: "In rendering a judgment, the court shall, taking into account the entire import of the oral argument and the results of the examination of evidence, freely determine the facts it finds to be true based on its conviction."

At its heart, Jiyū Shinshō Shugi means that judges are not bound by rigid, predetermined, or formalistic rules when assessing the probative value of evidence presented to them. Instead, they are entrusted to use their rational judgment, common sense, professional experience, and overall understanding of the case to weigh the evidence and arrive at factual conclusions. This principle marks a significant departure from older "statutory evidence systems" (hōtei shōko shugi), which might have prescribed, for example, that the testimony of two credible witnesses automatically proves a fact, or that certain types of documents have conclusive weight. Such formalistic systems were deemed too inflexible and ill-suited for the complexities of modern disputes.

The rationale for adopting Jiyū Shinshō Shugi includes:

• Nuanced Fact-Finding: It allows for a more holistic and case-specific evaluation, considering the unique circumstances and subtleties of each dispute.
• Comprehensive Consideration: It enables the court to take into account "the entire import of the oral argument," which includes not only formal evidence but also the parties' statements, demeanor, and the overall context of the proceedings.
• Judicial Professionalism: It places trust in the competence, impartiality, and experience of judges to make reasoned factual determinations.

Limits and Constraints on Free Evaluation

While the term "free" evaluation suggests broad discretion, this freedom is not absolute or arbitrary. It operates within important legal and rational constraints:

1. Adherence to Procedural Rules for Evidence ("Strict Proof" - Genkaku na Shōmei): For facts that form the direct basis of the substantive rights and obligations in dispute (principal facts, shuyō jijitsu), the evidence considered must have been formally introduced into the proceedings and examined in accordance with the rules of civil procedure (CCP Arts. 180-242). This requirement of "strict proof" ensures procedural fairness, allowing parties to be aware of the evidence being considered and to have an opportunity to challenge or rebut it. Judges cannot rely on their private knowledge or information obtained informally outside the courtroom (e.g., an unrecorded phone call to a potential witness) to establish these core factual findings. To do so would violate the Principle of Party Presentation (Benron Shugi) and fundamental due process rights, such as the right to cross-examine. Information properly obtained through formal procedural mechanisms, such as court-ordered clarification proceedings (shakumei shobun), can, however, become part of the "entire import of the oral argument" and be legitimately considered.
2. Rationality: Rules of Experience (Keiken-soku) and Logic (Ronri-soku): The judge's evaluation of evidence and subsequent fact-finding must be rational and consistent with established rules of experience and logical principles.
   • Rules of Experience (Keiken-soku): These are general maxims or understandings derived from human experience about how events typically unfold, how people generally behave in certain situations, or the ordinary course of affairs. They can range from everyday common sense to more specialized knowledge within particular fields (e.g., medical, engineering, financial practices).
   • When specialized or technical experience is necessary to understand the evidence or draw proper inferences, it is typically introduced into the proceedings through formal channels, such as expert testimony (鑑定 - kantei), expert participation in clarification proceedings (CCP Art. 151(1)(v)), or explanations provided by court-appointed expert commissioners (専門委員 - senmon iin). Crucially, parties must be given an opportunity to address and contest any specialized rules of experience upon which the court might rely.
   • A judicial decision that is based on a clear and significant error in the application of logic or generally accepted rules of experience can be challenged on appeal as a violation of law, specifically as a misapplication of CCP Article 247.

The Standard of Proof (Shōmei-do): How Certain Must the Court Be?

Shōmei-do refers to the requisite degree of conviction or certainty that the court must attain regarding the existence of a disputed fact before it can be accepted as proven for the purposes of the judgment.

