Civil Liberties and Criminal Procedure Under the Japanese Constitution

Introduction

Articles 31–40 of the Constitution create a comprehensive code of criminal procedure guarantees, reflecting the drafters’ determination to prevent the abuses of the prewar system. These provisions — supplemented by the Code of Criminal Procedure (1948) and Supreme Court case law — form the foundation of Japanese criminal justice.

Due Process: Article 31

Article 31 provides: “No person shall be deprived of life or liberty, nor shall any other criminal penalty be imposed, except according to procedure established by law.” The Supreme Court has held that this requires not merely formal compliance but fundamentally fair procedure.

The Right to Counsel: Article 34

Article 34 guarantees the right to counsel upon arrest. The state must provide counsel promptly upon request. In Ishizaka v. Japan (1964), the Court held that statements obtained without informing the suspect of the right to counsel may be excluded as involuntary.

Searches and Seizures: Article 35

Article 35 requires a warrant issued for “adequate cause” and particularly describing the place and things to be seized. Exceptions include searches incident to lawful arrest and consent searches. The exclusionary rule has been recognized but applied inconsistently; in the Marijuana Possession Case (1961), the Court held that illegally obtained evidence may be excluded if its admission would be “unfair.”

Cruel Punishments: Article 36

Article 36 absolutely forbids torture and cruel punishments. The Supreme Court has consistently held the death penalty constitutional. In Noritsugu v. Japan (1948) and subsequent decisions, the Court applied a proportionality test: capital punishment is constitutional when the crime is of extreme gravity and the penalty is not unusually cruel by contemporary standards.

The Right to a Speedy and Public Trial: Article 37

Article 37 guarantees a speedy and public trial by an impartial tribunal, the right to examine witnesses, compulsory process, and the right to counsel at state expense.

The Privilege Against Self-Incrimination: Article 38

Article 38 prohibits compelled self-incrimination. The corroboration requirement (Article 38(3)) — “No person shall be convicted or punished in cases where the only proof against him is his own confession” — is a distinctive feature of Japanese procedure, reflecting historical concern with coerced confessions.

Double Jeopardy: Article 39

Article 39 bars retrial after acquittal, even if new evidence is discovered.

The Right to Sue the State: Article 40

Article 40 creates a constitutional right to compensation for wrongful detention, implemented through the State Redress Act.

The Warrant System

The warrant requirement provides for judicial authorization based on probable cause. In practice, arrest warrants are issued routinely, with courts rarely questioning police applications.

Pre-Indictment Detention

The most criticized feature of Japanese procedure is the system of detention for up to 23 days before indictment, with routine renewal. The practice of substitute prison (daiyō kangoku) — holding suspects in police detention facilities under solitary confinement with intensive interrogation — has been repeatedly criticized by the UN Human Rights Committee and other international bodies.

Prosecutorial Discretion and the Inquest System

Prosecutors exercise broad discretion under the principle of prosecutorial discretion (kiso yūyo shugi). The Committee for the Inquest of Prosecution (Kensatsu Shinsakai), reformed in 2004, provides citizen review. A supermajority vote (8 of 11 members) that prosecution is warranted is now binding on prosecutors.

The Lay Judge System

The Lay Judge System (Saiban-in Seido, 2009) introduced citizen participation in serious criminal cases: six lay judges sit with three professional judges, deciding both guilt and sentence. The Supreme Court has upheld the system against constitutional challenges under Articles 18 and 37.

Conclusion

The criminal procedure guarantees create a framework of robust rights protections, but implementation has been uneven. The tension between constitutional promise and institutional practice — particularly in the substitute prison system and routine detention — remains the central challenge of Japanese criminal procedure law.