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Huayan

The Huayan school of Buddhism (, Wade–Giles: Hua-Yen, "Flower Garland," from the Sanskrit "Avataṃsaka") is a Mahayana Buddhist tradition that developed in China during the Tang dynasty (618-907). The Huayan worldview is based primarily on the Buddhāvataṃsaka Sūtra (, Flower Garland Sutra) as well as on the works of Huayan patriarchs, like Zhiyan (602–668), Fazang (643–712), Chengguan (738–839), Zongmi (780–841) and Li Tongxuan (635–730).

Another common name for this tradition is the Xianshou school (Xianshou being another name for patriarch Fazang).  The Huayan School is known as Hwaeom in Korea, Kegon in Japan and Hoa Nghiêm in Vietnam.

The Huayan tradition considers the Flower Garland Sutra to be the ultimate teaching of the Buddha. It also draws on other sources, like the Mahayana Awakening of Faith, and the Madhyamaka and Yogacara philosophies. Huayan teachings, especially its doctrines of universal interpenetration, nature-origination (which sees all phenomena as arising from a single ontological source), and the omnipresence of Buddhahood, were very influential on Chinese Buddhism and also on the rest of East Asian Buddhism. Huayan thought was especially influential on Chan (Zen) Buddhism, and some scholars even see Huayan as the main Buddhist philosophy behind Zen.

Origins of the Chinese Avataṃsaka tradition
The Buddhāvataṃsaka Sūtra (The Garland of Buddhas Sutra, or The Multitude of Buddhas Sutra) is a compilation of sutras of various length, some of which originally circulated as independent works before being combined into the "full" Avataṃsaka. One of the earliest of these texts, the Ten Stages Sutra (Daśabhūmika), may date from the first century CE. These various sutras were probably joined shortly before its translation into Chinese, at the beginning of the 5th century CE.

There are various versions of the Chinese Avataṃsaka (Chinese: Huāyán Jīng 華嚴經, "Splendid Flower Adornment Sutra"). The full sutra was translated into Chinese three times (in versions of 40, 60, and 80 fascicles or "scrolls", 卷). The earliest Chinese texts associated with the Avataṃsaka are the Dousha jing (Taisho 280), produced by Lokaksema (fl. 147–189) in the latter part of the second century CE, and the Pusa benye jing (Book of the Original Acts that Adorn the Bodhisattva, T. 281), translated by Zhi Qian (fl. ca. 220–257 CE) in the early to mid third century. There is evidence that these smaller or partial Avataṃsaka sutras circulated on their own as individual scriptures.

As soon as the large Huāyán Sūtra appeared in China, an exegetical tradition grew up around the text in order to explain it. The first translation of the larger Huāyán Sūtra (in 60 fascicles) is often dated to the Southern Dynasties era (c. 420–589), when a translation team led by Gandharan master Buddhabhadra produced a full Chinese translation of the text. There is also evidence of a Huāyán Sūtra tradition in the Northern Dynasties (386-581) era. The Avataṃsaka teachings are associated with figures like Xuangao (402-444) who led a community with Daorong at Binglingsi cave, and Zhidan (c. 429–490), who argued that only the Huāyán Sūtra teaches the "sudden teaching" (while other Mahayana texts teach the gradual teaching).

Xuangao, a disciple of Buddhabhadra, was associated with the teaching of the "Huāyán Samadhi" which is said to have been passed on to him by Buddhabhadra. According to Hamar, Xuangao's tradition is a precursor to the Huayan school and may have even composed the apocryphal Brahma's Net Sūtra (Fanwang Jing T1484). Xuangao's tradition is also associated with Chinese meditation cave grottoes such as the Yungang Grottoes, Maijishan Grottoes and the Bingling Temple Grottoes.

The origins of some of the teachings of the Huāyán school proper can also be traced back to the Dilun school, which was based on the Shidijing lun (十地經論), Vasubandhu's commentary to the Daśabhūmikā-sutra (which is part of the Avataṃsaka Sūtra) translated by Bodhiruci and Ratnamati. Dilun figures like Ratnamati's disciple Huiguang (468–537) emphasized the study of the entire Avataṃsaka and Dilun masters likely had their own commentaries on the text (but none have survived in full). Only a few extracts remain, such as parts of Huiguang's commentary and parts of Lingyu's (518–605).

Lingbian (靈辨, 477–522) was another early figure who studied and commented on the ''Avataṃsaka.  He is referred to by Fazang as a great devotee of Manjushri, and 12 fascicles of Lingbian's commentary to the Avataṃsaka survive, being the earliest significant Chinese commentary on the Avataṃsaka which is extant. ''

Tang dynasty patriarchs

The founding of the Huayan school proper is traditionally attributed to a series of five patriarchs who were instrumental in developing the school's doctrines during the Tang dynasty (618 to 907). These Huayan "patriarchs" (though they did not call themselves as such) were erudite scholar-practitioner who created a unique tradition of exegesis, study and practice through their writings and oral teachings. They were particularly influenced by the works of the Dilun and Shelun schools of Chinese Yogacara''. ''

These five patriarchs are: While the above list is the most common one, other Huayan patriarchal lists add different figures, such as Nagarjuna, Asvaghosa, Vasubandhu, and the lay master Li Tongxuan (, 635?-730), the author of the Xin Huayan Jing Lun (新華嚴經論, Treatise on the new translation of the Avatamsaka Sutra), a popular and lengthy commentary on the Avatamsaka. Li Tongxuan's writings on the Huayan sutra were particularly influential on later Chan Buddhists, who often preferred his interpretations.
 * 1) Dushun (, c. 557–640), a monk who was known as a meditator master and who was devoted to the Huayan sutra. He wrote several works, including the Discernments of the Huayan Dharmadhātu (Huayan fajie guanmen).
 * 2) Zhiyan (, c. 602–668), was a student of Dushun who is considered to have established most of the main doctrines of Huayan thought and is thus a crucial figure in the foundation of Huayan. Zhiyan also studied with various masters from the Dilun and Shelun schools, which were branches of Chinese Yogacara.
 * 3) Fazang (, c. 643–712), who was the Buddhist teacher of the Empress Wu Zetian (684–705) and is often considered the real founder of the school. He wrote numerous works on Huayan thought and practice including several commentaries on the Avatamsaka.  He also worked on a new translation of the Avatamsaka Sutra (in collaboration with various figures, including Śikṣānanda) in 80 fascicles.
 * 4) Chengguan (, c. 738–839), though he was not a direct student of Fazang (who died 25 years before Chengguan's birth), Chengguan further developed the Huayan teachings in innovative directions in his various commentaries and treatises. He was a student of Fashen (718–778), who was a student of Fazang's student Huiyuan. Chengguan's voluminous commentary to the new 80 fascicle Avatamsaka (the Da fang-guang fo huayan jing shu, 大方廣佛華嚴經疏, T. 1735), along with his sub-commentary to it (T. 1736), soon became the authoritative commentaries to the sutra in East Asia.
 * 5) Guifeng Zongmi (, c. 780–841), who is also known for also being a patriarch of Chinese Chán and for also writing on Daoism and Confucianism. His writings include works on Chan (such as the influential Chan Prolegomenon) and various Huayan commentaries. He was particularly fond of the Sutra of Perfect Enlightenment, writing a commentary and sub-commentary to it.