1. Not Absolute Certainty: Unlike mathematical proofs or the level of certainty sought in some natural sciences, civil litigation operates in a realm of probabilities based on often incomplete or conflicting information. Demanding absolute, 100% certainty for every fact would render it virtually impossible for any party to meet their burden of proof, effectively paralyzing the adjudicative process.
2. The Prevailing Standard: "High Degree of Probability" (高度の蓋然性 - Kōdo no Gaizensei):
   The dominant view in Japanese case law and legal scholarship is that for a fact to be considered proven in a civil case, the court must be convinced of its existence to a "high degree of probability." This standard is often elaborated as requiring a level of conviction where an ordinary, reasonable person, after considering all the evidence, would no longer harbor any substantial or reasonable doubt about the truth of the fact. While sometimes illustratively quantified as a 70-80% degree of certainty, this is not a mathematical formula but rather a qualitative benchmark for judicial conviction. The Supreme Court decision in the "Lumbaal Puncture Case" (October 24, 1975, Minshū Vol. 29, No. 9, p. 1417), which dealt with complex issues of medical causation, is frequently cited in discussions pertaining to this standard of proof.
3. Critiques and Alternative Perspectives: "Preponderance of Evidence" / "Superior Probability" (Yūetsu-teki Gaizensei Setsu):
   Despite its prevalence, the "high degree of probability" standard is not without its critics. Some scholars argue that it can be overly demanding, potentially leading to unjust outcomes in situations where a fact is more likely true than not (i.e., its probability exceeds 50%) but fails to reach the somewhat elusive 70-80% threshold of conviction. In such cases, where the evidence leaves the court in a state of genuine uncertainty (non liquet), the fact is deemed not proven, and the party bearing the burden of proof on that issue consequently fails.
   An alternative standard, sometimes advocated for, is akin to the "preponderance of the evidence" standard found in some common law jurisdictions. This "superior probability" theory (yūetsu-teki gaizensei setsu) would require the party with the burden of proof to merely persuade the court that their version of the facts is more probable than the opponent's (i.e., a probability greater than 50%). Proponents suggest that this standard might better align with the objective of discerning the most likely version of the truth based on the available evidence and could also incentivize both parties to more proactively present all relevant information from an earlier stage.
   However, the "high degree of probability" remains the formally endorsed and widely applied standard in Japanese civil practice. Nevertheless, it is acknowledged that courts may, in practice, implicitly adjust the rigor of its application based on factors such as the nature of the specific case, the inherent difficulty of proving certain types of facts, and underlying policy considerations.
4. "Proof" (Shōmei) versus "Prima Facie Showing" / "Making a Plausible Case" (Somei - 疎明):
   It is important to distinguish the standard of "proof" (shōmei) required for facts underpinning a final judgment on the merits from the lesser standard often sufficient for certain interim procedural decisions. For many interlocutory matters, such as determining jurisdiction or granting provisional remedies like injunctions or attachments (e.g., under Article 13 of the Civil Preservation Act), a "prima facie showing" or demonstration that the alleged facts are "plausible" or "likely true" – a standard known as somei – is often adequate. The methods for presenting somei can also be less formal, often relying on evidence that can be examined immediately (CCP Art. 188). This distinction reflects the different procedural contexts: final judgments demand a high degree of certainty, while interim measures often require quicker decisions based on a preliminary assessment of likelihood to prevent irreparable harm or secure future enforcement.
   Some legal scholars conceptualize this distinction not merely as a difference in the required degree of probability, but as a difference in the "degree of elucidation" (kaimei-do). Under this view, for somei, the court makes a finding based on less comprehensive information due to limitations on available evidence or the urgency of the situation, implicitly acknowledging that a more thorough examination of evidence might lead to a different conclusion later.

The Role of the Burden of Proof (Shōmei Sekinin) When Free Evaluation Fails

If, after meticulously evaluating all the evidence presented, the judge is unable to form a conviction that meets the required standard of proof (i.e., a "high degree of probability") regarding a disputed material fact, that fact is deemed "not proven." In such a situation of genuine uncertainty or non liquet, the legal mechanism of the burden of proof (shōmei sekinin) becomes determinative. The party who was assigned the burden of proving that particular fact will bear the adverse consequence of this failure of proof; effectively, they "lose" on that factual issue, and the fact will be treated as non-existent for the purpose of the court's legal reasoning. The allocation of this burden of proof for each essential fact (yōken jijitsu) is primarily determined by the structure and content of the applicable substantive law.

The illustrative case in Chapter 3-11 of the reference material, involving a dispute over an insurance claim following A's death in a car accident (where the insurer Q alleges suicide, an excluded event, while A's mother B claims it was an accident covered by the policy), highlights the critical impact of burden of proof allocation.

• If the insurance policy requires the claimant to prove that the death was "accidental" (i.e., not intentional on A's part) to trigger coverage, then B bears this burden. If the court remains uncertain whether the death was accidental or suicide, B would fail to meet her burden, and the claim would be dismissed. The Supreme Court adopted this approach for an accident insurance policy in a decision on April 20, 2001 (Minshū Vol. 55, No. 3, p. 682).
• Conversely, if the policy generally covers death by external event, but contains an exclusion for suicide, then B might only need to prove death by such an external event. The insurer, Q, would then bear the burden of proving that the specific exclusion (suicide) applies. If the court is uncertain about suicide, Q fails to prove the exclusion, and B would prevail. This approach has been adopted by the Supreme Court in cases involving fire insurance (December 13, 2004, Minshū Vol. 58, No. 9, p. 2419) and vehicle insurance (e.g., June 1, 2006, Minshū Vol. 60, No. 5, p. 1887; April 17, 2007, Minshū Vol. 61, No. 3, p. 1026).
  The precise wording of the insurance policy and the legal characterization of "accidental means" versus "suicide exclusion" can therefore be outcome-determinative when the evidence is scarce or ambiguous.

