# Tiantai

Tiantai or T'ien-t'ai (Chinese: 天台; pinyin: PRC Standard Mandarin:Tiāntāi) is an East Asian Buddhist school of Mahāyāna Buddhism that developed in 6th-century China. Tiantai Buddhism emphasizes the "One Vehicle" (Ekayāna) doctrine derived from the Lotus Sūtra as well as the philosophy of patriarch Zhiyi (538–597 CE). Brook Ziporyn, professor of ancient and medieval Chinese religion and philosophy, states that Tiantai Buddhism is "the earliest attempt at a thoroughgoing Sinitic reworking of the Indian Buddhist tradition." According to Paul Swanson, scholar of Buddhist studies, Tiantai Buddhism grew to become "one of the most influential Buddhist traditions in China and Japan."
Tiantai is sometimes also called "The Dharma Flower School" (天台法華宗), after its focus on the Lotus Sūtra, whose Chinese title translates to Subtle Dharma Lotus Flower Sutra. During the Sui dynasty (581–618), the Tiantai school became one of the leading schools of Chinese Buddhism, with numerous large temples supported by emperors and wealthy patrons. The school's influence waned and was revived again in the Tang by figures like Zhanran, expericing a second revival period during the Song dynasty. Chinese Tiantai remains a living tradition to this day, being particularly strong in Hong Kong and Zhejiang Province.
The Japanese Tendai school is also an influential tradition which branched off from Tiantai during the 9th century, and played a major role in the development of Japanese Buddhism. A Korean offshoot, the Cheontae school, was also established during the 12th century. Furthermore, Tiantai (and its offshoots) were very influential in the development of other forms of East Asian Buddhism, such as Chan and Pure Land.

## History

Unlike earlier schools of Chinese Buddhism, the Tiantai school was entirely of Chinese origin. The schools of Buddhism that had existed in China prior to the emergence of the Tiantai are generally believed to represent direct transplantations from India, with little modification to their basic doctrines and methods. However, Tiantai flourished as a native Chinese Buddhist school under the 4th patriarch, Zhiyi, who developed an original and extensive Chinese Buddhist system of doctrine and practice. After Zhiyi, the most influential figures in the Chinese tradition were Zhanran (in the Tang) and Zhili (in the Song), both of whom expanded on Zhiyi's teachings and defended the orthodox tradition.
Zhiyi's Tiantai school grew into a broad tradition which was able to absorb new influences and develop new creative methods over time. The tradition emphasized both scriptural study and meditative practice, and taught an inclusive array of Buddhist practices, from samatha-vipasyana meditation, to repentance rites and Pure Land practice.

### Early figures

The Indian Buddhist philosopher Nāgārjuna is traditionally taken to be the first patriarch of the Tiantai school. Madhyamaka works associated with Nāgārjuna like the Chung lun (Madhyamakaśāstra; Taishō 1564) and the Dà zhìdù lùn (T. no. 1509) are important sources for the Tiantai school.
The sixth century dhyāna master Huiwen (Chinese: 慧文) is traditionally considered to be the second patriarch of the Tiantai school. Through studying and meditating on the works of Nāgārjuna, Huiwen is considered by the Tiantai tradition to have awakened to the profound meaning of Nāgārjuna's teaching on the middle way.
Huiwen later transmitted his teachings to Chan master Nanyue Huisi (Chinese: 南嶽慧思, 515-577), who is traditionally figured as the third patriarch. During meditation, he is said to have realized the "Lotus Samādhi", indicating enlightenment and Buddhahood. He authored the Ta Ch'eng Chih Kuan (Mahāyāna-śamatha-vipaśyanā).
Huisi then transmitted his teachings to Zhiyi (Chinese: 智顗, 538-597), traditionally figured as the fourth patriarch of Tiantai, who is said to have practiced the Lotus Samādhi and to have become enlightened to the meaning of the Lotus Sutra. The above lineage was proposed by Buddhists of later times and do not reflect the popularity of the monks at that time.

### Zhiyi

Scholars such as Paul L. Swanson consider Zhiyi (Chinese: 智顗, 538–597 CE) to have been the major founder of the Tiantai school as well as one of the greatest Chinese Buddhist philosophers. He was the first to systematize and popularize the complex synthesis of Tiantai doctrine as an original Chinese tradition. Zhiyi and his direct students authored numerous exegetical works, and systematic manuals that explain the foundational cultivation methods of the Tiantai tradition (such as the Four Samadhis and the Lotus Repentance Rite).
Zhiyi analyzed and organized all Buddhist teachings into a comprehensive system of study and practice. Zhiyi used the Lotus Sutra and its teaching on the One Vehicle and skillful means as the foundation for this system. Zhiyi's classification culminated with the Lotus Sutra (and Nirvana Sutra), which he saw as the most complete and holistic teachings. His other innovations include a unique doctrine of a threefold truth (as opposed to the "two truths") along with a unique systematic exposition of Buddhist meditation and cultivation (found in his Mohe Zhiguan). Zhiyi's legacy also owes much to his disciple Guanding, who compiled the "three main works" of Zhiyi out of the master's lectures after Zhiyi's death.
Zhiyi spent much time on Tiantai Mountain (Zhejiang province), which became a major center for the tradition. "Tiantai" in modern simplified Chinese means "celestial platform"; however, according to traditional Chinese sources such as Zhanran, the word tai refers to three stars in a constellation (called Santai, "Three Tiers") which is located just below the Big Dipper. Two other key centers of the early tradition were Yu-Ch'uan monastery in Hubei (founded by Zhiyi himself), which was the site where Zhiyi preached the Mohe Zhiguan and the Profound Meaning of the Lotus Sutra, and the Chang'an region, including Mount Wutai.
Zhiyi and the other Tiantai masters of the Sui dynasty era who succeeded him also wrote numerous works on other sutras such as the Nirvana, Vimalakirti, and the Pure Land sutras. Zhiyi's Tiantai doctrine made made the tradition flexible enough to be adapted to various Buddhist practices and teachings. Zhiyi's Tiantai school received much imperial support during the Sui dynasty, because of this, it was the largest Buddhist school at the beginning of the Tang and thus suffered because of its close relationship with the house of Sui.

