Poetry:
Cao Pi's greatest breakthrough in poetry was the creation of the earliest seven-character poem "Two Poems of Yan". These two poems make the seven-character poem have a mature form and have epoch-making significance in the history of literature. This is beyond Zi Jian's power.
However, Cao Zhi's five-character poems have reached an unprecedented height. For example, Wang Biao's A White Horse, White Horse Essays, Miscellaneous Poems, Seven Wounded Poems, and Noda's Journey to the Yellowbird, etc. Cao Zhi's five-character poems are perfect in the expression of emotions and the use of themes, and they are a peak of five-character poems. Cao Pi's achievements in five-character poems are not so outstanding, and the copyright of some works is not clear with Cao Zhi.
Generally speaking, Cao Pi's poetic style is rather sad. Cao Zhi is vigorous and powerful.
Wen Fu:
Cao Pi's prose achievements are also relatively high, such as "A Book of Wu Zhi" and "Dian Lun Zi Xu". The main features are simple language and sincere feelings. Cao Zhi's prose is more magnificent. Moreover, due to different identities, most of Cao Pi's works reflect his personal leisure. Cao Zhi, on the other hand, reflects the tortuous fate and the feelings of grief and indignation.
Cao Zhi's achievements in the creation of Ci and Fu are even higher, with Luo Shenfu as its representative.
Cao Pi's Dian Lun Wen is an important literary theory work. Mr. Lu Xun said that Cao Pi's era was "the era of literary consciousness". Cao Pi's achievements as a literary critic are more outstanding. But as far as literary creation is concerned, personally, I prefer Cao Zhi.