Zhiyi - WikiHQ

Zhiyi (; 538–597 CE) also called Tiantai Dashi () and Zhizhe (, "Wise One"), was a Chinese Buddhist monk, philosopher, meditation teacher, and exegete. He is considered to be the founder of the Tiantai Buddhist tradition, as well as its fourth patriarch. Śramaṇa Zhiyi is widely regarded as one of the most influential figures in the development of East Asian Buddhist thought and practice. As the first major Chinese Buddhist thinker to construct a comprehensive religious system based primarily on Chinese interpretations, Zhiyi played a crucial role in synthesizing various strands of Mahayana Buddhism into a unique coherent framework.

Zhiyi relied on the teachings of the Lotus Sutra as the main basis for his system, though he also drew on numerous texts, such as the works of Nagarjuna. One of his central innovations was the Threefold Truth, which unifies the truths of emptiness, and provisional existence, with a holistic third truth: the middle. Zhiyi also developed an influential interpretation of the Lotus Sutra, which he used to interpret all other Mahayana Buddhist teachings. Zhiyi's comprehensive work on Buddhist practice, the (Great Cessation-Contemplation), outlines step-by-step instructions for Buddhist meditation and cultivation, combining traditional Indian methods with unique innovations. This text continues to serve as an influential guide for meditators across East Asian Buddhist traditions.

Biography

thumb|[[Stupa (pagoda) of Zhiyi at Zhenjue temple]]

Born with the surname Chen () in Huarong District, Jing Prefecture (now Hubei), Zhiyi lost his parents and hometown of Jiangling to the Western Wei army when he was just seventeen. He subsequently became a Buddhist monk at eighteen. As a young monk, he studied Mahayana sutras and Vinaya, and also recited the Threefold Lotus Sutra, under the guidance of Vinaya master Huikuang (d.u.).

At 23, Zhiyi met his most important teacher, Nanyue Huisi (515–577 CE), a meditation and Lotus Sutra master who would later be listed as Zhiyi's predecessor in the Tiantai lineage. On first meeting, Huisi is said to have greeted Zhiyi as an old friend, since he recognized that they had both been present in the Lotus Sutra assembly at Vulture's Peak. Under Huisi's tutelage (from 560 to 567), Zhiyi practiced the Lotus Samadhi Repentance, the Pratyutpanna Samadhi, the (the samādhi of freely flowing thoughts), the Lotus Sutra based "four practices of ease and bliss" (), and the meditative recitation of the Lotus Sutra.

In 567, Zhiyi (now 30 and approved by Huisi as his successor) traveled with several followers to Waguansi monastery at the Southern capital of Jinling (Jiangsu) to give teachings on the Lotus Sutra and the . He spent eight years at the capital teaching. Zhiyi also built a monastery on mountain Tiantai, which was later named Xiuchansi ().

Zhiyi is said to have thirty two direct disciples. Guanding (561–632) was his most influential disciple, since he was responsible for recording and preserving the master's legacy. It was Guanding who edited and published the master's lectures into the Mohe Zhiguan and the two great commentaries on the Lotus Sutra. Guanding also wrote his own original works, including two commentaries on the Nirvana Sutra. These key works were compiled and edited by Zhiyi's disciple Guanding (561–632) from Zhiyi's lectures and writings. The three texts are:

There is also another very important text by Zhiyi which is used as an introductory text to the study of Tiantai Buddhism. This is the twelve fascicle On the Four Teachings (, T 1929), which introduces the Tiantai view through an analysis of the fourfold teaching schema (which divides the Buddha's teaching into four aspects: Tripitaka, Shared, Separate, and Complete).

Important practice texts

These are the three Major Tiantai treatises studied in mainland Tiantai and Japanese Tendai and remain the cornerstone of the tradition's doctrine and practice.

Zhiyi also wrote three shorter works on meditation practice, explaining different approaches calming and insight practice:

Explanation of the Sequential Dharma Gates of Dhyāna Pāramitā ( T 1916), which presents his teachings on the "gradual and sequential" approach to calming and insight meditation and was written towards the beginning of Zhiyi's career
The (; lit Small Calming and Insight) was probably the first practical manual of meditation in China. With its direct influence on the Tso-chan-i, this smaller meditation treatise was very influential in the development of Chan meditation.
The Six Wondrous Dharma Gates ( T 1917), presents the "variable" approach to calming and insight.

Zhiyi is also known for having composed four repentance rites, which influenced later Chinese Buddhist rituals and remain part of the Chinese Buddhist repertoire today. His four main repentance rites are:

Repentance Ritual for the Lotus Sūtra Samādhi (, T 1941)
Vaipulya-samādhi Repentance Practice (),
Repentance Ritual of Petitioning Avalokiteśvara (),
Golden Light Repentance Practice ()

Other attributed works

There are also numerous other texts attributed to Zhiyi in the Taishō Tripiṭaka, though scholars are unsure of their provenance. Some of these may have been written by his disciples or later Tiantai authors. In particular, the works on Pure Land sutras and on Guanyin are seen by modern scholars as later works, while the commentaries on the Vimalakīrti Sūtra are seen as important authentic works of Zhiyi.

