These are the three ways of expression employed in The Book of Songs:

a narrative is a direct reference to an object or an event, an analogy

metaphorically likens one thing to another, and an association is an impromptu

expression of a feeling, a mood or a thought, or using an objective thing as

metaphor for sensibilities. Confucian scholars of the Han Dynasty summarized

and formulated this concept of narrative, analogy, and association, which later

became the basic principle and method in classical Chinese literary creation.