### Tang era and Zhanran

After the generations of Zhiyi and his disciple Guanding, Tiantai was eclipsed for a time by newer schools such as the East Asian Yogācāra, and Huayan schools, until the 6th patriarch Jingxi Zhanran (711–782) revived the school and defended its doctrine against rival schools such as the Huayan and Faxiang.
During the Tang Dynasty (618-907), a key Tiantai figure was Jingxi Zhanran (711-782), a great teacher and exegete who wrote three important commentaries on Zhiyi's three major works and instructed many influential monks. His writings defended the Tiantai tradition's unity of study and practice against various rival factions. The Tang era debates between the Faxiang school and the Tiantai school concerning the notion of universal Buddhahood were particularly heated, with the Faxiang school asserting that different beings had different natures and therefore would reach different states of enlightenment, while the Tiantai school argued in favor of the Lotus Sutra teaching of Buddhahood for all beings.
Zhanran's view of Buddha nature was expanded in his Jingangpi (Diamond Scalpel), which is the key source for the doctrine of "the Buddha-nature of Insentient Beings." This influential doctrine held that since buddha-nature was all-pervasive, even insentient objects like mountains, sounds and smells have buddha-nature. Thus, according to Zhanran, "every blade of grass, tree, pebble, and particle of dust is perfectly endowed with buddha nature". Zhanran also emphasized the importance of scripture (especially the Mohe Zhiguan), seeing it as having the power to transmit the Tiantai lineage, in contrast to Chan influenced views which saw lineage as transmitted "mind to mind", outside the scriptures.
The Tang era was also a period of increasing syncretism within the Tiantai tradition. One example of this tendency is the synthesis of Tiantai teaching and Chinese esoteric Buddhism taught by Yi Xing (682-727) and his followers. Tiantai monks also became key figures in Chinese Pure Land Buddhism during the Tang. Some of these key Pure Land figures affiliated with Tiantai include Chengyuan (712-802) and Fazhao (fl. 766). Tiantai authors also wrote at least five different Pure Land works during the Tang which were attributed to Zhiyi, including the Guan-jing-shu (a commentary to the Contemplation Sutra) and the Jingtu shiyilun (Discourse on Ten Doubts about Pure Land, T.1961).
Ziporyn writes that during the late Tang, Tiantai entered a time of crisis, "an age marked internally by the deterioration of distinctive Tiantai ideas and marked externally by the loss of crucial texts and monastic institutions, especially after the persecution of 845 (a period that saw the increased influence of Chan)."
During this latter Tang period, Huayan and Chan influences became increasingly prominent in some Tiantai lineages. Zhanran's disciple and seventh patriarch Daosui (796–805), and other figures such as Zhiyuan (768–844) and Daochang Ningfen are seen as exhibiting some of these influences. Daosui is important because he was the primary teacher of Saichō, the founder of the Japanese Tiantai tradition (known in Japanese as Tendai). Other Tiantai syncretists include Deshao (881–972) who was associated with the Fayan branch of Chan. His student Yongming Yanshou (954–974) attempted to unify Tiantai, Huayen and Yogacara teachings under a kind of idealism influenced by Zongmi, emphasizing what he called the "one pure formless mind".
Zhanran is a towering figure for the later Tiantai tradition. His commentaries were one of the few Tang sources that survive into the Song dynasty, where they would become the orthodox exegetical works for the Tiantai tradition as it attempted to rebuild after the chaos of the late Tang. However, Zhanran's influence during the Tang should not be overstated. Donner and Stevenson note that Tiantai was a diverse tradition from its very beginnings, with numerous traditions and lineages in different regions absorbing different influences (Chan, Huayan, the Pure Land of Shandao and the Tang esoterica of Amoghavajra). They write "such diversity suggests that we should speak in the plural when we speak of eighth-century Tiantai “tradition,” with Zhanran’s particular camp constituting but one among a number of semiautonomous lines."

### Song dynasty revival

The Song Dynasty (960-1279) saw efforts to revive the Tiantai school after the damages suffered during the Great Anti-Buddhist Persecution and the subsequent Huang Chao rebellion by importing many lost Tiantai works from abroad and reintegrating them into the weakened Chinese tradition.
By the time of the early Song dynasty, the increasing syncretism within the Tiantai tradition culminated in a famous debate known as the "home mountain" (shanjia) vs. "off mountain" (shanwai) debate. "Off mountain" supporters, as they were later polemically termed, supported the importation of Huayan-Chan doctrines (such as the "one pure mind") into Tiantai, claiming they were originally Tiantai doctrines which were fully compatible with Zhiyi's teaching. "Home mountain" supporters saw the original Tiantai view as different and superior to this new view influenced by Huayan and Chan, especially the works of Zongmi.
The most eminent figure during this debate was Patriarch Siming Zhili (960–1028), who wrote various commentaries on Zhiyi's works and defended the so called "Home mountain" view. Zhili's major criticisms included attacking Chan's failure to understand the necessity of the use of words and scriptural study as part of practice as well as criticizing Zongmi's view of a pure mind as the buddha-nature, arguing instead that the "three truths" as taught by Zhiyi are the ultimate reality. For Zhili, mind or consciousness has no special status relative to other types of phenomena, such as physical matter, and thus, all dharmas are metaphysically equal.
Over time, Zhili's "Home mountain" view turned out to be the most influential, and his works became part of the orthodox Tiantai canon during the Song dynasty. Ciyun Zunshi (964–1032) was another important figure in this second Tiantai revival. His work focused on the promotion of rituals for lay Buddhists and worked on converting the populace away from using blood, meat and alcohol for funerary and ancestral rites. Ciyi also promoted the practice of adopting local Chinese deities and spirits into the Buddhist religion as "vassals" or "retainers" and strongly promoted repentance rituals.
These two figures, along with Shengchang (959–1020) also became associated with the popularization of Pure Land practices and the foundation of lay Pure Land societies (called lotus societies, lianshe). Tiantai monk Mao Ziyuan (1096?-1166) took this one step further by establishing what became known as the "White Lotus Society" which allowed both men and women to attend together and even to preach and be in charge of society repentance halls as married clergy. Many of these Tiantai figures also wrote Pure Land treatises and commentaries. Another Tiantai Pure Land author is Zongxiao (1151–1214), author of the Lebang Wenlei, a Pure Land anthology.
Yet another important Tiantai figure of the late Song was Chegwan (?–971), a Korean monk who wrote an important introduction to Tiantai thought, A Guide to the Tiantai Fourfold Teachings. Due to the efforts of these Song era Tiantai figures, the school became one of the dominant forms of Buddhism during the Song, alongside of Chan.