Another important Huayan figure of the Tang era was Fazang's main disciple Huiyuan (慧苑, 673–743) who also wrote a commentary on the Avatamsaka Sutra. Because Huiyuan modified some of Fazang's interpretations, he was retroactively sidelined from the Huayan lineage of patriarchs by later figures like Chengguan who criticized some of his doctrinal positions''. '' According to Imre Hamar, Huiyuan compared the Daoist teachings on the origination of the world to the Huayan teaching on the dependent arising of the tathagatagarbha. Huiyuan also incorporated Daoism and Confucianism into his panjiao (doctrinal classification) system. Chengguan disagreed with this.

Liao and Xia developments
After the time of Zongmi and Li Tongxuan, Chinese Huayan generally stagnated in terms of new developments, and then eventually began to decline. The school, which had been dependent upon the support it received from the government, suffered severely during the Great Buddhist Persecution of the Huichang era (841–845), initiated by Emperor Wuzong of Tang. The school stagnated even further in the conflicts and confusion of the late Tang dynasty and the Five Dynasties and Ten Kingdoms (907-979) era.

After the fall of the Tang dynasty several Huayan commentaries were lost. However, during the Five Dynasties and Ten Kingdoms era, Huayan remained influential, being part of the "Huayan-Chan" lineages influenced by Zongmi which were very popular in the north, especially in the Khitan Liao Empire (916-1125) and the Tangut kingdom (1038-1227) of the Western Xia. Various masters from these non-Chinese kingdoms are known, such as Xianyan (1048-1118) from Kailong temple in Khitan Upper capital, Hengce (1049-1098), Tongli dashi from Yanjing, Daoshen (1056?-1114?), Xianmi Yuantong, from Liao Wutaishan, Zhifu (fl. during the reign of Liao Daozong, 1055–1101).

The Liao and Xia Huayan traditions were more syncretic, adopting elements of Zongmi's Heze Chan influenced Huayan, as well as Chinese Esoteric Buddhism (zhenyan), Hongzhou Chan, and even Tibetan Buddhism in some cases. Several texts from the Liao Huayan tradition have survived, such as master Daochen's (道㲀) Chan influenced Account of Mirroring Mind (Jingxin lu, 鏡心錄) and his esoteric influenced Collection of Essentials for Realization of Buddhahood in the Perfect Penetration of the Exoteric and Secret Teachings (Xianmi Yuantong chengfo xinyao, 顯密圓通成佛心要 T no. 1955). Another important Huayan esoteric source of this period is Jueyuan's sub-commentary on Yixing’s commentary to the Mahāvairocana sūtra.

According to Daochen, the best approach to Buddhahood is the “combined practice of the exoteric and esoteric” (xianmi shuangxiu, 顯密雙修) which is for those of the highest capacity. However, he also recommended that those of "middling and lesser faculties...can choose to practice a single method according to their preference, be it the exoteric or esoteric.” Daochen's esoteric teachings focused on the dharani of Cundi which he saw as "the mother of all Buddhas and the life of all bodhisattvas" and also drew on the Mani mantra. The combined use of both of these is found in the Kāraṇḍavyūha

sūtra.

Another Liao Tangut work which survives from this period is The Meaning of the Luminous One-Mind of the Ultimate One Vehicle (Jiujing yicheng yuan-ming xinyao 究竟一乘圓明心要) by Tongli Hengce (通理恆策, 1048–1098). The works of the Liao tradition are important because they served as one of the sources of the later Huayan revival during the Song.

Song revival
After the Five Dynasties and Ten Kingdoms, the Huayan lineage experienced a revival in the following Song dynasty (960-1279). Tang era Huayan commentaries which had been dispersed were returned in 1085 by the Goryeo monk Uicheon. Uicheon (義天, 1055–1101) was thus an important figure of this revival period. The chief Chinese Huayan figures of the Song dynasty revival were Changshui Zixuan (子璇, 965–1038), Jinshui Jingyuan (靜源, 1011–1088), and Yihe (義和, c. early twelfth century).

Jingyuan is known for his sub-commentary to Chengguan's Huayan sutra commentary, while Zixuan is famed for his twenty-fascicle Notes on the Meaning of the Śūraṅgama Sūtra (首楞嚴義疏注經). While the Huayan school is generally seen as having been weaker than Chan or Tiantai during the Song, it still enjoyed considerable support from Chinese elites and from Buddhist monastics. Another important figure in the Song revival of Huayan was Guangzhi Bensong (廣智本嵩, fl. 1040), a master from the from Kaifeng. He is well known for his Thirty gāthās on the Contemplation of the Dharma-realm and Seven syllables of the title of the Huayan (Huayan qizi jing ti fajie guan sanshi men song 華嚴 七字經題法界觀三十門頌, Taisho no. 1885). Some of his other works have survived in Tangut.

New Huayan practice and ritual manuals were also written during the Song, such as Jinshui Jingyuan's "Rites on Practicing the Vows of Samantabhadra" (Chinese: 華嚴普賢行願修證儀; Pinyin: Huáyán Pǔxián Xíngyuàn Xiūzhèng Yí, Taisho Supplement no. X1473). These rites were influenced by Tiantai school ritual manuals, as well as by earlier Huayan materials. Song era Huayan monks also developed distinctly Huayan forms of "concentration and contemplation" (zhi guan), inspired by Tiantai methods as well as the Avatamsaka sutra and Huayan thought.

Jinshui Jingyuan also helped organize some state recognized Huayan public monasteries, like Huiyin temple. Jingyuan is known for his association with Mount Wutai, which has been a key center for Huayan Buddhism since the Song dynasty.

In the later Song, there were also four great Huayan masters: Daoting, Shihui (1102-1166), Guanfu, and Xidi. During the Yuan dynasty, the Huayan master Purui also wrote various Huayan works.

Ming and Qing dynasties
During the Ming dynasty, Huayan remained influential. One important event during the early Ming was when the eminent Huayan monk Huijin (1355-1436) was invited by the Xuande Emperor (1399-1435) to the imperial palace to preside over the copying of ornate manuscripts of the Buddhāvataṃsaka, Prajñāpāramitā, Mahāratnakūṭa, and Mahāparinirvāṇa Sūtras. During the sixteenth century, Beijing was the center of Chinese Buddhist doctrinal study. During the late Ming, Kongyin Zhencheng (1547–1617), Lu'an (or Lushan) Putai (fl. 1511) of Beijing's Da Xinglong monastery and Yu’an Zhengui (born 1558) were some of the most influential scholars of Huayan thought. Huayan philosophy was also influential on some of the most eminent monks of the Ming era, including Zhibo Zhenke and Yunqi Zhuhong (1535–1615), both of whom studied and drew on Huayan thought and promoted the unity of practice (Chan and Pure Land) and study. Zhuhong himself was a student of Wuji Mingxin (1512-1574) of Bao'en monastery, who in turn was a disciple of Lu'an Putai. Another influential student of Wuji was Xuelang Hong'en (1545-1608), who became the most famous teacher in Jiangnan and lead revival of Huayan studies during this time. His main students include Yiyu Tongrun (1565-1624), Cangxue Duche (1588-1656), Tairu Minghe (1588-1640) and Gaoyuan Mingyu (fl. 1612).

During the Qing dynasty (1644-1912), Huayan philosophy continued to develop and exert a strong influence on Chinese Buddhism and its other traditions, including Chan and Pure Land. During the Qing, the most influential Huayan figures were Baiting Xufa (1641-1728) and Datian Tongli (1701-1782). Xufa wrote various works on nianfo, including: Short Commentary on the Amitabhasutra, and Straightforward Commentary on the Amitāyurdhyāna Sūtra”. Another influential figure was the lay scholar Peng Shaosheng (彭紹升, 1740–1796).