Profound Commentary on the Vimalakīrti Sūtra (, T 1777), an important work which was written by Zhiyi himself
Concise Commentary on the Vimalakīrti Sūtra (, T 1778)
Treatise on Contemplating the Mind (, T 1920), also called Treatise on the Churning of Milk, an authentic and important late work of Zhiyi
Commentary on the Vajracchedikā Prajñāpāramitā Sūtra (, T 1698)
Commentary on the Sūtra for Humane Kings (, T 1705)
Profound Meaning of the Golden Light Sūtra (, T 1783)
Textual Commentary on the Golden Light Sūtra (, T 1785)
Commentary on the Meaning of the Bodhisattva Precepts (, T 1811)
Essentials of Seated Meditation in the Practice of Calming and Contemplation (, T 1915)
The Four Foundations of Mindfulness (, T 1918)
Oral Instructions on Meditation from the Great Master Zhiyi of Tiantai (, T 1919)
Explanation of the Mahāprajñāpāramitā Enlightening-Thought Samādhi (, T 1922)
Gradual Entry into the Dharmadhātu (, T 1925)
The Fourfold Teachings (, T 1929)
Practice Methods for the Samādhi of the Expanded Teachings (, T 1940)
Treatise on Ten Doubts about the Pure Land (, T 1961)
The Five Expedient Gates of Mindfulness of the Buddha (, T 1962)
Profound Meaning of Avalokiteśvara (, T 1726)
Commentary on the Meaning of Avalokiteśvara (, T 1728)
Commentary on the Sūtra of Inviting Avalokiteśvara (, T 1800)
Commentary on the Sūtra on the Visualization of Amitāyus (, T 1750)
Notes on the Meaning of the Amitābha Sūtra (, T 1755)

Teaching

Interpretation of the Lotus Sutra

thumb|A scroll of the Lotus Sutra, Japan, Edo period

Zhiyi's exegetical works make use of a hermeneutical scheme called the fivefold profound meanings which can also be applied to any Buddhist sutra and was widely influential on later Chinese Buddhist exegesis. These five fundamental elements of interpreting a sutra are:

Explaining the title ()
Explaining the essence ()
Clarifying the main point ()
Discussing the function/application ()
Classification of the teachings ()

The longest section (2/3rds) of Zhiyi's Profound Meaning of the Wondrous Dharma Lotus Flower is his discussion of the title, which for Zhiyi reveals the Buddha's insight and contains the whole teaching of the Lotus Sutra. In discussing the term "wondrous" or "sublime" (), Zhiyi argues that this refers to ultimate reality itself (), which is the perfect interfusion of the three truths (). Furthermore, Zhiyi argues that the essential meaning of the Lotus Sutra is Suchness, the true nature of reality. He uses various terms for the Subtle Dharma, such as “the true aspect of reality” (), “true reality” (), and the Middle Way (), describing it as inexpressible, and beyond conceptual understanding.

Regarding the "main point" of the Sutra, Zhiyi describes it as "the cause and fruit of the Buddha’s own practice", which refers to Buddhahood itself, and the practices which lead one to it. Zhiyi sees the Lotus as the sutra which reveals the Buddha's pure insight, unmixed with any expedients and based on the ultimate truth. According to Zhiyi, previous sutras taught by the Buddha were still mixed with various secondary skillful means, but the Lotus directly communicates the Buddha's ultimate method. The absolute sublime meanwhile refers to a teaching that transcends all relative teachings and all dualisms, including notions of sublime or coarse, while also including all other teachings within it. Since this is a teaching beyond all discrimination and conceptualization, it is "inconceivable".

For Zhiyi, this ultimate non-dual teaching is the unique teaching only found in the Sublime Dharma Lotus Sutra, and is the essential meaning of the title.

Trace teaching

thumb|Illustration of the parable of the burning house from the Lotus Sutra. A father (Buddha) uses the idea of three carts to entice his sons out of a burning house ([[Saṃsāra|samsara). Afterwards, Buddha reveals that there is only one great magnificent ox-cart (the One Vehicle).]]

The first 14 chapters constitute the Trace Gate, since it presents the many "traces" arising from the "root" of enlightenment, and presents the Buddha as a "manifestation body". This section reveals the teaching of the One Vehicle () by revealing that all provisional teachings of the Three Vehicles (the , , and Bodhisattva paths) are nothing but expedient ways () to the Single Buddha Vehicle. This teaching emphasizes the Buddha’s skillful means in presenting various methods to different kinds of beings with varying capacities. In spite of their differences, all paths taught by the Buddha are said to eventually converge in the One Vehicle that leads all beings to Buddhahood. For Zhiyi, this means that while the various doctrines and methods taught by the Buddha in all the different sutras might sometimes seem contradictory, they are ultimately describing and leading to the same state (even if beings on those paths do not know it).

For Zhiyi, the Lotus Sutra<nowiki/>'s doctrine of the One Vehicle offered an inclusive meta-doctrine for understanding all Buddhist teachings. Zhiyi described the One Vehicle as "subtle" and "wonderful" compared to lesser, coarser teachings—though this distinction is only relative. From the ultimate perspective, the One Vehicle transcends comparison since no teaching exists outside it and it thus includes all the Buddha's teachings and in fact, is all the teachings. Thus, Zhiyi saw the One Vehicle as open and all-encompassing, integrating all of Buddhism into a single holistic framework. This One Vehicle teaching is also called the "Round" or "Complete" Teaching (), since it encircles everything, and lacks any sharp edges or divisions

Zhiyi saw the Complete teaching of the One Vehicle as being composed of four types of unity: 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 concepts teaches "the Subtle Dharma" (). As Zhiyi states in the Profound Meaning of Lotus Sutra: "various terms name one ultimate reality. Only one ultimate reality is given many names."

