In the early middle Tang Dynasty, from Dali to Zhenyuan, Tang poetry was at a low point between two high tides. Representative figures are Wei, Liu Changqing, Li Yi and "Ten Outstanding People in Dali Period". Most of them have experienced the Anshi Rebellion, so their poems reflect the destruction of society and the disadvantages of people's livelihood, but most of them are objective and calm descriptions and deep lamentations, lacking the strong feelings and shocking artistic appeal of poems in the prosperous Tang Dynasty. Li Yi and Lu Lun's frontier poems flourished in the Tang Dynasty. Wei and Liu Changqing's landscape poems are elegant and free, independent of Wang Wei and Meng Haoran. Most of the "Ten Talented Scholars in Dali Period" are door guests and powerful people, and his poems are paid for. As Jiao Ran said: "In the Dali period, poets ... stole the green hills and white clouds, and the spring breeze and grass were their own", and "the first thing in poetry was lost here" (Volume 4 of Poetic Style). They had many tasks, many methods, indifferent artistic conception, leisurely feelings and delicate descriptions. But there are too many carvings, and there are sentences without articles. In addition, there are Jie Yuan and Gu Kuang. With its quaint Yuefu style, it exposes the disadvantages of the times and reflects the sufferings of the people, which has become a realistic school between Du Fu and Yuan Juyi.
The middle Tang Dynasty, from the late Zhenyuan period to the Changqing period, is another climax of the development of Tang poetry. Compared with the prosperous Tang Dynasty, the poetry in the middle Tang Dynasty has changed: first, the realism tendency has been strengthened in content, and the subject matter has been broadened, such as exposing the profiteering of merchants, reflecting southern customs, describing the love between men and women, and summing up historical lessons. Second, there are many schools and styles in form. Bai Juyi, Yuan Zhen, Zhang Ji, Wang Jian, Li Shen and others advocated and participated in the New Yuefu Movement. They have a systematic and clear theory, which advocates giving full play to the stabbing effect of poetry, interfering with reality, inheriting and developing Du Fu's realism. In art, their Yuefu songs developed Du Fu's narrative skills. In particular, some Yuefu in Bai Yuan incorporated the techniques of legendary novels, with complete beginning and end, tortuous plot, delicate description and simple style. Zhang Ji's Wang Jian Yue Fu is different from Yuan Zhen's and Bai Juyi's epigrams in the refinement of epigrams. However, they all strive for simplicity, taking vulgarity as beauty, reflecting the aesthetic psychology of the citizen class and becoming the most influential school at that time. The other school is represented by Han Yu and Meng Jiao, including Li He, Jia Dao, Yao He and others. Their styles are different, but they all become beautiful in the strange rise and danger. Han (Yu) and Meng (Jiao) inherited the spirit of Du Fu's "never stop talking", took strangeness and anger as beauty, pursued shocking aesthetic taste, and formed a strange and dangerous style. Han Yu is talented and Meng Jiao is thoughtful. Both of them are good at ancient style and have the characteristics of "writing as poetry" Li He's Yuefu is strangely interesting, deep and beautiful. Jia Dao and Yao studied with ten gifted scholars, devoted themselves to the Five Laws, meditated on bitter songs, expressed their feelings of hardship, and formed a secluded scene and a lonely poetic style. Liu Zongyuan's poem "It happened in simple and ancient times, and its taste is light" (Su Shi's "Shu En Ji") is close to Tao Yuanming in style and is called Wei. His poems are different from Wei's, expressing deep sorrow and deep debt, and winning the essence of Chu Sao. Liu Yuxi's poems are good at praising history, hanging high in ancient times, vigorous and powerful, and are known as "poets". Liu (Zongyuan) and Liu (Yuxi) are not in the genre, but they can be unconventional. Third, the expression techniques are more abundant, with prose as poetry, discussion as biography, rhythm adjustment of characters' songs and lines, and legendary narration and writing of characters.
The middle and late Tang Dynasty, from Bao Li to middle and old age, is a transitional period of Tang poetry from prosperity to decline. There is a trend that the theme moves from the countryside to the stage, and the aesthetic interest turns to deep and quiet music to earn money. Representative figures Du Mu, Li Shangyin and Wen. They all have the ambition to serve the country and the world. Talent is ambitious, but it is not an extension. Their poems reflect the world implicitly or explicitly, stab the disadvantages of the times and express their feelings of worrying about the country, the people and the world. After being disappointed with the present situation and their official career, they all pursued the stimulation of sensuality and lewdness to varying degrees, and the themes describing the love between men and women in poems increased. Among them, Du Mu's ancient style is based on current events, expressing his robes and being impassioned. His teachings, especially the seven laws, are unrestrained and sometimes clumsy and sophisticated. Poems are accurate, beautiful and meaningful. Li Shangyin and Du Mu are also called "Little Du Li". Li Shangyin's pseudo-poems hurt people's feelings. He was depressed and frustrated, but his boldness of vision and brushwork were slightly inferior to Du Fu's. The implication was that he bent deeply, his thoughts were dense, his allusions were exquisite, and sometimes he was in danger. Wen's poems are not as good as Li Shangyin's. Yu Wen is good at Yuefu and Li Shen is good at Lv Qi. Both of them are famous for their poetic style, and they all say that some of their poems have an influence on the development of Ci from subject matter to expression.
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