The first is the breakthrough of restrictions. When we scan the history of literature, we will find that the development of poetry is a process of continuously reducing the connotation of "poetry" and expanding its extension.
Han Yuefu is a breakthrough in the Book of Songs, five-character poems are a breakthrough in four-character poems, seven-character poems are a breakthrough in five-character poems, and then words and phrases are a breakthrough in metrical poems.
We can see that every breakthrough will probably have a prosperous period of 200 to 300 years, and then there will be new breakthroughs.
But what is embarrassing is that the Ming and Qing Dynasties added up to 600 years, and there was no breakthrough in poetic style! In other words, in the past 600 years, I have been playing with sugar cane that my predecessors have chewed countless times!