Supriya Ghosh (Editor)

Vajrayana

Updated on
Edit
Like
Comment
Share on FacebookTweet on TwitterShare on LinkedInShare on Reddit

Vajrayāna, Mantrayāna, Esoteric Buddhism and Tantric Buddhism refer to the Buddhist tradition of Tantra, an esoteric system of beliefs and practices that developed in medieval India.

Contents

Vajrayāna is usually translated as Diamond Vehicle or Thunderbolt Vehicle, referring to the Vajra, a mythical weapon which is also used as a ritual implement.

According to Vajrayāna scriptures, the term Vajrayāna refers to one of three vehicles or routes to enlightenment, the other two being the Śrāvakayāna (also known as the Hīnayāna) and Mahāyāna.

Founded by Indian Mahāsiddhas, Vajrayāna subscribes to the literature known as the Buddhist Tantras.

Siddha movement

Elements of Tantric Buddhism can be traced back to groups of wandering yogis called mahasiddhas (great adepts). According to Reynolds (2007), the mahasiddhas date to the medieval period in North India (3–13 cen. CE), and used methods that were radically different than those used in Buddhist monasteries including living in forests and caves and practiced meditation in charnel grounds similar to those practiced by Shaiva Kapalika ascetics. These yogic circles came together in tantric feasts (ganachakra) often in sacred sites (pitha) and places (ksetra) which included dancing, singing, sex rites and the ingestion of taboo substances like alcohol, urine, meat, etc. It is interesting to note that at least two of the Mahasiddhas given in the Buddhist literature are actually names for Shaiva Nath saints (Gorakshanath and Matsyendranath) who practiced Hatha Yoga.

According to Schumann, a movement called Sahaja-siddhi developed in the 8th century in Bengal. It was dominated by long-haired, wandering yogis called mahasiddhas who openly challenged and ridiculed the Buddhist establishment. The Mahasiddhas pursued siddhis, magical powers such as flight and Extrasensory perception as well as liberation.

Tantras

Earlier Mahayana sutras already contained some elements which are emphasized in the Tantras, such as mantras and dharani. The practice of visualization of Buddhas such as Amitabha is also seen in pre-tantra texts like the Longer Sukhāvatīvyūha Sūtra.

Vajrayana developed a large corpus of texts called the Buddhist Tantras, some of which can be traced to at least the 7th century CE but might be older. The dating of the tantras is "a difficult, indeed an impossible task" according to David Snellgrove. The earliest such texts possibly include the Mahavairocana Tantra and the Guhyasamāja Tantra. They feature new deities and bodhisattvas and new forms of ritual practice such as mantras and some propagate "left-hand" (vamachara) practices such as the use taboo substances like alcohol, sexual rituals, and charnel ground practices which evocate fierce deities. Indeed, Ryujun Tajima divides the tantras into those which were "a development of Mahayanist thought" and those "formed in a rather popular mould toward the end of the eighth century and declining into the esoterism of the left", mainly, the Yogini tantras and later works associated with wandering antinomian yogis. Later monastic Vajrayana Buddhists reinterpreted and internalized these radically transgressive and taboo practices as metaphors and visualization exercises.

According to Ronald M. Davidson, the rise of Tantric Buddhism was a response to the feudal structure of Indian society in the early medieval period (ca. 500-1200 CE) which saw kings being divinized as manifestations of gods. Likewise, tantric yogis reconfigured their practice through the metaphor of being consecrated (abhiśeka) as the overlord (rājādhirāja) of a mandala palace of divine vassals, an imperial metaphor symbolizing kingly fortresses and their political power.

The Kalachakra tantra developed in the 10th century. It is farthest removed from the earlier Buddhist traditions, and incorporates concepts of messianism and astrology not present elsewhere in Buddhist literature.

Influence of Saivism

Various classes of Vajrayana literature developed as a result of royal courts sponsoring both Buddhism and Saivism. The Mañjusrimulakalpa, which later came to be classified under Kriyatantra, states that mantras taught in the Shaiva, Garuda and Vaishnava tantras will be effective if applied by Buddhists since they were all taught originally by Manjushri.

According to Alexis Sanderson, the Vajrayana Yogini-tantras draw extensively from Shaiva Bhairava tantras classified as Vidyapitha. A comparison of them shows similarity in "ritual procedures, style of observance, deities, mantras, mandalas, ritual dress, Kapalika accoutrements, specialized terminology, secret gestures, and secret jargons. There is even direct borrowing of passages from Saiva texts."

