A third vehicle
Vajrayāna means the Diamond, or Thunderbolt, Vehicle. It is also called Mantrayāna, the vehicle of mantra. Its goal is the Mahāyāna goal, Buddhahood for the sake of all beings, and its claim is about speed: that with the right methods, and the right teacher, what might take countless lifetimes can be done in far fewer.
Its scriptures are called tantras rather than sūtras. The earlier ones, such as the Mahāvairocana and the Compendium of Principles, took shape around the 7th and 8th centuries. Later ones, including the Hevajra and Cakrasaṃvara tantras, belong to the 9th and 10th.
How it worked
Practice begins with initiation, given face to face by a teacher who holds the lineage. The practitioner is given a mantra, a maṇḍala, and a form of an awakened being to visualise, and in time to identify with. Rather than approaching Buddhahood from a distance, the practitioner rehearses it.
Much of this was kept secret, and still is. Secrecy was partly protective: taken literally, and without the view of emptiness behind it, the imagery of these texts is easy to misread. The tradition is firm that the methods are means and not the goal. Compassion and the understanding of emptiness remain the point.
Monasteries and wanderers
Two kinds of people carried these traditions. One was the great monastic universities of eastern India, Nālandā, Vikramaśīla and Odantapurī, where tantra was studied alongside logic and philosophy. The other was the siddhas, wandering adepts outside monastic life, remembered in lists of eighty-four and in songs attributed to figures such as Saraha and Tilopa.
These teachings travelled. An earlier layer of esoteric Buddhism reached China and, through Kūkai, became Japanese Shingon. The later layer went north, into Tibet and the Himalayas, which is where it survives as a complete system today.
Why it matters
These traditions become the basis of Buddhism in Tibet and across the Himalayas.
History and tradition
What historians can say
Dating rests on manuscripts, on Chinese and Tibetan translations, and on the colophons that name translators and patrons. Ronald Davidson places the movement in the political fragmentation of early medieval India, and argues that tantric ritual borrowed the imagery of kingship: consecration, a court of attendants, a maṇḍala laid out like a realm. Buddhist and Śaiva tantra clearly borrowed from each other, and scholars still disagree about which way most of the borrowing ran.
What Buddhist tradition remembers
Tibetan traditions hold that the tantras were taught by the Buddha in other forms and other realms, and were kept out of circulation until there were people ready for them. Lineage prayers trace the transmission back through named teachers to Vajradhara, the Buddha in his tantric form.