Criminal Law in Japan

📅 July 7, 2026 📖 903 words 📂 criminal-law japan

Overview of Japanese Criminal Law

Japanese substantive criminal law is codified in the Penal Code (Keihō, Law No. 45 of 1907), extensively amended, with major reforms in 2017 and 2023 addressing sexual offences. The Code reflects German civil-law doctrinal structure, while criminal procedure (governed by the Code of Criminal Procedure, Law No. 131 of 1948) bears a strong American post-war overlay. The Constitution (1947) provides fundamental guarantees: nulla poena sine lege (Article 31), the privilege against self-incrimination (Article 38), and the prohibition of double jeopardy (Article 39).

General Part: Principles of Liability

Jurisdiction — The Penal Code applies to offences committed in Japan (Article 1) and provides for extraterritorial jurisdiction over certain offences by Japanese nationals (active personality, Article 2), offences against the state (protective jurisdiction), and piracy (universal jurisdiction).

Actus Reus and Mens Rea — Criminal liability requires kōi (prohibited act or omission) and hanzai ishi (criminal intent). Negligence (kashitsu) is punishable only where expressly provided (e.g., Article 211, negligent homicide). Causation (ingahōsoku) is assessed through the “rough and ready standard” (sōsō no kankeisei) — whether the conduct had a substantial effect on the result.

Defences — Self-defence (Article 36) excludes liability for unavoidable and proportionate defensive action against imminent unlawful infringement. Necessity (Article 37) excludes liability for acts to avert present danger where no other means exist and the harm caused does not exceed the harm averted. Insanity (Article 39) renders an act unpunishable; diminished capacity carries mandatory sentence reduction. The insanity threshold is high, and acquittals on this ground are rare. Mistake of law does not generally excuse, but the Supreme Court has recognised a limited exception where the defendant had reasonable grounds to believe their conduct lawful (Wakayama Case, 1978).

Special Part: Specific Offences

Homicide (Article 199) — Intentionally causing death, punishable by imprisonment with or without labour for life or for not less than five years. Japanese law does not distinguish degrees of murder; mitigating factors are considered at sentencing.

Theft and Property Offences — Theft (setto, Article 235) is taking another’s property without consent. Robbery (gōtō, Article 236) combines theft with force or intimidation. Fraud (sagi, Article 246), embezzlement (ōryō, Article 252), and breach of trust (hainin, Article 247) cover other dishonest acquisition.

Sexual Offences: The 2017 and 2023 Reforms — The 2017 amendment replaced the gender-specific crime of rape (gōkan, limited to female victims and vaginal intercourse) with a broader, gender-neutral structure. The 2023 amendment (effective July 2023) raised the age of consent from 13 to 16, bringing Japan into line with most developed jurisdictions. It replaced the requirement of force or intimidation with a consent-based model: Article 176 now defines a sexual offence as occurring where the other person has “not given consent,” listing eight non-exhaustive situations where consent is deemed absent (including intoxication, disability, violence, intimidation, and abuse of authority). The statute of limitations for sexual offences was also extended.

The Principle of Legality

Article 31 of the Constitution and the Penal Code’s structure embody nulla poena sine lege. Criminal laws must be prospective, clear, and non-retroactive (Article 39, Constitution). Analogy unfavourable to the accused is prohibited.

The Prosecution System

The Public Prosecutors Office (Kensatsu) is a hierarchically organised career bureaucracy within the Ministry of Justice. Prosecutors exercise broad discretion under Article 248 of the Code of Criminal Procedure: they may decline to prosecute even where probable cause exists, considering the offender’s character, the gravity of the offence, and the public interest. Approximately one-third to one-half of cases are disposed of through prosecutorial suspension (kiso yūyo). The Inquest of Prosecution (Kensatsu Shinsakai) — a panel of eleven randomly selected citizens — reviews non-prosecution decisions. Since 2009, the Inquest’s second recommendation to prosecute is binding.

Plea Bargaining (2016)

The 2016 Amendment introduced a formal plea-bargaining system (kyōyō seido) for specified economic crimes (corruption, antitrust, securities fraud, organised crime). A suspect who provides information against another may receive a reduced charge or leniency recommendation. The system does not extend to US-style charge-bargaining; the initiator must be represented by counsel, and the agreement must be in writing.

Punishment and the Death Penalty

Sanctions include the death penalty, imprisonment with and without labour, fines, detention, and minor fines. The death penalty is authorised for murder (Article 199) and robbery resulting in death. Execution is by hanging (kōshukei). The system has drawn international criticism for its secrecy (the Ministry of Justice does not disclose names of those executed until after the fact, and families are notified only hours before), the lengthy death row confinement (inmates may spend decades in solitary confinement), and the use of post-conviction indefinite detention for inmates whose mental health deteriorates. Japan’s courts have held that prolonged confinement does not violate the constitutional prohibition of cruel punishment (Noguchi Case, Supreme Court, 1963).

Relevant Statutes

Penal Code (Keihō), Law No. 45 of 1907
Code of Criminal Procedure, Law No. 131 of 1948
Act on the Inquest of Prosecution, Law No. 147 of 1948
Act on Criminal Cases Subject to the Participation of Saiban-in, Law No. 63 of 2004
Constitution of Japan (1947), Articles 31–40