Three basic features of Japan's system of criminal justice characterize its operations. First, the institutions—police, government prosecutors' offices, courts, and correctional organs—maintain close and cooperative relations with each other, consulting frequently on how best to accomplish the shared goals of limiting and controlling crime. Second, citizens are encouraged to assist in maintaining public order, and they participate extensively in crime prevention campaigns, apprehension of suspects, and offender rehabilitation programs. Finally, officials who administer criminal justice are allowed considerable discretion in dealing with offenders.
Until the Meiji Restoration in 1868, the Japanese criminal justice system was controlled mainly by daimyo. Public officials, not laws, guided and constrained people to conform to moral norms. In accordance with the Confucian ideal, officials were to serve as models of behavior; the people, who lacked rights and had only obligations, were expected to obey. Such laws as did exist were transmitted through local military officials in the form of local domain laws. Specific enforcement varied from domain to domain, and no formal penal codes existed. Justice was generally harsh, and severity depended upon one's status. Kin and neighbors could share blame for an offender's guilt: whole families and villages could be flogged or put to death for one member's transgression. (see Criminal punishment in Edo-period Japan for details)
After 1868 the justice system underwent rapid transformation. The first publicly promulgated legal codes, the Penal Code of 1880 and the Code of Criminal Instruction of 1880, were based on French models, i.e. the Napoleonic code. Offenses were specified, and set punishments were established for particular crimes. Both codes were innovative in that they treated all citizens as equals, provided for centralized administration of criminal justice, and prohibited punishment by ex post facto law. Guilt was held to be personal; collective guilt and guilt by association were abolished. Offenses against the emperor were spelled out for the first time.