"Blind navigation in the East China Sea" refers to Japanese monks crossing the sea to Jian Zhen when they are blind. And it was six times, and the first five failed.

The art of preaching in the poem refers to Buddhism spread by monks in Jian Zhen.

The current emperor. In the first year of Tianbao (742), he made his first eastward crossing. In the 12th year of Tianbao (753), he made the sixth eastward crossing and finally succeeded in reaching Japan. On May 6, 763 (the first year of Guangde in Tang Daizong, the seventh year of Junren Emperor Tian Ping Baozi), Jian Zhen died in Zhao Ti Temple in the Tang Dynasty. In other words, he mainly lived in Xuanzong period, and Xuanzong went to Japan in the last years. Until the death of Japan, the Tang Dynasty was in an Anshi rebellion, which went through three periods: Su Zong, Dai Zong and De Zong.

Nara City in Tang Dynasty shows that Jian Zhen spread advanced Buddhism and culture in Tang Dynasty to Nara. Nara is the capital of Japan, and Jian Zhen once lived in Tangzhaoti Temple in Nara.