Literary flexibility means that one should respect the rules for writing poetry or prose but not be bound by them; one should encourage change and innovation. The opposite of literary flexibility is literary rigidity under whose influence the writer mechanically imitates the forms of established writers without innovation. One way to attain literary flexibility in one’s works is to draw inspiration from others extensively and absorb their talent while refraining from sticking mechanically to the model. One should base oneself on his own feelings and the aesthetic principles so as to create new styles and new ways of expression. Influenced by the Chan spirit of liberal flexibility, literary critics of the Song Dynasty championed flexibility in literary pursuit and established it as an important principle guiding poetry and prose writing.
Those who wish to learn to write poetry should master literary flexibility. By this I mean that, while knowing all the rules for poetry, the poet goes beyond them to reflect unpredictable changes in his poetry yet without compromising the rules. The principle underlying this way of writing is that there should be set rules, yet they are not fixed; where there seem to be no rules, rules do exist. You can discuss literary flexibility with others only if they understand this principle. (Lü Benzhong: Foreword to The Collected Poetry of Xia Junfu)
In writing essays, it is necessary to maintain literary flexibility. If one is bound by the clichés of the classical masters and fails to produce novel ideas, this is what we call literary rigidity. Literary rigidity refers to mechanically copying others without permitting one’s own work to acquire new ideas. Literary flexibility, however, allows one’s work to free itself from clichés so that the work will not be stifled by stereotyped style of writing. Literary rigidity leads to a literary dead end, while literary flexibility encourages the birth of new ideas by going beyond the limitations of conventional way of writing. (Yu Cheng: Reflections from Devoted Reading)