Zhiyi also organizes all the various skillful means taught by the Buddha through the schema of the four doctrines or four siddhantas (which he takes from the ). In this schema, the Buddha teaches according to (1) worldly convention; (2) suited to an individual's habits and preconceptions; (3) as therapeutic counteragents for specific defilements; and (4) in terms of Ultimate Truth. The also states: "All is real, all is not real, all is both real and unreal, all is neither real nor unreal - this is called the Ultimate Reality about all dharmas. In this way, all the scriptures are everywhere speaking the Ultimate Truth." As Ziporyn writes "here the real nature of all phenomena is asserted to be none other than the principle of upaya itself, of a provisional positing that is perpetually exposed as false and superseded. The truth, in other words, is the process of falsehood (partial truth) leading to truth."

Zhiyi sees the term "lotus flower" () in the sutra's title as an allegorical expression which points to the relationship between the relative three vehicles and the ultimate One Vehicle. Just like the flower blossom exists for the sake of the fruit, the relative teachings of the three vehicles exist only because of the One Vehicle. Similarly, the trace teaching exists because of the origin teaching. The provisional truth exists in order to reveal the real, and the real ultimate exists within the provisional. Thus, the term "lotus flower" in the title also symbolizes the entire teaching of the sutra, the "opening of the provisional to reveal the real" and the relationship between the three truths.

Original teaching

The latter 14 chapters constitute the Original Gate or Root Teaching, which reveals that Śākyamuni Buddha is not a recently enlightened being but in fact has been a Buddha for countless aeons (it thus presents the "original" or "primordial" Buddha, ). This ancient Buddha’s birth, awakening under the Bodhi tree, and apparent passing away (into nirvana) is just a skillful means. In reality, he has been ever-present in this very world, which is actually a serene pure land.

Zhiyi sees the essence of this teaching as being contained in the following passage from the Lotus Sutra: "Since I have been becoming Buddha, for eternal ages in a life full of uncountable eons, I have been constantly abiding without ever extinguishing."

Threefold Truth and Threefold Contemplation

thumb|Statue of Zhiyi at the [[Tendai home temple of Enryaku-ji, Mount Hiei, Japan]]

The foundational underpinning of Zhiyi's system is his doctrine of the threefold truth (), which is seen as the ultimate "Principle" or " the Nature". Zhiyi's doctrine represents a significant adaptation of Nāgārjuna's Madhyamaka philosophy. While Nāgārjuna's system centers on two truths—the conventional and the ultimate—Zhiyi expanded this framework by adding a third category: the Middle. This innovation helped bridge the gap between the apparent dichotomy in the two truths model, and offered a more integrated and holistic view of reality.

Zhiyi's Threefold Truth schema can be explained as follows:

Emptiness (): This is the classic Mahayana teaching of Śūnyatā - fact that all phenomena lack inherent existence or self-nature (svabhāva). This corresponds to Nāgārjuna's ultimate truth, wherein all things are seen as empty due to their dependent origination.
Provisional or Conventional Existence (): Despite their emptiness, all phenomena appear and function within the realm of conditioned arising. They are also provisionally posited, and exist due to conceptualization (prajñapti), which also means that they are ultimately false. This reflects the mundane or conventional truth in Madhyamaka, which Zhiyi glosses as "the twelvefold conditioned co-arising of ignorance" and as "illusory existence". In Zhiyi's system, this teaching also corresponds to the various skillful means taught by the Buddha.
The Middle (): This truth is the unity of emptiness and provisional existence. It emphasizes that reality is simultaneously empty and conventionally existent, i.e. the two truths are one truth. Emptiness is just conventionality, and vice versa, and both also contain the unity of these two (the third truth, which also contains them both). As Ziporyn writes "the difference between the first two truths, indeed even their opposition, must be preserved along with their harmony or identity." Zhiyi viewed this Middle Truth as transcending all dualistic extremes (such as existence and non-existence, being and emptiness, defilement and purity, self and other), and yet also affirming both sides of them as unified and non-contradictory. Zhiyi describes the Middle as "wondrous being identical to true emptiness." It can be explained as "a simultaneous affirmation of both emptiness and conventional existence as aspects of a single integrated reality." It is also described by Zhiyi as the "inconceivable" ultimate in which “any one interfuses with all three, and the three, one”.

Zhiyi regarded these three truths as inseparable, emphasizing their mutual integration: each truth encompasses the others in a dynamic interplay rather than existing in isolation. One can only understand them as a whole, never apart. Zhiyi describes this as: "the perfect integration of the three truths: one-in-three, three-in-one" (). Ziporyn writes that "any of these three concepts, if thought through to the end, reveals itself to be simply another way of stating the other two."

Regarding the classic Mahayana two truths theory itself, Zhiyi explains that it can be understood in at least seven ways, each one more profound than the other. At the deepest level, Zhiyi provides the following description (which also integrates the basic idea of the middle truth): "The mundane truth refers to both illusory existence and the identity of illusory existence with emptiness, and the real truth refers to the fact that 'reality includes existence, includes emptiness, and includes neither existence nor emptiness' (the threefold truth)."

