Tantric Buddhism ［タントラ仏教］ ( Tantora-bukkyō): Also, Vajrayāna, Mantrayāna, or Esoteric Buddhism. A stream of Buddhist thought and practice that became formalized in India and flourished from the seventh to the eleventh century. Tantric Esotericism became a part of the broader Mahayana movement and represents an infusion of popular magic, mysticism, and ritual into the Indian schools of Buddhism. The Sanskrit word tantra means loom or warp of cloth, essential part, or doctrine.
  Tantra also refers to a class of Hindu or Buddhist scriptures on esoteric practices that developed rather late in the history of the literatures of those religions. They emphasize benefits that accrue from the recitation of mantras (magical formulas), the formation of mudras (hand gestures), the performance of rituals, the use of mandalas (ritual diagrams), and other practices. Tantric thought became a formalized stream within Mahayana Buddhism around the seventh century and spread to Central Asia, China, and Tibet. Tantric tradition is an important element of Tibetan Buddhism.
  Bu-ston, a Tibetan scholar of the fourteenth century, classified Indian Buddhist tantras into four general categories: Kriyā-tantra, dealing with ritual acts; Charyā-tantra, which combines ritual acts with meditation; Yoga-tantra, dealing chiefly with meditation; and Anuttarayoga-tantra, or supreme yoga tantras. The fourth form, Anuttarayoga-tantra, which was not introduced to China and Japan, is the strongest in sexual symbolism, identifying prajnā, or wisdom, as a female principle; upāya, or expedient means, as a male principle; and enlightenment as a union of these two. Some of its practitioners interpreted this symbolism literally and sought enlightenment in the sexual union of man and woman.
  The earliest esoteric Buddhist tantras, such as the Sanskrit texts of the Mahāvairochana Sutra and the Diamond Crown Sutra, were produced in India in the seventh century. In China, Esoteric Buddhism was introduced and established by the Indian monks Shan-wu-wei ( Shubhakarasimha, 637–735), Chin-kang-chih (Vajrabodhi, 671–741), Pu-k’ung (Amoghavajra, 705–774), and others. Its teachings were systematized to enable the attainment of Buddhahood in one’s present body. The Sanskrit Buddhist tantras were translated into Chinese and spread as esoteric sutras and teachings featuring mudras, mantras, and mandalas. In Japan, Kōbō (774–835; also known as Kūkai) formulated his own systematization of these teachings, founding the True Word (Shingon) school based upon them. Esoteric Buddhism was also accepted and developed by the Tendai school in Japan.