What is the "Principle of Free Evaluation of Evidence" in Japan and What Does It Mean for My Case?

In any lawsuit, the determination of facts is a cornerstone upon which the final judgment rests. But how do judges in Japan weigh the evidence presented by opposing parties? Unlike systems that might have rigid, formal rules dictating the value of specific types of evidence, Japanese civil procedure operates under the "Principle of Free Evaluation of Evidence," known as Jiyū shinshō-shugi (自由心証主義). This principle grants judges considerable discretion in assessing the probative value of evidence and forming their conviction about the truth of factual allegations. Understanding this doctrine is crucial for any business involved in litigation in Japan, as it directly impacts how evidence should be selected, prepared, and presented to the court.

I. Understanding the "Principle of Free Evaluation of Evidence" (Jiyū shinshō-shugi)

A. Definition and Legal Basis (Code of Civil Procedure, Art. 247)

The Principle of Free Evaluation of Evidence is enshrined in Article 247 of Japan's Code of Civil Procedure (Minji Soshō Hō 民事訴訟法):
"In rendering a judgment, the court shall, taking into account the entire import of oral arguments and the results of the examination of evidence, freely determine, based on its conviction, whether or not allegations of fact should be found to be true."
(原文：「裁判所は、判決をするに当たり、口頭弁論の全趣旨及び証拠調べの結果をしん酌し、自由な心証により、事実についての主張を真実と認めるべきか否かを判断する。」)

This provision empowers judges to:

• Consider all aspects of the oral arguments and all evidence examined.
• Use their "free conviction" (jiyū na shinshō 自由な心証) – their inner, reasoned belief formed through this comprehensive consideration.
• Determine the truth or falsity of factual allegations without being bound by formalistic, pre-determined rules on the weight or hierarchy of different types of evidence.

B. Historical Context: Rejection of Statutory Evidence Rules (Hōtei shōko-shugi 法定証拠主義)

Jiyū shinshō-shugi stands in contrast to the older "Statutory Evidence System" (Hōtei shōko-shugi 法定証拠主義), which existed in various forms historically in Japan and other civil law traditions. Under such systems:

• Specific types of evidence were assigned fixed probative values (e.g., the testimony of two male witnesses might outweigh that of one female witness, or a confession might be deemed conclusive proof – the "queen of evidence").
• Certain evidence might be automatically excluded or given little weight based on formal criteria rather than its actual reliability in a specific case.

The adoption of free evaluation aimed to move towards a more rational and flexible system focused on discovering the substantive truth by allowing judges to assess evidence based on its actual persuasive power in the context of the entire case, rather than by applying rigid, often arbitrary, legal formulae.

C. Core Components of Jiyū shinshō-shugi

1. No Pre-determined Hierarchy of Evidence: Japanese law does not stipulate that one type of evidence (e.g., documentary evidence) is inherently superior or more credible than another (e.g., witness testimony). Each piece of evidence is assessed on its own merits and in conjunction with all other evidence.
2. Free Assessment of Probative Value (Shōmei-ryoku 証明力): The judge has the discretion to determine how much weight or credibility to assign to each piece of evidence. This assessment considers factors like the reliability of the source, the circumstances under which the evidence came into being, its relevance to the facts in issue, its consistency with other evidence, and common sense.
3. Consideration of the "Entirety of Oral Arguments" (Kōtō benron no zen shushi 口頭弁論の全趣旨): This is a broad concept. It means the judge doesn't just look at isolated pieces of evidence but considers everything that has transpired during the oral hearing process. This can include:
   • The parties' allegations and the consistency (or lack thereof) in their positions.
   • The demeanor and responsiveness of parties and witnesses.
   • Admissions or concessions made during hearings.
   • The way parties have responded to the court's requests or questions (under its power of clarification, shakumei-ken 釈明権).
   • Any inexplicable failures to produce relevant evidence that a party would normally be expected to possess.

II. How Judges Evaluate Evidence under Jiyū shinshō-shugi

While "free," the judge's evaluation is not arbitrary. It is a reasoned process.

• Documentary Evidence (Shoshō 書証): Judges assess the authenticity of documents (e.g., are signatures genuine, has the document been altered?), their origin, the circumstances of their creation, the clarity and precision of their content, and their relevance to the disputed facts. Contemporaneous documents created in the ordinary course of business are often given significant weight.
• Witness Testimony (Shōnin jinmon 証人尋問): The credibility of a witness is paramount. Judges consider factors such as:
  • The witness's opportunity and capacity to observe the events they testify about.
  • Their demeanor on the stand (though this is assessed cautiously).
  • The internal consistency of their testimony and its consistency with other evidence.
  • Any potential bias, interest in the outcome, or relationship to the parties.
  • The plausibility of their account in light of common experience.
    Corroboration by other evidence often strengthens witness testimony.
• Expert Opinions (Kantei 鑑定): In cases involving specialized or technical knowledge (e.g., patent infringement, medical malpractice, complex financial transactions), expert opinions are often crucial. Judges evaluate:
  • The expert's qualifications, expertise, and impartiality.
  • The methodology and reasoning underlying the expert's conclusions.
  • The factual basis for the opinion.
  • The logical consistency and persuasiveness of the opinion.
    Judges are not legally bound by expert opinions and must form their own conviction, but well-reasoned and objective expert testimony carries considerable weight.
• Circumstantial Evidence (Jōkyō shōko 状況証拠) and Inferences (Suinin 推認): Direct evidence on a principal fact (shuyō jijitsu 主要事実) may not always be available. Judges routinely make findings by drawing logical inferences from established indirect facts (kansetsu jijitsu 間接事実) – facts that, while not directly proving the ultimate fact in issue, make its existence more or less probable when considered together and in light of experience.
• Standard of Proof: "High Degree of Probability" (Kōdo no gaizen-sei 高度の蓋然性): For a judge to find an alleged fact to be true in a civil case, they must be convinced to a "high degree of probability." This is generally understood to be a standard requiring more than a mere "preponderance of the evidence" (i.e., more likely than not, >50%) but less than the "beyond a reasonable doubt" standard used in criminal cases. It implies a strong conviction based on the evidence, though not necessarily absolute certainty.

