The Shingon (Tantric) tradition of Mahayana Buddhism arose in India in approximately the 6th century AD, although its roots go back many hundreds of years before that. It, too, adopted the position that none of the Hinayana (and now none of the Mahayana) was to be rejected.
If the world was indeed the body and the mind of Mahavairocana (Dainichi Nyorai), then all religious teachings possessed in some measure the Truth, and especially all Buddhist groups must possess this Truth in a greater or lesser degree. Tantrism began as a movement more concerned with the Practice of Buddhism than with any theoretical reformulation of doctrine.
The practice of Tantrism was primarily concerned with the means by, which once could attain Buddhahood, to supreme awakening in this very life. Since Tantrism was concerned with both the ritual and meditation practices leading to enlightenment, the Shingon tradition has developed highly complex and long rituals that monks and qualified laymen undergo to approach enlightenment. In general, Tantrism has been more concerned with practice than with doctrinal speculation.
The Shingon Buddhism school, in Japan formally introduced by Master Kukai, or Kobo-Daishi (774-835 AD), teaches us that all things of this world (all creatures as well as all inanimate things) are in essence the body of the chief deity, the Buddha Mahavairocana (Dainichi Nyorai).
All of the various other schools of Mahayana Buddhism posit in their world view the situation wherein man finds himself separated from the ideal state, from Buddhahood, and so must work himself up to that state. All schools of Buddhism view Enlightenment (Buddhahood, satori, or Nirvana) as a mental state, a state of mind wherein the mind is totally awakened to its real nature (totally and truly self-aware).
Thus, other schools would view the religious life as a life devoted to eliminating the evil in one’s mind, to purifying the mind and to concentrating the mind in and through meditation. The Shingon school, however, views the world as coming into existence through the permutations or changes in the mind of the Buddha Mahavairocana.
Thus Enlightenment for the Shingon Buddhist consists in the realization that he is, here and now, truly one with Mahavairocana. As long as he does not fully realize this, he is enmeshed in the realm of birth-and-death (samsara). When once he does realize this true state of things, then he attains full Buddhahood in this very life (sokushinjobutsu). A state of awakening in this life is thus the goal of Shingon Buddhism.
Kukai taught that all things in this world are to be regarded as Buddha’s and as deities, deserving of our love and respect. Various groups of these deities Buddha’s, and Buddha’s to be (Bodhisattvas) are especially venerated in Shingon Buddhism, and their pictorial and often highly symbolic representations are called Mandalas/Mandaras. (Since one of the distinctive features of Shingon Buddhism was its presentation of the major and minor deities in the form of Mandalas, this school of Buddhism was initially called the Mandara-Shu, the school of Mandalas.)