The Inner Sounds of the Heavens 太上[洞玄]灵宝诸天内音自然玉字

The Supreme [Mysterious Grotto] Lingbao Scripture of the Natural Jade Characters and Inner Sounds of the Thirty-Two Heavens (Taishang [Dongxuan] Lingbao Zhutian Neiyin Ziran Yuzi), also known as The Scripture of the Inner Sounds of the Heavens (Zhutian Neiyin Jing) or The Scripture of the Jade Characters and Inner Sounds (Neiyin Yuzi Jing).

One of the ancient Taoist Lingbao Scriptures, it was probably compiled in the late Eastern Jin Dynasty to the early Southern Dynasties (c. 4th–5th centuries CE). It was already recorded in Lu Xiujing’s Catalogue of Lingbao Scriptures (Lingbao Jingmu).

The original text consists of two scrolls, later divided into four scrolls, and is included in the Daozang (Taoist Canon) under the Dongzhen Bu (Section of the True Grotto) and Yujue Lei (Category of Jade Commentaries). Additionally, there is one fragmentary Dunhuang manuscript (P2431).

Attributed to the Heavenly True Emperor-Man (Tianzhen Huangren) as the narrator, the scripture states that there are eight heavens in each of the four directions (east, south, west, north), totaling thirty-two heavens. Above each heaven are eight "heavenly jade characters" (celestial runes), amounting to 256 characters in total. These are considered sacred celestial texts, naturally formed from condensed profound ethereal qi, and inscribed on jade slips—hence the name "Natural Jade Characters."

Taoist practitioners who possess these texts, understand their inner sounds, write, wear, and recite them can save countless beings and attain immortality. The first two scrolls detail the names of the thirty-two heavens, the functions of the jade characters (talismans) of each heaven, and the methods of writing and wearing the talismans.

The latter two scrolls, purportedly explained by the Heavenly True Emperor-Man, interpret the phonetics and meanings of the heavenly jade characters. The jade characters of each heaven are compiled into thirty-two "Grotto Chapters" (Dongzhang), each consisting of five-character lines with eight verses, and the purport and significance of each chapter and verse are elaborated respectively.