in internal debate over them is encouraged in some traditions. The other type of vipaśyanā is a non-analytical, "simple" yogic style called trömeh in Tibetan, which means "without complication". A meditation routine may involve alternating sessions of vipaśyanā to achieve deeper levels of realization, and samatha to consolidate them. Preliminary practices Vajrayāna is believed by Tibetan Buddhists to be the fastest method for attaining Buddhahood but for unqualified practitioners it can be dangerous. To engage in it one must receive an appropriate initiation (also known as an "empowerment") from a lama who is fully qualified to give it. The aim of preliminary practices (ngöndro) is to start the student on the correct path for such higher teachings. Just as Sutrayāna preceded Vajrayāna historically in India, so sutra practices constitute those that are preliminary to tantric ones. Preliminary practices include all Sutrayāna activities that yield merit like hearing teachings, prostrations, offerings, prayers and acts of kindness and compassion, but chief among the preliminary practices are realizations through meditation on the three principle stages of the path: renunciation, the altruistic bodhicitta wish to attain enlightenment and the wisdom realizing emptiness. For a person without the basis of these three in particular to practice Vajrayāna can be like a small child trying to ride an unbroken horse. The most widespread preliminary practices include: taking refuge, prostration, Vajrasattva meditation, mandala offerings and guru yoga. The merit acquired in the preliminary practices facilitates progress in Vajrayāna. While many Buddhists may spend a lifetime exclusively on sutra practices, an amalgam of the two to some degree is common. For example, in order to train in calm abiding, one might visualize a tantric deity. Guru yoga As in other Buddhist traditions, an attitude of reverence for the teacher, or guru, is also highly prized. At the beginning of a public teaching, a lama will do prostrations to the throne on which he will teach due to its symbolism, or to an image of the Buddha behind that throne, then students will do prostrations to the lama after he is seated. Merit accrues when one's interactions with the teacher are imbued with such reverence in the form of guru devotion, a code of practices governing them that derives from Indian sources. By such things as avoiding disturbance to the peace of mind of one's teacher, and wholeheartedly following his prescriptions, much merit accrues and this can significantly help