The Meaning of Akshobhya's Mantra - Part 1: HUM Like Lightning
The first section of a long essay on esoteric Buddhist mantras
Note: This essay may require more advanced knowledge of Buddhist theology and related esoteric concepts than my other works. If you’re a newcomer to these subjects, I highly suggest checking out my “introduction to Japanese Buddhism” series and my book “The Diamond Sword” (also on my Substack).
Chapter 1: Introduction
For centuries, Buddhists have pondered what kind of teachings will be able to liberate the hearts and minds of men as we continue into the depths of the age of decline and the demon king Mara is given free reign to all corners of the earth.
Pure Land Buddhists chant the name of Amida/Amitabha Buddha while anticipating rebirth in his land of infinite bliss and embracing his “other power.” Followers of the Nichiren tradition chant the Daimoku (Namu-Myoho-Renge-Kyo) on a daily basis, giving full faith to the profound teachings of the Lotus Sutra and to Shakyamuni Buddha of the “Lifespan Chapter.”
As one can plainly see from these examples, it’s been a common belief that appropriate teachings for the latter age can be encapsulated in mantras and simplified practices that work with the religious proclivities of practitioners, and we have seen these kinds of means produce astounding effects. After all, Pure Land Buddhism and the Nichiren schools have the highest number of lay followers in the entire country of Japan.
However, the Nembutsu and Daimoku are far from the only mantras we have been gifted via the teachings of the Buddhas, and the concept of “mantra” practice itself holds a great deal of complicated theological weight.
Esoteric Buddhism has hundreds of mantras, a vast array of practices found deep in ancient tomes and orally-transmitted tradition. Surely there are many others that could match the spiritual profundity of the aforementioned examples, right? In this piece, I want to give an explanation for just one of these, a short 3-word mantra found in Shingon Buddhist tradition.
To fully explore this topic, however, we must first develop a firmer grasp on what “mantras” are within the esoteric Buddhist context.
Chapter 2: The Mantra Path
It can be argued that the three most important characters of the Sanskrit alphabet are OM, A, and HUM, and the combination of these three not only becomes a mantra, but the sound of life itself.
OM fills the lungs with air, A is the source of all speech, representing not only human means of communication, but the signals that comprise how we experience the very cosmos via our consciousness. HUM is exhalation and the closing of the mouth, subsequently resulting in the cycle starting once again.
This is also the secret mantra of the Ni-o temple guardians that stand at the gates of many Japanese and Chinese Buddhist temples. The Ni-o are manifestations of the bodhisattva Vajrapani and wield the mighty vajra themselves. One is always open-mouthed, shouting “A” in righteous and compassionate fury. The other is closed-mouthed, with his diamond-like mind in a state of total focus, saying “UN” (which is the Japanese transliteration of HUM).
Together, these two syllables can form “AUM,” which can be interpreted as “OM.” When we place this new syllable at the beginning, as it is the common opening syllable for a mantra, we get “OM A HUM.” This phrase illustrates the end and beginning of all things; the source, the transformation, and finally the decay. It’s the sound of samsara; of birth, death, and rebirth.
This cycle has repeated on and on, over and over. For billions of trillions of years, your blood has been spilled; billions of trillions of gallons of blood. So much blood and so much suffering; on and on, over and over. Throughout this vast period of time, you’ve been every kind of being imaginable: an insect, a fish, a monkey, a dog, a beggar, a fool, a rich man, a king, and even a bodhisattva.
Long ago great golden bodhisattvas inhabited this earth, preaching the wonderful dharma and leading all other sentient beings to supreme liberation. They are our predecessors, and they waited underground for vast ages for the right time to re-emerge, finally doing so when Shakyamuni Buddha preached the wonderful dharma of The Lotus Sutra.
The earth opened up and the bodhisattvas came pouring out, golden and splendid, adorned with precious jewels and banners, they filled the air around the Buddha's vast assembly before being entrusted to perpetuate the dharma of The Lotus Sutra into the age of decline after the Buddha has passed into nirvana.
And so they did, and the teachings have been preserved for thousands of years. But these would not be the final teachings that would be given to us. In legends around the esoteric tantric texts, it's said that a monk named Nagarjuna received new forms of the dharma directly from a bodhisattva named Vajrasattva, the great "vajra being," inside of an iron stupa.