### Yuan, Ming and Qing

The defeat of the Song dynasty was a serious blow to Tiantai which suffered another setback during the Yuan dynasty, which supported Tibetan Buddhism. Furthermore, during the Yuan, Chan Buddhism continued to grow in popularity, while attacking the legitimacy of other schools. This period saw the Tiantai figure Huxi Huaize (fl. 1310) write his polemical treatise Record of Tiantai's Transmission of the Buddha's Mind-seal as an effort to defend the Tiantai tradition against Chan critiques.
The Ming Dynasty (1368–1644) saw further religious revivals among the major Chinese Buddhist schools, including Tiantai, particularly under the reign of the Buddhist friendly Wanli Emperor. The key figures of the Ming Tiantai Buddhist revival were Baisong Zhenjue (百松真觉, 1538-1589) and Youxi Chuandeng (幽溪传灯, 1554-1628). Both were Chan monks who converted to Tiantai and attempted to revive the tradition. These figures wrote new works, lectured widely, and published gazetteers. They also commented on the Śūraṅgama Sūtra, the most popular sutra of the time, from a Tiantai perspective. Their whose students revived ancestral Tiantai monasteries such as Gaoming and Ayuwang. Chuandeng wrote a work entitled On Nature Including Good and Evil which presents his ideas on doctrinal classification, the principle of nature-inclusion, and the practice of the Dharma-gate of inherent evil, attempting to harmonize these with Confucianism and the thought of the Śūraṃgama Sūtra.
Tianxi Shoudeng (1607–1675) was one of the most influential teachers and exegetes of Tiantai during the Qing Dynasty.

### Modern era

Dixian was the most influential figure in modern Tiantai, who carried the Tiantai lineage (specifically the Lingfeng lineage) from the late Qing into the 20th century. His student, the monk Tanxu (1875 – 1963), is known for having rebuilt various temples during the Republican era (such as Zhanshan temple in Qingdao) and for preserving the Tiantai lineage into the PRC era. During the Chinese Civil War, various dharma heirs of Dixian moved to Hong Kong, including Tanxu and Baojing. They helped establish the Tiantai tradition in Hong Kong, where it remains a strong living tradition today, being preserved by their dharma heirs.
Baojing's dharma heir, Jueguang, helped establish the Guanzong Temple in Hong Kong and transmitted the lineage to numerous monks from Korea, Indonesia, Singapore, Taiwan and mainland China. Tanxuan's heir, Yongxing, founded Xifang Temple in Hong Kong, as well as various temples in Malaysia and the United States (as well as the Texas Buddhist association and its Jade Buddha Temple). Furthermore, other monks from this lineage have helped to reintroduce the Tiantai tradition from Hong Kong back to the rest of mainland China, aiding in the reconstruction of Chinese Buddhism after the reform and opening up period.
During the modern era, Tiantai thought was also influential on some modern Chinese philosophers, like Mou Zongsan (1909 –1995).
The ancient Guoqing Temple at mount Tiantai, which had suffered from neglect and destruction, was renovated at the behest of Zhou Enlai. Guoqing Temple is now a major center of Chinese Tiantai Buddhism as well as remains a place of pilgrimage for Japanese Tendai Buddhists.

## Texts

The Tiantai school takes the Threefold Lotus Sūtra as the main scriptural authority (pratiśaraṇa). The supporting scriptures or retinue are considered to be the Da zhi du lun (the guide), the Mahāyāna Mahāparinirvāṇa Sūtra (the support), the Pañcaviṃśatisāhasrikā Prajñāpāramitā Sūtra (for methods of contemplation) and the Book of the Original Acts that Adorn the Bodhisattva (Pusa yingluo benye jing T. 24, No. 1485). Tiantai is often termed the "Four Sutras, One Treatise School" (四経一論) because of the strong influence of these texts on the tradition.
Apart from these, there other Mahayana sutras that are especially important in Tiantai. The Avataṃsaka Sūtra is also very highly regarded in Tiantai (and is widely quoted by Zhiyi) and it is seen as one of the subtlest sutras and to belong to the class of "complete" teachings. The Vimalakīrti Sūtra is also seen as an important sutra, and Zhiyi is known to have written two commentaries on this sutra. Other key sutras include the Golden Light Sutra (on which Zhiyi wrote commentaries), the three Pure Land sutras (central for Tiantai Pure Land), and the Brahma's Net Sutra (from which the tradition derives its bodhisattva precepts).
Indeed, the Tiantai school's study makes use of numerous sources. As noted by Donner and Stevenson: "when we examine the early [Tiantai] exegetical and textual record, we find that [Zhiyi] and his successors compiled treatises…for any number of sūtras other than the Lotus", noting that there was no real tendency to prefer any other single sutra.

### Tiantai Treatises

In addition to its doctrinal basis in Indian Buddhist texts, the Tiantai school's doctrinal study relies on numerous Chinese treatises written by the ancestors of the school (especially important are those of Zhiyi, Zhanran and Zhili). The three major Tiantai treatises studied in the tradition are the following works of Zhiyi:
* The Mohe Zhiguan (摩訶止觀, The Great Calming and Contemplation, T1911), the main meditation guide of the tradition. There are also three other meditation works by Zhiyi as well, with the Smaller Calming and Contemplation often used for beginners.
** Read with Zhanran's commentary: Zhiguan fuxing zhuan hongjue (止觀輔行傳弘決, T1912)
* The Fahua Xuanyi (法華玄義, The Profound Meaning of The Lotus Sutra, T1716)
** Read with Zhanran's commentary: Fahua Xuanyi Shiqian (法華玄義釋籤, T1717)
* The Fahua Wenju (法華文句, The Words and Phrases of The Lotus Sutra, T1718)
** Read with Zhanran's commentary: Fahua Wenju Ji (法華文句記, T1719)
There is also another set known as the Five Lesser Tiantai Treatises:
* The Guanyin Pusa Pumenpin Xuanyi (觀音菩薩普門品玄義, The Profound Meaning of the Universal Gate of Avalokitesvara Bodhisattva Chapter, T1726)
** Read with the Zhili's commentary: Guanyin Xuanyi Ji (觀音玄義記, T1727)
* The Guanyin Pusa Pumenpin Yishu (觀音菩薩普門品義疏, The Commentary on the Universal Gate of Avalokitesvara Bodhisattva Chapter, T1728)
** Read with Zhili's commentary: Guanyin Yishu Ji (觀音義疏記, T1729)
* The Jinguangming Jing Xuanyi (金光明經玄義, The Profound Meaning of the Golden Light Sutra, T1784)
** Read with Zhili's Commentary: Jinguangming Jing Xuanyi Shiyi Ji 金光明經玄義拾遺記
* The Jinguangming Jing Wenju (金光明經文句, The Words and Phrases of the Golden Light Sutra, T1785).
** Read with Zhili's commentary: Jinguangming Jing Wenju Ji 金光明經 文句記
* The Guan Wuliangshoufo Jingshu (観無量寿佛經疏, The Commentary on the Buddha of Immeasurable Life Sutra, T1750)
** Read with Zhili's commentary: Miaozongchao (妙宗鈔 , T1751)
Two other important treatises are Zhanran's Adamantine Scalpel (a work on Buddha-nature) and the Contemplation of Mind Treatise (Guanxinlun) by Zhiyi.

