Mid-Táng Daoist master and immortality-scholar, conventionally dated to have died at the beginning of the Tiānbǎo 天寶 era (742–756). One of the famous Eight Immortals (Bāxiān 八仙) of later legend, where he is called Zhāng Guǒlǎo 張果老 and associated with a white donkey that can be folded like paper. His historical biography is preserved in Jiù Táng shū 191 and in DZ 295 Xù xiān zhuàn 2.4b–6a.
In 734, Emperor Xuánzōng 玄宗 bestowed on Zhāng Guǒ the title Tōngxuán xiānshēng 通玄先生 and invited him to court. Principal surviving work:
- Huángdì yīnfú jīng zhù 黃帝陰符經註 (DZ 113, written before 734) — a Táng commentary on the Yīnfú jīng composed specifically to refute Lǐ Quán’s DZ 109 Jízhù. The Jiù Táng shū records that he also wrote a Yīnfú jīng xuánjiě 陰符經玄解.
Modern scholarship: Florian C. Reiter’s survey of the Yīnfú jīng literature; Anna Seidel’s work on the Eight Immortals cult; the entries on Bāxiān cults in Chinese and Japanese reference works. No CBDB record was found.