III. Limitations and Safeguards on Jiyū shinshō-shugi

The "freedom" in free evaluation is not unfettered. It operates within a framework of legal principles and safeguards designed to prevent arbitrary or unjust decisions.

1. Adherence to Logic and General Experience (Ronri-hōsoku / Keiken-soku 論理法則・経験則):
   The judge's conviction must be based on logical reasoning and be consistent with generally accepted principles of human experience and common sense. A factual finding that defies logic or runs contrary to widely accepted empirical knowledge can be challenged on appeal as an error in the application of Jiyū shinshō-shugi.
2. The Principle of Party Presentation (Benron-shugi 弁論主義):
   • Judges generally cannot base their factual findings on principal facts that have not been alleged by either party.
   • Facts that have been judicially admitted by a party concerning principal matters are generally binding on the court and cannot be contradicted by the judge's free evaluation, unless the admission is clearly invalid (e.g., contrary to public order or demonstrably false).
3. Burden of Proof (Shōmei sekinin 証明責任):
   Jiyū shinshō-shugi does not negate the rules on burden of proof. If, after a free evaluation of all the evidence and consideration of the entire import of oral arguments, the judge remains unconvinced about a material fact to the level of "high degree of probability" (i.e., the fact is non liquet – unclear), the party who bears the burden of proving that fact will fail on that issue. The judge cannot simply decide based on a hunch if the requisite level of persuasion is not met.
4. Admissibility of Evidence (Shōko nōryoku 証拠能力):
   While the probative value of admitted evidence is freely evaluated, the admissibility of evidence in the first place is subject to certain rules. For example:
   • Evidence protected by legal privilege (e.g., attorney-client privilege, though its scope in Japan differs from common law) may be excluded.
   • Illegally Obtained Evidence (Ihō shūshū shōko no haijo 違法収集証拠の排除): Evidence obtained through serious illegal means may be excluded if its admission would violate fundamental rights or procedural fairness, outweighing the interest in truth-finding. Japanese courts adopt a balancing test, considering the gravity of the illegality and the importance of the evidence. (Supreme Court, July 15, 1976, Keishu Vol. 30, No. 7, p. 1178, although a criminal case, laid down influential principles).
5. Requirement to State Reasons in the Judgment (Hanketsu riyū no kisai 判決理由の記載):
   Article 246 of the Code of Civil Procedure requires that a judgment state the reasons for the decision. For the factual findings, this means the court must explain, to a reasonable extent, how it evaluated the key evidence and why it reached its conclusions on disputed facts. This provides transparency, allows parties to understand the basis of the decision, and enables meaningful appellate review of the fact-finding process (primarily to check for violations of logic, experience, or other procedural rules).

IV. Practical Implications for Businesses in Japanese Litigation

The Principle of Free Evaluation of Evidence has significant practical ramifications:

• Quality and Persuasiveness of Evidence are Paramount: Since judges are not bound by formal rules about which evidence is "better," the focus must be on presenting evidence that is inherently credible, reliable, verifiable, and logically persuasive.
• Importance of Corroboration: While no specific number of witnesses or documents is legally required, presenting multiple, consistent pieces of evidence that support a factual assertion generally strengthens its persuasiveness.
• Witness Preparation is Crucial: Witnesses should be prepared to testify clearly, consistently, and truthfully. Their credibility will be scrutinized. Documentary evidence that supports or contradicts witness testimony will be weighed.
• Effective Use of Expert Testimony in Complex Cases: In disputes involving specialized technical, scientific, or financial knowledge, well-reasoned, objective, and clearly explained expert opinions can be highly influential. However, the opposing party may present their own expert, and the judge will ultimately evaluate all expert input.
• Understanding the "Entirety of Oral Arguments": A party's overall conduct during the litigation can influence the judge's general impression (shinshō 心証 – inner conviction or impression). Consistency in arguments, responsiveness to court inquiries, and a generally cooperative (though firm) attitude can be subtly beneficial. Conversely, evasiveness or contradictory statements can undermine credibility.
• No "Smoking Gun" Guarantees Victory (Necessarily): Even if a party believes they have a "smoking gun" piece of evidence, its ultimate weight will be determined by the judge in the context of all other evidence and arguments.

Conclusion

The Principle of Free Evaluation of Evidence (Jiyū shinshō-shugi) is a cornerstone of the Japanese fact-finding process in civil litigation. It entrusts judges with significant discretion to weigh evidence and ascertain the truth based on their reasoned conviction, free from rigid formalistic constraints. For businesses, this underscores the critical importance of building a robust and persuasive case through high-quality, credible evidence. Success hinges not merely on the volume of evidence, but on its ability to convince a discerning judge to a "high degree of probability" that the asserted facts are true, all while navigating the essential boundaries set by logic, general experience, and overarching procedural principles.