## Philosophy

David Chappell lists the most important Tiantai teachings as being The Threefold Truth and the corresponding Threefold Contemplation, The Fourfold Teachings, The Subtle Dharma, and The Non-conceivable Discernment (or the "Inconceivable Mind"). Brook Ziporyn writes that Tiantai's "rigorous theoretical edifice" uses "modes of argumentation and praxis that are derived squarely from Indian Buddhism" but applies these "in the service of ideals and metaphysical conclusions that are rooted deeply in the indigenous philosophical traditions."

### The Threefold Truth

The Tiantai school's main philosophical principle is The Threefold Truth (emptiness, existence, and the middle; 空假中 kong, jia, zhong). According to Paul Swanson, this is the "central insight" around which the Tiantai system revolves. This view was developed by Zhiyi's reading of Nāgārjuna's Madhyamaka philosophy, especially its doctrine of two truths. The Threefold Truth comprises the following:
* All phenomena are empty (śūnya, 空 kong) of any independent self-nature or essence (svabhava), this corresponds to the Mahayana concept of the "ultimate" or real (paramārtha) truth and emptiness (shunyata) which Zhiyi defines as "the sign of the true nature of reality."
* Phenomena exist (假, jia) in a provisional manner, they can be said to conventionally arise through causes and conditions (i.e. dependent origination). This corresponds to the conventional or mundane truth (saṁvṛti) of the classic Mahayana two truths, which Zhiyi glosses as "the twelvefold conditioned co-arising of ignorance" and as "illusory existence".
* The middle truth (中, zhong): phenomena are both empty of existence and exist provisionally. According to Dan Lusthaus: "it is ‘middle’ because neither the provisional nor the empty truth about the table fully captures its reality. It is both provisional and empty, and simultaneously neither provisional nor empty. As Zhiyi put it, ‘wondrous being is identical to true emptiness’." Swanson writes that this is "a simultaneous affirmation of both emptiness and conventional existence as aspects of a single integrated reality." The middle truth for Zhiyi transcends all dualities and avoid all extremes, such as existence and non-existence, being and emptiness, mundane truth and real truth, or defilement and purity.
While the threefold truth can be explained conceptually in this way, for Zhiyi, the highest and most subtle meaning of the threefold truth is ultimately indescribably and beyond words. It is also fully integrated and inclusive of all the Buddhadharma and of all mundane and ultimate truths as well. According to Zhiyi, "the supreme truth of the middle path" is "the reality of non-duality", as well as "the enlightened perception of all Buddhas and bodhisattvas." Zhiyi also states that it is also called "the truth of one reality", as well as "emptiness" (空 kong), "Buddha-nature" (佛性 fóxìng), Thusness (Skt. tathātā, 如如 ruru), tathāgatagarbha (如来藏 rulaizang), and the Dharmadhatu (法界 fajie).

#### The Threefold Contemplation

The Threefold Truth may be contemplated independently as the "three contemplations", an important theme in Zhiyi's Mo ho chi kuan. The threefold contemplation, also described as the threefold cessation and insight, consists of what Zhiyi calls a "graded contemplation":
* Cessation as insight into the true essence of reality - This consists in contemplating the emptiness of all phenomena and their lack of own being (svabhava).
* Cessation as insight into expedient conditions - This consists in contemplating the conventional existence of all things, i.e. dependent arising or as Zhiyi describes it "the non-emptiness of emptiness", which means that emptiness is not nothingness.
* Cessation as an end to both discriminatory extremes - A contemplation which is the simultaneous unity of both 1 and 2 and which is totally beyond conceptualization and thought.
There are different levels of subtlety of this threefold contemplation, the deepest of which is when all three aspects are contemplated as a simultaneously non-dual unity which according to Zhiyi is when all three aspects are "present in one thought" (一心) which is "beyond conceptual understanding". According to Chappell:
   The first contemplation involves moving from the world of provisionality to seeing its emptiness, which is a different process from the second contemplation in which we move beyond emptiness and back into an acceptance of the role of provisional existence. Only in the third contemplation do we find the balance involving the previous two insights based on the Middle Path of the One Mind.

### The Unity of the Dharmadhatu

Since the three truths are one, and this truth is a single unity, Tiantai thinkers see the whole of reality is as being a single interpenetrating whole, one integrated existence. This holism is described in different ways, such as "the interinclusiveness of the ten realms" or "the interpenetrating unity of all aspects of reality". According to Swanson, in this view, "everything contains everything else, and the whole contains all things." Zhiyi illustrates this idea with the simile of the drunk man from the Mahāparinirvāṇa Sūtra, who perceives the sun as spinning around due to his condition, but in reality there is just one sun and this is confirmed by sober people. However, Zhiyi also points out that even this idea of "one truth" is just a concept, and as such it is ultimately inadequate, since "each and every truth is inexpressible" and "the one truth actually no truth".
According to Brook Ziporyn, the Tiantai school's holism is derived from an extremely important passage from the Lotus Sutra which states:
   Only a Buddha together with a Buddha knows the ultimate reality of all things: how they appear, what their natures are, what they're made of, what they are capable of, what they are doing, what their causes are, what their conditions are, what their effects are, what their consequences are, and the way in which all these factors from beginning to end are equally ultimate and are ultimately one and the same.
Ziporyn argues that this passage points at the idea "that each particular aspect of the world as we see it and feel it is ultimately real, that each one is in fact the Absolute itself, the Buddha-nature, the final fact about the universe" and that "each thing, each appearance, each action" is "the ultimate reality “of ” all other things."

