Jianzhen (688-763) was born in Yangzhou City, Jiangsu Province. He was a Chinese Vinaya master and the founder of Japanese Vinaya (a discipline sect).

Jianzhen became a monk at the age of 14 and left his hometown for Luoyang and Chang'an to study when he was twenty years old. At the age of 21, he became a monk in Chang'an. He apprenticed to many celebrated monks such as Dao'an, Hengjing and so on. He not only was conversant with Vinaya but also mastered abundant knowledge of medicine, architecture, sculpture and so on, which was an important reason that Jianzhen could make great progress with Vinaya.

At the age of 40, Jianzhen returned to his hometown Yangzhou in 733 and took charge of Daming Temple. He spent 10 years in promulgating the theories of Vinaya and was known as a Vinaya master like Dao'an. At the same time, he constructed many temples and Buddha statues, wrote three works of Tripitaka and was devoted to beneficence. Through such deeds he got much experience of leadership and cultivated many experts in various majors, which facilitated his travel to Japan.

At the invitation of Japanese monks studying in China, Jianzhen decided to go to Japan to spread Vinaya in 742. He tried six times to cross to Japan but failed due to heavy storms. The extreme conditions of his attempts rendered him blind by the time he succeeded in 753. Japanese highly respected Jianzhen. The Mikado showed his welcome at Jianzhen's arrival and invited him to teach at the Tōdaiji Temple. Jianzhen was also responsible for the establishment of such temples as Toshodaiji where he taught and spread Vinaya. From then on, the Japanese Vinaya came into being and Jianzhen was the founder.

Jianzhen and his disciples were not only proficient in Vinaya but also familiar with the doctrines of the Tiantai Sect of Buddhism. Among the canons they had taken to Japan most were about Tiantai Sect. Thus they were also the pioneers of Tiantai Sect to Japan.

Jianzhen had much experience on temple architecture and statue sculpture. Many of his disciples were eminent architects and sculptors. Constructions in Toshodaiji were all planed and constructed by Jianzhen and his disciples. Toshodaiji became the model of Japanese Buddhist arts that influenced later temples greatly.

Jianzhen was also familiar with medicine and was regarded as the founder of Japanese pharmaceutics. It is recorded that Jianzhen could easily determine whether the medicine was right just by smelling. Most of his disciples were good at Chinese verses, which greatly influenced Japanese literature.

Jianzhen's visit to Japan added new elements into Japanese culture and promoted the Sino-Japan cultural exchange.