According to Shan Hai Jing, in which dynasty did China already know about the existence of the Japanese?

Through the study of ancient myths in China, especially the Classic of Mountains and Seas, it is found that the record of Fusang in the Classic of Mountains and Seas is much earlier than that of Liang Shu. It is believed that as early as ancient times, China and Japan had close geographical exchanges, and mainland immigrants went to Japan to explore their sources during the Emperor Yao era. Shan Hai Jing is not an absurd work, but a valuable work about ancient mountains and rivers, land and sea, geography, humanities, clans and products ~