Criminal Procedure in Japan

Introduction

Japanese criminal procedure is governed by the Code of Criminal Procedure (Keiji Soshō Hō, Act No. 131 of 1948, effective 1 January 1949), which replaced the Meiji-era Code of 1922. The 1948 Code was enacted during the Allied Occupation and reflects significant American influence, particularly in its warrant requirements, the right to counsel, and the establishment of an adversarial trial structure. The Constitution of Japan provides the overarching framework, guaranteeing due process (Article 31), the privilege against self-incrimination (Article 38), the right to a speedy trial (Article 37), and the right to examine witnesses (Article 37).

The Code has been extensively amended. Major reforms in 2004 introduced the lay judge system (saiban-in seido). The 2016 reforms added a limited plea-bargaining mechanism for certain economic crimes and expanded audio-visual recording of interrogations. The 2023 reforms revised the rules on sexual offences and introduced protections for vulnerable witnesses.

Investigation

Criminal investigations are conducted by the police (keisatsu) and the public prosecutors (kensatsukan). The prosecutor has the power to direct the police in their investigations (Article 193 CCP). The investigation may involve the seizure of evidence, the search of premises, and the interrogation of suspects.

Warrants. Article 35 of the Constitution requires a judicial warrant for any entry, search, or seizure. The CCP codifies this requirement in Articles 218 and 219. A judge may issue a warrant upon a showing of probable cause. Emergency exceptions permit warrantless searches in certain circumstances (Article 220 CCP), and a warrantless arrest is allowed for flagrante delicto (Article 213).

Arrest and Detention. A suspect may be arrested on a warrant (taiho) issued by a judge. Following arrest, the suspect must be brought before a judge within 48 hours (Article 205 CCP). The judge then decides whether to order pre-indictment detention (kōryū). The period of pre-indictment detention may be extended in blocks of ten days, up to a maximum of 23 days (Articles 207–208 CCP). Suspects are often held in police detention cells (daiyō kangoku), a practice that has attracted criticism from international human-rights bodies.

Interrogation. Interrogation of suspects is conducted in the absence of defence counsel as a matter of practice, though the suspect has the right to consult counsel. The 2016 reforms introduced a system of audio-visual recording of interrogations for certain serious offences (those subject to the saiban-in system). The Supreme Court has held that a confession obtained by coercion or prolonged interrogation is inadmissible (Hakamata Jiken).

The Indictment Decision

Japan operates a prosecutorial monopoly on indictment: only public prosecutors may bring charges. Article 248 CCP gives the prosecutor broad discretion not to prosecute even where sufficient evidence exists. The prosecutor may suspend prosecution (kiso yūyo) — a form of conditional non-prosecution used widely for minor offences, often coupled with the suspect’s payment of compensation or an apology.

Where the prosecutor declines to prosecute, the victim may seek review by the Committee for the Inquest of Prosecution (Kensatsu Shinsa Kai), a body of eleven randomly selected citizens. Since 2009, if the Committee twice recommends indictment, a court-appointed lawyer must prosecute the case.

Pre-Trial Proceedings

The preliminary hearing (shinsa) is a pre-trial conference, introduced in the 2004 reforms, at which the court and the parties identify the disputed issues and plan the trial. The prosecution must disclose a specified category of evidence at this stage. The 2016 reforms introduced a tiered disclosure system: Type I evidence (the core of the prosecution case) must be disclosed early; Type II (exculpatory evidence) must be disclosed when the defence makes a specific request; Type III (other relevant evidence) is disclosed on further order of the court.

Since 2016, the prosecutor and the defence may hold a pre-indictment discussion meeting (kōgi-mae no gōi), in which they may discuss the possibility of a guilty plea and the charges to be brought. This is Japan’s version of plea bargaining, but it is limited to cases involving economic crime and regulatory offences.

Trial

The criminal trial is conducted in an adversarial framework, though the judge retains an active role in questioning witnesses and may call evidence on the court’s own motion.

Opening Statement. The prosecutor makes an opening statement, outlining the charges and the evidence. The defence may also make an opening statement.

Examination of Evidence. The prosecution presents its evidence first. Documentary evidence is extensively used: the CCP permits the admission of written statements (kensatsu chōsho, keisatsu chōsho) and expert reports. The defendant has the right to confront witnesses, but prior written statements are routinely admitted if the witness is present for cross-examination. The defence may then present its own evidence.

Saiban-in System. For serious offences — murder, robbery causing death, arson of an inhabited structure, and certain drug offences — the case is tried by a mixed panel of six lay judges (saiban-in) and three professional judges. The lay judges are randomly selected from the voter roll. They deliberate jointly with the professional judges on both guilt and sentence. The system was introduced in 2009 to enhance public participation in the criminal justice system.

Standard of Proof. The prosecution must prove guilt beyond a reasonable doubt. The Supreme Court has held that the standard requires the judge to have “inner conviction” (naii — Sōen Jiken, 1973). In practice, the conviction rate in Japanese criminal trials exceeds 99%, a statistic that has drawn scholarly attention and foreign criticism.

Judgment. The court delivers a verdict of guilty or not guilty. A judgment of conviction must state the reasons and specify the sentence (Article 335 CCP). Acquittals are rare but are reported in high-profile cases, such as the Shiraishi Jiken and Hakamata Jiken retrials.

Sentencing

The sentencing hearing follows the verdict on guilt. The prosecution makes a sentencing recommendation (kankoku), and the defence presents mitigating evidence. Victim impact statements are permitted. The court determines the sentence within the statutory range, taking into account the nature and gravity of the offence, the defendant’s culpability, and mitigating factors.

Appeal

The defendant has an automatic right to kōso appeal to the High Court against a conviction (Article 372 CCP). The kōso appeal may raise questions of fact and law. The High Court reviews the record and may affirm, reverse, or modify the sentence.

A further appeal, jōkoku, lies to the Supreme Court only on constitutional grounds or conflicts with precedent (Article 405 CCP). The Supreme Court exercises discretion in granting jōkoku.

Post-Conviction Remedies

Retrial (saishin) is available where new evidence casts doubt on the conviction (Articles 435–436 CCP). The retrial procedure has been used in several high-profile capital cases. The Hakamata case, in which the convicted person spent 47 years on death row before being acquitted on retrial in 2024, is the most prominent recent example.