OSAKA — Imagine, if you will, Japan in 2018. Following the historic Lower House election in 2009, the country passed legislation that abolished the 47 prefectures and thousands of smaller local governments.

In their place are 10 semiautonomous regions with the authority to decide for themselves how to distribute most of their tax revenues.

By 2018, the central government's role has been reduced to conducting foreign policy and providing for the common welfare.