A fu is a written command. It is drawn in cinnabar ink on yellow paper in a script derived from seal characters but deliberately illegible to laypeople, and it is not effective as a drawing — it must be activated by a priest with the correct register, using breath, hand seals and the impression of a wooden ritual seal. The logic is entirely bureaucratic: the talisman is an order addressed to named spirit officials, and the priest's register is what authorises him to issue it, exactly as a warrant requires an officer of a particular rank. Fu are pasted over doorways and beds, sewn into clothing, carried in a pouch, or burned and the ash stirred into water and drunk, which is a standard treatment for illness and fright. Talisman-drawing is one of the defining competences of the Zhengyi tradition, which is often described as the branch of talismans and communal ritual, in contrast to the Quanzhen emphasis on interior cultivation.