Amoghavajra (Sanskrit: अमोघवज्र amoghavajra; Chinese: 不空, pīnyīn: Bùkōng, Japanese: Fukū; Korean: 불공) (705–774) was a prolific translator who became one of the most politically powerful Buddhist monks in Chinese history, acknowledged as one of the eight patriarchs of the doctrine in Shingon lineages.
Born in Samarkand of an Indian father and Sogdian mother, he went to China at age 10 after his father's death. In 719, he was ordained into the saṃgha by Vajrabodhi and became his disciple. After all foreign monks were expelled from China in 741, he and some associates went on a pilgrimage to gather texts, visiting Sri Lanka, Southeast Asia and India. During this voyage, he apparently met Nagabodhi, master of Vajrabodhi, and studied the Tattvasaṃgraha system at length. He returned to China in 746 with some five hundred volumes.
In 750, he left the court to join the military governorship of Geshu Han, for whom he conducted large-scale tantric initiations at field headquarters. In 754, he translated the first portion of the Tattvasaṃgraha (T. 865), the central yoga tantra of Esoteric Buddhism, which became one of his most significant accomplishments. He regarded its teachings as the most effective method for attaining enlightenment yet devised, and incorporated its basic schema in a number of writings. Amoghavajra was captured in general An Lushan's rebellion but in 757 was freed by loyalist forces, whereupon he performed rites to purify the capital and consolidate the security of the Tang state. Two years later, he initiated the emperor Suzong as a cakravartin. In 765, Amoghavajra used his new rendition of the Scripture for Humane Kings in an elaborate ritual to counter the advance of a 200,000-strong army of Tibetans and Uyghurs which was poised to invade Changan. Its leader, Pugu Huaien, dropped dead in camp and his forces dispersed.
The opulent Jinge Temple on Mt. Wutai was completed in 767, a pet project of Amoghavajra's, and one of his many efforts to promote the bodhisattva Mañjuśrī as the protector of China. Amoghavajra continued to perform rites to avert disaster at the request of the emperor Tang Daizong. On his death in 774, three days of mourning were officially declared, and he posthumously received various exalted titles. The Chinese monks Huilang, Huiguo and Huilin were among his most prominent successors. Seventy-seven texts were translated by Amoghavajra according to his own account, though many more, including original compositions, are ascribed to him in the Chinese canons.