Zongmi （780-841）， also commonly referred to by the monastic title of Guifeng 圭峰. Tang dynasty scholar-monk， installed as fifth patriarch of the Huayan schools as well as a patriarch of the Heze 荷泽 Chan lineage. He wrote a number of vitally important essays on the current situation of Buddhism in Tang China， and is one of the most important figures in East Asian Buddhist history in terms of providing modern scholars with a clear analysis of the development of Chan and Huayan and the general intellectual/religious climate of his times. Unlike some of his more radical and cryptic Chan contemporaries， he was a sober-minded and meticulous scholar who wrote extensive critical analyses of the various Chan and scholastic sects of the period， as well as numerous scriptural exegesis. Zongmi was， like many later Korean monks on whom he extended his influence， deeply interested in both the practical and doctrinal aspects of Buddhism， and especially concerned about the means of the harmonization of the views of those who tended toward exclusivity in either direction. Zongmi studied deeply all the major texts of the Chinese Buddhist canon of his time， specializing in those works with Huayan， tatha^gatagarbha and Chan affinities. He was deeply affected by Huayan thought and is famous for his work in the area of doctrinal classification， i.e.， attempting to account of the apparent disparities in the Buddhist doctrines by categorizing them according to their specific aims. Although he conducted other important studies on texts such as the Huayan jing 华严经 ， Awakening of Faith 起信论， and Diamond Sutra 金刚经， and dealt with such issues as the rapprochement of the three teachings and the relationship of various schools of Chan， Zongmi's work on the Sutra of Perfect Enlightenment （Yuanjue jing 圆觉经）was the centerpiece of his scholarly career. His most important work on the sutra was his Yuanjue jing da shou （Great Commentary on the Sutra of Perfect Enlightenment 圆觉经大疏）. During the process of finishing this work， Zongmi wrote a series of abridgments， expansions and digressions on it. Other noted works include the Renyuan lun （人源论Inquiry into the Origin of Humanity; see Gregory （1995）） and the Chanyuan zhuquan jidu （禅源诸诠集都Origins of the Various Chan Teachings）. For a full-length study of Zongmi's thought see Gregory （1991）.