Vajrayana

Vajrayāna, otherwise known as Mantrayāna, Guhyamantrayāna, Tantrayāna, Indo-Tibetan Buddhism, Tantric Buddhism, and Esoteric Buddhism, is a vehicle in the Mahāyāna Buddhist tradition that emphasizes esoteric practices and rituals aimed at rapid spiritual awakening. Emerging between the 5th and 7th centuries CE in medieval India and present-day Pakistan, Vajrayāna Buddhism incorporates a range of techniques, including the use of mantras, dhāraṇīs, mudrās, mandalās, and the visualization of deities and Buddhas. These practices are designed to transform ordinary experiences into spiritual paths toward enlightenment and liberation, often by engaging with aspects of desire and aversion in a ritualized context.
A distinctive feature of Vajrayāna Buddhism is its emphasis on esoteric transmission, where teachings are passed directly from teacher to student through initiation ceremonies. Tradition asserts that these teachings have been passed down through an unbroken lineage going back to the historical Buddha, sometimes via other Buddhas or bodhisattvas. This lineage-based transmission ensures the preservation of the purity and effectiveness of the teachings. Practitioners often engage in deity yoga, a meditative practice where one visualizes oneself as a deity embodying enlightened qualities to transform one's perception of reality. The tradition also acknowledges the role of feminine energy, venerating female Buddhas and ḍākiṇīs, and sometimes incorporates practices that challenge conventional norms to transcend dualistic thinking.
Vajrayāna has given rise to various sub-traditions across Asia. In Tibet, it evolved into Tibetan Buddhism, which became the dominant spiritual tradition, integrating local beliefs and practices. In Japan, it influenced Shingon Buddhism, established by Kūkai, emphasizing the use of mantras and rituals. Chinese Esoteric Buddhism also emerged, blending Vajrayāna practices with existing Chinese Buddhist traditions, however this is no longer a separate sect and has mostly mixed in with normal exoteric Buddhism. Each of these traditions adapted Vajrayāna principles to its cultural context while maintaining core esoteric practices aimed at achieving enlightenment.
Central to Vajrayāna symbolism is the vajra, a ritual implement representing indestructibility and irresistible force, embodying the union of transcendental wisdom and compassion. Practitioners often use the vajra in conjunction with a bell during rituals, symbolizing the integration of male and female principles. The tradition also employs rich visual imagery, including mudrās, complex mandalās, and depictions of wrathful deities that serve as meditation aids to help practitioners internalize spiritual concepts and confront inner obstacles on the path to enlightenment.

Terminology

In medieval India, the initial terms that were used to refer to the tantric Buddhist tradition were Mantranāya and Mantrayāna. Later, other terms were adopted, like Vajrayāna.
In Tibetan Buddhism practiced in the Himalayan regions of India, Nepal, Tibet, and Bhutan, Buddhist Tantra is most often termed Vajrayāna and Secret mantra. The vajra is a mythical weapon associated with Indra that was said to be indestructible and unbreakable and extremely powerful. Thus, the term is variously translated as Diamond Vehicle, Thunderbolt Vehicle, Indestructible Vehicle, and so on.

The vajra, or diamond, is an adamantine symbol. A diamond has two qualities: it has the power to shatter all ordinary stones, and conversely, no stone can break a diamond. The actual vajra is the mind that has the realization of the ultimate truth inseparably merged with a special kind of tantric bliss. That is why the vajra, or diamond, is the symbol of the tantric path and its result: the wisdom of nondual emptiness and bliss.

In Chinese Esoteric Buddhism, it is generally known by terms such as Zhēnyán, Tángmì or Hanmì '', Mìzōng, or Mìjiao. The Chinese term mì 密 is a translation of the Sanskrit term Guhya''.
In Japan, Buddhist esotericism is known as or by the term Shingon, which also refers to a specific school of 2=真言宗.
The term "Esoteric Buddhism" is first used by Western occultist writers, such as Helena Blavatsky and Alfred Percy Sinnett, to describe theosophical doctrines passed down from "supposedly initiated Buddhist masters."

Origins

According to David B. Gray, Vajrayana originated from pre-existing Tantric traditions, also known as 'Tantrism', which emerged within Hinduism during the first millennium CE. These early Hindu tantric practices had a profound influence on South Asian Mahāyāna Buddhism, leading to the development of distinct Buddhist tantric traditions, which arose in the 7th century CE, rapidly spread across Southeast, East, and Central Asia, giving rise to distinct traditions in East Asia and Tibet.

History

Mahasiddhas and the tantric movement

Tantric Buddhism is associated with groups of wandering yogis called mahasiddhas in medieval India. According to Robert Thurman, these tantric figures thrived during the latter half of the first millennium CE. According to John Myrdhin Reynolds, the mahasiddhas date to the medieval period in North India and used methods radically different from those used in Buddhist monasteries, including practicing on charnel grounds.
Since Tantra focuses on the transformation of poisons into wisdom, the yogic circles came together in tantric feasts, often in sacred sites and places, which included dancing, singing, consort practices, and the ingestion of taboo substances like alcohol, urine, and meat. At least two of the mahasiddhas cited in the Buddhist literature are comparable with the Shaiva Nath saints 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 mahasiddhas who openly challenged and ridiculed the Buddhist establishment. The mahasiddhas pursued siddhis, magical powers such as flight and extrasensory perception as well as spiritual liberation.