These new teachings were not from Shakyamuni Buddha, but directly from the “dharma” body of the Buddha, or rather the ultimate unborn source of all Buddhist teachings. Per the Shingon Buddhist patriarch Kukai’s treatise “On the Differences Between the Exoteric and Esoteric Teachings”:
“According to the explanation in the Adamantine Pinnacle Sutra of the secret treasury (T. 18: 288a), the transformation body of the Tathagata expounds the doctrines of the three vehicles for bodhisattvas yet to enter the [ten] stages, for those of the two vehicles, and for ordinary people, while the other-enjoyment body expounds the exoteric One Vehicle for bodhisattvas of the ten stages - these are both exoteric teachings; the Own-nature and [Self-]enjoyment Buddhas each together with their attendants expound a gateway to the three mysteries for their own enjoyment of Dharma bliss - this is called the esoteric teaching. These gateways to the three mysteries represent the sphere of the wisdom innerly realized by the Tathagata.”
This new vehicle has been commonly dubbed Vajrayana or "the way of diamond/lightning," and focuses on several elements that were largely absent from many earlier texts; for instance, mandala, mudra, and mantra or "true speech."
While the Shingon priest Kakuban wrote that “when one enters the Shingon teaching, all words [and by extension all sounds of the voice] are mantras,” the main focus of mantra practice is on “mantra” of the “true speech” variety, which Kukai described in his treatise "Sound, Sign, and Reality":
They are able to express the reality of all dharmas without error and without falsehood, and therefore they are called “true speech."
The path outlined above gave us sentient beings in the age of decline (or "latter age") a way to connect with the unborn cosmic Buddhas via the "three mysteries'' of mind, body, and speech, despite the crooked nature bestowed upon us by the world of spiritual decay we have been born into.
Per Kakuban’s “Illuminating Secret Commentary on the Five Cakra’s and Nine Syllables'':
Upon entering this teaching a little, three great asamkhyeya [kalpas] are transcended in the single recitation of the syllable “A.” Boundless blessings and wisdom are contained in the diamonds of the three mysteries. The eighty thousand toils change into ghee.
The five skandhas suddenly become Buddha wisdoms. The mantras resounding from an opened mouth destroy offenses. The mudras made by raising the hands and moving the legs enhance blessings. The wonderful visualization rising from the mind is created by oneself. Mental activity suddenly becomes samadhi, that is, it is perfected.
A destitute woman in a filthy courtyard suddenly raises the banner of the cintamani, and in the dark room of ignorance suddenly the light of the sun and moon shines.
As the above passage implies, mandalas and other visualizations give us focus for meditation, corresponding with the mind. The mudras give us a focus for our bodies, and the mantras give us access to the hidden “true speech” of the Buddhas.
Through this "mantra practice" it is believed that man is able to merge object and subject, known and knower, mind and emptiness, and ultimately realize his place within the interconnected whole of the universe. Per the Mahavairocana Sutra:
"... the mind, which has the characteristic of empty space,is free from all differentiation and non-differentiation. Why is that? That whose nature is the same as empty space is identical to the mind, and that whose nature is the same as the mind is identical to bodhi.
In this manner, Lord of Mysteries, the three entities of mind, the realm of empty space, andbodhi are without duality. They have compassion as their root and are fulfilled by the pāramitā of expedient means. For this reason, Lord of Mysteries, Iteach the dharmas in this manner so as to make the multitudes of bodhisattvas purify the bodhi-mind and know their mind."
Kukai expounds on the nature of the mind as a "consciousness element" that is not separate from the rest of the elements:
"In the exoteric teachings the four elements are regarded as non-sentient, but the esoteric teaching explains that they are the samaya bodies of the Tathagata. The four elements are not separate from the mind element. Although mind and matter are different, their nature is the same.
Matter is mind, and mind is matter, and they are [mutually] unhindered and unobstructed. The knower (lit., “wisdom”) is the known (lit., “object”), and the known is the knower; the knower is the [truth-]principle [that is known], and the [truth-]principle is the knower—they are [mutually] unobstructed and absolutely free."
This merging of known and knower (or object/mind and wisdom) corresponds to the two Buddhas of the Lotus Sutra, Shakyamuni and Prabhutaratna, seated side by side in a jeweled stupa:
"Then from within the stupa the Buddha Prabhutaratna offered half of his seat to the Buddha Shakyamuni, saying: 'O Shakyamuni Buddha, please take a seat here!'
