The mathematics of recidivism are gloomily compelling for the would-be convict. Even with a frugal diet and dirt-cheap accommodation, a single Japanese retiree with minimal savings has living costs more than 25 per cent higher than the meagre basic state pension of Y780,000 ($6,900) a year, according to a study on the economics of elderly crime by Michael Newman of Tokyo-based research house Custom Products Research.
Even the theft of a Y200 sandwich can earn a two-year prison sentence, say academics, at an Y8.4m cost to the state.
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The geriatric crime wave is accelerating, and analysts note that the Japanese prison system — newly expanded and at about 70 per cent occupancy — is being prepared for decades of increases. Between 1991 and 2013, the latest year for which the Ministry of Justice publishes figures, the number of elderly inmates in jail for repeating the same offence six times has climbed 460 per cent.
The surging rates of crime among the elderly disguise a darker trend than mere contempt for the law, say economists and criminologists. Retiree crime is rising more quickly than the general demographic ascent into old age that will put 40 per cent of the Japanese population over 65 by the year 2060.