At the beginning of the Qing period, the chao guan (a Chinese official's hat) was worn on semi-formal occasions without its usual ornate spike. The Yongzheng Emperor appears to have felt that this was unsatisfactory. In 1727 he introduced a new type of hat insignia which could be worn in place of the ornate spike with less formal court attire, and also with ordinary dress when dealing with official business. The new insignia was a large round bead of material of the appropriate colour mounted on a gilt base. The highest ranking officials wore plain opaque red buttons, while the lowest wore silver. Opaque blue was the fourth rank, while transparent and opaque white indicated the fifth and sixth ranks respectively.