#### Three Thousand Realms in One Thought Moment

One of the ways this holistic doctrine is explained is the idea of "Three Thousand Realms in a Single Thought Moment" or "The Presence of All Three Thousand Aspects of Existence as Each Moment of Experience" (一念三千). According to this teaching, the various realms of existence of Buddhist cosmology are all interconnected and interpenetrating. Each of these realms can manifest within an individual's mind, meaning that states of existence are not only external places of rebirth but also modes of experience and perception. Zhiyi explained that each thought contains the ten dharma realms, and since each realm includes all others, this results in one hundred dharma realms. Each of these realms further contains thirty worlds, culminating in a total of three thousand worlds within each thought moment.
This concept emphasizes the interpenetrating nature of reality, where each thought encompasses all phenomena. Jacqueline Stone notes that this reflects a mutually inclusive relationship between every ordinary thought and the entirety of existence. The number three thousand arises from multiplying key Buddhist categories: the ten realms of beings, their mutual inclusion, the ten suchnesses, and the three realms. This doctrine presents a holsitic view of reality where distinctions such as Buddha and ordinary being, subject and object, or sentient and non-sentient are seen as unified and interdependent within each moment of thought.
Despite this unified view, Zhiyi used various frameworks to describe reality, such as the two truths, the threefold truth, and the ten realms. He also employed the Three Subtle Dharmas (sentient beings, Buddha, and mind) and the Ten Suchnesses to explain this interconnected nature. Zhiyi taught that by observing one's mind and thoughts, one can perceive the entirety of reality and achieve Buddhahood. Drawing from the Avatamsaka Sutra, he emphasized that contemplating the mind allows one to realize the Buddha’s dharma fully. He referred to this integrated reality as "the inconceivable mind" (不思議心), which embodies the three thousand dharmas and the threefold truth.

### The Subtle Dharma: One Reality, One Vehicle, many Skillful Means

The Tiantai school's soteriology is based on the doctrine of the "One Vehicle" (Skt. ekayāna, traditional Chinese: 一乘; pinyin: Yīchéng) found in the Lotus Sutra. Tiantai sees all the various Buddhist teachings, scriptures and practices as being part of a single holistic vehicle (yana) leading to Buddhahood. The discrepancies and seeming contradictions in all the different teachings of the sutras are only due to the fact that these various teachings are all "expedient means" (upāya) that are taught according to the different needs and capacities of sentient beings. According to Zhiyi, even though there numerous sutras with many varied teachings, the intent of the Buddha is to lead all sentient beings to Buddhahood. Similarly, just as there are different practices, there are different ways to describe the same unified reality (i.e. emptiness and the threefold truth). Thus, Zhiyi states in the Fa hua hsuan i "various terms name one ultimate reality. Only one ultimate reality is given many names." This ultimate reality is "one yet many, many yet one". It is many because there are diverse phenomena that arise and perish dependent on causes and conditions and it is one because all of this is equally empty.
Indeed, Zhiyi outlines four types of oneness: the oneness of the teachings (all teachings of the Buddha are non-contradictory and have one intent), the oneness of the practices (all lead to Buddhahood), the oneness of persons (all will attain Buddhahood), and the oneness of reality. According to Zhiyi, any text which is consistent with these concept teaches "the Subtle Dharma" (miao-fa).
This doctrine provided a unifying and inclusive framework which could be used to understand all Buddhist teachings. According to Jacqueline Stone, Zhiyi's view of the One Vehicle of the Lotus Sutra is that conventionally, it is "subtle" and "wonderful" in comparison with lesser teachings which are coarse. However this is only true in a relative sense. Ultimately, the Lotus Sutra's Subtle Dharma is "not established in comparison to anything else, for there is nothing outside it to which it might be compared." From this absolute perspective, the Lotus Sutra's One Vehicle is "open and integrated" according to Zhiyi, and includes all other Buddhist teachings and skillful means. From the ultimate point of view, all distinctions of "true" and "provisional" are dissolved since all teachings are expressions of the One Vehicle. According to Stone, "this is an egalitarian, inclusive reading, in which all teachings in effect become "true". But from the relative standpoint, a clear distinction is preserved between the "true" and the "provisional"; this is a hierarchical, potentially even exclusive reading, which emphasizes the superiority of the Lotus Sutra over other teachings."

### Buddhahood and Buddha-nature

Zhiyi's teaching on Buddhahood, as presented in The Profound Meaning of the Lotus Sutra, emphasizes the integration of Buddhahood with all aspects of reality. He describes three ways of understanding the causes for Buddhahood: (1) each of the ten dharma realms contains the other nine, meaning all beings possess the potential for Buddhahood; (2) the nine non-Buddha realms are inherently linked to Buddhahood; and (3) all realms are empty of inherent existence and aligned with the threefold truth. As for the result, Buddhahood is pervasive throughout the universe, was attained by the Buddha in the distant past (as described in the Lotus Sutra), and manifests in countless forms to aid sentient beings. Consequently, Zhiyi asserts that Buddhahood is not separate from ordinary existence but is fully integrated with it, with the mind, Buddhas, and sentient beings being fundamentally interconnected.
Zhiyi's interpretation of Buddha-nature is structured around three interconnected aspects: Buddha-nature as the conditional cause of Buddhahood, the complete cause, and the direct cause. The conditional cause refers to the inherent potential in sentient beings to practice the Dharma and cultivate conditions that lead to enlightenment. The complete cause emphasizes the intrinsic presence of wisdom in all beings, which, once uncovered, reveals the true nature of reality. Lastly, the direct cause signifies that all beings already participate in the ultimate reality of thusness. Zhiyi’s concept of Buddha-nature is closely linked to his theory of the threefold truth, which unites emptiness, conventional reality, and the middle way. While some scholars, such as Ng Yu-Kwan, emphasize a "Middle Way–Buddha Nature" concept in Zhiyi’s thought which sees buddha-nature as a positive, dynamic and active force which is present in and non-dual with the world. Scholar scholars like Paul Swanson argue that this active view of buddha-nature is less central in Zhiyi’s original texts and instead see Zhiyi’s view as consistent with Madhyamaka's emphasis on emptiness.
The later Tiantai thinker Zhanran is best known for advancing the doctrine of the Buddha-nature of insentient beings, which became central to Tiantai thought. In works such as The Adamantine Scalpel, Zhanran argues that all phenomena, including seemingly lifeless objects like plants, stones, and sounds, possess Buddha-nature. He grounded this view in the Tiantai doctrine of universal inclusion, which teaches that all things, sentient or insentient, are interconnected and interpenetrating. For Zhanran, Buddha-nature is synonymous with Suchness, the ultimate reality that is both unchanging and responsive to conditions. Because Suchness pervades all things without exception, even insentient objects participate in this universal Buddha-nature. This view reflects the influence of Huayan Buddhism, particularly Fazang’s theory of "Suchness according with conditions," which asserts that the absolute reality manifests itself in the diversity of phenomena.
Both Zhiyi and Zhanran share a vision of Buddha-nature as pervasive and intrinsic to all reality, an active potential within sentient beings, rooted in their capacity for wisdom and practice. Zhanran expanded on this concept to assert that Buddha-nature is equally present in insentient things, thereby emphasizing the non-duality between beings and their environment. This theory would become the subject of much debate in the history of Tiantai Buddhism.

