Literally, Ichinen sanzen can be translated as "moment of existence" and "three thousand aspects." Each moment of existence of all living beings (ichinen) is endowed with all three thousand realms of phenomena (sanzen). Ichinen means a moment of life. Ichi means "one" and signifies the one ultimate truth or the Middle Way of the Dharma nature. A single moment of existence encompasses all the elements that form a common mortal's life, such as body and mind, and cause and effect. The term refers to all forms of existence. Sanzen includes every single phenomenon in the entire universe. This doctrine teaches that even the smallest bit of life possessed by any single entity is actually endowed with all phenomena of the three thousand different realms.
Nichiren Daishonin says in the Gosho, "Kanjin no Honzon Sho (Thesis on the Fundamental Object of Veneration)":
"When he (T'ien-t'ai) finally revealed in the "Great Concentration and Insight" (Maka shikan) the way to perceive the true nature of life, he at the same time used the "three thousand realms" as a way to understand it. This is the ultimate truth of his teachings."(Gosho, p.645)
Thus, Ichinen sanzen is the ultimate principle of Buddhism and the ultimate truth of the Lotus Sutra.
The Doctrine of Ichinen Sanzen
This doctrine was systematized by T'ien-t'ai using concepts such as the Ten Factors of Life revealed in the Theoretical Teaching of the Lotus Sutra (Shakumon), and the Mutual Possession of the Ten Worlds and the Three Realms of Existence, which were revealed in the Essential Teaching (Honmon). The doctrine of Ichinen sanzen was expounded for the first time in Volume Five, Chapter Seven of T'ien-t'ai's "Great Concentration and Insight" (Maka shikan). In developing the theory of Ichinen sanzen, T'ien-t'ai placed primary focus on the Ten Factors of Life which were preached in the Hoben ("Expedient Means"-2nd) Chapter of the Theoretical Teaching. He borrowed the doctrine of the Essential Teaching of the Lotus Sutra to clarify that a single entity of life possesses three thousand realms. Volume Five of the "Great Concentration and Insight" states:
"At each moment, life is endowed with the Ten Worlds. Concurrently, each of the Ten Worlds is endowed with all the others. Therefore, an entity of life actually possesses one hundred worlds. Each of these worlds possesses, in turn, thirty realms. This means that in the one hundred worlds there are three thousand realms. "Three thousand realms" might also be read as "three thousand factors." But the number is the same. The only difference lies in the method of expansion. The three thousand realms of existence are all possessed by a single entity of life. If there is no life, that is the end of the matter. If however, there is even the slightest bit of life, it contains all the three thousand realms.... This is what we mean when we speak of the "region of the unfathomable." (Quoted in "Kanjin no Honzon Sho"; Gosho, p.644)
Each moment of a common mortal's life contains all Ten Worlds. Each of these worlds, itself, possesses within it the Ten Worlds, making one hundred worlds. Each of these one hundred worlds possesses the ten factors of life, making one thousand factors of life. Each of these factors of life possesses the three realms of existence, which makes a total of three thousand realms of existence.
The relationship between ichinen (a single moment of existence) and sanzen (three thousand realms) is not temporal. In other words, a single moment of existence does not precede the appearance of the three thousand realms, nor do the three thousand realms precede a single moment of existence. Neither preconditions the other. Additionally, they are not two separate principles existing simultaneously. They are intrinsically one. "Endowed with,” in the above Gosho quote, is used to show this principle of oneness.
The Mutual Possession of the Ten Worlds, the Ten Factors of Life, and the Three Realms of Existence T'ien-t'ai categorized the life conditions that could be manifested in a single moment of life into ten states. We call them the Ten Worlds. They are Hell, Hunger, Animality, Anger, Humanity, Rapture, Learning, Realization, Bodhisattva, and Buddhahood. Each of these worlds, from Hell to Buddhahood, is endowed with all the others. This is called the mutual possession of the Ten Worlds. The Daishonin tells us in the Gosho, "The Opening of the Eyes":
"The principle of Ichinen sanzen begins with an understanding of the mutual possession of the Ten Worlds or states of existence."(Gosho, p.526)
Thus, the concept of Ichinen sanzen was developed based on the Mutual Possession of the Ten Worlds. The doctrine of the Mutual Possession of the Ten Worlds was not expounded in the pre-Lotus Sutra teachings. This explains why the people of the two vehicles (Learning and Realization) were said to be unable to attain enlightenment. The Ten Factors of Life is a doctrine that divides the true entity of all phenomena into ten aspects. The word "factors" (nyoze) indicates that all forms of phenomena, just as they are, express the true aspect of the Middle Way. The Hoben Chapter of the Lotus Sutra states:
"The true entity of all phenomena can only be understood and shared between Buddhas. (Yui butsu yo butsu. Nai no ku-jin. Sho-ho jis-so.) This reality consists of the appearance, nature, entity, power, influence, inherent cause, relation, latent effect, manifest effect, and their consistency from beginning to end. (Sho-i sho-ho. Nyoze so. Nyoze sho. Nyoze tai. Nyoze riki. Nyoze sa. Nyoze in. Nyoze en. Nyoze ka. Nyoze ho. Nyoze hon-makku-kyoto.)"(Kaiketsu, p. 24)
Nyoze so is form, appearance or behavior that we can see. Nyoze sho is original nature or character. Nyoze tai is entity or substance. Nyoze riki is potential power or capacity. Nyoze sa is action influenced by potential power. Nyoze in is inherent cause or a direct cause that brings effect. Nyoze en is a relational or subordinate cause that supports an inherent cause. Nyoze ka is latent effect that results from inherent cause. Nyoze ho is a manifest effect that appears when a latent effect becomes manifest. Nyoze hon-makku-kyoto illustrates that Nyoze so and Nyoze ho are ultimately equal.