The threefold ultimate reality is thus a single integrated whole. To describe this unified triple truth, Zhiyi used the simile of a drunk man who perceives the sun as spinning around, while in reality there is just one sun (a simile found in the ). According to Donner and Stevenson, the triple truth was also seen by Zhiyi as a tetralemma, which includes emptiness, and conventional existence, alongside the simultaneous affirmation and simultaneous negation of existence and emptiness. However, Zhiyi also warned that one must not cling to this idea of "one truth" either, since ultimately it is beyond all words and concepts. Thus, the single truth can also be described as "no truth": "the one truth is no truth; all truth is at rest. Each and every one is inexpressible. It is necessary to say "no truth" for the sake of those who have not fulfilled attainment, and in their attachments give rise to delusion. For those who have real attainment, there is , for those vainly speculating, there is none."

Each aspect of the one truth has a corresponding contemplative aspect. This is known as the Threefold Contemplation () and is based on a passage from the (Taisho no. 1485):

Entering Emptiness from the Conventional (): This practice begins by contemplating the dependent, conditioned nature of all phenomena, thereby discerning their emptiness of self-existence (svabhava). This corresponds to the contemplation of the two truths and aligns with the insight of arhats and bodhisattvas following foundational Buddhist teachings.
Entering the Conventional from Emptiness (): Having recognized emptiness, one sees that emptiness is also empty and "re-enters" the conventional. This step reaffirms the practical, provisional existence of things (as interdependent arisings), enabling compassionate engagement with the provisional world. This corresponds to the wisdom of bodhisattvas in Mahayana teachings.
Contemplation of the Middle Way (): This practice harmonizes the previous two insights, transcending conceptual distinctions. Emptiness and existence are "simultaneously illumined and simultaneously eradicated". The middle reflects the wisdom of the Buddha and the ultimate teaching. It is a non-dual simultaneous contemplation of the two truths.

Zhiyi emphasized that the highest form of contemplation is "perfect and immediate calming and contemplation," where all three truths are perceived as a unified whole in a single instant of awareness. 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", and is thus beyond all words and concepts, even though it can be called by various names like "Buddha-nature" (), Thusness ( ), (), and the (). In his commentary to the Vimalakirti Sutra, Zhiyi also glosses the contemplation of the middle as "the long-abidingness of phenomena (dharmas)" (, which can also mean the "enduring presence of the Dharma") which "infers the permanence of the Dharmakaya". He also states that the enduring presence of dharma/s "means to lead [beings] to realize buddha-nature and so to abide in the Great Nirvana". Zhiyi developed his theory of a threefold truth by drawing on Nāgārjuna's which explains the two truths as: "We state that whatever is dependent arising, that is emptiness. That is dependent upon convention. That itself is the middle path" (MMK, XXIV.18). Swanson also notes that various scholars have criticized Zhiyi for adding a third "truth", when no Indian author explains Madhyamaka this way. However, according to Swanson, the major point of Zhiyi's analysis is that reality is a single integrated truth (which may be explained with two or three aspects). As such, it is not a deviation from classical Madhyamaka. Swanson thinks that one of the main reasons for this development is that it was a useful device for undoing Chinese misunderstandings of the two truths (such as seeing them as referring to being and non-being, to two separate levels of reality or to an essential reality and its functions).

From the practical point of view, Ziporyn writes that the Tiantai threefold truth implies that all teachings and views can be ultimate, all can lead to liberation (depending on circumstances). Unlike with the earlier Buddhist theory of the simile of the raft, in which conventional truths are to be discarded upon awakening (as one no longer needs a raft after crossing a river), in the Tiantai model, conventional truths are the endowment of liberation and are not abandoned. Rather, they are fully mastered by bodhisattvas when they reach buddhahood in order to save all beings. Thus, conventional truths are not just the means to attain buddhahood but are also "the very content of buddhahood". As Ziporyn writes "ultimate truth is simply a name for the totality of conventional truths and the virtuosic mastery of being able to move unobstructed from one conventional truth to another, as the situation demands, to the comprehension of the way they fit together or can function together, or the way in which they are each, as it were, “versions” of the other. Ultimate truth is the non-obstruction between conventional truths, the fact that they all interpenetrate, that in their non-absoluteness each is simply a different way of saying what the others say."

The Sublime mutual inclusion

Zhiyi understood reality as a single integrated whole in which each part contains the whole. This is the doctrine of "mutual entailment" or mutual inclusion (). This interfused holism has been described in different ways, such as "the interinclusiveness of the ten realms" or "the interpenetrating unity of all aspects of reality". According to Swanson, for Zhiyi "everything contains everything else, and the whole contains all things." This also means that each religious teaching or practice leads to and includes the entirety of Buddha's teaching, which is the sublime intent of the Lotus Sutra as understood by Zhiyi.

This holism is also another meaning of the term "wondrous" or "sublime" (miao) found in the title of the Sublime Dharma Flower Sutra. Common glosses of this term include "inconceivability", "beyond conceptual understanding," and even "miraculous". Swanson writes <nowiki>the gist of Zhiyi's standpoint is that the term 'subtle'</nowiki> (miao) refers to any teaching, doctrine, practice, and so forth, which includes the concept of unity or integration." The ten realmsm considered exhaustive of all cosmology, are: the hell, ghost, animal, asura, human, deva, sravaka, pratyekabuddha, bodhisattva and Buddha realms. Each of these states of existence can be experienced in one's own mind, understood as ways of seeing the world, as well as actual realms of existence one can be reborn in.