### Classification of teachings

An extension of Tiantai's doctrine of the One Vehicle is its classification of the Buddha's teachings (called a panjiao) into the "Five Periods and Eight Teachings" which helps explain how different teachings relate to each other. The Tiantai classification system is based on Zhiyi's writings, but was significantly expanded by later figures into its mature form. According to Peter Gregory, Japanese scholars like Sekiguchi Shindai have shown that the mature system was developed by Zhanran and that Zhiyi never presents a single system of "Five Periods and Eight Teachings" (though he does use the "five flavors" and four teachings).
From the Tiantai point of view, the One Vehicle teaching of the Lotus is called a ‘Round Teaching’, which means that it encircles all other coarser teachings, and lacks any sharp edges or divisions. The Tiantai view is that the highest teaching is a holistic and all encompassing teaching which includes all Buddhist views and practices.

#### Five Periods

The Five Periods are five periods in the life of the Buddha in which, according to Tiantai exegetes, he delivered different teachings, aimed at different audiences with a different level of understanding. The Five Periods are:
* The Avatamsaka Period. For twenty-one days after his awakening, the buddha delivered the Avatamsaka Sutra, one of the highest sutras, but this was not widely understood.
* The Agama Period. For twelve years, the Buddha preached the Agamas, including the preparatory teachings of the Four Noble Truths and dependent origination.
* The Vaipulya Period. For eight years, the Buddha delivered the Mahāyāna or Vaipūlya (expanded) teachings, such as the Vimalakirti Sutra, the Śrīmālādevī Sūtra, the Suvarnaprabhasa Sutra and other Mahāyāna sutras.
* The Prajña Period. For twenty-two years, the Buddha taught the Mahāyāna Prajñaparamita-sutras.
* The Lotus and Nirvana Period. In the last eight years, the Buddha preached the doctrine of the One Buddha Vehicle, and delivered the Lotus Sutra and the Nirvana Sutra just before his death.

#### Eight Teachings

The Eight Teachings are a classification of different types of Buddhist teaching. They consist of the Fourfold Teaching, and the Fourfold Method:
The Fourfold Teachings are called teachings because they are "that which discloses the principle and converts beings" according to Zhiyi. They are:
* Tripitaka Teaching: the Sutra, Vinaya and Abhidharma, in which the basic teachings are explained. According to David Chappell, the main elements of this teaching is "the thirty seven conditions for enlightenment, austerity, precepts, intellectual analysis of emptiness, the Six Perfections, and meditation" and the main view is the "arising-and-perishing among the ten realms of existence."
* Shared Teaching: the teaching of emptiness, which is shared by Mahayana and Theravāda. This corresponds to the first of the three contemplations and the practices of the ten stages of the bodhisattva that are shared with the Theravāda.
* Distinctive Teaching: the teachings of the Bodhisattva path. This corresponds to the second of the three contemplations. It "involves practices summarized by Chih-i into Fifty two Stages of a Bodhisattva" according to Chappell.
* Complete (Round) Teaching - the complete and perfect teaching, which is beyond words and concepts. It can be found in the Lotus Sutra and the Avatamsaka Sutra. This corresponds to the third of the three contemplations. According to Chappell, "the Complete Teaching moves beyond stages to see the identity and interpenetration of all the various practices, ideas, and values based on Suchness, Buddha-nature, and the Inconceivable Perceptual Process. Nevertheless, it also has its own set of unique practices such as the Five Repentances."
The Fourfold Method:
* Gradual Teaching, a method for those with medium or inferior abilities that advances towards Buddhahood step by step
* Sudden Teaching, the Distinctive Teachings and the Complete Teaching for those with superior abilities
* Secret Teaching, teachings which are transmitted without the recipient being aware of it
* Variable Teaching, a method with no fixed teaching, but various teachings for various persons and circumstances

#### The Four Siddhanta

Another way that Tiantai thinkers like Zhiyi classify the Buddhist teachings is through the four siddhantas, which are four principles that the Buddha used to teach the Dharma derived from the Da zhidu lun. According to David W. Chappell, the four siddhantas are:
   (1) First of all, the Buddha used ordinary or mundane modes of expression, (2) then he individualized his teaching and adapted it to the capacities of his listeners, (3) he further altered it in order to respond to and diagnose the spiritual defects of his hearers, and (4) finally all his teaching was based on the perfect and highest wisdom. The first three are conditioned and finite, whereas the last is inconceivable and ineffable.
According to Chappell, the main idea of the Tiantai understanding of the Buddha's method of teaching is the "receptivity-and-response appropriate to a person's capacities", or "communication based on receptivity-and response". According to Chappell this means that "not only the form of the teaching, but also the quest for enlightenment (bodhicitta) arises during an interaction involving a response to the capacities and needs of a person."

