Lurking in the minefield of Buddhist terminology that makes even the briefest of excursions into Tibet so bewildering is the distinction between sutras and Tantras. To understand the difference properly it is useful to go back to the schism in Buddhism that gave rise to the two major schools of Hinayana and Mahayana. The Hinayana school is the older, and is based on the teachings of Sakyamuni, the historical Buddha, which were recorded in the Sutras of the Pali Canon. These sutras can be translated as their Biblical equivalent 'Scriptures'.

So far so good. The situation is complicated, however, with the rise of Mahayana. Mahayanists claimed to have discovered another body of sutras which were entrusted to supernatural beings until sufficiently spiritually advanced human beings appeared in the world to receive them. In this way a second, Mahayana, canon came into being. It also set the precedent that Buddhist practice could be informed not only by the teachings of a living Buddha, but through revelations that came from beyond this world.

As the name suggests Tantras are associated with Tantric Buddhism, also known as Vajrayana. Just as sutras reveal the teachings of Sakyamuni, every Tantra can be traced back to a revelation from a particular deity. Tantra have their origin in Indian devotional cults. They involve practices and rituals that were revealed to an adept by a particular deity and then transmitted by that adept to a disciple and so on through many hundreds of years. In this sense, Tantra need not be written down, and may sometimes be orally transmitted.

The earliest Tibetan Tantra are associated with the Nyingmapa order and came to Tibet via Guru Rinpoche in the 8th century. They are practiced by all Tibetan schools of Buddhism and are called the Old Tantra. The later schools of Tibetan Buddhism - Kagyupa and Sakyapa - supplemented these Tantra with revelations of their own, and these came to be known as the New Tantra. The New Tantra are all associated with places in Tibet visited by Guru Rinpoche, and 'discoverers' (tedon) of these Tantras are thought to be manifestations of Guru Rinpoche's students.