Baiting Xufa and Peng Shaosheng were known for their synthesis of Huayan thought with Pure Land practice which is termed "Huayan-Nianfo". For the scholar monk Xufa, the practice of nianfo (contemplation of the Buddha) was a universal method suitable for everyone which was taught in the Avatamsaka Sutra and could lead to an insight into the Huayan teachings of interpenetration. Xufa generally defended the mind-only Pure land view which saw the Pure land and Amitabha Buddha as reflections of the “one true mind” (yixin 一心, zhenxin 真心) or the "one true dharmadhatu." Similarly, for Peng Shaosheng, Amitabha was synonymous with the Vairocana Buddha of the Avatamsaka sutra, and the pure land was part of Vairocana's Lotus Treasury World. As such, the practice of nianfo and of the methods of the Avatamsaka would lead to rebirth in the Pure land (which is non-dual with all worlds in the universe) and see Buddha Amitabha (which is equal to seeing all Buddhas).

Korean Hwaôm

In the 7th century, the Huayan school was transmitted into Silla Korea, where it is known as Hwaôm. This tradition was transmitted by the monk Uisang (의상대사, 625–702), who had been a student of Zhiyan together with Fazang. After Uisang returned to Korea in 671, established the school and wrote various Hwaôm works, including a popular poem called the Beopseongge, also known as the Diagram of the Realm of Reality, which encapsulated the Huayan teaching. In this effort, he was greatly aided by the powerful influences of his friend Wonhyo, who also studied and drew on Huayan thought and is considered a key figure of Korean Hwaôm. Wonhyo wrote a partial commentary on the Avataṃsaka Sūtra (the Hwaŏm-gyŏng so). Another important Hwaôm figure was Chajang (d. between 650 and 655).

After the passing of these two early monks, the Hwaôm school eventually became the most influential tradition in the Silla Kingdom until the end of the kingdom. Royal support allowed various Hwaôm monasteries to be constructed on all five of Korea's sacred mountains, and the tradition became the main force behind the unification of various Korean Buddhist cults, such as those of Manjushri, Maitreya and Amitabha. Important figures include the Silla monk Pŏmsu who introduced the work of Chengguan to Korea in 799, and Sŭngjŏn, a disciple of Uisang. Another important figure associated with Hwaôm was the literatus Ch’oe Ch’iwŏn. He is known for his biographies of Fazang and Uisang, along with other Huayan writings. Towards of the end of Silla, Gwanhye of Hwaeomsa and Master Heuirang (875-927 CE) were the two most important figures. During this period Hwaeomsa and Haeinsa Temples formed two sub-sects of Hwaeom who disputed with each other on matters of doctrine.

The Hwaôm school remained the predominant doctrinal school in the Goryeo Dynasty (918–1392). An important figure of this time was Gyunyeo (923–973). He is known for his commentary on Uisang's Diagram of the Realm of Reality. He also unified the southern and northern factions of Hwaeomsa and Haeinsa. Korean Buddhism declined severely under the Confucian Joseon Dynasty (1392–1910). All schools were forced to merge into one single school, which was dominated by the Seon (Korean Zen) tradition. Within the Seon school, Hwaôm thought would continue to play a strong role until modern times and various Hwaôm commentaries were written in the Joseon era.

Japanese Kegon

Kegon (華厳宗) is the Japanese transmission of Huayan. Huayan studies were founded in Japan in 736 when the scholar-priest Rōben (689–773), originally a monk of the East Asian Yogācāra tradition, invited the Korean monk Shinjō to give lectures on the Avatamsaka Sutra at Kinshōsen Temple (金鐘山寺, also 金鐘寺 Konshu-ji or Kinshō-ji), the origin of later Tōdai-ji. When the construction of the Tōdai-ji was completed, Rōben became the head of the new Kegon school in Japan and received the support of emperor Shōmu. Kegon would become known as one of the Nanto Rikushū (南都六宗) or "Six Buddhist Sects of Nanto". Rōben's disciple Jitchū continued administration of Tōdai-ji and expanded its prestige through the introduction of imported rituals.

Kegon thought would later be further popularized by Myōe (1173–1232), the abbot and founder of Kōzan-ji Kegon temple. Myōe combined the Kegon lineage with Tendai and Shingon esoteric lineages. He was a prolific scholar monk who composed over 50 works. Myōe promoted the practice of the mantra of light (kōmyō shingon) as simple efficacious practice that was available to all, lay and monastic. He also promoted the idea that this mantra could lead to rebirth in Amitabha's pure land, thus providing a Kegon alternative to popular Japanese Pure Land methods.

Over time, Kegon incorporated esoteric rituals from Shingon, with which it shared a cordial relationship. Its practice continues to this day, and includes a few temples overseas.

Another important Kegon figure was Gyōnen (1240–1321), who was a great scholar (who studied numerous schools including Madhyamaka, Shingon, and Risshu Vinaya) and led a revival of the Kegon school in the late Kamakura era. He was also known as a great historian of Japanese Buddhism and as a great Pure Land thinker. His Pure Land thought is most systematically expressed in his Jōdo hōmon genrushō (淨土法門源流章, T 2687:84) and it was influenced by various figures of his day, such as the Jodo monk Chōsai, and the Sanron figure Shinkū Shōnin, as well as by his understanding of Huayan thought.

In the Tokugawa period, another Kegon scholarly revival occurred under the Kegon monk Hōtan (1657-1738. a.k.a. Sōshun, Genko Dōjin) and his disciple Fujaku (1707-1781).

Modern Era
During the Republican Period (1912–1949), various monks were known for their focus on Huayan teaching and practice. Key Huayan figures of this era include Cizhou (1877–1958), Zhiguang (1889–1963), Changxing, Yingci, Yang Wenhui, Yuexia, Shouye, and Kefa. Some of these figures were part of a network of Huayan study and practice.

In 1914, Huayan University, the first modern Buddhist monastic school, was founded in Shanghai to further systematize Huayan teaching and teach monastics. It helped to expand the Huayan tradition into the rest of into East Asia, Taiwan, and the West. The university managed to foster a network of educated monks who focused on Huayan Buddhism during the 20th century. Through this network, the lineage of the Huayan tradition was transmitted to many monks, which helped to preserve the lineage down to the modern day via new Huayan-centred organizations that these monks would later found.

Several new Huayan Buddhist organizations have been established since the latter half of the 20th century. In contemporary times, the largest and oldest of the Huayan-centered organizations in Taiwan is the Huayan Lotus Society (Huayan Lianshe 華嚴蓮社), which was founded in 1952 by the monk Zhiguang and his disciple Nanting, who were both part of the network fostered by the Huayan University. Since its founding, the Huayan Lotus Society has been centered on the study and practice of the Huayan Sutra. It hosts a full recitation of the sutra twice each year, during the third and tenth months of the lunar calendar. Each year during the eleventh lunar month, the society also hosts a seven-day Huayan Buddha retreat (Huayan foqi 華嚴佛七), during which participants chant the names of the buddhas and bodhisattvas in the text. The society emphasizes the study of the Huayan Sutra by hosting regular lectures on it. In recent decades, these lectures have occurred on a weekly basis.

Like other Taiwanese Buddhist organization's, the Society has also diversified its propagation and educational activities over the years. It produces its own periodical and runs its own press. It also now runs a variety of educational programs, including a kindergarten, a vocational college, and short-term courses in Buddhism for college and primary-school students, and offers scholarships. One example is their founding of the Huayan Buddhist College (Huayan Zhuanzong Xueyuan 華嚴專宗學院) in 1975. They have also established branch temples overseas, most notably in California's San Francisco Bay Area. In 1989, they expanded their outreach to the United States of America by formally establishing the Huayan Lotus Society of the United States (Meiguo Huayan Lianshe 美國華嚴蓮社). Like the parent organization in Taiwan, this branch holds weekly lectures on the Huayan Sutra and several annual Huayan Dharma Assemblies where it is chanted. It also holds monthly memorial services for the society's spiritual forebears.

