Can Recorded Interrogations Be Used as Evidence in Japanese Courts? The Debate Over Admissibility for Substance and Credibility

A significant reform in Japanese criminal procedure was the introduction in Heisei 28 (2016) of mandatory audio and video recording of suspect interrogations (取調べの録音・録画, torishirabe no rokuon-rokuga) for certain types of serious cases, such as those tried under the lay judge system (saiban-in seido, 裁判員制度) or those investigated by special prosecution units. The primary stated objectives of this "visualization" of interrogations were to ensure the accurate establishment of the voluntariness of any confessions made by the suspect and to contribute to the overall appropriateness and fairness of the interrogation process itself.

While the use of these recordings to verify the voluntariness of a suspect's statements is explicitly provided for in the Code of Criminal Procedure (CCP, Art. 301-2) and is largely uncontroversial, a complex legal debate has emerged regarding their admissibility for other purposes. Specifically, can these recordings be used as:

1. Substantive evidence (実質証拠, jisshitsu shōko) to directly prove the truth of the facts asserted in the suspect's recorded statements?
2. Auxiliary evidence for credibility (信用性の補助証拠, shin'yōsei no hojo shōko) to support or undermine the reliability of a written interrogation record (供述調書, kyōjutsu chōsho) or related in-court testimony by assessing the suspect's demeanor and the context of the interrogation?

Japanese courts, particularly at the High Court level, have begun to grapple with these questions, revealing a cautious and often restrictive approach.

The Established Use: Verifying Voluntariness

Under Article 301-2 of the CCP, if a prosecutor requests the admission of a written statement containing a confession or other self-incriminating admission by the defendant, and the voluntariness of that statement is disputed, the prosecutor must request the examination of the audio/video recording of the relevant interrogation period. This ensures that the court (including lay judges) can observe the circumstances under which the statement was made to determine if it was truly voluntary and not the product of coercion or improper inducement. This statutory mandate makes the recording a crucial piece of evidence for resolving disputes over the admissibility of confessions based on their voluntariness.

The Contentious Frontier: Recordings as Substantive Evidence

Using the recorded interrogation as substantive evidence means relying on the content of the suspect's out-of-court oral statements, as captured on the recording, to directly prove the elements of the alleged crime.

During the legislative discussions leading to the 2016 reforms, it was generally understood by many participants that if a written interrogation record (a chōsho)—which is itself a form of hearsay summarizing a suspect's statements—can be admitted as substantive evidence under certain conditions (e.g., CCP Art. 322 for a defendant's own statements), then logically, an audio/video recording of the actual oral statements should not be inherently less admissible. The absence of an explicit provision in the 2016 law detailing the substantive use of recordings was, by some interpretations, not intended as a prohibition but rather reflected an assumption that existing evidentiary principles would govern, or that such use was self-evident.

However, courts have approached this with considerable trepidation. The Tokyo High Court decision of August 10, 2016 (Hanrei Jihō No. 2329, p. 98), is illustrative. In this case, the defendant had made incriminating statements during a recorded interrogation but recanted them at trial. The prosecutor sought to introduce the recording not only to show voluntariness but also as substantive evidence of the earlier confession and to allow the court to assess its credibility by observing the defendant's demeanor. The trial court refused to admit the recording for these broader purposes, citing a lack of necessity (as the content of the alleged confession had already been made clear through the defendant's in-court testimony about his prior statements) and expressing skepticism about the reliability of judging truthfulness from demeanor alone.

The Tokyo High Court upheld the trial court's decision. It voiced strong reservations about the general use of interrogation recordings as substantive evidence, highlighting several concerns:

• Legislative Intent: The primary purpose of the 2016 recording mandate was to prevent coerced confessions and ensure procedural fairness, not necessarily to create a new avenue for introducing substantive evidence.
• Risk to Trial Dynamics: Allowing routine substantive use could lead to trials becoming excessively focused on the lengthy review of interrogation footage. This might undermine the principles of directness and orality in court (where live testimony is preferred) and could give undue prominence to out-of-court statements made in the less controlled environment of an interrogation room.
• Demeanor Unreliability: The court was particularly skeptical about the idea that judges or lay judges could reliably determine the truthfulness of a recorded statement based on the suspect's demeanor during the interrogation.
• Contradicting Reform Goals: Encouraging the substantive use of recorded confessions might inadvertently perpetuate the very over-reliance on confessions that the broader criminal justice reforms aimed to reduce.

An Even More Disputed Use: Recordings as Auxiliary Evidence for Credibility

If not used to prove the crime itself, can recordings be used to help the court decide whether a written confession (chōsho) or related testimony is believable? This involves using aspects of the recording—such as the suspect's demeanor, coherence, consistency, emotional state, and the interaction with interrogators—to assess the credibility of the formal confession statement.

The Tokyo High Court decision of August 3, 2018 (Hanrei Jihō No. 2389, p. 3), a notable case often referred to as the Imaichi jiken (今市事件), dealt extensively with this issue. In this murder trial, the defendant's recorded confessions were central. The trial court admitted portions of the interrogation recordings explicitly as auxiliary evidence to assess the credibility of the defendant's written confessions.

