Women's prisons reflect a transition in Japanese society that merges unique cultural traditions with modernization. The Corrections Bureau is responding to a remarkable increase in the number of female inmates. The women's physical facilities compare well with U.S. women's prisons. The training of prison officers and their task performance is of high quality. Japan's women's prisons are part of a single penal system that applies uniform standards for facilities' operations and facilitates the planning and mobilization of resources at the national level. The emphasis on prison labor provides purpose to penal confinement in Japan that is often lacking in the United States. Data on female inmate infractions and official responses reflect a control system that operates effectively within an orderly environment having an insignificant level of violence. Sociocultural changes occurring in Japan are manifested in inmate attitudes, staff role expectations, and correctional policy. The early effects on stimulant-drug offenders is suggestive of possible developments in these areas. 7 notes, 4 tables. (Author summary modified)