In Mainland China, Huayan teachings began to be more widely re-propagated after the end of the Cultural Revolution. Various monks from the network of monks fostered by the original Huayan University, such as Zhenchan (真禪) and Mengcan (夢參), were the driving factors behind the re-propagation as they travelled widely throughout China as well as other countries such as the United States and lectured on Huayan teachings. In 1996, one of Mengcan's tonsured disciples, the monk Jimeng (繼夢), also known as Haiyun (海雲), founded the Huayan Studies Association (Huayan Xuehui 華嚴學會) in Taipei, which was followed in 1999 by the founding of the larger Caotangshan Great Huayan Temple (Caotangshan Da Huayansi 草堂山大華嚴寺). This temple hosts many Huayan-related activities, including a weekly Huayan Assembly. Since 2000, the association has grown internationally, with branches in Australia, Canada, and the United States.

Influence
The doctrines of the Huayan school ended up having profound impact on the philosophical attitudes of East Asian Buddhism. According to Wei Daoru their theory of perfect interfusion was "gradually accepted by all Buddhist traditions and it eventually permeated all aspects of Chinese Buddhism." Huayan even is seen by some scholars as the main philosophy behind Chan Buddhism.

Huayan thought had a noticeable impact on East Asian Esoteric Buddhism. Kukai (774-835) was deeply knowledgeable of Huayan thought and he saw Huayan as the highest exoteric view. Some of Kukai's ideas, such as his view of Buddhahood in this body, was also influenced by Huayan ideas.

During the post-Tang era, Huayan (along with Chan) thought also influenced the Tiantai school. Tiantai school figures who were influenced by Huayan and Chan were called the "off mountain" (shanwai) faction, and a debate ensued between them and the "home mountain" (shanjia) faction.

Huayan thought was also an important source for the Pure Land doctrine of the Yuzu Nembutsu sect of Ryōnin (1072–1132). Likewise, Huayan thought was important to some Chinese Pure Land thinkers, such as the Ming exegete Yunqi Zuhong (1535–1615) and the modern lay scholar Yang Wenhui (1837–1911).

On Chan
Chinese Chán was profoundly influenced by Huayan, though Chán also defined itself by distinguishing itself from Huayan. Guifeng Zongmi, the Fifth Patriarch of the Huayan school, occupies a prominent position in the history of Chán. Mazu Daoyi, the founder of the influential Hongzhou school of Chan, was influenced by Huayan teachings, like the identity of principle and phenomena. He also sometimes quoted from Huayan sources in his sermons, like Dushun's Fajie guanmen (Contemplation of the Realm of Reality). Mazu's student Baizhang Huaihai also draws on Huayan metaphysics in his writings.

Dongshan Liangjie (806–869), the founder of the Caodong lineage, formulated his theory of the Five Ranks based on Huayan's Fourfold Dharmadhatu teaching. The influential Caodong text called Sandokai, attributed to Shitou, also draws on Huayan themes. In a similar fashion, Linji, the founder of the Linji school, also drew on Huayan texts and commentaries, such as Li Tongxuan's Xin Huayan Jing Lun (新華嚴經論, Treatise on the new translation of the Avatamsaka Sutra). This influence can also be seen in Linji's schema of the "four propositions". According to Thomas Cleary, similar Huayan influences can be found in the works of other Tang dynasty Chan masters like Yunmen Wenyan (d. 949) and Fayen Wenyi (885-958).

During the Song dynasty, Huayan metaphysics were further assimilated by the various Chan lineages. Cleary names Touzi Yiqing (1032-1083) and Dahui Zonggao (1089–1163) as two Song era Chan figures which drew on Huayan teachings. The Ming era Chan master Hanshan Deqing (1546-1623) is known for promoting the study of Huayan and for his work on a new edition of Chengguan's commentary on the Huayan sutra.

A similar syncretism with Zen occurred in Korea, where the Korean Huayan tradition influenced and was eventually merged with Seon (Korean Zen). The influence of Huayan teachings can be found in the works of the seminal Seon figure Jinul. Jinul was especially influenced by the writings of Li Tongxuan.

Huayan thought has also been influential on the worldview of Thich Nhat Hanh, particularly his understanding of emptiness as "Interbeing".

Huayan sutra
The Huayan school's central text is the Avataṃsaka Sūtra (Flower Garland Sutra, Ch. Huāyán Jīng), which is considered the supreme Buddhist revelation in this tradition. There are three different translations of the work in Chinese and other related sutras as well. According to Paul Williams, the Avataṃsaka Sūtra is not a systematic philosophical work, though it does contain various Mahayana teachings reminiscent of Madhyamaka and Yogacara, as well as mentioning a pure untainted awareness or consciousness (amalacitta).

The sutra is filled with mystical and visionary imagery, focusing on figures like the bodhisattvas Samantabhadra and Manjushri, and the Buddhas Shakyamuni, and Vairocana. Vairocana is the universal Buddha, whose body is the entire universe and who is said to pervade every atom in the universe with his light, wisdom, teachings, and magical emanations.

According to the Huayan sutra: The realm of the Buddhas is inconceivable, no sentient being can fathom it....The Buddha constantly emits great beams of light, in each light beam are innumerable Buddhas....The Buddha-body is pure and always tranquil, the radiance of its light extends throughout the world....The Buddha's freedom cannot be measured— It fills the cosmos and all space....With various techniques it teaches the living, sound like thunder, showering the rain of truth....All virtuous activities in the world come from the Buddha's light....In all atoms of all lands Buddha enters, each and every one, producing miracle displays for sentient beings: Such is the way of Vairocana....In each atom are many oceans of worlds, their locations each different all beautifully pure. Thus does infinity enter into one, yet each unit's distinct, with no overlap....In each atom are innumerable lights pervading the lands of the ten directions, all showing the Buddhas’ enlightenment practices. The same in all oceans of worlds. In each atom the Buddhas of all times appear, according to inclinations; While their essential nature neither comes nor goes, by their own power they pervade the worlds. All these awakened activities and skillful techniques (upaya) are said to lead all living beings through the bodhisattva stages and eventually to Buddhahood. These various stages of spiritual attainment are discussed in various parts of the sutra (book 15, book 26).

An important doctrine that the Huayan school drew from this sutra is the idea that all levels of reality are interrelated, interpenetrated and interfused, and so "inside everything is everything else". As the Huayan sutra states:"They . . . perceive that the fields full of assemblies, the beings and aeons which are as many as all the dust particles, are all present in every particle of dust. They perceive that the many fields and assemblies and the beings and the aeons are all reflected in each particle of dust."According to Dumoulin, the Huayan vision of "unity in totality allows every individual entity of the phenomenal world its uniqueness without attributing an inherent nature to anything". According to Williams, this interfused vision of the cosmos is the total realm of all phenomena, the "Dharma realm" (Dharmadhatu) as seen from the point of view of a Buddha. The focus of the Huayan sutra is thus how to attain this contemplative universal vision of ultimate reality, as well as the miraculous powers of Buddhas and bodhisattvas with which they communicate their vision of the ultimate truth.

