The Outer Tantras are the second three divisions in the ninefold division of practice according to the Nyingma school of Tibetan Buddhism. This system divides the whole of the Buddhist path into three divisions of three and is in contrast to the division of the Sarma, or New Translation schools which use a fourfold division. The three divisions of the Outer Tantra correspond to the lower three category of tantras of the New Translation schools.
As well as being differentiated in terms of emphasis in practice, the three categories of Outer Tantra are also textual categories, with lists of texts assigned to each category; for which see the individual articles for each section. The stages of the lower tantras can be divided into 4 parts; empowerments; vows and commitments; close retreats; common and uncommon attainments. Every tantra requires the empowerment of a guru in order to enter and proceed along the path, and normally there are a number of different empowerments for different practices, and in addition the Bodhisattva and Tantric vows must be taken. A close retreat involves intense sessions of meditation in the practice of deity yoga, and the common and uncommon attainments are the occultpowers, or siddhis, that are obtained as a result of that practice.
Kriyatantra
These form a large subgroup that appeared between the 2nd and 6th centuries. The Kriya tantras focus on ritual actions. Each centres on a particular Buddha or Bodhisattva, and many are based on dharanis. Examples include the Mahāmegha Sutra, the Ārya-mañjushrī-mūla-kalpa, the Subhāhu-pariprcchā Sutra, and the Aparimitāyur-jñāna-hrdaya-dhāranī. Also included in this category are some Mahayana texts such as the Heart Sutra and, in some editions, versions of some texts found in the Pali Canon. The Mañjusrimulakalpa, which later came to classified under Kriyatantra, states that mantras taught in the Saiva, Garuda and Vaisnava tantras will be effective if applied by Buddhists since they were all taught originally by Manjushri.
Charyatantra
This is a small class of texts that probably emerged after the 6th century. In these tantras, Vairochana emerges as the principal deity, with all the other buddhas and bodhisattvas being seen as emanating from him. The best known example is the Mahā-vairocanābhisambodhi Tantra, also known as the Mahavairocana Sutra, which became a foundational text for the Shingon School of Japan. There is also the Vajrapani empowerment tantra. Charyatantra, is the second of the outer tantras, and although it maintains a strong emphasis on external ritual actions, like Kriyatantra, the emphasis is now upon obtaining liberation through meditation. It is therefore externally similar to kriya tantra, and internally similar to Yogatantra. The empowerments required are similar to that of kriyatantra, except there is a 4-fold vase empowerment.
Yogatantra
Yoga tantra is the last and highest of the outer tantras, and here external rites are seen as much less important than internal practices. The empowerments given are the empowerment of the 5 Buddha families, and the empowerment of the Vajra master, and disciples must take on the commitments of the 5 buddha families, and take the tantric vows. The path is split into 4 seals; the great seal of body, the seal of the speech of Dharma, the seal of the mind of commitment, and the seal of enlightened actions. These tantras likewise focus on Vairocana, and include the Sarva-tathāgata-tattva-samgraha Tantra and the Sarva-durgati-parishodhana Tantra. While Vairochana maintains his position as principal deity, he is now envisaged as being in the centre of 5 buddha families instead of 3, each family belonging to one of the wisdom buddhas. Again, these ideas are very influential in Japan, notably Shingon buddhism. The Shurangama Sutra and the Shurangama Mantra from which it comes can be included in this category. According to Venerable Tripitaka Master BhikshuShramana Hsuan Hua's "Shurangama Mantra Commentary", the Shurangama Mantra mystically and literally includes all of the Buddha Dharma in its entirety, and its focus is on the Five Dhyana Buddhas and their retinues of Dharmapalas and wrathful deities in male and female forms. The primary wrathful Goddess of the Shurangamma Mantra tantric practice is the Great White Umbrella Deity form of Avalokiteshvara Bodhisattva, an important practice in Tibetan Buddhism.