The Guhyasiddhi of Padmavajra, a work associated with the Guhyasamaja tradition, prescribes acting as a Shaiva guru and initiating members into Saiva Siddhanta scriptures and mandalas. The Samvara tantra texts adopted the pitha list from the Shaiva text Tantrasadbhava, introducing a copying error where a deity was mistaken for a place.

Philosophical background

According to Louis de La Vallée-Poussin and Alex Wayman, the view of the Vajrayana is based on Mahayana Buddhist philosophy, mainly the Madhyamaka and Yogacara schools. The major difference seen by Vajrayana thinkers is Tantra's superiority due to being a faster vehicle to liberation containing many skillful methods (upaya) of tantric ritual.

The doctrine of Buddha-nature, as outlined in the Ratnagotravibhāga of Asanga, was also an important theory which became the basis for Tantric views. The fundamental theory of Tantric practice is that of transformation and is outlined in the following quote from the Hevajra tantra:

Those things by which evil men are bound, others turn into means and gain thereby release from the bonds of existence. By passion the world is bound, by passion too it is released, but by heretical Buddhists this practice of reversals is not known.

As Snellgrove (1987) notes, this doctrine is also already present in Asanga's Mahayana-sutra-alamkara-karika and therefore it is possible that he was aware of Tantric techniques, including sexual yoga.

Indian Tantric Buddhist philosophers such as Buddhaguhya, Vimalamitra and Ratnākaraśānti continued the tradition of Buddhist philosophy and adapted it to their tantric commentary. After monks such as Vajrabodhi and Śubhakarasiṃha brought Tantra to Tang China (716 to 720), tantric philosophy continued to be developed in Chinese and Japanese by thinkers such as Yi Xing and Kūkai.

Likewise in Tibet, Sakya Pandita (1182-28 - 1251), as well as later thinkers like Longchenpa (1308–1364) expanded on these philosophies in their Tantric commentaries and treatises. The status of the tantric view continued to be debated in medieval Tibet. Tibetan Buddhist Rongzom Chokyi Zangpo (1012–1088) held that the views of sutra such as Madhyamaka were inferior to that of tantra, as Koppl notes:

By now we have seen that Rongzom regards the views of the Sutrayana as inferior to those of Mantra, and he underscores his commitment to the purity of all phenomena by criticizing the Madhyamaka objectification of the authentic relative truth.

Tsongkhapa (1357–1419) on the other hand, held that there is no difference between Vajrayana and other forms of Mahayana in terms of prajnaparamita (perfection of insight) itself, only that Vajrayana is a method which works faster.

Place within Buddhist tradition

Various classifications are possible when distinguishing Vajrayana from the other Buddhist traditions. Vajrayana can be seen as a third yana, next to Hinayana and Mahayana. Vajrayana can be distinguished from the Sutrayana. The Sutrayana is the method of perfecting good qualities, where the Vajrayāna is the method of taking the intended outcome of Buddhahood as the path. Vajrayana, belonging to the mantrayana, can also be distinguished from the paramitayana. According to this schema, Indian Mahayana revealed two vehicles (yana) or methods for attaining enlightenment: the method of the perfections (Paramitayana) and the method of mantra (Mantrayana). The Paramitayana consists of the six or ten paramitas, of which the scriptures say that it takes three incalculable aeons to lead one to Buddhahood. The tantra literature, however, claims that the Mantrayana leads one to Buddhahood in a single lifetime. According to the literature, the mantra is an easy path without the difficulties innate to the Paramitayana. Mantrayana is sometimes portrayed as a method for those of inferior abilities. However the practitioner of the mantra still has to adhere to the vows of the Bodhisattva.

Goal

The goal of spiritual practice within the Mahayana and Vajrayana traditions is to become a Sammāsambuddha (fully awakened Buddha), those on this path are termed Bodhisattvas. As with the Mahayana, motivation is a vital component of Vajrayana practice. The Bodhisattva-path is an integral part of the Vajrayana, which teaches that all practices are to be undertaken with the motivation to achieve Buddhahood for the benefit of all sentient beings.

In the Sutrayana practice, a path of Mahayana, the "path of the cause" is taken, whereby a practitioner starts with his or her potential Buddha-nature and nurtures it to produce the fruit of Buddhahood. In the Vajrayana the "path of the fruit" is taken whereby the practitioner takes his or her innate Buddha-nature as the means of practice. The premise is that since we innately have an enlightened mind, practicing seeing the world in terms of ultimate truth can help us to attain our full Buddha-nature.

