Vajrayana Buddhists affirm tantra as a swift and powerful vehicle to enlightenment, the "diamond" or "thunderbolt" way. Building on the Mahayana, it employs a distinctive repertoire of means: mantra, visualisation of deities (yidam) as embodiments of enlightened qualities, sacred diagrams (mandala), ritual gesture (mudra), and yogic disciplines, all transmitted through initiation and guided by a qualified teacher. The claim is that these methods, harnessing the very energies of body and mind, can accomplish in one lifetime what other paths take many lives to reach.
Tibetan doxography organises tantric texts into four classes of increasing intensity, Kriya, Charya, Yoga, and Anuttarayoga (highest yoga tantra), the last of which contains material describing transgressive elements, ritual use of substances otherwise forbidden and sexual symbolism among them, that Indian and Tibetan commentators have long debated how literally to read. Some lineages and periods have practised such elements literally under strict initiatory supervision, while most later Tibetan monastic scholasticism, especially the celibate Geluk tradition formalised by Tsongkhapa in the fourteenth and fifteenth centuries, reinterprets the highest tantras' transgressive imagery symbolically, as maps of internal psycho-physical processes rather than instructions for literal conduct.