On appeal, the Tokyo High Court was highly critical of how the trial court used these recordings. It found that the trial court, while claiming to use the recordings merely to assess the credibility of the written confession, had effectively gone further. The trial court had relied on the defendant's demeanor and manner of speaking in the recordings to directly infer the defendant's guilt regarding the crime's core facts (e.g., that the confession appeared "voluntary" and "not induced," therefore likely true and indicative of guilt). The High Court viewed this as an improper use of demeanor evidence from the recording as if it were substantive proof of the crime itself, potentially violating Article 317 of the CCP (which allows for free evaluation of evidence but within legal limits and based on rationality).

More broadly, the High Court in the Imaichi case expressed profound skepticism about the reliability and appropriateness of using recorded demeanor to judge the credibility of confessions:

• Risk of Misjudgment: The court warned that judging credibility based on a suspect's appearance or mannerisms during a police interrogation is fraught with danger. A suspect might appear calm yet be lying, or appear agitated yet be truthful but under stress. Such assessments can be highly subjective and lead to "impression-based, intuitive judgments."
• Oversimplification of Truth/Falsity: The court cautioned against a simplistic binary view that a "voluntary-looking" demeanor equates to a truthful confession. False confessions can be given "voluntarily" for a variety of complex reasons, a possibility that demeanor analysis might obscure.
• Focus on Objective Indicators: The High Court stressed that the credibility of a confession should primarily be assessed based on objective factors: consistency with other established facts, the presence of "secret knowledge" (details only the perpetrator could know), internal consistency, and overall rationality, rather than on subjective impressions gleaned from watching a recording of the interrogation.

The High Court concluded that using recordings to assess credibility through demeanor analysis could actually hinder a careful, objective evaluation of a confession's reliability by overemphasizing subjective factors.

Judicial Concerns and the Path Forward

The cautious stance taken by these High Court decisions reflects several underlying concerns:

1. The Unreliability of Demeanor: There is a deep judicial skepticism about the ability of anyone, including judges and lay judges, to accurately determine truthfulness based on a person's demeanor, especially in the unique and often stressful environment of a police interrogation.
2. The Power of Visuals and Potential Prejudice: Video evidence can be compelling. A recorded confession, even if its content is questionable or if it was obtained under subtle pressures not immediately apparent, might unduly sway fact-finders due to its visual impact.
3. Maintaining Trial-Centered Justice (公判中心主義, kōhan chūshin shugi): There's a concern that if interrogation recordings are too readily admitted for purposes beyond verifying voluntariness, trials could transform into reviews of pre-trial investigative materials, diminishing the importance of live, in-court testimony and cross-examination.
4. The Specter of Over-Reliance on Confessions: Despite reforms, Japan's criminal justice system has historically faced criticism for an over-reliance on confessions. A tool designed to make interrogations fairer (recordings) should not inadvertently lead back to confessions—albeit recorded ones—becoming the primary focus of trials.
5. Practical Burdens: Reviewing potentially hours of interrogation footage can be extremely time-consuming for courts, particularly for lay judges, and may not always be a proportionate use of court resources if the evidentiary value for substantive or credibility purposes is limited.

Is There a Middle Ground?

While the High Court rulings discussed express strong reservations, they do not necessarily represent an absolute ban on any use of recordings beyond proving voluntariness. Some arguments for carefully circumscribed broader use include:

• Recordings provide a more complete and arguably more accurate account of what a suspect said than a written summary prepared by an investigator.
• If a defendant disputes the accuracy of a written chōsho, or claims statements were taken out of context, the recording could be the best evidence to clarify what actually transpired.
• In limited situations, aspects of the interrogation environment or interaction captured on tape (beyond just demeanor) might legitimately bear on the credibility of a statement, provided they are assessed critically and not as a simple truth-detector.

The current legal landscape suggests that admissibility for these broader purposes will be determined on a case-by-case basis, with courts exercising significant discretion. The "necessity" (hitsuyōsei, 必要性) of admitting the recording for a specific, legitimate purpose beyond voluntariness will be a key factor. Given the prevailing judicial caution, particularly regarding demeanor-based inferences, any attempt to use recordings substantively or for credibility faces an uphill battle and must be carefully justified against the risks of prejudice and misjudgment.

Conclusion

The introduction of mandatory audio/video recording of interrogations marks a pivotal reform in Japanese criminal justice, primarily aimed at enhancing transparency and protecting against coerced confessions. Its role in verifying the voluntariness of statements is statutorily clear and accepted. However, the question of whether these recordings can, or should, be used more broadly—as direct substantive evidence of the crime or as auxiliary proof of a confession's credibility—remains a complex and actively debated area.

The influential Tokyo High Court decisions from 2016 and 2018 signal a strong judicial inclination to restrict such broader uses, driven by concerns about the unreliability of demeanor evidence, the potential for prejudice, and the desire to uphold the principles of a trial-centered justice system that does not unduly rely on pre-trial confessions. While not an absolute prohibition, these rulings suggest that any party seeking to use interrogation recordings for purposes beyond voluntariness must overcome a high threshold of demonstrating clear necessity and convincing the court that such use will genuinely aid, rather than distort, the pursuit of truth and a fair trial. The law in this area is still evolving, and future Supreme Court pronouncements may further clarify the permissible boundaries.