A nice light topic
The pension service website seems like a good place to start, but there are still unanswered questions.
What exactly is required to join if you haven't been paying in? How many years are you obliged to pay in back payments? How many years can you pay if you want to get further towards vesting?
There is also the matter of this rumoured change from vesting in 25 years to vesting in 10 (which would make the system much more attractive to people joining halfway). Is that going to happen? If so, when?
And the thing about getting free years of eligibility for the time you weren't in Japan back to the age of 20...
I have a bit more time for projects over the next couple of months, so am planning to pop into the local pension office and ask them some questions.
If you have any questions you'd like me to add to my list please let me know in the comments or via the contact form if you would like more privacy. Deadline end of this week!