Zhāng Yòuxīn 張又新
Mid-Tang official and bāguān shíliùzǐ 八關十六子 partisan, zì Kǒngzhāo 孔昭. Native of Lùzé 陸澤 in Shēnzhōu 深州 (modern Shēnxiàn 深縣, Héběi). Great-grandson of Zhāng Zhuó 張鷟 (the famous Wǔ-Zhōu-period Cháoyě qiānzǎi author) and son of Gōngbù shìláng Zhāng Jiàn 張薦.
Zhuàngyuán jìnshì of Yuánhé 9 (814) — that is, top jìnshì of his examination cohort — at the unusually-early age. The combined evidence of his own Jiānchá shuǐ jì (which records that he had just achieved his examination success when, in Yuánhé 9 / 814, he encountered the manuscript at Jiànfúsì) and the Shìzú dàquán compilation by the Yuán-period bibliographer fixes his jìnshì year and rank precisely. He rose through Yòu bǔquè (Right Reminder-Counsellor) and various central offices. He attached himself to the political faction of Lǐ Féngjí 李逢吉, becoming one of the bāguān shíliùzǐ (Eight-Pass Sixteen-Disciples) — Lǐ Féngjí’s network of partisan dependents. When Lǐ was promoted to Shānnán dōngdào jiédù shǐ, Zhāng was made his xíngjūn sīmǎ; he was later implicated in the Tián Bēi 田伾 affair and demoted to Jiāngzhōu cìshǐ (the XīnTángshū and JiùTángshū misread this as Tīngzhōu 汀州; Zhāng himself in the Jiānchá shuǐ jì calls himself “Cìshǐ of Jiǔjiāng” — that is Jiāngzhōu, modern Jiǔjiāng — confirming the correct reading).
Later under Lǐ Xùn 李訓’s rising influence Zhāng was rehabilitated and promoted to Xíngbù lángzhōng and then Shēnzhōu cìshǐ. With Lǐ Xùn’s death (in the Gānlòu Incident of 835) Zhāng was again demoted; he ended his career as Zuǒsī lángzhōng. His biography is in XīnTángshū 175.
His one surviving work, the Jiānchá shuǐ jì 煎茶水記 (KR3i0025) of Yuánhé 9 (814) or shortly after, is the foundational text of Chinese water-connoisseurship — the systematic ranking of water sources for tea-brewing — and the principal Tang tea-supplement to Lù Yǔ’s Chájīng.