The main expression method of The Book of Songs is also the main expression method of ancient Chinese poetry. This statement was first put forward by Zhou Li Chun Guan. Later, Preface to Mao Poetry inherited this statement. They all confuse three content styles (style, elegance and praise) with three expression techniques (fu, bi and xing), which are collectively called six poems or six meanings, and the concept is rather vague. Until the Tang Dynasty, Confucius' Mao Shi Zheng Yi said: "Style, elegance and praise are variants of poetry; Fu, Bi and Xing are different words in poetry. Those with different sizes get six meanings, and fu, comparison and xing are the uses of poetry, while style, elegance and praise are the achievements of poetry. Using the other three things to achieve these three things is the same as righteousness, and another volume is needed to distinguish the three-body and three-methods more accurately. This view is still used now.
There are two explanations about Fu, Bi and Xing. One explanation is that Fu, Bi and Xing are closely related to political education and satirical suggestions. It was Zheng Xuan in the Han Dynasty who first made this explanation. The positive significance of this explanation lies in its direct inspiration to the theory of "Beauty is better than pleasure" advocated by Chen Ziang and Bai Juyi in the Tang Dynasty. The negative influence is that many poets wander away from the artistic image and unilaterally pursue the so-called trivial meaning of poetry. Another explanation is to understand Fu, Bi and Xing as simple artistic thinking and expression. Zheng Zhongxian of Han Dynasty made this explanation, and regarded comparison as a figure of speech and xing as a means to help plants, animals and birds understand their meaning. This explanation was inherited by many later scholars, such as Zhiyu in Jin Dynasty, Li and Zhu in Song Dynasty. Their exposition accurately summarizes the basic characteristics of Fu, Bi and Xing as means of expression.
The induction and study of Fu, Bi and Xing is of great significance in the development of China's ancient poetry theory and poetry creation. It not only deepens and perfects the theoretical understanding of the artistic thinking and expression methods of poetry, but also promotes the enrichment and perfection of poetry creation, which has played a positive role in promoting the development of ancient poetry.
I hope it helps you!