The Expanded Commentary on Dao De Jing 道德真经广圣义

Composed by Du Guangting at the end of the Tang Dynasty, this work was roughly completed in the first year of the Tianfu reign period (901).

Originally consisting of thirty volumes, the version in the Daozang (Daoist Canon) is divided into fifty volumes and included in the Yujue (Jade Commentary) category of the Dongshen Section.

The "expanded sage's meaning" elaborated in this work refers to Emperor Xuanzong of Tang’s commentary and subcommentary on the Daodejing. After quoting Emperor Xuanzong’s commentary and subcommentary in full, Du Guangting’s own interpretations are marked with the phrase "Yi yue" (It is said that), resulting in a rather verbose text. Its ideological tenet is rooted in the Chong Xuan (Double Mystery) philosophy. The preface to the book lists sixty commentaries on the Laozi, which is of considerable documentary value, though the chronological records of two commentaries—those by Sun Deng and Meng Anpai—are inaccurate.