The specialist at the centre of Korean Muism is the mudang, usually a woman, and the tradition's central event is the gut, a ritual that can run from a few hours to several days.
There are two broad routes into the role, and the distinction is basic to how Korean practice is organised. The kangsinmu is chosen by the spirits, typically through sinbyeong, a wasting illness, dreams, hallucinations and disturbance that resists medical treatment and is diagnosed as a spirit demanding acceptance. It resolves when the person accepts, is initiated by an established mudang who becomes her spiritual mother, and receives a guardian spirit through whom she works. This type predominates in the centre and north of the peninsula. The seseummu inherits the role through family, ordinarily through the female line, and is trained rather than called; this type was concentrated in the south and southwest and is now much reduced in number.
A gut is not a service attended by a congregation but a commissioned performance for a client household, held for a specific purpose: to cure illness, to secure a business or a fishing fleet, to settle a dispute in the family, to send a dead relative safely on, or to bring general good fortune. It proceeds through a sequence of numbered segments, each addressing a different spirit, with an ensemble of drums, gongs and reed pipe, costume changes, dancing, offered food and wine, and sung invocation.
The point at which the spirit is present speaks through the mudang, giving diagnosis, complaint, demand and reassurance, and frequently scolding the family, is called gongsu. Family members answer back, bargain, weep and laugh. The tone is not solemn: gut are noisy, often funny, and openly emotional, and their therapeutic effect on a household in trouble is one of the things Korean scholarship has emphasised most.