Shi (诗) is a major genre of ancient Chinese literature, the earliest literary form that emerged in China. Observing the requirements of a certain rhythm, rules of rhyming, number of characters, and type of verses, and using concise language and rich imagination, it reflects social life and conveys thoughts and emotions. Shi and wen (文) are two principal forms of ancient Chinese literature. Shi, as referred to by the ancient Chinese, consists of the older type of poetry and the latter type of poetry. It generally does not include ci (词lyric) and qu (曲melody), which appeared as literary genres after the Tang Dynasty. The older type of shi is also called gufeng (古风), meaning ancient style, which is a general appellation for all kinds of poetic forms produced prior to the latter type of shi, except the style employed in the odes of Chu. With relatively few restrictions in rules and forms, shi is not constrained by any antithetical arrangement or a fixed tone pattern, and its rhyme is fairly free. In addition, the length of a piece is not limited. A verse may have four, six, seven, or a mixed number of Chinese characters. The latter type of shi is also called gelüshi (格律诗), meaning poetry with fixed patterns. Its number of characters, rhyming, tone pattern, and antithetical arrangement are all strictly fixed. A poem of this type may contain four lines (known as jue绝), each with five or seven characters, or eight lines (known as lü律), each with five or seven characters. Occasionally, it is much longer than normal, expanding to one and a half dozen lines, which is referred to as pailü (排律). The difference between shi, and ci and qu is that the former is not set to music, while the latter may be set to music and sung. Shi has existed as a literary form for more than 2,000 years in China. Ancient Chinese used shi to connect humans with nature, voice aspirations, and give expression to emotions. It embodied the spirit and aesthetic pursuits of literature and art in ancient China, which is very different from the West, which only sees poetry as a category of literature. In ancient China, Confucian thought played an important guiding role in poetic creation, while Daoist and Buddhist thoughts had a profound influence on the theory of poetry's artistic conception. Since "The Book of Songs" was China's earliest collection of poems, later generations also used shi to refer to "The Book of Songs" in particular.
Shi gives expression to aspirations while songs are verses for chanting. In singing, shi undergoes changes in tempo and tone; then it harmonizes sounds with meter and melody. (The Book of History)
Shi expresses aspirations through written words, whereas songs do so via chanting. Dancing is a sequence of body movements to project one's emotions. All these three forms of art come forth from the heart, accompanied by musical performance. (The Book of Rites)
The four seasons bring changes in scenery, which in turn stir one's emotions. One gives expression to such emotions through dancing and chanting. Poetry thus illuminates heaven, earth and humans, making everything clear and bright. The gods in heaven rely on it to perform sacrificial rituals and the spirits in the nether world use it to communicate with the world. Among those which move heaven, earth and the spirits, nothing comes near poetry! (Zhong Rong: Preface toThe Critique of Poetry)
（推荐：教育部 国家语委 供稿：北京外国语大学 外语教学与研究出版社）