The Huayan zong school， one of the major schools of Chinese Buddhism， the doctrines of which ended up having profound impact on the philosophical attitudes of all of East Asian Buddhism. Established during the period of the end of the Sui and beginning of Tang dynasties， this school centered on the philosophy of interpenetration and mutual containment which its founders perceived in the Huayan jing 华严经. Yet despite basic reliance on this sutra， much of the technical terminology that the school becomes famous for is not found in the sutra itself， but in the commentarial works of its early founders. The founding of the school is traditionally attributed to a series of five "patriarchs" who were instrumental in developing the schools doctrines. These five are: Dushun 杜顺， Zhiyan 智俨， Fazang 法藏， Chengguan 澄观 and Zongmi 宗密. Another important figure in the development and popularization of Huayan thought was the lay scholar Li Tongxuan 李通玄. Some accounts of the school also like to extend its patriarchship earlier to A/svaghos!a 马鸣 and Na^ga^rjuna 龙树. Although there are certain aspects of this patriarchal scheme which are clearly contrived， it is fairly well accepted that these men each played a significant and distinct role in the development of the school: for example， Dushun is known to have been responsible for the establishment of Huayan studies as a distinct field; Zhiyan is considered to have established the basic doctrines of the sect; Fazang is considered to have rationalized the doctrine for greater acceptance by society; Chengguan and Zongmi are understood to have further developed and transformed the teachings. After the time of Zongmi and Li Tongxuan the Chinese school of Huayan generally stagnated in terms of new development， and then eventually began to decline. The school， which had been dependent upon the support it received from the government， suffered severely during the purge of 841-5， never to recover its former strength. Nonetheless， its profound metaphysics， such as that of the four dharmadha^tu 四法界 of interpenetration， had a deep impact on surviving East Asian schools， especially the Chan school.
The greatest lasting impact of the Huayan school was to be seen in Korea， where it was transmitted by Uisang 义湘， who had been， along with Fazang， a student of Zhiyan. After Uisang returned to Korea in 671， he worked vigorously toward the establishment of the Hwaom school on the peninsula. In this effort， he was greatly aided by the powerful influences of his friend Wonhyo 元晓， who although not an official representative of the school， relied deeply on Hwaom metaphysical principles to establish his concept of "interpenetrated Buddhism 通佛教." After the passing of these two early monks， the Hwaom school became strongly established under the influence of a long series of Hwaom masters. The Hwaom school remained in the position of predominant doctrinal school in Korea up till the end of the Koryo period， when it was placed into a forced merger with the Son school 禅宗. Within the Son school， Hwaom thought would continue to play a strong role， and continues as such to modern times.
Huayan studies were founded in Japan when， in 736， the scholar-priest Ro^ben 良辩 （originally a Hosso^ 法相 specialist） invited the Korean Simsang 审祥 to give lectures on the Huayan jing at Konshu-ji 金钟寺. When the construction of To^daiji 东大寺 was completed， Ro^ben entered that temple to formally initiate Kegon as a field of study in Japanese Buddhism， and the Kegon shu^ would become known as one of the "six Nara 奈良 schools." Kegon thought was later be popularized in Japan by Myo^e 明惠， who combined its doctrines with those of the esoteric school 密教， and Gyo^nen 凝然， who is most responsible for the establishment of the To^daiji lineage of Kegon.
The most important philosophical contributions of the Huayan school were in the area of its metaphysics， as it taught the doctrine of the mutual containment and interpenetration of all phenomena shishiwuai 事事无碍: that one thing contains all things in existence， and that all things contain one.