[Book Review] Kukai's 'Benkenmitsu-nikyoron' — A World Opened Beyond Words

Introduction: Teachings that Unfold in Silence

Buddhism has supported the hearts of many people over a long period of time. While its teachings may seem unified, they are actually composed of various overlapping layers. Kukai's 'Benkenmitsu-nikyoron' (Treatise on the Differences Between the Exoteric and Esoteric Teachings) presents the two paths of Exoteric and Esoteric Buddhism as if to gently illuminate these layers. This is not to place one above the other or to treat one as inferior. Rather, it seems to softly indicate multiple entrances that open up when a person faces the world.

Exoteric Buddhism (Kengyo) is the teaching that the Buddha indicated through words. It overlaps with the journey we take as we open books and read words to understand. On the other hand, Esoteric Buddhism (Mikkyo) is depicted as a path toward a much greater expanse through a world of symbols that transcend words. For Kukai, these two were not in opposition, but were different forms for reaching the same truth.

Kukai first fully acknowledges the depth of Exoteric Buddhism. Based on the breadth of the world shown by the advanced philosophy of Mahayana Buddhism, and having firmly grasped the importance of the journey of accumulating 'understanding,' he positioned Esoteric Buddhism as another realm that opens up even further beyond that. The path of understanding guided by words, and the realization that opens up where words are transcended. Both are felt to be indispensable practices for a person facing the world.

Here, while tracing 'Benkenmitsu-nikyoron,' I would like to carefully look at how Exoteric and Esoteric Buddhism are depicted. Let us enter that world as if lighting a lamp in the silence of the night.

Chapter 1: What is Exoteric Buddhism? — The Path of Understanding Guided by Words

Exoteric Buddhism is a broad domain centered on the teachings that Shakyamuni spoke to people throughout history. It ranges from basic teachings like the Four Noble Truths and the Eightfold Path to the magnificent philosophy of Mahayana Buddhism. Kukai believed that within this Exoteric Buddhism, there are various layers from shallow to deep stages. One of its highest points lies in Mahayana Buddhism, which speaks of the philosophy of non-duality.

Non-duality is the idea that things that appear to be in opposition at first glance, such as life and death, or worldly desires and enlightenment, originally share a single reality. Kukai first looks at this deep point affirmatively. He acknowledges that even within Exoteric Buddhism, there resides a power that approaches the essence of the world.

So, what characterizes Exoteric Buddhism? It lies in the point of heading toward understanding through words. As a historical existence, Shakyamuni preached teachings tailored to many people. This is called the 'preaching of the Response Body (Ojin).' Words have the strength of being easy to understand and allowing one to deepen understanding step by step. On the other hand, words inevitably have limits. While the range that can be explained by words seems broad, an expanse that cannot be fully put into words remains outside of it.

Kukai does not deny this limit, but rather accepts it as an important characteristic. While Exoteric Buddhism holds firm power as a path of understanding, it plays the role of quietly indicating that other possibilities are open beyond it.

Chapter 2: What is Esoteric Buddhism? — A Place Where the World Itself Speaks

At the center of Esoteric Buddhism is the idea of the 'preaching of the Dharma Body (Hosshin).' The Dharma Body refers to the essence of the Buddha itself. Unlike the Shakyamuni who appears in history, the Dharma Body is the great activity that flows at the foundation of the world. Kukai personified this Dharma Body as Mahavairocana and symbolically depicted its expanse.

In general Mahayana Buddhism, the Dharma Body is considered a formless existence without words. However, Kukai boldly restructures that understanding. He thought that the Dharma Body also has preaching. The resonance of mantras, the shapes of mudras, and the structure of mandalas. These are all considered to be forms expressed so that people can perceive the deep rhythm emitted by the world itself. Touching the activity at the bottom of the world through the power of symbols, rather than through explanation by words. That is the path of Esoteric Buddhism.

The reason Esoteric Buddhism is called 'secret' is not because its content is hidden. It is because there are parts that cannot be fully opened by understanding words alone, and it is only opened when the practitioner resonates with the activity of the Buddha through body, speech, and mind. This is the form called the practice of the Three Mysteries (Sanmitsu). If Exoteric Buddhism is a path of understanding, Esoteric Buddhism can be said to be a path of experience and intuition.

For Kukai, both were important methods for a person to face the world. When Esoteric Buddhism is positioned as a realm that opens up outside of Exoteric Buddhism, based on the depth of the latter, the two paths do not conflict, but quietly resonate as forms heading toward the truth from different angles.

Chapter 3: The Difference Between Exoteric and Esoteric — Where the Two Paths Touch

The difference between Exoteric and Esoteric Buddhism is often spoken of in terms of depth. However, what Kukai indicated is not a story about which one is superior. Rather, if we think of it as a difference in how to approach the world, the overall picture can be seen softly.

Exoteric Buddhism is a tradition where Shakyamuni, having appeared in this world as a transformation body, taught through words tailored to various people. Words are certainly convenient and create a path for understanding. However, relying on words also means leaving behind parts that words cannot fully capture. No matter how profound the teaching, it is always accompanied by the contours of what can be expressed.

Esoteric Buddhism, on the other hand, is considered a teaching based on the preaching of the Dharma-kaya. The Dharma-kaya is the truth itself that flows at the foundation of the world. Its function, symbolized by the name Mahavairocana, is always open even before it 'reaches' us as words.Symbols such as mantras, mudras, and mandalasare gateways for that open function to touch people. What is important here is that the Dharma-kaya shown by Esoteric Buddhism is not an existence that can be touched simply by approaching it, but rather one thatpossesses an expanse that cannot be fully touched even if one triesto do so. By continuing to head toward it, the practitioner receives a faint resonance.

