first, "unique material" means that a poet should have a unique talent for poetry creation. It is necessary to accumulate in books and theories, but to be high on the realm of articles and righteousness. It is a manifestation of "wonderful understanding", not a manipulation and preaching of articles and principles.
second, "unique interest" refers to an aesthetic interest and artistic realm with self. It is an expression of aesthetic characteristics, which is caused by the poet's "interest", so most of the poems in the prosperous Tang Dynasty are based on it and have rich and meaningful aesthetic interest, which is very different from the truth, rationality and discussion in the Song Dynasty.
Third, poetry should have the characteristics of "endless meaning", that is, the poetic language can be finished and plain, while the artistic conception of poetry is endless and interesting.
influence: Yan Yu opposed the bad tendencies of "poetry based on words", "poetry based on argument" and "poetry based on talent" in Song poetry. Putting forward is to have artistic conception and the poet's own aesthetic taste. It is necessary to be "enlightened" rather than "poor in chapter and reason", and to have "other materials" rather than fiddling with words. It provides a reference for future generations' poetry creation.