Koken

A koken is a special kind of stage attendant. They are actually dancer-actors who assist rather than stage-technicians, and they need to know every movement of a dance so that they can bring props at exactly the right time or adjust a costume just the right way. They are totally visible - and in fact dressed in formal kimono, but are "invisible" as they are not really part of the scene. The invisible-visibles!
In 'Odori: The World of Kabuki Dance', Fujima Monyo will act as kôken. He will dance the first piece in the program as a su-odori - meaning he will wear formal monsuki (a kimono with a family crest) and hakama (pleated trousers) - and then work as an assistant for the other three dances. The kôken is totally critical and can make or break a performance.