Most prisons spend a lot of time and effort keeping inmates from escaping, but a greater challenge is convincing some convicts to leave.
Among developed economies, Japan has one of the highest proportions of elderly prisoners. Crimes committed by senior citizens have quadrupled over the past two decades. Today, almost one in five convicts is over 60.
The soaring costs of caring for these graying jailbirds are an added pressure on Prime Minister Shinzo Abe's government, which is already burdened by a world-class debt load equal to roughly 240 percent of gross domestic product.