The Buddha Shakyamuni immediately entered the stupa and sat cross-legged on half of the seat."
The Buddha Prabhutaratna realized the doctrine of the Lotus Sutra many ages ago, but did not preach a single word of it, as the time was not right for such a teaching. Instead he entered into a "nirvana" and, like the golden bodhisattvas from inside the earth, waited for the right time to re-emerge.
However, this is all expedient means. In truth, Prabhutaratna is always in the the ten directions, waiting for the "knower" to realize the Lotus dharma:
"This Buddha Prabhutaratna
Always roams the ten directions
In a jeweled stupa
In order to hear this sutra."
This is because Prabhutaratna is the embodiment of the Lotus Dharma itself. He is the "known," while Shakyamuni Buddha is the aforementioned "knower." By empowering written and spoken letters, the Buddhas have supplied us with the path required to take the same seat and realize supreme unity with true wisdom. Per the Mahavairocana Sutra:
“Lord of Mysteries, what is the mantra path of the Tathagatas? It is, namely, the empowering of these written letters. Lord of Mysteries, with the words of truth, the four noble truths, the four stations of mindfulness, the four supernatural faculties, the ten powers of a Tathagata, the six paramitas,the seven precious [limbs] of bodhi, the four Brahmic abodes, and the eighteen unshared qualities of a buddha that the Tathagatas have accumulated and cultivated during immeasurable hundreds of thousands of kotis of nayutas of eons...
Lord of Mysteries, in short, with the Tathagatas’ knowledge of an omniscient one, the power of the own-merit and knowledge of all the Tathagatas, the power of the knowledge of their own vows, and the power of the empowerment of the entire Dharma realm, and in conformity with the varieties of beings, they reveal the mantra teachings.”
Chapter 3: Secret Speech
So what does all of this mean in practical terms? It means that every “true speech” mantra, and even the syllables of said mantras, are imbued with complex dharmic significance that can potentially be gleaned from appropriate usage. This is why mantra is sometimes also referred to as “secret speech.”
A great example of this is the syllable "A," which is often associated with the cosmic Buddha Mahavairocana, whose form is made up of the 6 elements themselves. "A" is the origination point of all language. It is the first sound a baby is able to make immediately after leaving the womb, and thus can be said to represent not only all possible speech, but all possibilities in general within our world of transformation.
This doctrine is expounded by Mahavairocana Buddha himself within the Mahavairocana Sutra:
"The letter A is the essence of all mantras,
And from it there issue forth everywhere immeasurable mantras;
All frivolous arguments cease, and it is able to produce skillful wisdom.
Lord of Mysteries, why is [the letter A] the essence of all mantras?
The Buddha, honored among two-legged beings, has taught that the letter A is called the seed.
Therefore, everything is like this, [having the letter A as its seed,]and it rests in all the limbs;
Having allocated it as appropriate, bestow it everywhere in accordance with the rules.
Because that primordial letter (i.e., A) pervades the augmented letters,
The letters form sounds, and the limbs arise from this…”
The Shingon patriarch Kukai was very interested in this kind of memetic framework. In fact, it's said that his first significant experience in Buddhism was hearing a monk chanting the Akasagarbha Bodhisattva (Jpn: Kokuzo Bosatsu) mantra out in a forest.
Before the advent of Shingon and Tendai esoteric practices (or “Mikkyo”), esoteric Buddhism had filtered into Japan in a piecemeal fashion. A legend around Kukai tells of his encounter with Akasagarbha in a dream wherein the bodhisattva urged him to go to China to study the Mahavairocana Sutra.
And so he did. At the dawn of the 9th century, Kukai traveled to China and became a student of Vajrabodhi and Amoghajavra’s lineage. He was a genius, receiving a full transmission of that era's Chinese esoteric practices within only two years. The most notable of these were around the Womb Realm and Diamond Realm mandalas, which correspond to the Mahavairocana Sutra and Vajra Peak Sutra respectively.
After bringing everything back over to Japan and founding Shingon (or “true speech”) Buddhism, Kukai's continued fascination with mantra resulted in one of his more famous treatises: “The Meaning of the Word HUM,” in which he dissects the vast hidden. symbolism within a singular syllable.