According to this teaching, the ten realms of existence of Buddhist cosmology are all interconnected and interpenetrating. Furthermore each realm (or phenomenon) contains all others or "inherently entails" all others, hence they are "mutually inclusive" (in the same way that each of the three truths contain the others). Each thing or thought has a kind of potential which can be "opened up" to reveal all other things; every thing leads to everything else, and so "the whole is present in each part; every particular is itself the whole". Thus we can say that "one short thought contains all of reality" and "the Buddha and ordinary worldlings, body and mind, cause and effect, subject and object, sentient and non-sentient are mutually encompassed in every moment of thought." This does not mean that each phenomenon literally contains every thing else however, but that "as a sound is contained in a musical instrument", each phenomenon has the same nature (xing), which can lead to or become all other things. Ziporyn compares this to how the setup of a joke can be both serious by itself and funny (in the context of the whole joke and its punchline). Regarding the Three Dharmas, Zhiyi quotes from the Avatamsaka Sutra which states: "there is no distinction between the mind, Buddha, and sentient beings." Since the Three Dharmas are non-dual and the mind is the most accessible of the three, one can contemplate the whole of reality, including Buddhahood itself, by contemplating one's own mind.

Zhiyi explains this by citing another passage from the which states that "if one disports one's mind in the (all of reality) as if in space, then one will know the objective realm of all Buddhas." However, this "inconceivable mind" must not be understood as a kind of idealism in which reality arises from a single pure mind (a concept which would become influential in later Chinese Buddhism, especially in Zen). While this model presents a certain kind of non-duality, it emphasizes the ontological primacy of the "one mind" as pure and true, while perceiving worldly phenomena as illusory by-products of deluded consciousness. Zhiyi, however, proposed a different interpretation of Mahayana non-dualism. He rejected the idea that phenomena arise from an original mind or foundational consciousness. Instead, he described a relationship beyond vertical causation (mind generating phenomena) or horizontal containment (all things existing within mind). As Zhiyi writes:<blockquote>Were the mind to give rise to all phenomena, that would be a vertical . Were all phenomena to be simultaneously contained within the mind, that would be a horizontal . Neither horizontal nor vertical will do. It is simply that the mind is all phenomena and all phenomena are the mind... is subtle and profound in the extreme; it can neither be grasped conceptually nor expressed in words. Therefore, it is called the realm of the inconceivable. </blockquote>Zhiyi’s view reinterprets the world not as a mere realm of delusion, but as one with enlightenment itself, the “real aspect of all dharmas”. Thus, Buddhist practice is not about returning to a supposed original purity but about awakening to wisdom directly within the complexities of ignorance and worldly experience.

Classification of teachings

In order to provide a comprehensive framework for Buddhist doctrine, Zhiyi sometimes described the various Buddhist teachings into the five types or "five flavors" of the teaching, each suitable for certain types of beings. This classification schema (panjiao) is based on a passage from the Nirvana Sutra which compares five phases of the teachings to the extraction of ghee from milk. Zhiyi also uses another simile: the sun's progression throughout the day. These five teaching flavors are:

The Tripitaka Teachings () which represents the Hinayana teachings on the four noble truths, renunciation and attainment of arhatship. Zhiyi writes that these teachings rely on entering emptiness "through the analysis of provisional existence," and remains incomplete as it relies on the duality between existence and emptiness.
The Shared Teachings () which emphasizes the understanding of emptiness through "experiencing provisional existence (as empty)", a principle that applies across all Buddhist paths. It prepares practitioners for deeper Mahayana insights but is not itself complete, since it relies on mere negation and is thus only a partial truth.
The Distinct Teachings () which are exclusively Mahayanist and rely on "entering provisional existence from emptiness." This teaching establishes the middle truth, but this is an "Exclusive Middle" (), a middle which transcends (but does not include) the previous teachings, and also includes "non-emptiness". Thus it is "distinct" or "separate". In this teaching, spiritual progress unfolds gradually through fifty-two bodhisattva stages, which are distinct and require the cutting off of the defilements. It also lacks the full integration of the Complete teaching, since it does not include within it the Hinayana for example or evil persons like Devadatta. Despite reaching the middle truth, its methods are seen as somewhat cumbersome due to reliance on gradualism and dualism.
The Complete/Round Teaching () which directly reveals the complete ultimate truth "all at once" without reliance on provisional methods. This is the holistic truth of the “Non-exclusive Middle” () which includes all the four teachings within it. The Lotus teachings are only superior from the relative point of view (since it communicates the ultimate intent of the Buddha directly), but from the ultimate perspective (the absolute sublime), all the flavors and teachings are the same as the Complete teaching.

Therefore, according to Zhiyi, the Buddha-realm is deeply integrated with all other aspects of reality, inseparable from all things:<blockquote>How can there be any dharma distinct from the Buddha? There cannot. All of the hundred realms and thousand suchnesses are the objective realm of the Buddha.</blockquote>Buddhahood is not detached from the rest of reality, but pervades all the other nine realms and dwells within them. The difference is that a Buddha knows reality as it really is. As such, the three subtle dharmas (sentient beings, Buddhas and mind) are interfused, a single whole in which the three dharmas "are not distinct" as the says. For Zhiyi, there is an inconceivable unity and difference (and both, and neither), in the relationship between beings and Buddhas due to the principles of equality and non-dwelling. This means that Buddhas are in the minds of all beings, and at the same time, all beings are in the minds of the Buddhas and bodhisattvas. This interfusion is true because beings and buddhas are ultimately not fixed to any single identity (non-dwelling), and are equally distributed, omnipresent and all-pervasive (equality). According to Swanson, Zhiyi's view of Buddha-nature is "an active threefold process which involves the way reality is, the wisdom to see reality as it is, and the practice required to attain this wisdom".