This difference can be understood not as a comparison of endpoints, but as a difference in how one faces the world. Exoteric Buddhism carefully layers paths of understanding through words, while Esoteric Buddhism walks a path of participation through the experience of symbols. Each has its own inherent depth, and they overlap in realms that cannot be seen by either one alone.

Chapter 4: The World Kukai Saw — The Universe Opening as Symbols

What Kukai gazed upon in Esoteric Buddhism was the deep rhythm inherent in the universe itself. Mantras were not considered mere words, but the resonance of sound itself was thought to be connected to the structure of the world. Mudras harmonize with the workings of the world through hand shapes, and mandalas envelop the practitioner as a space that symbolizes the form of the universe. These are not separate tools, but can be said to bewindows for people to receive the behavior of the world itself.

Here, Kukai strongly pushed forward the idea of the Dharma-kaya. The Dharma-kaya is a function that expands without remaining in any specific form or shape. It is by no means an object within reach. No matter how deeply one contemplates it, one cannot fully grasp its entirety. What the practitioner touches is, at most, one end of it, like a shadow of its expanse. That is precisely why the endeavor to touch the Dharma-kaya continues while containing the nature of being unable to fully touch it.

Then,the symbols of Esoteric Buddhism become not merely 'tools for conveying teachings,' but the very attitude of heading toward something that cannot be fully touched. When facing a mandala, one is overwhelmed by its intricacy, while simultaneously realizing that it is impossible to understand everything, and that this impossibility holds significant meaning. When chanting a mantra, the practitioner entrusts themselves to the deep function residing in the sound itself, but the source of that sound cannot be grasped. Indeed, the sensation that the closer one gets, the further away it moves, begins to open up.

The Esoteric Buddhism that Kukai speaks of is supported by both that 'attempt to touch' and 'inability to fully touch.' What symbols open is a space where the world resonates as a teaching just as it is, and within it breathes an expanse that cannot be reached by understanding through words. That is precisely why the structure where Esoteric Buddhism exists upon the foundation of Exoteric Buddhism naturally arises.

Chapter 5: Contemporary Significance — Awareness Opening Outside of Words

So, what meaning does the relationship between Exoteric and Esoteric Buddhism depicted by Kukai have for us today? One thing that can be said is that a perspective that can be cherished even in the modern age resides where both the attitude toward understanding and awareness beyond words are opened.

We rely on words in many situations. Explaining, understanding, and organizing. The path of Exoteric Buddhism overlaps exactly with this endeavor. However, we also encounter sensations that cannot be captured by words. These might be joy, sadness, or perhaps insights that are difficult to verbalize. Esoteric Buddhism was depicted as a path to accept such 'awareness opening outside of words' in the form of symbols.

What Kukai emphasized was not a binary opposition where one is right and the other is wrong. Rather, it is a view that there are multiple layers that emerge when a person faces the world, and that these layers create an expanse while casting shadows on each other. The path toward understanding and the attitude toward that which cannot be fully touched. Where these two gently overlap is the world that a person opens.

Exoteric Buddhism, which uses words, and Esoteric Buddhism, which opens to symbols. Between them breathes Kukai's gaze, which cherishes that which cannot be fully reached. There is an expanse that cannot be fully touched even if one tries, and by heading toward it, one can re-examine the world from a different angle. In time spent quietly opening a book late at night, that awareness might gently become a light.

Conclusion: A Path Toward That Which Cannot Be Fully Touched

The relationship between Exoteric and Esoteric Buddhism that Kukai depicted in 'Benkenmitsu-nikyoron' was not one of superiority or inferiority. A path to deepen understanding through words, and a path to open oneself to the world itself through symbols. By gently placing the two side-by-side, rather than one denying the other, he carefully brings out the contours that each possesses. It seems that multiple gateways for when a person faces the world are quietly acknowledged there.

Exoteric Buddhism is a path to understand the world through words. That path, which gradually expands one's perspective while following stages, overlaps with the intellectual endeavors we perform daily. The attitude of trying to explain, organize, and understand holds an important power for people to draw the world closer to them. Kukai firmly affirmed this power and acknowledged the depth and breadth of Exoteric Buddhism.

However, no matter how much one explains with words, there is still a realm that is left behind. The more words one layers, the more something that quietly expands outside of them can emerge. What Esoteric Buddhism opens is that realm. When facing symbols such as mantras, mudras, and mandalas, the practitioner does not try to understand the world, but tries to touch the workings of the world. At that moment, one encounters an expanse that cannot be fully touched even if one tries. Yet, that very inability to be fully touched takes on significant meaning.

The reason Kukai called Esoteric Buddhism 'secret' also lies in this untouchability. It is not secret because it is hidden, but because it cannot be opened through the understanding of words alone. When you open yourself to symbols, the world begins to resonate as a teaching in its own right. However, you cannot fully grasp that resonance. Even so, by continuing to touch its fragments, one may feel a small light being lit within oneself. Esoteric Buddhism may well be the path toward that light.

Exoteric and Esoteric Buddhism may seem to face in different directions, but in reality, they appear to draw a single circle. The endeavor to understand the world through words, and the awareness that opens up outside of words. As each complements the other, they gradually broaden one's perspective. The two paths depicted by Kukai are not in opposition but are layered, casting shadows upon each other while opening up new horizons.

When you gently close 'Benkenmitsu-nikyoron' in the silence of the night, the world may sometimes appear a little deeper than usual. What reaches us through words and what spreads out beyond words. The sense of fluctuation born between them may quietly encourage us in our daily lives.The journey toward that which we cannot fully touch, even when we try, may seem like a detour, but I believe it is an important path that enriches the human heart.