well, actually it does, since mandatory retirement is not 55. One can retire at 55 at some places and get a pension if one has been in the system for 25 years, but most don't. Actual retirement is later and there is talk of making it even later, to 65: Here is a bit from a site on this matter:
The official retirement age at medium and large Japanese companies is
60 for both men and women, and it is quite rigidly enforced, even for
top executives.
Most Japanese do not stop working at age 60. The OECD reports that Japanese men generally continue to work until almost age 70,
You can find this at:
http://www.becker-posner-blog.com/archives/2005/06/later_retiremen.htmlamong others