There are two schools of pre-Qin poetry, one is The Book of Songs and the other is The Songs of the South. As for the ballads scattered in the pre-Qin classics, regardless of the north and south, everyone is equal, or close to the Book of Songs, or like the Songs of the South, and the two styles coexist. The reason is that ancient ballads are basically the same, but they are recorded in words after being sung orally, or they are faithful to the prototype, scattered and close to spoken language, and their styles are like Sao; Or slightly refined, it is neat and easy to recite, and the style is like "poetry." For example, the Song of Wen Zi in Chu State should be in the form of Sao, but what we see in Shuo Yuan is a typical poetic style. Yan Guo's Song of Yishui should be in the form of poetry. What is recorded in the history books is actually a typical Sao style. Even the same ballad is found in the book "Jin Sao" and the book "Jin Shi". For example, Lu Nv's Song of Huang Qi, recorded in Biography of Women, is a prose style with scattered language and "Xi" in every sentence; However, the four words of "Xi" are also omitted in Lei Ju of Literature and Art.. From this point of view, ancient ballads are actually the same origin of * * in "poetry" and "Sao", and they are divided into two bodies because of the different written records.
Moreover, the compilation and evolution of The Book of Songs has been refined from oral to written, and it is also based on music, rhythm and conciseness, thus forming a four-sentence structure with basically two beats per sentence.