Furthermore, because all things are interconnected and interfused, the Buddha (and his cosmic body and universal light) is present everywhere and so is his wisdom, which is said to be all pervasive. As chapter 32 of the sutra states: "in the class of living beings there is no place where the wisdom of Tathagata is not present."

Other key scriptures
The Awakening of Faith in the Mahayana (Dasheng Qixin Lun, 大乘起信論) was another key scriptural source for Huayan masters like Fazang and Zongmi, both of whom wrote commentaries on this treatise. The Lotus sutra was also seen as an important scripture in Huayan. Various Huayan masters saw the Lotus sutra as a sutra of definitive (ultimate) meaning alongside the Avatamsaka. Fazang also considered the Lankavatara sutra to be a definitive sutra, and he wrote a commentary on it. The Sutra of Perfect Enlightenment was also particularly important for the Huayan patriarch Zongmi.

Commentaries and treatises
The Huayen patriarchs wrote numerous other commentaries and original treatises. Fazang for example, wrote commentaries on the Avatamsaka, the Lankavatara Sutra, the Awakening of Faith, the Brahmajāla Sūtra (Taisho no. 40, no. 1813) and the Ghanavyūha Sūtra (no. X368 in the supplement to the Taisho canon, Xu zang jing 續藏經 vol. 34).

Perhaps the most important commentaries for the Chinese Huayan school are Fazang's commentary on the Avatamsaka Sutra, the Huayan jing tanxuan ji (華嚴經探玄記, Record of Investigating the Mystery of the Avatamsaka sutra) in 60 fascicles and Chengguan's Extensive Commentary on the Buddhāvataṃsaka sutra (Da fang-guang fo huayan jing shu, 大方廣佛華嚴經疏, T. 1735), and his sub-commentary (T. 1736)''.  Other Huayan figures like Zhiyan, and Li Tongxuan also wrote influential commentaries on the Huayan sutra''.

Fazang wrote a number of other original Huayan treatises, such as Treatise on the Golden Lion, which is said to have been written to explain Huayan's view of interpenetration to Empress Wu. Another key Huayen treatise is On the Meditation of the Dharmadhātu attributed to the first patriarch Dushun.

Peter N. Gregory notes that the Huayan commentarial tradition was: "not primarily concerned with a careful exegesis of the original meaning of the scripture." Instead it was concerned with specific doctrines, ideas and metaphors (such as nature origination, the dependent arising of the dharmadhatu, interfusion, and the six characteristics of all dharmas) which was inspired by scripture.

Doctrine
Huayan thought seeks to explain the nature of the Dharmadhatu (法界, fajie, the realm of phenomena, the Dharma realm), which is the world as it is ultimately, from the point of view of a fully awakened being. In East Asian Buddhism, the Dharmadhatu is the whole of reality, the totality of all things. Thus, Huayan seeks to provide a holistic metaphysics that explains all of reality.

Huayan philosophy is influenced by the Huayan sutra, other Mahayana scriptures like the Awakening of Faith and the Lotus Sutra, as well as by the various Chinese Buddhist traditions like Chinese Yogacara, the buddha-nature schools like Shelun and Dilun, and Madhyamaka (Sanlun). Huayan patriarchs were also influenced by non-buddhist Chinese philosophy.

Some key elements of Huayan philosophy are: the interpenetration and interfusion (yuanrong) of all phenomena (dharmas), "nature origination," (xingqi) - how phenomena arise out of an ultimate principle, which is buddha-nature, or the "One Mind", how the ultimate principle (li) and all phenomena (shi) are mutually interpenetrated, the relation between parts and the whole (understood through the six characteristics), a unique Huayan interpretation of the Yogacara framework of the three natures (sanxing) and a unique view of Vairocana Buddha as an all pervasive cosmic being.

Interpenetration

A key doctrine of Huayan is the mutual containment and interpenetration (xiangru) of all phenomena (dharmas), also known as "perfect interfusion" (yuanrong, 圓融). This is associated with what is termed "dharmadhatu pratityasamutpada" (法界緣起, fajie yuanqi, the dependent arising of the whole realm of phenomena), which is Huayan's unique interpretation of dependent arising. This doctrine is described by Wei Daoru as the idea that "countless dharmas (all phenomena in the world) are representations of the wisdom of Buddha without exception" and that "they exist in a state of mutual dependence, interfusion and balance without any contradiction or conflict." According to the doctrine of interpenetration, any phenomenon exists only as part of the total nexus of reality, its existence depends on the total network of all other things, which are all equally connected to each other and contained in each other.

According to Fazang, since the sum of all things determines any individual thing, “one is many, many is one” (yi ji duo, duo ji yi). Furthermore, according to Fazang “one in many, many in one” (yi zhong duo, duo zhong yi), because any dharma penetrates and is penetrated by the totality of all things. Thomas Cleary explains this Buddhist holism as one which sees the universe "as one single nexus of conditions in which everything simultaneously depends on, and is depended on by, everything else. Seen in this light, then, everything affects and is affected by, more or less immediately or remotely, everything else; just as this is true of every system of relationships, so is it true of the totality of existence." In this worldview, all dharmas are so interconnected that they are fused together without any obstructions in a perfectly harmonious whole (which is the entire universe, the Dharmadhatu).

In the Huayan school, the teaching of interpenetration is depicted through various metaphors, such as Indra's net, a teaching which may have been influenced by the Gandhavyuha chapter's climax scene in Vairocana's Tower. Indra's net is an infinite cosmic net that contains a multifaceted jewel at each vertex, with each jewel being reflected in all of the other jewels, ad infinitum. Thus, each jewel contains the entire net of jewels reflected within.

Other Huayan metaphors included a hall of mirrors, the rafter and the building, and the world text. The rafter-building metaphor can be found in Fazang's famous “Rafter Dialogue”. Fazang argues that any rafter (any part) is essential to the existence of its building (standing in for the universe, the dharmadhatu). Likewise, the identity and existence of any rafter is also dependent on it being part of a building (otherwise it would not be a rafter). Therefore, any phenomenon is necessarily dependent upon all phenomena in the universe, and because of this, all phenomena lack any metaphysical independence or essential nature (svabhava).

The six characteristics
One framework which is used by the Huayan tradition to further explain the doctrine of interpenetration is the "perfect interfusion of the six characteristics" (liuxiang yuanrong 六相圓融). Each element of the six characteristics refers to a specific kind of mereological relation. The six characteristics are:

 * 1) Wholeness / universality (zongxiang): each dharma (like a rafter) is characterized by wholeness, because it takes part in creating a whole (like a building), and each dharma is indispensable in creating the whole.
 * 2) Particularity / distinctness (biexiang): a dharma is characterized by particularity (e.g. any specific rafter) as far as it is a numerically distinct particular that is different from the whole.
 * 3) Identity / sameness (tongxiang): each dharma is characterized by a certain identity with all other parts of the whole, since they all mutually form the whole without conflict.
 * 4) Difference (yixiang): each dharma is different, since they have distinct functions and appearance, even while being part of a single whole.
 * 5) Integration (chengxiang): each dharma is integrated together with other dharmas in forming each other and in forming the whole, and each dharma does not interfere with every other dharma.
 * 6) Non-integration / disintegration (huaixiang): the fact that each part maintains its unique activity and retains its individuality while making up the whole.

