Nanto Rokushu (南都六宗)
Nanto Rokushu' (also called 'Nanto Rikushu') is the general term of the six Buddhist sects which flourished mainly in Heijo-kyo (the capital of Japan in the Nara period) in the Nara period. It is also called 'Nara Bukkyo' (Buddhism in Nara).
The Hosso sect (based on the theory of Yuishiki [vijñapti-mātratā or Consciousness-only])
The Sanron sect (based on San-ron [three important papers] including "Chu-ron" ["Mūlamadhyamaka-kārikā" or "Fundamental Verses on the Middle Way"], "Junimon-ron" ["Dvadasamukha-sastra" or "Twelve Gate Treatise"], and "Hyaku-ron" ["Sata-sastra" or "One Hundred Verses Treatise"])
The Kusha sect (based on the theory of the Setsuissai-ubu School [Sarvāstivāda])
The Jojitsu sect (based on a paper "Jojitsu-ron" ["Satyasiddhi-sastra"])
The Kegon sect (based on a sutra "Kegon-kyo" ["Mahāvaipulya Buddhāvataṃsaka Sūtra" or "Avatamsaka Sutra"])
The Ritsu sect (based on a book of a commandment "Shibun-ritsu" ["Dharmaguptika-vinaya"])
In addition, in those days people had not called them 'Nanto Rokushu,' it was later used for distinguishing from 'Heian Nishu' (the Tendai sect and the Shingon sect) which flourished mainly in Heian-kyo (the capital of Japan in the Heian period) after the Heian period. In those days there were a few temples which followed a particular sect. In the Heian period, 'Shingon-in' (mantra hall), a branch temple of the Shingon sect was placed in Todai-ji Temple which is today regarded as Sohonzan (the head temple of a Buddhist sect) of the Kegon sect. In this way, Nanto Rokushu was gradually affected by the Esoteric Buddhism (Heian Nishu).
In addition, these sects were initially written with a Chinese character '衆' ('shu' literally 'people') such as 法相衆 (Hosso-shu, the Hosso sect) and 華厳衆 (Kegon-shu, the Kegon sect). However, it is said that by the erection of the Great Buddha of Todai-ji Temple (around year 748), they had been written with a Chinese character '宗' ('shu' literally 'sect') for '衆,' as are they today.
It is said that unlike Heian Buddhism and Kamakura Buddhism which emphasized relief work for the common people, these six sects of Nanto Rokushu had an academic atmosphere as an important factor, they were groups of learned priests studying mainly the doctrines of Buddhism. In other words, they were the Buddhism under the Ritsuryo system; the priests of these sects were just scholars studying Buddhism under the protection of the nation, and as for actual religious activity, they just performed some magical prayers for the idea of Chingo-Kokka (guarding the nation by Buddhism). However, it is said that Dosho, who went to China, learned the dogma of the Hosso sect from Genjo and introduced it to Japan, was not satisfied with such activities under the national control as a Buddhist, so he was engaged in an independent mission among the common people though digging wells and building bridges in various regions. In addition, it is said that Gyoki, who was also engaged in an independent mission for the common people, had studied under Dosho.
The Ritsu sect
The founder was Ganjin (Jianzhen); the central temple was Toshodai-ji Temple.
The Kegon sect
The founder was Roben (or Ryoben) and Shinsho (or Shinjo); the central temple was Todai-ji Temple.
The Sanron sect
The founder was Ekan (Hyegwan); the central temple was Todai-ji Nanin Temple.
The Jojitsu sect
The founder was Dozo; the central temples were Gango-ji Temple and Daian-ji Temple.
The Hosso sect
The founder was Dosho; the central temples were Kofuku-ji Temple and Yakushi-ji Temple.
The Kusha sect
The founder was Dosho; the central temples were Todai-ji Temple and Kofuku-ji Temple.
These six sects of Nanto Rokushu were, rather than religious sects, like schools studying ideas each other, and they had been prospering mainly at Todai-ji Temple.