Evidence in Civil Proceedings (Japan)

Introduction

The law of evidence in Japanese civil proceedings is primarily codified in the Code of Civil Procedure (Minji Soshō Hō, 1996, as amended). Unlike common‑law systems, Japan does not maintain a comprehensive code of evidence separate from the procedural code. The CCP’s provisions on evidence, found in Book II, Chapter V (Articles 179–250), are supplemented by the judge’s inherent power to manage the evidentiary process and evaluate evidence freely.

The Principle of Free Evaluation of Evidence

Article 247 CCP states the foundational principle: “The court shall determine the truth of factual allegations based on the entire import of the oral argument and the evidence examined.” This is the principle of free evaluation of evidence (jiyū shinshō shugi). The judge is not bound by formal rules of weight or admissibility, as a common‑law judge would be.

The principle has two implications. First, the court may consider any evidence that is logically relevant, subject only to limited exclusionary rules (such as the privilege against self-incrimination and the prohibition on evidence obtained by torture). Second, the court is free to assess the credibility of witnesses, the authenticity of documents, and the persuasive force of expert opinions without mechanical presumptions.

Limitations. The free evaluation principle is not unlimited. The court must give reasons for its factual findings (Article 253 CCP). A finding that is wholly unsupported by the evidence or that contradicts the only available evidence may be overturned on kōso appeal.

The Burden of Proof

The burden of proof (kyoshō sekinin) is allocated according to the principle that each party bears the burden of proving the facts that are favourable to its legal position. This is the rule of ei incumbit probatio qui dicit, non qui negat (he who asserts must prove, not he who denies). In practice, the burden follows the substantive law: the plaintiff must prove the constitutive facts of the right it asserts; the defendant must prove the facts that defeat that right (such as payment, waiver, or prescription).

Prima Facie Evidence. Japanese courts sometimes employ a prima facie or presumptive approach where the direct proof of a fact would be disproportionately difficult. For example, in a tort case the court may infer causation from the existence of a harm and the defendant’s conduct, shifting the burden to the defendant to rebut the inference.

The Standard of Proof

The standard of proof in Japanese civil proceedings is debated. The orthodox view is that the standard is “high probability” (kōdo no kakushin): the judge must be convinced that the fact in issue is highly probable. The Supreme Court has articulated the standard as requiring a state of “certainty” (kakushin) that is “consistent with the dictates of common sense and experience” (Nissan Jidosha Jiken, Supreme Court, 1979).

A minority view argues that the standard is a preponderance of the evidence, on the ground that the risk of error should be borne equally by both parties. However, the dominant academic and judicial position is that the civil standard is higher than the mere balance of probabilities, though lower than the criminal standard of beyond a reasonable doubt.

Documentary Evidence

Documentary evidence (shōshō) is the most important category of evidence in Japanese civil litigation. Parties rely heavily on written materials: contracts, correspondence, public registers, invoices, and medical records.

Authenticity. A document must be authentic to be admitted. A private document is presumed to be authentically executed if the signature or seal of the maker is proved (Article 228(4) CCP). A public document is presumed authentic if it appears to have been executed by a public officer in due form (Article 228(2) CCP). The opposing party may challenge authenticity; if the challenge is not sustained, the document is admitted.

Document Production Orders. Japan does not have a broad discovery regime comparable to the US system. Instead, Article 220 CCP provides a limited document production mechanism. A party may apply to the court for an order directing the opposing party or a third party to produce a specified document. The applicant must identify the document with reasonable specificity and show that it is relevant to the case.

Five Exemptions. Article 220 enumerates five categories of documents that are exempt from production: (1) documents relating to the maker’s criminal prosecution or conviction; (2) documents containing secrets concerning public officers’ duties; (3) documents concerning secrets that would prejudice the public interest; (4) documents containing technical or professional secrets; and (5) documents prepared exclusively for the party’s own use (such as internal legal opinions and litigation strategy documents). The privilege against self-incrimination is also protected.

The court reviews the claimed exemption in camera if necessary. If the order is disobeyed without good cause, the court may deem the facts asserted by the applicant to be true (Article 224 CCP).

Witness Examination

Witness testimony (shōnin jinsō) is governed by Articles 190–206 CCP. Any person with knowledge of the facts may be a witness, unless the facts are subject to a privilege.

Examination Procedure. The examination proceeds through three stages:

• Examination-in-chief (shujin jinsō) — the party who called the witness asks questions.
• Cross-examination (han-jinsō) — the opposing party asks questions.
• Re-examination (sai-jinsō) — the party who called the witness asks further questions.

The judge may intervene at any time to ask clarifying questions (Article 202 CCP). The court has the power to call a witness on its own motion (Article 191 CCP).

Privileges. A witness may refuse to testify on grounds of close family relationship (Article 196 CCP), professional privilege (for lawyers, doctors, and certain other professionals — Article 197 CCP), and the privilege against self-incrimination (Article 198 CCP).

Expert Evidence

Expert evidence (kantei) may be ordered by the court on its own motion or at the request of a party (Article 213 CCP). The court appoints the expert, who is typically an academic, a medical practitioner, or a professional in the relevant field.

The expert submits a written opinion and may be examined orally (Article 215 CCP). The parties may also retain their own experts, whose opinions are submitted as documentary evidence rather than formal expert evidence. This dual system — court-appointed expert (kantei) and party-retained expert (jizen kantei) — is characteristic of Japanese civil procedure.

Inspection

Inspection (kenshō) is governed by Articles 232–234 CCP. The court may inspect the site, objects, or persons to ascertain facts. An inspection report is prepared and becomes part of the record.

Party Examination

Party examination (tōjinsha jinsō) permits the court to examine a party (the plaintiff or defendant) as a source of evidence (Articles 207–211 CCP). This is distinct from the party’s own testimony in support of its own case. A party who refuses to appear or to answer may be subject to an adverse inference.

The Hearsay Rule

Japan does not have a formal hearsay rule analogous to that of the common law. Written statements recounting out-of-court declarations are admissible if they are relevant and if the declarant is available for cross-examination. The court weighs hearsay evidence according to its reliability in the circumstances.

Admissibility and Exclusion

The CCP does not contain a general exclusionary rule for illegally obtained evidence. However, the Supreme Court has held that evidence obtained by means that “violate fundamental constitutional values” may be excluded if its admission would “undermine the fairness of the proceedings” (Mitsui Kōzan Jiken, 1999). This doctrine is rarely applied in civil cases.