Zhìshǒu 智首 (567–635) was the leading Sìfēnlǜ Vinaya master of the Suí–early-Táng transition and is conventionally counted as the Eighth Patriarch of the Chinese Sìfēnlǜ school. Lay surname Huángfǔ 皇甫. Native of Āndìng 安定. Ordained as a child at Yúnménsì 雲門寺 in Xiāngzhōu under Zhìmín 智旻; took full ordination at twenty-two and studied Vinaya under Dàohóng 道洪 (alongside more than seven hundred fellow students, surpassing all of them). He began lecturing on Vinaya before the age of thirty; his moral conduct and clarity of teaching earned high contemporary praise.
For thirty years following the Rén-shòu era (601–604) Zhì-shǒu was the unrivalled Vinaya authority in the imperial capital. Under early-Tang Sui Dà-yè, he was installed at the Dà Chán-dìng dào-chǎng 大禪定道場. In Tài-zōng Zhēn-guān 8 (634), Empress Tài-mù endowed Hóng-fú-sì 弘福寺 in Cháng’ān; Zhì-shǒu was summoned as its shàng-zuò 上座 (senior abbot) and served as its sēng-gāng 僧綱 (saṃgha overseer). He died on the fourth month of the following year (Zhēn-guān 9 = 635), aged sixty-nine. His most consequential disciple was Dào-xuān 道宣 (道宣, 596–667), founder of the Nán-shān-lǜ; other disciples included Dào-shì 道世 (道世), Huì-mǎn 慧滿, Dào-xìng 道興, and Zhì-xìng 智興.
Zhìshǒu was a productive Vinaya commentator; only a single juan (juan 9) of his Sìfēnlǜ shū 四分律疏 (KR6k0164) survives in the Manji canon (the source-text head signs the work as 沙門釋智者撰, Composed by Zhìzhě/Zhìshǒu — the form 智者 here is a graphic variant of 智首 traditional in some Manji witnesses, and the work is correctly attributed to Zhìshǒu in catalog and historical sources).
Sources: Fóguāng 5026; DILA Buddhist Person Authority A001269; Xù gāosēng zhuàn j. 22 Zhìshǒu zhuàn (T2060).