Does "Double Walls in Pre-Qin Period" refer to The Book of Songs and Songs of the South?

Yes .. Pre-Qin poetry is divided into two schools, one is based on The Book of Songs, and the other is represented by The Songs of the South, which are called "Double Walls". They have become the sources of China's classical poetry and its literary realism and romanticism respectively, and their position in the history of China literature is extremely lofty. ..