From the Japan Times.
The proposal looks to be a partial integration in 2015, and full integration by 2018.
What do you think “integration” means? To me, it’s that the National Tax Agency will start to be the collector of final resort of Japanese pension contributions. This is how it’s done in America, and most other countries with a national or federal pension program. The contributions are designated “premiums”, but the premiums are treated as a tax.
Yet one more reason to get your Blue Book if you intend to be around Japan for a while. The new residence card means there is a database somewhere showing whether or not you’ve enrolled in the pension. In a matter of a couple of years, someone from the tax agency will have a role in seeing that the money that you (and your employer) aren’t paying is paid.