"Kai" has two meanings in ancient Chinese. One is letters. Su Shi's Eight Poems with Wang Minzhong said, "I want to say goodbye to you, but I want to ask you a few questions." The second is official documents. Fu Qian's Interpretation of "Popular Literature": Enlightenment of Official Belief.

Liu Xie's Wen Xin Diao Long is a masterpiece of literary theory in the Wei, Jin and Southern and Northern Dynasties. There is a special article "Playing Qi", which discusses the two styles of "playing" and "Qi". The related text is: "Only when Guo Wei wrote a note, the cloud began to smell. At the end of the play, the clouds are still blowing away. Since the Jin Dynasty, there have been two ways to play with words and expressions. Zheng Chen's words and deeds are different; Let the master thank you, and you can say goodbye.

This passage is translated into modern Chinese: it was not until the watch of Wei Dynasty that "Kevin" was used, or "Sincerity" was said at the end of the performance. After the Jin dynasty, the use of "qi" was quite common and also had the function of expression. When stating political views and discussing state affairs, "Qi" is a branch of "drama"; In the aspect of resignation, "Qi" is a branch of "Biao".