This choice in syllable is not accidental, as HUM is one of the most important within the mantra framework. It is no exaggeration to say that this one character/syllable holds within it all of the Buddhist teachings I have been attempting to pass along with my writing.
HUM is described in the Mahavairocana Sutra as a “designation of a Buddha-Crown,” along with “OM,” “PHAT,” and “HRIH.” It’s worth noting that “OM” represents the mind of awakening and is sometimes associated with Vairocana, while “HRIH” is associated with Amida Buddha and his lotus family, which includes Avalokiteshvara (Jpn: Kannon Bosatsu).
HUM is in turn the seed character of the Buddha Akshobhya and in a greater sense represents the vajra family, which includes the legendary bestower of these teachings, namely the Lord of Mysteries Vajrasattva (Jon: Kongosatta Bosatsu), as well as the wrathful Wisdom King and subjugator of Mahesvara (Jpn: Daijizaiten) in the Vajra Peak sutra cycle Trailokyavijaya (Jpn: Gozanze Myo-o).
It also sometimes represents the extremely important Japanese esoteric figure Aizen Myo-o who, in the Shingon iconographical text Byakuhosho compiled by the monk Choen in 1284, was dubbed the “HUM-King.” Alternatively, Aizen is represented by the “double HUM” character, which is two “HUMs” combined into one. This is because Aizen is actually “HUM” in two parts, something I will get into more detail about later.
So what exactly does HUM mean? Thankfully we don’t have to do too much digging to figure this out, as we have Kukai’s treatise on the matter to reference as needed. According to Kukai, the Siddham script character for HUM is made up of four different parts that come from other characters: HA, A, U, and MA. These are all attributed superficial and hidden meanings.
The superficial meanings for these characters are as follows:
HA - “The letter Ha means ‘cause.’ In Sanskrit it is ‘hetu,’ which means ‘causal condition.’”
A - “... the sound A is contained in the letter Ha; it is, namely, the mother of all letters, the essence of all sounds, and the source of all reality.”
U - “… , the letter U signifies the diminution (Skt.: Una, ‘deficiency’) of all things. If one sees the letter U, then one realizes that all things are impermanent, entail suffering, are empty and without self, and so on.”
MA - “... as for the meaning of the letter Ma, in Sanskrit one says [a]tma[n], which is translated as ‘self.’ There are two kinds of self: 1) the self of people, and 2) the self of things.”
These are fairly easy to understand, as they’re all concepts discussed thoroughly within Buddhist literature. We have “causation,” “unborn source,” “transience,” and “self” (which is a doctrine refuted by Buddhism). The secret meanings are a bit more complicated, and require a certain understanding of esoteric doctrine to decode. Once again, however, we have Kukai’s work to help us out.
Let’s start with the letter A, for reasons that will be apparent soon. According to Kukai, the letter A “signifies ‘non-birth.’ If something comes into existence by taking hold of causes and conditions, then it does not have any [inherent] nature of its own. Therefore, it is deemed to be ‘empty.’”
Therefore, as the representative of the original unborn vajra body, “A” is used to reveal the true empty and undifferentiated nature of all things. In this way, it can be seen as a decoder for the hidden meanings of the other three letters. Kukai uses “causation” (represented by the letter HA) to illustrate this point. He explains further:
Again, ”the gateway of the letter A stands for the non-birth of all things”:[…] all speech throughout the three realms is dependent on words, and words are dependent on letters. Therefore, the Siddham (i.e., Sanskrit) letter A is also regarded as the mother of all letters. Know then that the true meaning of the gateway of the letter A is also like this, pervading the meaning of all things.
What is the reason for this? Among all things there are none that are not born of various conditions, and everything that is born of conditions has a beginning and an origin. Now, if one examines these generative conditions, [it is found that] they too are born of various causes and conditions, and if one follows these conditions one after another, which should one regard as their origin[al cause]? When one observes in this manner, one then realizes the ultimate state of original non-birth, which is the origin of the myriad things.
Just as one hears the sound A when one hears all speech, so one sees the ultimate state of original non-birth when one sees the birth of all things. If one sees the ultimate state of original non-birth, this is equivalent to knowing one’s own mind as it really is, and knowing one’s own mind as it really is corresponds to the wisdom of an omniscient one. Therefore, Vairocana has made this single letter his mantra.