Experiencing ultimate truth is said to be the purpose of all the various tantric techniques practiced in the Vajrayana. Apart from the advanced meditation practices such as Mahamudra and Dzogchen, which aim to experience śūnyatā, the empty nature of the enlightened mind that can see ultimate truth, all practices are aimed in some way at purifying the impure perception of the practitioner to allow ultimate truth to be seen. These may be ngöndro "preliminary practices" or the more advanced techniques of the tantric sādhanā.

Esoteric transmission

Vajrayana Buddhism is esoteric in the sense that the transmission of certain teachings only occurs directly from teacher to student during an empowerment and cannot be simply learned from a book. Many techniques are also commonly said to be secret, but some Vajrayana teachers have responded that secrecy itself is not important and only a side-effect of the reality that the techniques have no validity outside the teacher-student lineage. In order to engage in Vajrayana practice, a student should have received such an initiation or permission:

If these techniques are not practiced properly, practitioners may harm themselves physically and mentally. In order to avoid these dangers, the practice is kept "secret" outside the teacher/student relationship. Secrecy and the commitment of the student to the vajra guru are aspects of the samaya (Tib. damtsig), or "sacred bond", that protects both the practitioner and the integrity of the teachings."

The teachings may also be considered "self-secret", meaning that even if they were to be told directly to a person, that person would not necessarily understand the teachings without proper context. In this way the teachings are "secret" to the minds of those who are not following the path with more than a simple sense of curiosity.

Vows and behaviour

Practitioners of the Vajrayana need to abide by various tantric vows or samaya of behaviour. These are extensions of the rules of the Prātimokṣa and Bodhisattva vows for the lower levels of tantra, and are taken during initiations into the empowerment for a particular Anuttarayoga Tantra. The special tantric vows vary depending on the specific mandala practice for which the initiation is received, and also depending on the level of initiation. Ngagpas of the Nyingma school keep a special non-celibate ordination.

A tantric guru, or teacher, is expected to keep his or her samaya vows in the same way as his students. Proper conduct is considered especially necessary for a qualified Vajrayana guru. For example, the Ornament for the Essence of Manjushrikirti states:

Distance yourself from Vajra Masters who are not keeping the three vows

who keep on with a root downfall, who are miserly with the Dharma,
and who engage in actions that should be forsaken.
Those who worship them go to hell and so on as a result.

Tantra techniques

While Vajrayana includes all of the traditional practices used in Mahayana Buddhism such as meditation and the paramitas, it also includes a number of unique practices which are seen as more advanced and effective. One of these practices is meditation on a yidam, or personal deity, which involves the recitation of mantras, prayers and visualization of the deity along with the associated mandala with consorts and attendants. Another form of Vajrayana practice are certain meditative techniques associated with Mahamudra and Dzogchen. In Japanese Shingon, meditative ritual use of mantra, mudra and visualization, known as "The Three Mysteries" is central to tantric practice.

An important element of these advanced practices is the need for ritual initiation, termed empowerment (Sanskrit: abhiseka, Tibetan: wang) by a guru. They are traditionally preceded by the practice of "preliminaries" (ngondro) which are meant as preparation.

The Vajrayana is based on the concept of "skillful means" (Sanskrit: upaya) as formulated in Mahayana Buddhism. It is a system of lineages, whereby those who successfully receive an empowerment or sometimes called initiation (permission to practice) are seen to share in the mindstream of the realisation of a particular skillful means of the vajra Master. In the Vajrayana these skilful means mainly relate to tantric, Mahamudra or Dzogchen practices. Vajrayana teaches that the Vajrayana techniques provide an accelerated path to enlightenment which is faster than other paths.

Another distinctive feature of Vajrayana Buddhism is its unique rituals, which are used as a substitute or alternative for the earlier abstract meditations. They include death rituals (see phowa), tantric feasts (ganachakra) and Chöd, in which the yogi ceremonially offers their body to be eaten by tantric deities.

Symbols and imagery

The Vajrayana uses a rich variety of symbols and images.

The Vajra

The Sanskrit term "vajra" denoted the thunderbolt, a legendary weapon and divine attribute that was made from an adamantine, or indestructible, substance and which could therefore pierce and penetrate any obstacle or obfuscation. It is the weapon of choice of Indra, the King of the Devas in Hinduism. As a secondary meaning, "vajra" refers to this indestructible substance, and so is sometimes translated as "adamantine" or "diamond". So the Vajrayana is sometimes rendered in English as "The Adamantine Vehicle" or "The Diamond Vehicle".