Implications of interpenetration
The Buddhist doctrine of interpenetration also has several further implications in Huayan thought: Furthermore, according to the lay Huayan master Li Tongxuan, all things are just the one true dharma-realm (Ch. yi zhen fajie), and as such, there is no ontological difference between sacred and secular, awakening and ignorance, or even between Buddhahood and living beings. Because of the unity of ordinary human life and enlightenment, Li also held that Chinese sages like Confucius and Laozi also taught the bodhisattva path in their own way.
 * Truth is understood as encompassing and interpenetrating falsehood (or illusion), and vice versa (see also: two truths)
 * Purity (Śuddha) and goodness is understood as interpenetrating impurity and evil
 * Practicing any single Buddhist teaching entails the practicing of all other teachings
 * Ending one mental defilement (klesha) is ending all of them
 * The past contains the future and vice versa, all, three times are interfused
 * Practicing in one bodhisattva stage (bhumi) entails practicing in all bodhisattva stages

The Huayan doctrines of interfusion and non-duality also leads to several seemingly paradoxical views. Some examples include: (1) since any phenomenon X is empty, this implies X is also not X; (2) any particular phenomenon is an expression of and contains the absolute and yet it retains its particularity; (3) since each phenomenon contains all other phenomena, the conventional order of space and time is violated.

The ultimate principle and nature-origination
Another important metaphysical framework used by Huayan patriarchs is that of principle (理, li, or the ultimate pattern) and phenomena (shi). 'Principle' is the ultimate reality, which is ultimate reality (paramārtha-satya) which is endless and without limits, while phenomena (shi) refers to the impermanent and relative dharmas.

In Fazang's influential Essay on the Golden Lion (Taishō no. 1881), Fazang uses the statue of a golden Chinese lion as a metaphor for reality. The gold itself stands in for the ultimate principle, while the appearance and relative shape of the lion statue is the relative and dependent phenomena as they are perceived by living beings. Because the ultimate principle is boundless, empty and ceaseless, it is like gold in that it can be transformed into many forms and shapes. Also, even though phenomena appear as particular things, they lack any independent existence, since they all depend on the ultimate principle.

Furthermore, Huayan sees the ultimate principle and the relative phenomena as interdependent, unified and interfused, that is to say, they are non-dual. According to Paul Williams:

"First, noumenon and phenomena mutually interpenetrate and are (in a sense) identical. There is no opposition between the two. The one does not cancel out the other. Second, Fazang explains elsewhere that since all things arise interdependently (following Madhyamika), and since the links of interdependence expand throughout the entire universe and at all time (past, present, and future depend upon each other, which is to say the total dharmadhatu arises simultaneously), so in the totality of interdependence, the dharmadhatu, all phenomena are mutually interpenetrating and identical."The ultimate principle is associated with various Mahayana terms referring to ultimate reality, such as the "One Mind" of the Awakening of Faith, Suchness, the tathagatagarbha (the womb of tathagatas), buddha-nature, or just "nature". This nature is the ontological source and ground of all phenomena''.  This is a key idea in Huayan thought which is called "nature-origination" (xingqi''). The term derives from chapter 32 of the Avatamsaka Sutra, titled Nature Origination of the Jewel King Tathagata (Baowang rulai xingqi pin, Skt. ''Tathâgata-utpatti-sambhava-nirdesa-sûtra). ''

Nature origination refers to the manifestation of the ultimate nature in the phenomenal world and its interfusion with it.  That is to say, the ultimate pure nature is interdependent on and interpenetrates the entire phenomenal universe, while also being its source. For Huayan patriarchs like Fazang, the ultimate nature is thus seen as non-dual with all relative phenomena. Because the ultimate source of all things is also interdependent and interconnected with them, it remains a ground which is empty of self-existence (svabhava) and thus it is not an independent essence, like a monotheistic God.

The Cosmic Buddha Vairocana
In the cosmology of the Avatamsaka sutra, our world is just one of the immeasurable number of worlds in a multiverse called "Ocean of worlds, whose surface and inside are decorated with an arrangement of flowers" (Kusumatalagarbha-vyuhalamkara-lokadhatu-samudra). The Avatamsaka states that this entire cosmos has been purified by the Buddha Vairocana through his bodhisattva practices for countless aeons, after having met countless Buddhas. The sutra also states that our world is in Vairocana's buddhafield. Vairocana is closely associated with Shakyamuni Buddha, in some cases he is even identified with him in the Avatamsaka Sutra. Huayan generally sees Shakyamuni as an emanation body (nirmanakaya) from the ultimate Buddha Vairocana ("The Illuminator"). Furthermore, Huayan thought sees the entire universe as being the very body of Vairocana, who is seen as a supreme cosmic Buddha. Vairocana is infinite, his influence and light is limitless, pervading the entire universe. Furthermore, Vairocana is really the ultimate principle (li), the Dharmakaya, Suchness and "the substance underlying phenomenal reality". However, while Vairocana as ultimate principle is eternal, it also transforms and changes according to the needs and conditions of sentient beings. Furthermore, Vairocana is empty, interdependent and interfused with all phenomena in the universe. Thus, Vairocana is both immanent (due to its dependent and interfused character) and transcendent (as the immutable basis of all things).

According to Fazang, while the nirmanakaya Shakyamuni taught the other Mahayana sutras, Vairocana teaches the Avatamsaka Sutra through his ten bodies which are: the All-Beings Body, the Lands Body, the Karma Body, the Śrāvakas Body, the Pratyekabuddha Body, the Bodhisattvas Body, the Tathāgatas Body, the Wisdom Body, the Dharma Body, and the Space Body. Fazang sees these ten bodies as encompassing all phenomena (animate and inanimate) in the "three realms", i.e. the entire universe.

Classification of Buddhist teachings

In order to understand the vast number of texts and teachings they had received from India, Chinese Buddhist schools developed schematic classifications of these various teachings (called panjiao), such as the Five Periods and Eight Teachings of the Tiantai school.

The Huayan school patriarch Zhiyan developed a five tiered doctrinal classification of the Buddha's teaching which was expanded on by later figures such as Fazang. The five tiers are:
 * 1) The Hinayana teachings found in the Agamas and Abhidharma which is grounded in not-self (anatman). Fazang calls this "the teaching of the existence of dharmas and the non-existence of the self".
 * 2) The Mahayana teachings which focus on emptiness, non-arising and lack of form, and include the Prajñaparamita sutras, Yogacara teachings on consciousness, and Madhyamaka sources like the Mulamadhyamakakarika.
 * 3) The "Final" Mahayana teaching which according to Fazang teach the "eternal nature of the tathagatagarbha". Fazang writes that this teaching is based on buddha-nature sources like the Mahāyāna Mahāparinirvāṇa Sūtra, the Awakening of Faith, the Lankavatara, Srimaladevi sutra, Ratnagotravibhaga, and Dilun shastra.
 * 4) The Sudden Teaching, which is non-verbal and non-conceptual. This was associated with Vimalakirti's silence in the Vimalakirti sutra by Fazang. Chengguan also associated this with the "sudden enlightenment" teachings of the Chan school.
 * 5) The Complete or Perfect (Ch: yuan, lit. "Round") Teaching of the Avatamsaka sutra and Huayan which teach both the interpenetration of principle (or buddha-nature) and phenomena as well as the interpenetration of all phenomena with each other.

Huayan and Chan had doctrinal arguments regarding which would be the correct concept of sudden awakening. The teachings of the Chan school were regarded as inferior by Huayan masters, a characterization which was rejected by Chan masters.

Practice

The Huayan school developed numerous practices as part of their conception of the bodhisattva path. These include devotional practices, studying, chanting and copying of the Avatamsaka sutra, repentance rituals, recitation of dharanis, and meditation. These various elements might also be combined in ritual manuals such as The Practice of Samantabhadra's Huayan Dharma Realm Aspiration and Realization (華嚴普賢行願修證儀, Taisho Supplement, No. X1473) by Jinshui Jingyuan (靜源) which are still practiced together by Huayan communities during day long events.