### The Six Degrees of Identity

Tiantai's explanation of the path of the bodhisattva was set forth in Zhiyi's doctrines of the Six Degrees of Identity. The Six Degrees of Identity provide an important path schema for the Tiantai school. These six degrees of realization are as follows:
* Identity in Principle (理即, Liji): All beings and things are inherently identical with Buddhahood, even without awareness of this fact or practice. This is like owning treasure without knowing it.
* Identity in Name (名字即, Mingziji): Through hearing or understanding Buddhist teachings, one becomes aware of this inherent Buddha-nature, like being told about the hidden treasure.
* Identity in Practice (観行即, Guanxingji): Actively engaging in contemplation and practice to manifest this Buddha-nature, like beginning to clear the ground and dig for the treasure.
* Identity in Resemblance (相似即, Xiangsiji): Progress in practice results in wisdom resembling true enlightenment, like nearing the treasure through persistent digging.
* Partial Identity (分真即, Fenzhenji): A partial realization of Buddha-nature, beginning at the first bodhisattva stage and extending to near-complete enlightenment. This is like seeing the treasure within its chest.
* Ultimate Identity (究竟即, Jiujingji): Full enlightenment, with Buddha-nature completely realized and ignorance fully eradicated. This is like uncovering and using the treasure.

### Non-dual Ethics

This non-dual Tiantai teaching of the interfusion of all phenomena and experiences also holds that there is a non-duality of good and evil, which also applies to happiness and suffering, Buddha and Mara (the demon of Death). As noted by Ziporyn, the view that "each experience we have includes not only itself but also all other experiences of all other sentient beings at all times" is related to the idea that "Buddhahood inherently includes every form of evil, that these evils can never be destroyed, and that they do not need to be destroyed (“The evil inherent in the Buddha-nature,” “Buddhahood does not cut off evil”)." Ziporyn further explains this seemingly paradoxical doctrine as follows: "our joy also includes sorrow, our sorrow also includes joy; our evil includes good, our good includes evil; our delusion includes enlightenment, our enlightenment includes delusion."

## Practice

Tiantai Buddhism emphasizes the integration of meditative practice, doctrinal study, and ritual observance. Central to Tiantai practice is the system of the Four Samadhis, along with numerous ritual practices. These practices aim to cultivate concentration (samadhi) and insight (vipasyana), leading to the realization of the Three Truths. Tiantai meditation techniques are closely tied to the teachings of the Lotus Sutra, which is regarded as the supreme expression of the Buddha's Dharma. Other common Tiantai practices include rites for conferring bodhisattva precepts and the use of esoteric practices like dhāraṇīs and mantras.

### Meditation (zhiguan)

According to Charles Luk, in China it has been traditionally held that the meditation methods of the Tiantai are the most systematic and comprehensive of all. Tiantai meditation is primarily described as "zhi-guan", the union of calming or cessation (止 zhǐ, from skt. śamatha) and contemplation or insight (觀 guān, from vipaśyanā). Zhiguan (止観), also known as calming and insight (śamatha-vipaśyanā), is a comprehensive system of Buddhist meditation developed by the Chinese Tiantai master Zhiyi. For Zhiyi, zhiguan is not limited to meditation alone but encompasses all Buddhist practices, integrating ethical conduct, mental stillness, and the cultivation of wisdom.
The practice of zhiguan can be understood as comprising two interconnected yet distinct facets. Zhi may be described as a state of "cessation" or "stopping". In this stage, the chaotic and disordered thoughts typical of everyday experience are calmed, allowing the mind to rest in tranquility. This mental stillness is both a prerequisite for and a result of the second phase: Guan, which may be translated as "contemplation" or "clear seeing". This contemplative process focuses on observing the mind without discrimination and seeing all phenomena as empty. Embracing the universal truth of emptiness, the practitioner refrains from imposing hierarchies of value on what is observed. This includes rejecting any notion that oneself or any aspect of oneself is exempt from the impartial nature of transience.
Zhiyi identified two modes of zhiguan practice: seated meditation and the practice of maintaining a calm and insightful mind in daily activities. He favored this comprehensive understanding of zhiguan over the term "chan" (zen), which he considered more restrictive. In practical terms, Tiantai teaches three approaches to cultivating zhiguan: gradual and successive practice, variable practice tailored to individual needs, and perfect and sudden practice, which directly apprehends reality without reliance on progressive stages. Each method reflects different levels of spiritual capacity and conditions.
Zhiyi's magnum opus, the Móhē Zhǐguān details Zhiyi’s extensive meditation curriculum, organized into four key frameworks: the "twenty-five skillful means," the "four samādhis," the "ten objects of contemplation," and the "ten modes of contemplation." The twenty-five skillful means include preparatory practices like precept-keeping, sensory restraint, and associating with spiritual friends. The four samādhis describe different meditative approaches such as constant sitting, constant walking, alternating sitting and walking, and mindfulness during all activities. The ten objects of contemplation focus on various aspects of existence, while the ten modes provide structured ways to contemplate them, such as "contemplating mind as the inconceivable" (the central mode), arousing compassion, dismantling false views, and practicing detachment.
Zhiyi saw the four samadhis as the main pillar of Tiantai meditation practice. These are:
* Constant Sitting Samādhi (常坐三昧): This practice involves 90 days of uninterrupted seated meditation, fostering deep concentration and inner calm. It draws from the Mañjusri Prajñaparamita Sutra.
* Constant Walking Samādhi (常行三昧): Practiced for 90 days, this method involves mindful walking, often in a designated space or around a Buddha statue. It is based on the Pratyutpanna Samādhi Sutra and emphasizes Amitābha recitation, influencing Pure Land practices.
* Half-Walking, Half-Sitting Samādhi (半行半坐三昧): This combines seated and walking meditation in alternating periods. Linked to the Lotus Sutra and the Great Correct and Equal Dhāranī Sutra, it is often practiced during repentance rituals like the Hokke Senbo.
* Neither Walking nor Sitting Samādhi (非行非坐三昧): This flexible practice transcends fixed postures, encouraging meditative awareness in all daily activities. It emphasizes mindfulness as an ongoing state rather than a structured practice.
Zhiyi’s highest form of zhiguan, the "perfect and sudden" method, emphasizes immediate insight into the true nature of reality. This approach directly contemplates reality as inherently unified, with no distinction between samsara and nirvana, suffering and liberation. In this state, all phenomena are seen as aspects of the Middle Way, where quiescence (cessation) and illumination (contemplation) are simultaneous and inseparable. Through this method, practitioners realize that ultimate reality is fully present in every aspect of experience, requiring no staged progression or sequential cultivation.
The Tiantai school also teaches various other forms of meditation under the rubric of Zhiyi's zhi-guan teaching, such as mindfulness of breathing (Skt. ānāpānasmṛti). In his Six Dharma Gates to the Sublime, Zhiyi outlines a meditation method based on this clasic Buddhist practice.