Zhiyi's Profound Meaning of the Lotus Sutra explains Buddha-nature through three non-dual aspects: Zhiyi states in his Profound Meaning of the Lotus Sutra that the teaching of emptiness "fails to expound the permanence of buddha-nature." Furthermore, as Zhiyi writes in the Profound Meaning of the Lotus Sutra, by "eradicating clinging to emptiness", one speaks of "no-emptiness", and thus:<blockquote>Those of sharp faculties say that no-emptiness is a wondrous existence (), and so teach no-emptiness. Those of sharpest faculties, upon hearing somebody speak of no-emptiness, say that it is the , and that all dharmas move toward the .</blockquote>The view of "Middle Way–Buddha Nature" is found in Zhiyi's Profound Commentary on the Vimalakīrti Sūtra which states that "what is called liberation is the realization of the Middle-Way Buddha-nature," while seeing the emptiness teaching of the shared doctrine as a "one sided principle".

Zhiyi's positive account of buddha-nature (which he also describes as "no-emptiness", ), includes the doctrine of emptiness, but goes beyond it in affirming permanence and dynamic function. Yu-Kwan sees Zhiyi's understanding of buddha-nature as being defined by three characteristics: ever-abidingness (), meritorious function () and embracing various dharmas ().

Yu-Kwan highlights Zhiyi's understanding of the truth as dynamic function () as the most important aspect of buddha-nature for Zhiyi. Function or "great function without limits" means that ultimate truth is always positively and actively working for the transformation of sentient beings. In some cases, Zhiyi also qualifies Buddha-nature as "mind" (xin), with terms like "buddha-nature true mind", "self-nature pure mind" and "middle true principle mind", as well as statements like "Mind is the Buddha-nature". This understanding of buddha-nature in terms of mind highlights how it is a dynamic force in the world. Zhiyi also used other terms throughout his work such as sublime existence (), empty buddha-nature. Thus, Zhiyi writes "even a single color or smell is the middle way. The dharma of the middle way embraces all dharmas". This idea was later expanded into a full theory of "the Buddha-nature of the insentient" by Zhanran.

Zhiyi critiqued as one sided the idea of a pure nature as the single source of all reality found in the Dilun school (which he termed “self-production”, ). He likewise critiqued the Shelun school idea that reality arises solely from defiled nature (which he termed “other-production”, ). Instead, Zhiyi argued for a view in which good and evil are both equally part of the same non-dual ultimate reality. This is a direct consequence of his argument that all phenomena are inherently included () in all other phenomena and that each of the ten realms contains all others. This interpenetration and mutual inclusion of all dharmas, regardless of whether they are considered good or evil, is a key characteristic of Reality in Zhiyi's view. Due to the interfusion of all phenomena, Zhiyi is thus able to affirm that “One thought of ignorance is the mind of dharma-nature” () and “afflictions are exactly bodhi (awakening).” Zhiyi writes in the Profound Meaning of the Lotus Sutra that "without evil there is no good. turning evil over is precisely the fulfillment of good.” Thus, the concepts of good and evil are relative, since each depends on the other. The complete teaching is the highest kind of good, and from this supreme understanding, samsara and nirvana are fully non-dual.

Zhiyi explicitly addresses the doctrine of inherent evil in works like the . According to Ziporyn, the locus classicus of the idea is in the Profound Meaning of the Guanyin. In this work, Zhiyi explains Buddha-nature through the lens of the Three Causes: Direct Cause (Suchness), Revealing Cause (wisdom), and Conditioning Cause (practices and merits). Zhiyi asserts that the Revealing Cause and Conditioning Cause aspects also include both good and evil, while distinguishing between inherent () and cultivated () good and evil. Sentient beings who commit evil cut off cultivated good but retain inherent good. Buddhas cut off cultivated evil, but retain inherent evil. This signifies that inherent good and evil are fundamental aspects of buddha-nature that cannot be eliminated, since they are part of reality itself. Because of this, they can also serve as "Dharma-gates". Since even evil acts and defilements can lead one to Buddhahood in a certain way, Zhiyi writes that desires, anger, ignorance and the ten evil deeds can all be "seeds" of Buddhahood.