Textual practices
According to Paul Williams, one of the central practices for the Huayan tradition was the recitation of the Avataṃsaka Sūtra. The chanting, studying and copying of the sutra was often done in "Huayen Assemblies" (Huayanhui), who would meet regularly to chant the sutra. Chanting the entire sutra could take anywhere from a few weeks to several months. Regular chanting of important passages from the sutra is also common, particularly the Bhadracaryāpraṇidhāna (The Aspiration Prayer for Good Conduct), sometimes called the "Vows of Samantabhadra". Solo chanting practice was also common, and another common element of reciting the sutra was bowing to the sutra during the chanting. Since this practice is time-consuming, it was also often done in solitary retreats called biguan, which could last years.

Copying the entire sutra (or passages from the sutra) by hand was also another key practice in this tradition and some sutra copyists were known for their excellent calligraphy. This practice was also sometimes combined with chanting and bowing as well. Another element that was sometimes added to this practice was to use one's own blood in the process of sutra copying (sometimes just blood mixed with the ink). This blood writing was rare, but it was done by a few celebrated figures, like Hanshan Deqing (1546-1623) and the Republican Period monk Shouye.

Contemplation of Buddhas and bodhisattvas
Another practice which is often highlighted in the Avatamsaka sutra is that of buddhānusmṛti (Ch. nianfo), contemplation of the Buddha.

In Chinese Buddhism, one popular method of contemplating the Buddha is to recite the Buddha's name. The practice of reciting the names of the Buddhas was also seen as a way to achieve rebirth in Vairocana's Pure Land, the Lotus Treasury World (Skt. Padmagarbha-lokadhātu; Ch. Lianhuazang shijie 蓮花藏世界). This Pure Land contains the entire universe, including our world, and it is identical with the entire Dharmadhatu. As such, for Huayan, our own world (known as the "Sahā world") is also the Lotus Storehouse Pure Land. Huayan also saw Vairocana's Pure land as non-dual and interfused with Amitabha's Pure Land of Sukhavati.

The practice of Buddha contemplation was promoted by various figures, such as the Huayan patriarchs Chengguan, Zongmi, the Goryeo monk Gyunyeo (923–973) and Peng Shaosheng, a householder scholar of the Qing dynasty.

The patriarch Guīfēng Zōngmì taught four types of buddhānusmṛti (nianfo), a schema that was also adopted by later Chinese figures: These four types of nianfo are the following:
 * “Contemplation of the name” (chēngmíng niàn 稱名念), modeled on The Perfection of Wisdom Sutra preached by Mañjuśrī (Taisho. 232). One selects Buddha, faces their direction, and then one mentally "holds" (chēngmíng 稱名) the sound of the name until one has a vision of all buddhas.
 * “Contemplating an image” (guānxiàng niàn 觀像念), based on the Great Jewel Collection Sutra (大寶積經, Dà bǎojī jīng, T.310), which entails contemplating the form of a Buddha by using a Buddha image.
 * “Contemplating the visualization” (guānxiǎng niàn 觀想念), this entails contemplating a Buddha's body without the aid of a physical image, and is based on sutras like Sutra on the samadhi-ocean of the contemplation of the Buddha (T.643) and Sutra on the samadhi of seated meditation (T.614).
 * “Contemplating the true mark” (shíxiàng niàn 實相念), which entails the contemplation of the Dharmakaya, the true nature of all dharmas, Dharmata. This is "the true nature of the Buddha" according to The Perfection of Wisdom Sutra Preached by Mañjuśrī, which is "unproduced and unextinguished, neither going nor coming, without name and without feature".

Another leading figure in the teaching of Huayan Nianfo was the 12th century Song monk Yihe (義和) who combined the method of nianfo with Huayan meditation teachings and the practice of the ten vows of Samantabhadra and saw this practice as a method of realizing the Huayan vision of ultimate reality. During the Qing, Baiting Xufa (1641-1728) and the lay scholar Peng Shaosheng (1740–1796) further promoted Huayan-Nianfo methods.

Huayan Pure Land practice also sometimes included devotion to bodhisattvas like Avalokiteshvara. This promoted by figures like the Korean monks Ŭisang and Ch'ewŏn. This devotion included the practice of chanting the names of bodhisattvas and visualizing them in meditation.

Meditation and the fourfold Dharmadhatu
Various Huayan texts provide different frameworks for the practice of meditation and the development of samadhi. Huayan sources mentions two key samadhis, the ocean-seal samadhi (Ch. haiyin sanmei) and the huayan samadhi (huayan sanmei). Some key Huayan sources which discuss meditation include Dushun's Contemplation of the Realm of Reality (Fajie guanmen) and The Ending of Delusion and the Return to the Source (Wangjin huanyuan) attributed to Fazang. Another key text is the "Cessation and Contemplation in the Five Teachings of Huayan" (Huayan wujiao zhiguan 華嚴五教止觀).

Dushun's meditative framework was based on three main stages of contemplation: (1) understanding emptiness as the true nature of all dharmas, (2) understanding that all dharmas are harmonious with the truth, and (3) understanding that all dharmas do not obstruct each other and that each dharma contains all other dharmas.

The theory of the "fourfold Dharmadhatu" (sifajie, 四法界) eventually became the central meditative framework for the Huayan tradition. This doctrinal and meditative framework is explained in Chengguan's meditation manual titled "Meditative Perspectives on the Huayan Dharmadhatu" (Huayan Fajie Guanmen, 華嚴法界觀門) and its commentaries. The Dharmadhatu is the goal of the bodhisattva's practice, the ultimate nature of reality which must be known or entered into. According to Fox, the Fourfold Dharmadhatu is "four cognitive approaches to the world, four ways of apprehending reality".

These four ways of seeing reality are:

 * 1) All dharmas are seen as particular separate events or phenomena (shi 事). This is the mundane way of seeing and is not a contemplation or meditation, but the pre-meditative perspective.
 * 2) All events are an expression of li (理, the ultimate principle), which is associated with the concepts of "true emptiness", “One Mind” (yi xin 一心) and Buddha nature. This is the first level of Huayan meditation.
 * 3) This is the “non-obstruction of principle and phenomena” (lishi wuai 理事無礙), i.e. their interpenetration and interfusion.
 * 4) All events / phenomena interpenetrate (shishi wuai 事事無礙), which refers to how "all distinct phenomenal dharmas interfuse and penetrate in all ways" (Zongmi). This is also described as “universal pervasion and complete accommodation.”

According to Fox, "these dharmadhatus are not separate worlds – they are actually increasingly more holographic perspectives on a single phenomenological manifold...they more properly represent four types or orders of perspectives on experience." Furthermore, for Huayan, this contemplation is the solution to the problem of suffering which lies in the "fixation or attachment to a particular perspective. What we think are the essences of objects are really therefore nothing but mere names, mere functional designations, and none of these contextual definitions need necessarily interfere with any of the others."

Regarding the practical application of this teaching, Baiting Xufa correlated the practice of nianfo with the fourfold Dharmadhatu as follows:

 * 1) Nianfo on the level of the realm of phenomena refers to reciting the name of the Buddha as if the Buddha was external to oneself.
 * 2) Nianfo on the level of the ultimate principle refers to reciting nianfo while knowing it as mind-only (cittamatra).
 * 3) Nianfo practice on the level of “non-obstruction of principle and phenomena” refers to a nianfo practice which has transcended notions like "buddha", "mind" and "name of the buddha".
 * 4) Nianfo on the level of the interpenetration of all dharmas refers to the realization that the name of Buddha and the mind is all pervasive throughout the one true dharmadhatu.