### Repentance rites

Since the time of Zhiyi (538-597), the Tiantai tradition developed a sophisticated set of repentance rituals connected to the Lotus Sutra. These repentance practices (which also drew on other texts like the Golden Light Sutra) were grounded in the five-fold method of repentance, which includes acts of repentance, prayer, sympathetic joy, merit transference, and bodhisattva vows. Despite their name, Tiantai repentance rites are not just focused on purifying past misdeeds. Instead, they are multifaceted rituals with numerous aspects, including the cultivation of refuge, devotional faith, bodhicitta, virtue and meditative insight.
Tiantai repentance rituals like the Lotus Repentance, the Invocation of Guanyin Repentance and the Great Compassion Repentance, include both "repentance through activity"—involving prostrations, offerings, chanting, recitation of mantras—and "repentance through principle," in which practitioners contemplate the emptiness of all phenomena. Zhiyi's Lotus Samadhi Rite of Repentance is the most prominent Tiantai ritual. It blends the two main aspects of repentance into an extensive ritual, encouraging practitioners to purify their minds while deepening their understanding of the Dharma. According to Daniel Stevenson, "since the end of the sixth century, the Lotus repentance, as set forth in Zhiyi's manual, has constituted one of the mainstays of practice in the Tiantai school, and its ritual forms continue to govern practice in the modern world."
The Lotus Samadhi Rite of Repentance drew inspiration from two key texts: the Meditation on Samantabhadra Sutra and the "Chapter on Peaceful Practices" in the Lotus Sutra. The former emphasizes repenting misdeeds connected to the six senses, while the latter highlights non-discriminatory awareness and formless repentance—a practice where the mind realizes its inherent emptiness, transcending distinctions of virtue and vice. Zhiyi maintained that both "practices of form" and "formless practice" were essential in the earlier stages of cultivation, yet both are ultimately abandoned upon achieving profound realization. In this view, repentance was not merely an act of confession but a process of understanding the interdependent nature of reality.
Stevenson outlines the practice of the Lotus Repentance as follows:
* purification of the altar site
* purification of the practitioner
* incense offering
* veneration of deities
* confession of past misdeeds, with transfer of merits and prayers
* chanting the Lotus Sutra while circumambulating the altar
* taking the three refuges
* retiring to a separate solitary location in which one practices seated meditation or individual recitation of the Lotus Sutra
Repentance rituals in the Tiantai tradition evolved to meet the needs of Chinese society, blending Buddhist doctrine with popular beliefs about cosmic retribution and ancestral influence. The practice became central to Chinese Buddhist culture, especially in the form of public repentance ceremonies held during festivals such as the Ghost Festival. These ceremonies often aimed to alleviate the suffering of deceased relatives and were seen as acts of collective merit. Prominent Tiantai figures like Zunshi expanded upon Zhiyi's work by systematizing repentance ceremonies, contributing to the development of distinct rituals such as the Lotus Repentance and the Golden Light Repentance.

### Textual practices

In addition to repentance, textual practices centered around Lotus Sutra devotion is also n important part of Tiantai practice. Tiantai emphasizes the veneration of the Lotus Sutra itself as a sacred text, often treating it as the embodiment of the Buddha. Practices such as copying the sutra (or sponsoring such an act), reciting it (as a solitary practice or in a group), teaching it or listening to its teachings, and performing related devotional acts are believed to generate merit and wisdom. Through these practices, Tiantai Buddhism aims to balance meditative insight with ritual devotion, offering a comprehensive path toward enlightenment.
The Lotus Sutra itself emphasizes the merit of reading, reciting, copying, and teaching the text. In accordance with this, Zhiyi established recitation rites that incorporated ritual elements such as offerings, group chanting, prostration, and ritual purification. The devotional aspect of these rites highlights the belief that the Lotus Sutra embodies the Buddha's presence and wisdom. Related practices included visualizations of buddhas and bodhisattvas or even extreme acts of self-sacrifice to demonstrate devotion (such as burning off fingers, or copying the sutra in one's own blood).

## Key Ancestors

The following ancestors or patriarchs (zǔ 祖) are some of the most important masters in Chinese Tiantai:
* Nāgārjuna (3rd century CE)
* Huiwen (d.u.)
* Nanyue Huisi (515-577)
* Zhiyi (538–597), also called Zhizhe
* Guanding 561–632)
* Zhiwei (?–680)
* Huiwei (634–713)
* Xuanlang (673–754)
* Zhanran (711–782), also called Miaole
* Daosui (806–820)
* Guangxiu (771–843)
* Wuwai (813–885)
* Yuanxiu (?–885)
* Qingsong (d.u.)
* Yiji (919–987)
* Yitong (927–988)
* Siming Zhili (960–1028), also known as Siming Fazhi
* Zhenjue (1537–1589)
* Chuandeng (1554–1628)
* Ouyi Zhixu (1599–1655)
* Dixian (1858–1932)

## Influence

David Chappell writes that although the Tiantai school, "has the reputation of being...the most comprehensive and diversified school of Chinese Buddhism, it is almost unknown in the West" despite having a "religious framework that seemed suited to adapt to other cultures, to evolve new practices, and to universalize Buddhism". He attributes this failure of expansion to the school having "narrowed its practice to a small number of rituals" and because it has "neglected the intellectual breadth and subtlety of its founder".

## Influence of Traditional East Asian medicine

Zhiyi 智顗 often talked about meditation with the treatment of disease. Particularly drawing of his insights from the Maha Samatha (摩诃止观), the Children’s Samatha (童蒙止观) and the Initial Approach to the Chan Sect (次第禅门). His conception was influenced by Traditional Indian Buddhist Ayurvedic medicine, Taoism and elements of worship from Chinese folk religion forming a Buddhist medical cultural system that was specifically designed for the Chinese culture and was based on the etiology and pathological theory of Traditional Chinese medicines treatment and prevention of disease, pain and suffering.