Fureai Kippu, in Japanese ふれあい切符, meaning literally "Caring Relationship Tickets" is a complementary social currency, based upon hours of volunteering service.
The basic unit is an hour of service to an elderly person. Sometimes seniors help each other and earn the credits, other times family members in other communities earn credits and transfer them to their parents who live elsewhere. These credits accumulate- users may keep them for when they become sick or elderly themselves, then use the credits in exchange for services. Alternatively, the users may transfer credits to someone else.
A surprising part of the project has been that the elderly tend to prefer the services provided by people paid in Fureai Kippu over those paid in yen. This was found to be due to the nature of the relationship and personal connection. To convert this community service to yen would seem to dilute the community ethic.
-- Wikipedia page "Fureai Kippu"