QC circle
QC is an abbreviation for "Quality Control". A QC circle is a small group of people in front-line workplaces who continuously manage and improve the quality of products, services, and work. Small group activities are performed on a voluntary basis, and they are carried out while exercising creativity and promoting self- and mutual-education through the use of QC concepts, methods, etc.
※(Reference): From JUSE HP "The Basics of QC Circle"