Suǒ Jìng 索靖 (239–303), zì Yòuān 幼安, of Dūnhuáng 燉煌 in Jiǔquán 酒泉 (Liángzhōu 涼州). One of the great Western-Jìn calligraphers, regarded together with Wèi Guàn 衛瓘 as the principal heir of Zhāng Zhī’s 張芝 zhāngcǎo 章草 (regulated cursive) tradition; the Jìn shū records the contemporary saying Yītái èr miào 一臺二妙 (“the One Bureau and the Two Marvels”) for the pair as colleagues in the Imperial Secretariat. CBDB id 275110 records him under Western Jìn but supplies no lifedates; the standard Jìn shū 60 biography places his birth in 239 and his death in 303, fighting for the imperial party against Hé Jiàn’s 河間王 forces during the Bāwáng zhī luàn 八王之亂.
A maternal grand-nephew of Zhāng Zhī (“the Sage of Cursive” 草聖), Suǒ inherited the family-school zhāngcǎo; his self-composed Cǎoshū zhuàng 草書狀 (KR3h0091) — preserved entire in Jìn shū 60 and Tàipíng yùlǎn 747 — is one of the earliest extant Chinese rhapsodies on cursive script and a foundational document for the East-Asian theory of cǎoshū. He served as Shàngshū láng 尚書郎 and Yǎzhōu cìshǐ 雅州刺史; held the title Pèiguó gōng 沛國公 from his role in suppressing the Hé Jiàn uprising. The Suǒ-shi of Dūnhuáng remained a calligraphic lineage into the Táng (Suǒ Jìng’s autograph specimens, including the Yuèyí tiē 月儀帖 and Chūshī sòng 出師頌, are central to the TángSòng fǎtiē 法帖 tradition, though the surviving rubbings are all later transcriptions).