A vajra is also a scepter-like ritual object (Standard Tibetan: རྡོ་རྗེ་ dorje), which has a sphere (and sometimes a gankyil) at its centre, and a variable number of spokes, 3, 5 or 9 at each end (depending on the sadhana), enfolding either end of the rod. The vajra is often traditionally employed in tantric rituals in combination with the bell or ghanta; symbolically, the vajra may represent method as well as great bliss and the bell stands for wisdom, specifically the wisdom realizing emptiness.

Imagery and ritual in deity yoga

Representations of the deity, such as statues (murti), paintings (thangka), or mandala, are often employed as an aid to visualization, in Deity yoga. Mandalas are sacred enclosures, sacred architecture that house and contain the uncontainable essence of a yidam. In the book The World of Tibetan Buddhism, the Dalai Lama describes mandalas thus: "This is the celestial mansion, the pure residence of the deity."

All ritual in Vajrayana practice can be seen as aiding in this process of visualization and identification. The practitioner can use various hand implements such as a vajra, bell, hand-drum (damaru) or a ritual dagger (phurba), but also ritual hand gestures (mudras) can be made, special chanting techniques can be used, and in elaborate offering rituals or initiations, many more ritual implements and tools are used, each with an elaborate symbolic meaning to create a special environment for practice. Vajrayana has thus become a major inspiration in traditional Tibetan art.

Vajrayana textual tradition

The Vajrayana tradition has developed an extended body of texts:

Though we do not know precisely at present just how many Indian tantric Buddhist texts survive today in the language in which they were written, their number is certainly over one thousand five hundred; I suspect indeed over two thousand. A large part of this body of texts has also been translated into Tibetan, and a smaller part into Chinese. Aside from these, there are perhaps another two thousand or more works that are known today only from such translations. We can be certain as well that many others are lost to us forever, in whatever form. Of the texts that survive a very small proportion has been published; an almost insignificant percentage has been edited or translated reliably.

Literary characteristics

Vajrayana texts exhibit a wide range of literary characteristics—usually a mix of verse and prose, almost always in a Sanskrit that "transgresses frequently against classical norms of grammar and usage," although also occasionally in various Middle Indic dialects or elegant classical Sanskrit.

Dunhuang manuscripts

The Dunhuang manuscripts also contain Tibetan Tantric manuscripts. Dalton and Schaik (2007, revised) provide an excellent online catalogue listing 350 Tibetan Tantric Manuscripts] from Dunhuang in the Stein Collection of the British Library which is currently fully accessible online in discrete digitized manuscripts. With the Wylie transcription of the manuscripts they are to be made discoverable online in the future. These 350 texts are just a small portion of the vast cache of the Dunhuang manuscripts.

Schools of Vajrayana

Although there is historical evidence for Vajrayana Buddhism in Southeast Asia and elsewhere (see History of Vajrayana above), today the Vajrayana exists primarily in the form of the two major traditions of Tibetan Buddhism and Japanese Esoteric Buddhism in Japan known as Shingon (literally "True Speech", i.e. mantra), with a handful of minor subschools utilising lesser amounts of esoteric or tantric materials.

The distinction between traditions is not always rigid. For example, the tantra sections of the Tibetan Buddhist canon of texts sometimes include material not usually thought of as tantric outside the Tibetan Buddhist tradition, such as the Heart Sutra and even versions of some material found in the Pali Canon.

Tibetan Buddhism

The Tibetan Buddhist schools, based on the lineages and textual traditions of the Kangyur and Tengyur of Tibet, are found in Tibet, Bhutan, northern India, Nepal, southwestern and northern China, Mongolia and various constituent republics of Russia that are adjacent to the area, such as Amur Oblast, Buryatia, Chita Oblast, the Tuva Republic and Khabarovsk Krai. Tibetan Buddhism is also the main religion in Kalmykia.

Vajrayana Buddhism was established in Tibet in the 8th century when Śāntarakṣita was brought to Tibet from India at the instigation of the Dharma King Trisong Detsen, some time before 767.

Nepalese Newar Buddhism

Newar Buddhism is practiced by Newars in Nepal. This is the only form of Vajrayana Buddhism in which the scriptures are written in Sanskrit. Its priests do not follow celibacy and are called vajracharya (literally "diamond-thunderbolt carriers").

