About 90 Japanese scholars are studying in China, the most famous of which is Konghai. In 804 (the twentieth year of Zhenyuan), he came to China to study Tantric Buddhism in Qingyuan Temple in Chang 'an, and when he returned home, he brought back more than 180 Buddhist scriptures and founded Tantric Buddhism in Japan. He also made an in-depth study of Japanese literature and writing, and made important contributions to the cultural exchange between China and Japan. Japanese monks also went to Japan to communicate with the cultures of China and China, among which Jian Zhen monks made the greatest contribution.

Jian Zhen, surnamed Chunyu, is from Yangzhou. He has a deep research on Legalism and taught in daming temple, Yangzhou. At the invitation of Emperor Shengwu, Japan, he traveled to Japan. After six efforts, he went through difficulties and obstacles and became blind. Finally, he arrived in Japan with his disciples in 754 (the thirteenth year of Tianbao), when he was nearly 70 years old. Jian Zhen introduced legalism to Japan, and at the same time, he also taught the Buddhist temple architecture, sculpture, painting and other arts to Japan. The existing Japanese Tang and Zhao Temple was built by Jian Zhen and his disciples, which has an important influence on Japanese architecture. Jian Zhen is proficient in medicine, especially pharmacology. Although he is blind, he can distinguish various drugs through his nose and sense of smell, which has contributed to the development of Japanese medicine.