This diagram, part of an active webpage of the relevant Japanese ministry, says it all.
As you can see, there is a bucket for each of:
national health care
long-term care (for those 40 and older)
So where, now, the practice seems to be that you can fly under the radar, it looks like, effective July 15, 2012 at the latest, it will not be so easy to fly under the radar.
Link to a nice little brochure about the new card (PDF).