Tantric Theravada

Tantric Theravada or "Esoteric Southern Buddhism" is a term for Vajrayana from Southeast Asia, where Theravada Buddhism is dominant. The monks of the Sri Lankan, Abhayagiri vihara once practiced forms of Vajrayana which were popular in the island. Another tradition of this type was Ari Buddhism, which was common in Burma. The Tantric Buddhist 'Yogāvacara' tradition was a major Buddhist tradition in Cambodia, Laos and Thailand well into the modern era. This form of Buddhism declined after the rise of Southeast Asian Buddhist modernism.

Bai Azhaliism

Azhaliism (Chinese: 阿吒力教 Āzhālìjiào) is an Esoteric Buddhist religion practiced among the Bai people of China.

Chinese Esoteric Buddhism

Esoteric teachings followed the same route into northern China as Buddhism itself, arriving via the Silk Road sometime during the first half of the 7th century, during the Tang dynasty, just as Buddhism was reaching its zenith in China, and received sanction from the emperors of the Tang dynasty. During this time, three great masters came from India to China: Śubhakarasiṃha, Vajrabodhi, and Amoghavajra. These three masters brought the esoteric teachings to their height of popularity in China. During this era, the two main source texts were the Mahāvairocana Abhisaṃbodhi Tantra, and the Tattvasaṃgraha Tantra. Traditions in the Sinosphere still exist for these teachings, and they more or less share the same doctrines as Shingon, with many of its students themselves traveling to Japan to be given transmission at Mount Koya.

Esoteric methods were naturally incorporated into Chinese Buddhism during the Tang dynasty. Śubhakarasiṃha's most eminent disciple, Master Yixing (Ch. 一行), was a member of the Chán school. In such a way, in Chinese Buddhism there was no major distinction between exoteric and esoteric practices, and the northern school of Chán Buddhism even became known for its esoteric practices of dhāraṇīs and mantras.

The practice of Tantric Buddhism in Western Xia led to the spread of some sexually related customs. Before they could get married to men of their own ethnicity when they reached 30 years old, Uighur women in Shanxi in the 12th century had children after having sex with multiple Han Chinese men, with her desirability as a wife corresponding to if she had been with a large number of men.

During the Yuan dynasty, the Mongol emperors made Esoteric Buddhism the official religion of China, and Tibetan lamas were given patronage at the court. A common perception was that this patronage of lamas caused corrupt forms of tantra to become widespread. When the Mongol Yuan dynasty was overthrown and the Ming dynasty was established, the Tibetan lamas were expelled from the court, and this form of Buddhism was denounced as not being an orthodox path.

In late imperial China, the early traditions of Esoteric Buddhism were still thriving in Buddhist communities. Robert Gimello has also observed that in these communities, the esoteric practices associated with Cundī were extremely popular among both the populace and the elite.

In China and countries with large Chinese populations such as Taiwan, Malaysia, and Singapore, Esoteric Buddhism is most commonly referred to with the Chinese term Mìzōng (密宗), literally "Esoteric Tradition" or "Mystery Tradition". Traditions of specifically Chinese Esoteric Buddhism are most commonly referred to as Tángmì (唐密), "Tang Esotericism" or "Tang Mysteries", or Hànchuán Mìzōng (漢傳密宗), "Han Transmission of the Esoteric Tradition" (Hànmì 漢密, "Han Mysteries", for short), or even Dōngmì (東密), "Eastern Esotericism" or "Eastern Mysteries", separating itself from Tibetan and Newar traditions. These schools more or less share the same doctrines as Shingon. There is an ongoing revival of Tangmi or Hanmi in contemporary China.

Shingon Buddhism

The Shingon school is found in Japan and includes practices, known in Japan as Mikkyō ("Esoteric (or Mystery) Teaching"), which are similar in concept to those in Vajrayana Buddhism. The lineage for Shingon Buddhism differs from that of Tibetan Vajrayana, having emerged from India during the 9th-11th centuries in the Pala Dynasty and Central Asia (via China) and is based on earlier versions of the Indian texts than the Tibetan lineage. Shingon shares material with Tibetan Buddhism–-such as the esoteric sutras (called Tantras in Tibetan Buddhism) and mandalas – but the actual practices are not related. The primary texts of Shingon Buddhism are the Mahavairocana Sutra and Vajrasekhara Sutra. The founder of Shingon Buddhism was Kukai, a Japanese monk who studied in China in the 9th century during the Tang dynasty and brought back Vajrayana scriptures, techniques and mandalas then popular in China. The school mostly died out or was merged into other schools in China towards the end of the Tang dynasty but flourished in Japan. Shingon is one of the few remaining branches of Buddhism in the world that continues to use the siddham script of the Sanskrit language.

