Though the prison population in Japan is remarkably small compared to other countries, there have been increases in recent years among certain demographics. The media is particularly sensitive to elderly inmates. Less remarked upon are female prisoners.

A Ministry of Justice study released last year stated that arrests of women had been on the increase since 1993 and numbered about 50,000 in 2015. Arrests of women stood at about 20 percent of all arrests, but the number of older women being arrested was rising, and at a higher rate than that for elderly men. Until 1998, less than 20 percent of women arrested were over 50. Since 2010 this cohort represents more than 40 percent of women arrested. The vast majority were for theft-related crimes, mainly shoplifting.

As a result there are more women in prison. A 2014 report by the online magazine News Post 7 said there were about 5,000 women in penal institutions that year — a fivefold increase over 1992 — as opposed to about 60,000 men. A 2017 article in the Nihon Keizai Shimbun says that the female prison population started to increase in 1990 and has risen to the point where the capacity for women inmates is insufficient to handle demand.