Alleviating the Burden of Proof: Presumptions and Related Doctrines

Recognizing that meeting the "high degree of probability" standard can be exceptionally challenging in certain situations, particularly where direct evidence is lacking or where one party has disproportionate access to relevant information, Japanese law and judicial practice employ various doctrines designed to alleviate the burden of proof or assist the party bearing it:

1. Legal Presumptions (Hōritsu-jō no Suitei): These are presumptions explicitly established by statute. When a party proves a specified basic fact (Fact A), the law directs that another fact (Fact B, the presumed fact) is to be taken as true, unless and until the opposing party adduces sufficient evidence to rebut the presumption. This effectively shifts the burden of producing evidence (and sometimes the burden of persuasion) regarding the non-existence of Fact B to the opponent. An example is the presumption of negligence on the part of the possessor or owner of a defective structure that causes harm (Civil Code Art. 717(1) proviso).
2. Factual Presumptions (Jijitsu-jō no Suitei or 推認 - Suinin): These are not mandated by statute but are inferences that a court may draw based on proven indirect facts, guided by common sense, logic, and general rules of experience. For example, from proof that a letter was properly addressed, stamped, and mailed, a court might infer that it was delivered to the addressee. The opposing party can rebut such a factual presumption by challenging the underlying indirect facts, by questioning the applicability or strength of the experiential rule being invoked, or by presenting other facts that weaken or negate the inference. Unlike legal presumptions, factual presumptions generally do not formally shift the ultimate burden of proof for the main fact.
3. Prima Facie Proof / "An-Schein Beweis" / Doctrines Analogous to Res Ipsa Loquitur (Ichidan no Suitei - 一応の推定 - literally, "Presumption for the Time Being" or "Provisional Presumption"): This judicially developed doctrine is particularly significant in tort litigation, especially in areas like medical malpractice or certain types of accident cases where the plaintiff faces inherent difficulties in directly proving specific acts of negligence or the precise chain of causation. If the plaintiff can prove a certain pattern of facts that, according to common experience or specialized knowledge, typically and strongly suggests the existence of negligence or causation on the part of the defendant, the court may make a "provisional presumption" of that negligence or causation. This does not definitively establish the fact, but it places a burden on the defendant to come forward with evidence offering a plausible alternative explanation for the events or demonstrating that they were not, in fact, negligent or that their actions did not cause the harm. If the defendant fails to provide a satisfactory rebuttal, the court may then find the presumed fact (negligence or causation) to be established. Ichidan no suitei is a flexible tool used by courts to address evidentiary imbalances and to promote fairness when direct proof is elusive but the circumstances strongly point towards a particular conclusion. The reference material suggests that if the claimant (B) in the insurance case bears the burden of proving "accidental death," this doctrine of ichidan no suitei might be invoked to assist her. If B establishes facts such as A's general lack of suicidal ideation, positive future plans, and circumstances of the accident that are outwardly consistent with a typical traffic accident, the court might provisionally presume the death was accidental, thereby requiring the insurer Q to produce robust evidence to support its suicide contention.

Court's Discretion in Assessing the Amount of Damages (CCP Art. 248)

A specific provision, Article 248 of the CCP, addresses situations where the court is satisfied that damage has indeed occurred as a result of the defendant's wrongful act, but determining the precise monetary amount of that damage is extremely difficult due to the nature of the harm or the available evidence. In such cases, the court is empowered to determine a reasonable amount of damages, taking into account the entire import of the oral argument and the results of the evidence examination. This grants the court a degree of discretion in quantifying damages where exact calculation is impracticable, preventing a valid claim from failing entirely due to such evidentiary challenges related to quantum. While primarily concerned with the amount of damages rather than the liability-creating facts themselves, this provision reflects a broader pragmatic approach within the Japanese system to deal with inherent difficulties in proof.

Conclusion

The Principle of Free Evaluation of Evidence (Jiyū Shinshō Shugi) grants Japanese judges significant discretion in weighing evidence and making factual determinations. However, this freedom is not unbridled; it is constrained by the demands of rationality, adherence to logical principles and established rules of experience, and the overarching requirements of procedural fairness. The standard of proof generally required in civil cases is a "high degree of probability," a benchmark demanding a strong level of judicial conviction. When this standard cannot be met regarding a disputed fact, the allocation of the burden of proof becomes decisive. To mitigate the harshness that can result from strict application of the burden of proof, particularly in situations of evidentiary difficulty, Japanese law and jurisprudence utilize various tools, including legal and factual presumptions, and the doctrine of ichidan no suitei. This intricate interplay of principles reflects the Japanese civil justice system's continuous endeavor to balance the ideals of legal certainty and procedural rigor with the pragmatic pursuit of substantively just outcomes in individual cases.