Introduction of the Saiban-in System and Reformation of Criminal Procedure in Japan

In 2004, Japan enacted a statute (the Saiban-in Act) to introduce a system oflay participation in criminal trials. In the new system, six people selected randomlyfrom among the citizens in each case would serve as Saiban-in (lay assessor)and, in collaboration with three professional judges, engage themselves indeciding both guilt and sentence in the trials involving capital and other seriousoffenses.1)After five years of preparation, the Saiban-in Act came into force on May 21,2009. In the four years and eight months since the first Sainban-in trial was heldin August that year, 6,530 defendants were tried by the mixed panel courts, inwhich 36,837 citizens served as Saiban-in and 12,597 as supplementarySaiban-in.2)The introduction of this new system, which almost necessarily accompanied severalimportant revisions in the Code of Criminal Procedure (CCP), has already led tonot only dramatic changes in the management and manner of criminal trials butalso significant developments in judicial precedents. It also seems to have beenchanging the attitudes of criminal justice professionals and even the public viewson criminal law and justice in the long run. In the following parts, I will give a brief survey on the backgrounds of theintroduction of the Saiban-in system and the ongoing reform which it has broughtabout in the Japanese criminal procedure.