Tantras

Mahāyāna sutras contain "proto-tantric" material, such as the Gandavyuha and the Dasabhumika, which might have served as a central source of visual imagery for Tantric texts. Later Mahāyāna texts like the Kāraṇḍavyūha Sūtra expound the use of mantras such as Om mani padme hum, associated with vastly powerful beings like Avalokiteshvara. The Heart Sutra also includes a mantra.
Vajrayāna Buddhists developed a large corpus of texts, 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.
Some of the earliest of these texts, Kriya tantras such as the Mañjuśrī-mūla-kalpa, teach the use of mantras and dharanis for mostly worldly ends, including curing illness, controlling the weather and generating wealth. The Tattvasaṃgraha Tantra, classed as a "Yoga tantra", is one of the first Buddhist tantras that focuses on liberation as opposed to worldly goals. In another early tantra, the Vajrasekhara, the influential schema of the five Buddha families is developed. Other early tantras include the Mahāvairocana Abhisaṃbodhi and the Guhyasamāja.
The Guhyasamāja is a Mahayoga class of Tantra, which features forms of ritual practice considered "left-hand", such as use of taboo substances like alcohol, consort practices, and charnel ground practices that evoke wrathful deities. Ryujun Tajima divides the tantras into those that were "a development of Mahāyānist thought" and those "formed in a rather popular mould toward the end of the eighth century and declining into the esoterism of the left". This "left esoterism" mainly refers to the Yogini tantras and later works associated with wandering yogis. This practice survives in Tibetan Buddhism, but it is rare for this to be done with an actual person. It is more common for a yogi or yogini to use an imagined consort.
Later tantras such as the Hevajra Tantra and the Chakrasamvara are classed as "Yogini tantras" and represent the final form of development of Indian Buddhist tantras in the ninth and tenth centuries. 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.
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, which saw kings divinized as manifestations of gods. Likewise, tantric yogis reconfigured their practice through the metaphor of being consecrated as the overlord of a mandala palace of divine vassals, an imperial metaphor symbolizing kingly fortresses and their political power.

Relationship to Shaivism

The question of the origins of early Vajrayāna has been taken up by various scholars. David Seyfort Ruegg has suggested that Buddhist tantra employed various elements of a "pan-Indian religious substrate" that is not specifically Buddhist, Shaiva or Vaishnava.
According to Alexis Sanderson, various classes of Vajrayāna literature developed as a result of royal courts sponsoring both Buddhism and Shaivism. The relationship between the two systems can be seen in texts like the Mañjusrimulakalpa, which later came to be classified under Kriya tantra, and 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.
Sanderson notes that the Vajrayāna Yogini tantras draw extensively from the material also present in Shaiva Bhairava tantras classified as Vidyapitha. Sanderson's comparison of them shows similarity in "ritual procedures, style of observance, deities, mantras, mandalas, ritual dress, Kapalika accouterments like skull bowls, specialized terminology, secret gestures, and secret jargons. There is even direct borrowing of passages from Shaiva texts." Sanderson gives numerous examples, such as the Guhyasiddhi of Padmavajra, a work associated with the Guhyasamaja tradition, which prescribes acting as a Shaiva guru and initiating members into Saiva Siddhanta scriptures and mandalas. Sanderson says that the Samvara tantra texts adopted the pitha list from the Shaiva text Tantrasadbhāva, introducing a copying error where a deity was mistaken for a place.
Davidson argues that Sanderson's arguments for direct influence from Shaiva Vidyapitha texts are problematic because "the chronology of the Vidyapitha tantras is by no means so well established" and "the available evidence suggests that received Saiva tantras come into evidence sometime in the ninth to tenth centuries with their affirmation by scholars like Abhinavagupta " Davidson also notes that the list of pithas or sacred places is "certainly not particularly Buddhist, nor are they uniquely Kapalika venues, despite their presence in lists employed by both traditions." He adds that, like the Buddhists, the Shaiva tradition was involved in the appropriation of Hindu and non-Hindu deities, texts, and traditions, an example being "village or tribal divinities like Tumburu".
Davidson adds that Buddhists and Kapalikas as well as other ascetics mingled and discussed their paths at various pilgrimage places and that there were conversions between the different groups. Thus he concludes:

The Buddhist-Kapalika connection is more complex than a simple process of religious imitation and textual appropriation. There can be no question that the Buddhist tantras were heavily influenced by Kapalika and other Saiva movements, but the influence was apparently mutual. Perhaps a more nuanced model would be that the various lines of transmission were locally flourishing and that in some areas they interacted, while in others they maintained concerted hostility. Thus the influence was both sustained and reciprocal, even in those places where Buddhist and Kapalika siddhas were in extreme antagonism.

Davidson also argues for the influence of non-Brahmanical and outcaste tribal religions and their feminine deities.