The fifth Tiāntái patriarch (天台五祖), the principal disciple and amanuensis of 智顗 Tiāntái Zhìyǐ (538–597). Sobriquets Zhāngān dàshī 章安大師 (“Master Zhāng’ān”, from his birthplace), Fǎyún 法雲 (“Dharma-Cloud”), and Zǒngchí zūnzhě 總持尊者 (“Venerable of Universal-Holding”). Born Suí Wéndì Kāihuáng 1 (= 561); died Táng Zhēnguān 6 (30 August 632 / seventh day of the eighth lunar month), age 72. DILA A004896.
His role in the Tiāntái-school’s textual history is foundational: he was the principal recorder (jì 記) of Zhìyǐ’s lectures, taking down in writing the entire body of Zhìyǐ’s oral teachings that subsequently became the canonical San dà bù 三大部 (“Three Great Works”) of the Tiāntái school: the Mohē zhǐguān 摩訶止觀 (T1911), the Fǎhuá xuányì 法華玄義 (T1716), and the Fǎhuá wénjù 法華文句 (T1718). Without Guàndǐng’s amanuensis labour, the Tiāntái-school’s doctrinal foundation would have been lost.
He also recorded Zhìyǐ’s lecture-notes on the Rénwáng-jīng (T1705 = KR6c0204), the Vimalakīrti-nirdeśa-sūtra, the Pure Land sūtras, and others. After Zhìyǐ’s death in 597, Guàndǐng continued the transmission of the school at Mt Tiāntái’s Guóqīng-sì 國清寺 (founded by Zhìyǐ; Guàndǐng oversaw its construction), and trained the next generation of Tiāntái scholars.
He is one of the most important figures in the Sòng-and-later Tiāntái lineage construction, posthumously honoured as the fifth patriarch (after Huìwén, Huìsī, Zhìyǐ, and a place sometimes given to Lóngshù as the originator of the lineage). His personal scholarly output is dwarfed by his amanuensis role for Zhìyǐ, but it is precisely that role that made the Tiāntái doctrinal heritage transmissible to subsequent generations.