The term guan refers to a headdress worn by men of power and official business. Guan were designed to be worn over top knots of hair, and different functions called for different guan. The Mian guan was a royal headdress used to conduct sacrifices to heaven. Twelve strands of jade beads hung in front and back of the emperor’s hat. The strands hung in the following color order: white for metal, yellow for earth, green for wood, red for fire, and black for water.