The above passage directly references a line from the Mahavairocana Sutra, which reads as follows:
"World-honored One, just as, for example, the element of water is a delight for the support (i.e., bodies) of all beings, so too is the knowledge of an omniscient one a benefit and joy for gods and worldlings. World-honored One, what is the cause, what is the root, and what is the culmination of this knowledge?”
…”The bodhi-mind is its cause, compassion is its root,and expedient means is its culmination. Lord of Mysteries, what is bodhi? It means to know one’s mind as it really is."
This effectively summarizes the entire goal of Shingon Buddhism in three parts: wisdom, compassion, and skillful means (original cause, outcome, and ultimate practice). In this sense, the letter A is everything that esoteric Buddhism strives towards. It is supreme self-realization in a single sound.
Now that the real meanings for both the letters A and HA have been revealed, we move on to U. Kukai has this to say:
… the Dharma realm of the one mind is everlasting like the single void, and its wisdom, [like] dust motes in number, is originally existent like, for example, the Three Luminaries (i.e., sun, moon, and stars).
Even though Mount Sumeru may violate the Milky Way and a storied tower cleave the heavens, that [space] is not diminished thereby is an attribute of the great void; even though the flood [at the end] of the eon [of cosmic destruction] may set the earth adrift and the raging fire [at the end of the eon of cosmic destruction] may burn the palaces [of the gods], that [space] is not increased thereby is an attribute of the great void.
The empty space of the one mind is also like this: even though the ground of ignorance may have no bounds and self-pride, like Mount Sumeru, have no peak, the empty space of the one mind is from the beginning everlasting and is neither impaired nor decreased thereby. This is the real meaning of the letter U.
Essentially, the letter U takes on the attributes of Trailokyavijaya, the one who conquers the three worlds of desire, form, and formlessness. As the wrathful protector of the vajra family, Trailokyavijaya is intimately connected with Akshobhya and Vajrasattva, and therefore the syllable HUM as well.
Through his subjugation of the realms of the gods, he illustrates the stainless indestructible nature of the Buddha’s pure dharma realm pitted against the impure and empty realms of transformation. I discussed this in the sixth chapter of my work “The Diamond Sword”:
Like the Buddha Prabhutaratna in the Lotus Sutra waiting silently and patiently under the earth for thousands of years before springing forth at just the right time, the wonderful dharma will remain hidden under the mud and mire, waiting for the right opportunity to bloom forth beautifully once again…
This process is represented by figures like Trailokyavijaya and Heruka. Wicked beings in ages ruled by Mara will inevitably be punished and ruined by the winds of karma, yet the universal truths of the dharma will always remain pure and unscathed, waiting to be discovered by those in touch with their intrinsic Buddha-nature. Trailokyavijaya and Heruka can be seen as the fires that rage at the end and beginning of all things, never truly extinguishing even for a moment.
Even through the most evil of ages, the eternal cosmic Buddha’s work continues ever onward, never tiring for even a moment. This is why, in the wrathful form of Trailokyavijaya, Mahavairocana Buddha is called the “Conqueror of the Three Worlds.”
Via the letter A, we see the indestructible nature of the unborn origin of all things, inverting the superficial meaning of the letter U and revealing its true esoteric profundity. Per Kukai: “Because all things (dharmas) are originally unborn, the gateway of the letter U stands for non-diminution…”
This leaves us finally with the letter MA. As you may recall, the superficial meaning of MA is “atman” or “self,” either of a “person” or a “thing.” We can once again combine this with the emptiness shown by the letter A to reveal its pure essence. Kukai explains:
“Person” means the fourfold Dharma body, and “thing” (dharma) means all things, ranging from one Dharma realm, one thusness, and one bodhi to eighty-four thousand things indescribably [numerous] like minute dust motes in number.
These fourfold Dharma bodies are immeasurable in their number, but their essence is of one form and one flavor, and there is no this or that. There being no this or that, how can there be a self?
With the “self” doctrine inverted, the hidden meaning of MA is finally revealed in full. “MA” is Mahavairocana and his myriad of transformations via the samaya body of the six elements. There is ultimately one “self” (Mahavairocana) of one “flavor”: the flavor of the dharma realm.
