เครื่องรางยันต์ฮู้ (ฝูลู่ ยันต์เต๋า)Fu talisman符籙

The illegibility is the design, and it has a history. Yang Zhaohua notes that a number of the earliest known Taoist talismans were simple and legible, and that later examples became deliberately cryptic in order to signal their divinity. James Robson and Gil Raz have argued that the incomprehensibility of the written forms is central to a talisman's perceived authority and efficacy, and is one of talismanic script's defining features. By the Eastern Jin dynasty, 317 to 420, it was already held unnecessary for a user to be able to decipher the writing: Ge Hong wrote in the Baopuzi that as long as the inscription was correct, use did not depend on the user reading it. Ge Zhaoguang, of Fudan University, calls the unreadability a kind of linguistic archaism, built to be incomprehensible — "a veil of unfathomable otherwordliness" that lets only a small number of qualified clergy produce them properly.

The writing has been medicine for as long as it has been anything. Known in medical writings as zhuyou, the use of talismans ran alongside drugs, meditation, acupuncture, astrology and massage; the Way of the Taiping was healing patients with it at least as far back as the Eastern Han. Zhuyou held official support from the Sui to the late Ming, and declined when acupuncture was recognised by the imperial court as a medical discipline in the sixth century. It is rejected by traditional Chinese medicine and still widely used by folk healers, and in the twentieth century, as Western psychology arrived, it began to be read as a Chinese counterpart of hypnosis.

The script also travelled. Fulu are not confined to Taoism: they were taken into several forms of Chinese Buddhism, and they lie behind the ofuda used in Japanese Buddhism and Shinto and the bujeok of Korean shamanism. On coins, fulu usually open and close the inscription of a Taoist coin charm, and most of those charms ask Lei Gong, the god of thunder, to protect the carrier from evil spirits and misfortune. Many coin talismans in the script have not been deciphered; in one specimen talismanic script was written side by side with Chinese characters that may be its gloss.

The Daozang records the fulu sect's history in the second chapter of each of its three grottoes, where fulu are said to originate in the condensation of clouds in the sky.

Written by a priest of the fulu pai, an informal grouping of priests from different schools of Taoism. The way of writing the characters is passed down in secret from a Taoist priest to their disciples and treated as a special craft for communicating with local deities and spirits; style, incantations and the mudras used in making them differ from sect to sect, and even the invocations for a single deity vary. This atlas prints that and no script.

Still written. Zhuyou continues to be widely used among Chinese folk healers, and paper talismans are issued at temples across the Chinese-speaking world — the Taiwanese peace charm is the everyday form. Whether a talisman works has never been the question a priest is asked; the question is who wrote it.