The three factors of appearance, nature, and entity are the substance of all phenomena. The six factors of power, influence, inherent cause, relation, latent effect, and manifest effect are the functions of all phenomena. All things in this universe exist and occur in these ten ways.
Next, the Three Realms of Existence are: the realm of the Five Components, the Realm of Living Beings and the Realm of the Environment. These realms are categories of phenomena arising from the unity of causes and conditions, and do not exist independently of each other. The Realm of the Five Components illustrates that the five components (form, perception, conception, volition, and consciousness) vary from person to person. The Realm of living beings refers to the truth that the lives of common mortals who are formed by the temporary union of the five components experience different worlds of the Ten Worlds. The Realm of the Environment illustrates that there are differences in the places where the common mortals of the Ten Worlds dwell.
Actual and Theoretical Ichinen Sanzen
As stated above, the doctrine of Ichinen sanzen was expounded by T'ien-t'ai for the first time in the "Great Concentration and Insight" (Maka shikan). Its conceptual origin is found in the Essential Teaching of the Lotus Sutra (Honmon). T'ien-t'ai's approach was to utilize the passages of the Theoretical Teaching (Shakumon) from the perspective of the Essential Teaching. Theoretical Ichinen sanzen is not specifically T'ien-t'ai's concept. Though Ichinen sanzen is the ultimate truth of Buddhism, there is a difference between Actual Ichinen sanzen and Theoretical Ichinen sanzen.
Shakyamuni Buddha taught the true nature of life from the perspective of the true entity of all phenomena in the Hoben Chapter of the Theoretical Teaching (Shakumon) of the Lotus Sutra. The Buddha of the Theoretical Teaching was Shakyamuni Buddha, preaching from the standpoint of the Buddha who first attained enlightenment during his lifetime in India. Since the Three Mystic Principles of the True Cause, True Effect, and True Land had not yet been expounded, the doctrines of the Mutual Possession of the Ten Worlds and Ichinen sanzen remained only a theoretical possibility. T'ien-t'ai borrowed the doctrines of the Essential Teaching and taught the principle of Ichinen sanzen from the perspective of the Middle Way, which is the universal truth possessed by common mortals. This is Theoretical Ichinen sanzen.
On the other hand, in the Juryo ("Life Span"-16th) Chapter of the Essential Teaching, Shakyamuni Buddha taught the Three Mystic Principles of the True Cause, True Effect, and True Land. The integration of the Three Mystic Principles reveals when and where (land) Shakyamuni Buddha's practice (cause) and enlightenment (effect) occurred. His enlightenment was not theoretical; it was actual. We learn from this that all things in the universe are the actual entity of Ichinen sanzen and therefore, all living beings can actually attain enlightenment. This is Actual Ichinen Sanzen from the standpoint of Shakyamuni's Buddhism of the Harvest.
However, from the viewpoint of Nichiren Daishonin's Buddhism, both Actual and Theoretical Ichinen sanzen are still only considered theoretical. The Daishonin states in the Gosho, "On the True Cause" (Honnin-myo sho):
"If the teaching is understood from the perspective of Shakyamuni Buddha's property-of-action aspect of a single lifetime, it is the surface truth, so the Lotus Sutra is included in the category of Theoretical Ichinen sanzen. Even the Juryo Chapter of the Essential Teaching is understood as the Theoretical Teaching......[However] The teaching hidden in the depths [of the Juryo Chapter] does not extend to any practices other than the Nam-Myoho-Renge-Kyo of the "direct attainment of enlightenment." It is the Ichinen sanzen of the true practice, the Mystic Law [through which the common mortal at the stage] of Myoji-soku actually attained enlightenment in the remote past." (Gosho, p.1684)
In the Age of Mappo, even the Juryo Chapter of the Essential Teaching (Honmon) becomes only a theoretical doctrine. It serves to illustrate the true Essential Teaching hidden in the depths of the Juryo Chapter: the five or seven characters of Nam-Myoho-Renge-Kyo. The remote past of Gohyaku-jindengo, which was referenced in the Essential Teaching, is inconceivably remote, but it is still a finite point in time. Furthermore, the Buddha of the Essential Teaching is the Buddha whose way of instructing the people was the same as the Shakyamuni Buddha who had earlier taught that he attained enlightenment for the first time in India. That is why, looked at from the deepest perspective, the Juryo Chapter is also considered Theoretical Ichinen sanzen.