Tendai Buddhism

Although the Tendai school in China and Japan does employ some esoteric practices, these rituals came to be considered of equal importance with the exoteric teachings of the Lotus Sutra. By chanting mantras, maintaining mudras, or practicing certain forms of meditation, Tendai maintains that one is able to understand sense experiences as taught by the Buddha, have faith that one is innately an enlightened being, and that one can attain enlightenment within the current lifetime.

Shugendō

Shugendō was founded in 7th century Japan by the ascetic En no Gyōja, based on the Queen's Peacocks Sutra. With its origins in the solitary hijiri back in the 7th century, Shugendō evolved as a sort of amalgamation between Esoteric Buddhism, Shinto and several other religious influences including Taoism. Buddhism and Shinto were amalgamated in the shinbutsu shūgō, and Kūkai's syncretic religion held wide sway up until the end of the Edo period, coexisting with Shinto elements within Shugendō

In 1613 during the Edo period, the Tokugawa Shogunate issued a regulation obliging Shugendō temples to belong to either Shingon or Tendai temples. During the Meiji Restoration, when Shinto was declared an independent state religion separate from Buddhism, Shugendō was banned as a superstition not fit for a new, enlightened Japan. Some Shugendō temples converted themselves into various officially approved Shintō denominations. In modern times, Shugendō is practiced mainly by Tendai and Shingon sects, retaining an influence on modern Japanese religion and culture.

Academic study difficulties

Serious Vajrayana academic study in the Western world is in early stages due to the following obstacles:

  1. Although a large number of Tantric scriptures are extant, they have not been formally ordered or systematized.
  2. Due to the esoteric initiatory nature of the tradition, many practitioners will not divulge information or sources of their information.
  3. As with many different subjects, it must be studied in context and with a long history spanning many different cultures.
  4. Ritual as well as doctrine need to be investigated.

Buddhist tantric practice are categorized as secret practice; this is to avoid misinformed people from harmfully misusing the practices. A method to keep this secrecy is that tantric initiation is required from a master before any instructions can be received about the actual practice. During the initiation procedure in the highest class of tantra (such as the Kalachakra), students must take the tantric vows which commit them to such secrecy. "Explaining general tantra theory in a scholarly manner, not sufficient for practice, is likewise not a root downfall. Nevertheless, it weakens the effectiveness of our tantric practice."

Terminology

The terminology associated with Vajrayana Buddhism can be confusing. Most of the terms originated in the Sanskrit language of tantric Indian Buddhism and may have passed through other cultures, notably those of Japan and Tibet, before translation for the modern reader. Further complications arise as seemingly equivalent terms can have subtle variations in use and meaning according to context, the time and place of use. A third problem is that the Vajrayana texts employ the tantric tradition of twilight language, a means of instruction that is deliberately coded. These obscure teaching methods relying on symbolism as well as synonym, metaphor and word association add to the difficulties faced by those attempting to understand Vajrayana Buddhism:

In the Vajrayana tradition, now preserved mainly in Tibetan lineages, it has long been recognized that certain important teachings are expressed in a form of secret symbolic language known as saṃdhyā-bhāṣā, 'Twilight Language'. Mudrās and mantras, maṇḍalas and cakras, those mysterious devices and diagrams that were so much in vogue in the pseudo-Buddhist hippie culture of the 1960s, were all examples of Twilight Language [...]

The term Tantric Buddhism was not one originally used by those who practiced it. As scholar Isabelle Onians explains:

"Tantric Buddhism" [...] is not the transcription of a native term, but a rather modern coinage, if not totally occidental. For the equivalent Sanskrit tāntrika is found, but not in Buddhist texts. Tāntrika is a term denoting someone who follows the teachings of scriptures known as Tantras, but only in Saivism, not Buddhism [...] Tantric Buddhism is a name for a phenomenon which calls itself, in Sanskrit, Mantranaya, Vajrayāna, Mantrayāna or Mantramahāyāna (and apparently never Tantrayāna). Its practitioners are known as mantrins, yogis, or sādhakas. Thus, our use of the anglicised adjective “Tantric” for the Buddhist religion taught in Tantras is not native to the tradition, but is a borrowed term which serves its purpose.

References

Vajrayana Wikipedia