Furthermore, the distinction between Buddhas and evil sentient beings is not one of nature, but of cultivation. Thus, the nature shared by both also includes evil. Ultimately for Zhiyi, the buddha-nature shared by Buddhas and all beings is interfused with all dharmas, and thus must also encompass evil. Zhiyi cites the in defense of this view, which states " goes into the non-Dharma, follows and understands perfectly the Buddha-Dharma," and also: "all kinds of afflictions are the seeds of the ". As Zhiyi writes in a celebrated passage of the <blockquote>Understanding purifies practice, and practice promotes understanding. Illuminating and enriching, guiding and penetrating, they reciprocally beautify and embellish one another. They are like the two hands of a single body, which, working together, keep it clean. is not just a matter of clearing away impediments and overcoming obstacles in order to inwardly advance one’s own enlightenment. One must also achieve a thorough comprehension of the sutras and treatises so that one can outwardly reveal to others what they have not heard before. </blockquote>This understanding of the unity of "doctrine and practice" () is compared to unbalanced and mistaken engagements with either element (the scholar who does not meditate, or the meditation (chan) master who does not study). He compares the unlearned meditator to someone who improperly grasps a fiery torch (samadhi), burning himself. The scholar who does not practice meanwhile, is compared to a pauper who counts someone else's money. For the Zhiyi and the Tiantai tradition in general then, Buddhist practice must integrate both if it is to be effect. This is obvious in the second step of the six identities, a classic schema for the Tiantai path, which includes “hearing the doctrine” and “acquiring verbal comprehension” of the perfect teaching.

Calming and insight (zhiguan)

Zhiyi's works on meditation (, ) and calming and insight (, , also translated as "cessation-and-contemplation") comprise the most systematic and extensive works on Buddhist meditation practice written in imperial China. Already in Zhiyi's and are said to be the most essential and foundational element of Buddhist pracitce, since "cessation is the preliminary gate for overcoming the bonds , contemplation is the proper requisite for severing delusions."

In the more mature , Zhiyi's understanding of the term is all encompassing, going beyond the traditional understanding which merely applies to specific aspects of meditation. For Zhiyi, zhi and guan include within it all Buddhist practices. In essence, Zhiyi writes, zhiguan "encompasses dharmas." This is because refers to the static aspects of Buddhist practice, all the ways of "stopping" and bringing to "cessation" negative qualities (like defilements and delusions), including ethics (sila), while refers to all dynamic aspects of wisdom () and insight which lead us to seeing reality clearly. Thus, the states: "There are many ways to enter the true reality of nirvana, but none that is more essential or that goes beyond the twofold method of cessation-and-contemplation."

Zhiyi's mature understanding of has a threefold aspect:

Effect: This refers to the effects of all religious practices: they help calm and still the mind (and the afflictions), and they develop wisdom.
Reality: Finally, Zhiyi also understands as referring to ultimate reality itself, which has the nature of "quiescence and illumination" or "cessation and luminosity".

Swanson also writes that Zhiyi held that there are two modes of : that of sitting in meditation , and that of "responding to objects in accordance with conditions", which is further refined as abiding in the natural state of a calm and insightful mind under any and all activities and conditions. Thus, the term zhiguan can encompass all activities and actions. According to Swanson, Zhiyi preferred this more comprehensive term over the term "chan" (zen), which he saw as more limited.

When it comes to practical application of (cessation-contemplation), Zhiyi outlines three approaches to its cultivation:

Gradual and successive : In which one progresses through various aspects of the path gradually, beginning with refuge and precept keeping, followed by and so forth, step by step.
Variable (or undetermined) : Though it involves no particular predetermined stages, it may draw on or alternate the gradual and the sudden approaches to varying degrees, and the worldly or supreme perspectives, depending on an individual's needs.
Perfect and sudden : the instant and direct contemplation of ultimate reality, the "real mark", "true aspect" () or ""

Zhiyi also emphasized the importance of balancing the dual aspects of cessation and contemplation, writing "these two aspects are like the two wheels of a cart, or the two wings of a bird; if one side is cultivated disproportionately, then one falls prey to mistaken excess." Zhiyi also refers to them as the "supporting activity" for the contemplation of the Dharmadhatu (all of reality). It is the contemplation of the enlightened ones who see true reality as perfectly interfused, as "one thought containing three thousands worlds" and as the threefold truth. A person with the sharpest faculties can rely on this mode alone, while other individuals might not attain liberation from their attempts at practicing it, in which case they would then need to practice the other modes.

Arousing compassionate thoughts: one arouses great compassion, bodhicitta (the intention to become a Buddha for the sake of all) and takes the bodhisattva vows. Incidentally, it is Zhiyi who developed the fourfold bodhisattva vows which are standard in East Asian Buddhism today (drawing them from various sutras).
Skillful means for easing one's mind: this refers to various methods for calming the mind, to be used as appropriate, depending on one's needs.
Thorough deconstruction of dharmas: deconstructing all phenomena, especially the afflictions and wrong views, thereby eliminating all attachments.
Knowing what eases and what obstructs the path: Involves discerning the appropriate or obstructed conditions in contemplative practice, distinguishing between beneficial and detrimental aspects of mental states.
Cultivating the steps to the path: the thirty-seven aids to awakening
Regulating through auxiliary methods: if obstructions to samadhi appear, one practices the six perfections, as well as the five antidotes: breath meditation, meditation on impurity, compassion meditation, dependent arising contemplation and Buddhanusmrti.
Knowing the stages: focuses on cultivating the five repentances: Repentance, Worship, Sympathetic Joy, Transfer of Merit, taking bodhisattva vows; as well as and five stages in their practice.
Peace through patient recognition: not letting oneself be moved by external conditions, good or bad.
Avoiding passionate attachment to dharmas: if one is unable to enter true reality by the above nine means, this means attachment is still strong.