All of this is contained within the single syllable HUM, and therefore embodied by Akshobhya Buddha himself. Akshobhya represents the “mirror knowledge” of the tathagatas, meaning he reveals us and the world around us for what these things truly are, and he holds the vajra because it is the tool used to destroy illusions of discrimination.
With the mighty vajra, Akshobhya’s vajra family descends like lightning. They cut off all craving with diamond blades and destroy the impure world of transformation to reveal Mahavairocana’s great mandala of the dharma realm hiding underneath. This is what is meant by HUM.
Aizen Myo-o, a member of the vajra family himself, is “HUM” in two parts, because he is made up of both “Aizen” and “Zenai.” Zenai is the vajra or, in the case of the word HUM, he is the letter A. Aizen is the rest of the letters held within HUM, i.e. the impure world of the “self” and of empty transient things.
When Zenai, embodying the self-realized mind of enlightenment, combines with Aizen, he reveals the purified dharma realm in the form of the wrathful yet eternally compassionate Wisdom King Aizen Myo-o. The two halves each say the mantra “HUM,” resulting in the symbol of the “double HUM.”
The double HUM can also be interpreted as the combination of HUM and KHAM, the seed syllable for Fudo Myo-o (Acala). Fudo is the head of the Wisdom Kings and, while he wields a vajra blad, transcends the Buddha families as a guardian to all mandalas. Kukai describes him like this:
This deity is the patriarch of all Buddhas throughout the three ages and ten directions, and he is honored by all bodhisattvas in the forty-two stages. Nonetheless he assumes the form of a messenger with a squint eye, appears as a servant with a queue hanging down [over his left shoulder], stoops down from the honorable position that he has already attained, and feeds on the leftover scraps of novices. This means that although he is high[-ranking], he does not vaunt himself, and although he harms himself, he attracts surfeit.
There exists a two-headed form of Aizen Myo-o in combination with Fudo Myo-o. Fudo shares a title with Akshobhya: The Immovable One. They both embody the true nature of the unborn eternal Buddha in their unflinching, unwavering steadfastness, and Fudo is even considered a wrathful form of Akshobhya in some Vajrayana schools. The combination of Fudo with Aizen strikes through the passions with the vajra blade and summons forth Mahavairocana’s palace of eternal light while raining down compassion.
This combination can also help illustrate that Aizen Myo-o is not separate from Akshobhya, but can be said to represent the active elements of Akshobhya’s wisdom working within the world of transformation. He is Akshobhya’s retinue combined into one wrathful form of Vajrasattva who wields the passions as expedient means.
Taking Akshobhya Buddha and Aizen Myo-o as a pair constitutes the Middle Path of the bodhisattva between emptiness and transformation (the uncompounded and compounded), and the trio of Akshobhya, Vajrasattva, and Aizen Myo-o forms a triple-ring in the same way Amida Buddha, Majusri (Jpn: Monju Bosatsu), and Yamantaka (Jpn: Daiitoku Myo-o) do.
Supreme compassion with the manifested appearance of blood covers Aizen Myo-o’s originally pure white skin, staining him red and invoking the eternally compassionate vajra family of Amida Buddha. This is why one of Aizen Myo-o’s other seed characters is the HRIH of the lotus family. All of this ends in the skillful means of Buddhist practice, effectively completing the Shingon trinity.
This is HUM.
HUM is the sound that startles us awake from the dream.
HUM is the vajra that brings down enlightenment like lightning.
HUM is the eradication of notions of self.
HUM is the diamond mind that summons forth compassion.
HUM is both strength and gentleness working in tandem.
HUM is the dismantling of all the wrong views of the philosophers.
HUM is the blazing flame-like energy of the Wisdom Kings.
HUM is the crashing waves on the ocean of the collective consciousness.
HUM is the floods and fires at the end of all things, razing the world of illusion for good.
HUM is the great bliss of ultimate wisdom.
However, HUM only forms one part of Akshobhya’s full mantra, which consists of three words: OM AKSHOBHYA HUM. Next we will dive into what these words mean in combination with each other.
As always, thank you for reading, and I hope to see you in Part 2.
Sources cited:
https://www.bdkamerica.org/product/shingon-texts/
https://www.bdkamerica.org/product/the-lotus-sutra-revised-second-edition/
https://www.bdkamerica.org/product/the-vairocanabhisambodhi-sutra/