The Kegon School of Buddhism (華厳宗 Kegon-shū) flourished in the early centuries of Japanese Buddhist history and was one of the largest of the Six Sects of Nara (南都六宗 Nanto Rokushū). It is based on the Huayan or Flower Garland school of Buddhism and was introduced in Japan by the Chinese monk Tao-hsüan (道璿 Dōsen, 702-760 CE) and the Korean monk Kor Simsang (審祥 Shinjō, d. 742).
Rōben (良弁、朗弁、良辨、朗辨, 689-773 CE), a priest at the Tōdai-ji in Nara, who had invited Shinjō to give lectures at the temple, was an early expert on the Kegonkyō (華厳経), the Avataṃsaka Sūtra, one of the most influential Mahayana sutras of East Asian Buddhism. During the Kamakura Period Gyōnen (凝然, 1240-1321) of the Tōdai-ji and Myōe (明恵, 1173–1232), also known as Kōben (高弁), of the Kōzan-ji in Kyōto, who introduced Vajrayāna (doctrines of Tantric Buddhism) into Kegon, were the highest authorities in the school.
Although it fell into inactivity, later on, there have been several distinct Kegon scholars on the Avataṃsaka Sūtra, such as the monk Sōshun, also known as Hōtan (僧濬, 1659-1738) who advocated a harmonisation of Kegon and Tendai; Kegon also absorbed esoteric rituals from Shingon. Nowadays, the Tōdai-ji, with 47 secondary temples, is still the central temple of this small Buddhist school.
In the Nara Period (710-794), six Buddhist sects were officially recognised. They were all of academic nature and came from Korea and China during the reign of Prince Shotoku. They were introduced in the following order:
The Kusha and the Jōjitsu are considered "text schools", not truly independent sects with their priesthood; they focused on the exegesis of the Kusharon (倶舎論, Abhidharmakośakārikā, or Verses on the Treasury of Abhidharma by Vasubandhu) and the Jōitsuron (成實論 Sādhyasiddhiśāstra by Harivarman). The Kusharon was studied by members of the Hossō sect, the Jōjitsuron by the Sanron clergy.
- Sanron (三論 "Three Treatise School", East Asian Mādhyamaka),
- Jōjitsu (成實宗 Tattvasiddhi, a sect of Nikaya Buddhism)
- Hossō (法相宗 East Asian Yogācāra)
- Kusha (倶舎宗 Abhidharma-focused Nikaya Buddhism)
- Risshū (律宗 Vinaya-focused Nikaya Buddhism)
Only the Hossō sect with its headquarters at the Yakushi-ji and the Kōfuku-ji, the Ritsu (Risshū) with its headquarters at the Tōshōdai-ji, and the Kegon sect with its headquarters at the Tōdai-ji survived until today. The Sanron sect - the major Buddhist school in the pre-Nara and early Nara Period, declined rapidly in the 9th century and disappeared altogether in the 14th century. Presently, over one hundred temples, mainly in the Nara region, belong to one of the three remaining Nara schools.
- Nussbaum, Louis-Frédéric, Japan Encyclopedia, Harvard University Press 2005