The contemplation of the buddhalight
The lay scholar-practitioner Li Tongxuan (635-730) developed a unique meditative practice based on the 9th chapter of the Avatamsaka sutra. The practice, named "the contemplation of Buddhalight" (foguang guan), focused on tracing the universal light which is radiated by the Buddha in one's mind and expanding one's contemplation further and further outwards until it fills the entire universe. This contemplation of the Buddha's light leads to a state of joyful tranquility which leads to insight into emptiness.

The meditative teachings of Li Tongxuan were especially influential on the Japanese Kegon monk Myōe, who promoted a similar practiced that he termed "the Samadhi of Contemplating the Buddha's Radiance" (Japanese: bukkō zanmaikan, 佛光三昧觀).

Esoteric practices

Fazang promoted the practice of several dharanis, such as the Xuanzang's version of the Dhāraṇī of Avalokiteśvara-ekadaśamukha.

The synthesis of Huayan with Chinese Esoteric Buddhist practices was a feature of the Buddhism of the Khitan Liao Dynasty. Jueyuan, a Huayan monk from Yuanfu Temple during the Liao Dynasty and author of the Dari jing yishi yanmi chao, practiced esoteric rituals like Homa and Abhiseka based on the Vairocanābhisaṃbodhi Sūtra and the tradition of Yixing. Furthermore, according to Sorensen, the iconography of the Huayan Vairocana Buddha and the Esoteric Mahavairocana also became fused during the post-Tang period.

Perhaps the most important figure in the synthesis of Huayan and Chinese Esoteric Buddhism was the 11th century monk Daoshen (道蝗), author of the Xianmi yuantong chengfo xinyao ji (顯密圓通成佛心要集 Collection of Essentials for the Attainment of Buddhahood by Total [Inter-]Penetration of the Esoteric and the Exoteric, T1955). The work is divided into three parts. Part one summarizes the Huayan philosophy, which Daoshen sees as the highest form of the explicit or manifest Buddhist teachings. It also discusses the praxis of Huayan, here called “cultivating the ocean of Samantabhadra’s practices”, which includes numerous exoteric Buddhist practices such as breath meditation, meditation on emptiness, prostrations, offerings, confession rites, vows, and buddha name recitation. The second part of this work teaches esoteric Buddhism or mantra method (Mijiao, Zhenyan), with a focus on the Cundi dharani and other mantras (like the Mani mantra) which are said to have many powerful effects and is recommended even for laypersons. Finally, the third part promotes "the systematic integration of exoteric doctrine and occult practice, arguing that each is incomplete without the other, whether they are practised in sequence or in tandem."

According to Gimello:"Daozhen’s central thesis in the work is that the “body” of Huayan doctrine and the envisaged image of Cundi are somehow co-inherent, and that by invoking the presence of the goddess we somehow confirm the truth of the doctrines and render them practically efficacious. In other words, Daozhen holds that if one recites Cundi dharani and/or visualizes the dharani in its graphic form as an array of Sanskrit letters or Chinese characters, and then imagines the goddess’s anthropomorphic bodily image emerging from the intoned and envisioned syllables of the spell, all the while performing the corresponding manual gestures (mudra), one will thereby both quicken and verify the truth of the doctrines, and one will do this not merely allegorically but also, if I may say so, sacramentally."Important esoteric texts used in the Liao tradition included the: Cundī-dhāraṇī, the Usṇīsavijayā-dhāranī, the Nīlakaṇthaka-dhāranī and the Sutra on the Great Dharma Torch Dhāraṇī ( 大法炬陀羅尼 經, Da faju tuoluoni jing) among others. In the Liao, stupas, pagodas and statues were often empowered with dharanis and mantras. These structures would often be filled or inscribed with dharanis, sutras, or mantras like the Six syllable mantra of Avalokiteshvara. Pillars inscribed with dhāraṇīs and mantras were also common.

The synthesis of Esoteric Buddhist practice with Huayan Buddhism remained popular during the Jin dynasty (1115–1234), where Usṇīsavijayā and Cundī practices were some of the most popular. A similar synthesis of Huayan-Chan Buddhism (derived from Zongmi) with esoteric Buddhist teachings and practices from Tibetan Buddhism (mainly Sakya and Kagyu) also occurred in Buddhism of the Western Xia (1038–1227) dynasty.

Dharanis like the Cundī-dhāraṇī, the Usṇīsavijayā-dhāranī, and the Nīlakaṇthaka-dhāranī remain important in modern Huayan Buddhism and are chanted in modern Dharma assemblies. Another dharani / esoteric practice in modern Huayan is the contemplation of the 42 Avatamsaka syllables (a version of the arapacana alphabet, which is a contemplation found in various Mahayana sources).

The Japanese Kegon school was known for adopting many esoteric mantras and practices from the Shingon school. The Kegon monk Myōe was known for his widespread promotion of the popular Mantra of Light (kōmyō shingon, 光明眞言). Due to influence from the Shingon school, today's Kegon school retains numerous esoteric Buddhist elements.

The path and sudden awakening

The Huayan school defended a sudden awakening view. This is because the buddha-nature is already present in all sentient beings, and also because their theory of universal interpenetration entails that Buddhahood is interfused with the very first stage of a bodhisattva's path. Thus, according to patriarch Fazang, “when one first arouses the thought of enlightenment [ bodhicitta] one also becomes perfectly enlightened”.

Similarly, Huayan master Li Tongxuan writes:"The first access of faith in the mind of the practitioner is in itself the culmination of the entire path, the very realization of final Buddhahood.... ‘Faith’ or confidence in the possibility of enlightenment is nothing but enlightenment itself, in an anticipatory and causative modality."This interpenetration of all elements of the path to awakening is also a consequence of the Huayan view of time, which sees all moments as interfused (including a sentient being's present practice and their eventual future Buddhahood aeons from now). Since time itself is empty, all moments (past, present, and future) are interfused with each other. As Fazang writes, "beginning and end Interpenetrate. On each [bodhisattva] stage, one is thus both a Bodhisattva and a Buddha." As such, Huayan does not understand a bodhisattva's progress through the bodhisattva stages (bhumis) as being linear. Instead, as soon as one reaches the earlier stages of  "perfection of faith" (which is part of Huayan's 52 bhumi model), one has also acquired all the stages, as well as Buddhahood. This doctrine of "enlightenment at the stage of faith" (信滿成佛, xinman cheng fo) was a unique feature of Huayan and was first introduced by Fazang.

In Huayan, Buddhahood transcends all concepts, times and stages. Because practice cannot create something that is not immanent, Huayan sees the bodhisattva path as simply revealing what is already there (buddha-nature, which is buddhahood itself concealed within sentient beings). In spite of this doctrine, Huayan patriarchs also argued that the gradual practices of the bodhisattva stages are still necessary. This is because all stages retain their particularity even while being wholly interfused and only through the practice of the bodhisattva path does the immanent Buddhahood manifest.

Thus, according to Li Tongxuan "there is no other enlightenment" than simply following the bodhisattva path, and furthermore:"Primordial wisdom is made manifest through meditation; cultivation does not create it or bring it into being. If one simply follows the Bodhisattva Path and learns the bodhisattva practices, primordial wisdom will shine forth of itself...."Similarly, patriarch Zongmi held that Buddhahood is reached through "sudden awakening followed by gradual cultivation" and he also held that "sudden and gradual are not only not contradictory, but are actually complementary".

title: Huayan