Perfect and sudden contemplation

One of the most famous passages in the (which is often chanted in Tiantai temples and actually derives from Guanding's introduction) summarizes Zhiyi's view of the "perfect and sudden" () aspect of zhiguan which does not rely on stages:<blockquote>The perfect and sudden involves taking the true aspects as the object from the very beginning. Whatever is made to be the object , it is the Middle; there is nothing that is not truly real. reality itself (dharmadhatu) is fixed as the object, and one’s thoughts are integrated with reality itself, there is not a single color nor scent that is not the Middle Way. It is the same for the realm of the individual , the realm of the Buddha, and the world at large. All aggregates and senses are thusness; therefore there is no suffering that needs to be removed. Since ignorance and the exhausting dust are indivisible with bodhi-wisdom, there is no origin to be severed. Since the extremes and false views are the Middle and the right , there is no path to be cultivated. Since samsara is nirvana, there is no extinguishing to be realized. Since there is no suffering and cause, there is no mundane world; since there is no path and no extinction, there is no transcendent world. There is purely the single true aspects ; there are no separate things outside these true aspects. For things in themselves (dharmata) to be quiescent is called “cessation”; to be quiescent yet ever luminous is called “contemplation.” Though earlier and later are spoken of, they are neither two nor separate. This is called perfect and sudden cessation-and-contemplation.

Non-elimination of defilements

According to Zhiyi, for those who have attained the ultimate perspective, "the mundane dharmas are themselves the ultimate Dharma...there is no need to forsake the mundane and adhere to the sacred". This identification of worldly phenomena with the ultimate reality and nirvana means that liberation is achieved in the phenomenal world itself, not apart from it. As such, liberation does not ultimately require the elimination of the defilements. This doctrine of the "non-elimination" () of defilements is expressed by Zhiyi in numerous ways throughout his works. For example, Zhiyi states that "defilements are awakening", "ignorance is wisdom", and "the realm of mara is the realm of Buddha".

The fact that "the assemblage of defilements do not obstruct and nirvana" is called the "inconceivable liberation". Zhiyi also argues that the ultimate Dharma-nature and defilements are two modes of the same reality, like water and ice. Since their difference is insubstantial, realizing their mutual inclusion in one pure non-dual thought is precisely what can allow us to transform ignorance into wisdom, like thawing ice into water. This view of the non-elimination of all dharmas also relates to Zhiyi's view of ultimate reality as "embracing all dharmas" and including all phenomena in a single thought. Non-elimination also supports the meritorious function of a buddha or bodhisattva, who could use any dharma in their manifestation of skillful means.

Identity in Principle (): All beings are inherently identical with the principle of reality (), regardless of awareness or practice. This is the stage of most common people, they are a Buddha but have no clue of it. Zhiyi compares this to a poor person who owns a house with buried treasure but is unaware of it.
Verbal Identity (): Awareness arises through hearing or reading Buddhist teachings, representing conceptual understanding without deep practice. It is like a friend pointing out the treasure’s location to the poor person, bringing awareness to what was previously unknown.
Identity in Practice (): At this stage, one engages in active contemplation and meditative practice aligned with Buddhist principles. It is like clearing away the weeds and starting to dig for the treasure.
Identity in Resemblance (): Practice matures, and understanding increasingly resembles true wisdom; corresponds to the "Ten Degrees of Faith", the first ten of the fifty two bodhisattva stages taught in Zhiyi's system. This is like digging closer to the treasure, gradually nearing its discovery.
Partial Identity (): Partial realization of Buddha's wisdom; begins with the first bhumi and extends to virtual enlightenment. It is compared to opening the treasure chest and seeing its contents.
Ultimate Identity (): Complete enlightenment, marking the full realization of Buddha-nature and the eradication of ignorance. It is like fully retrieving and using the treasure, with nothing more to uncover.

This schema provides a gradual analysis of how, as we practice the path, we grow increasingly aware of own nature as Buddha. For Zhiyi, our understanding of our identity with the Buddha must be balanced. Those who exaggerate their own realization of identity become arrogant, while those who emphasize their difference to the Buddha lose faith in themselves and their practice.

For Zhiyi, the various stages of the path are not necessarily linear, since according to Guanding (Zhiyi's main disciple) "when you enter the first abode, one stage is all the stages...all are ultimate, all are pure, and all involve full mastery." This means that the actual attainment of Buddhahood, and the process of becoming a Buddha (the stages of the path) are inseparable. Since Buddhahood is atemporal, being and becoming a Buddha is beyond time and stages. Thus, awakening suspends any successive order in linear temporality, meaning that any stage on the path is non-dual with Buddhahood itself (just like the root teaching and the trace teaching of the Lotus Sutra are non-dual). The practice of the path and Buddhahood are “inconceivably one”, and thus, from an ultimate point of view, becoming Buddha and being Buddha are paradoxically the same thing. Zhiyi wrote this ritual in order to promote the cultivation of the Lotus Samādhi, which refers to a type of samādhi that practitioners can attain through practice of the Lotus Sūtra. This ritual would receive further supplementations during the Song dynasty (960-1279). Usually held on the days of new and full moon or Uposatha, the precepts are recited according to the seven categories. Many Āgama sūtras teach repentance by way of contemplating signs such as hells, poisonous snakes, the white mark (between the eyebrows) and others.

For example, Zhiyi makes use of Indian medical systems based on the "four great elements" () along with Chinese theories of the "five internal organs" () to explain the nature of different diseases and their causes. He also discusses various treatment methods such as herbal remedies, meditation to calm the mind (), six therapy (), twelve-breath therapy (), and the recitation of mantras.