Since the 1980s Japan has undergone a number of mental health law reforms culminating in the 2005 forensic law. This added to its enactments on involuntary commitment, long-term aged care and substitute decision making, bringing Japan into focus as an industrialized state now possessed of a full package of civil and forensic provisions. This article seeks to demonstrate that the new forensic law cannot achieve its own stated goals without seeking to put into place financial and administrative supports aimed to integrate the myriad of patient populations that will be inevitably affected by the new forensic system. In order to avoid the widespread syndrome that has already been experienced internationally of warehousing mentally ill offenders in jails, it is critical that the Japanese government develop effective and culturally sensitive techniques for dealing with low risk populations through a diversionary process. Furthermore, although the legislation addresses serious crimes, it is imperative that policies be put into place to avoid directing young offenders, violent patients from the general hospital system, the developmentally handicapped, already convicted persons found in hospital settings and problematic cases in the correctional system, to the new forensic units established by the legislation. It is only though contemplating unintended outcomes of the legislation that the Japanese government will be able to avoid the ongoing stigmatization and prolonged institutionalization of mentally ill populations. Despite apparent cultural differences internationally vetted human rights requirements must be properly protected, not only in the forensic context, but throughout the mental health system at large. The coordination of services and the development of specialty training are necessary conditions for the realization of improved and humane conditions for mentally ill persons in Japan.