The prosperity of Tang poetry stems from the innovation of early Tang poetry, and the rise of frontier poems is an important opportunity and a remarkable symbol of this innovation. Li Shimin, Emperor Taizong, was a pioneer of innovation. He created a series of frontier works, and clearly advocated "using the songs of immortal heroes to make the sound worse" (Ten Prefaces to Emperor Jing) and "taking water vulgarity as purity, taking chat as literary quality" (holding together and being quiet on three sides). The four great poets and Chen Ziang were the important figures in the early Tang Dynasty, and the creation of frontier poems was an important achievement of their innovation. Especially among Chen Ziang's thirty-eight encounter poems, the famous ones are Cang Dingling fortress, Ding Hai's Old Clouds and Dusks, The North Wind Blows the Sea Trees, This is Your Son, Chao Jinzhong Jun, Seven Ancient Poems Collected by Liu Jushi, Sending to the Army, Youzhou Tower and so on, all of which are famous frontier fortress works. The style of Han and Wei advocated by him has been the most prominent performance in these poems. The appearance of Chen Ziang is thought-provoking. At that time, the growing development of society and the participation of intellectuals in politics contributed to the atmosphere of poetry circles paying attention to the national economy and people's livelihood. Frontier wars are related to the rise and fall of the national movement and are highly valued. Therefore, the most outstanding poet who can represent the trend of the times is almost destined to be born here. Chen Ziang's frontier poems are rich in content. Among them, there are praises of patriotism, complaints about the hardships of military defense, and more ridicule of ordinary generals and criticism of the court's missteps. These contents were later recited repeatedly and became the basic theme of frontier fortress poems. In form, Chen Ziang prefers antique style to innovation, but he also pays attention to absorbing modern style. His "Youzhou Tower" is even more unconventional in structure and syntax, which means that it is unique as you said and has become an eternal family.