The term refers to the differentiation of the form and style of a literary work. It means that before putting words on paper, one needs to decide on the form and style appropriate to the thoughts and feelings to be expressed so as to produce a fine literary work with a high degree of harmony between form and content. In creating literary works, ancient scholars tended to decide on the style before writing. Literary critics in the Wei, Jin, and Southern and Northern dynasties discussed in detail the artistic features and rules of all literary styles and stressed that authors must choose an appropriate form or style to express their thoughts and sentiments and strictly follow the rules of the style, language form, and writing technique required by the chosen form or style. This, they believed, was the only way to create excellent literary works. Contrary to the term “style differentiation,” the term poti (破体) or “breakingdown styles” refers to the integration of different styles or forms of literary works by breaking down their boundaries. Style differentiation sometimes refers to differentiating the form or style of a literary work in order to attain a lofty character and realm of literature.
- 夫情致异区，文变殊术，莫不因情立体，即体成势也。势者，乘利而为制也。 （刘勰《文心雕龙·定势》） （作品所表达的思想情趣既有所区分，文章的创作手法也要因之变化，但都是依照思想感情确定文章的体式，就着体式形成文章的气势。文章的这种气势，是就着文体自身的特点进行创作而形成的。）
Since literary works express different ideas, temperaments, and tastes, the writing skills and techniques used should also differ in order to suit the content. It is the content of a literary work that determines its style, which in turn gives strength to the work. Such strength comes from writing in accordance with the style of the literary work. (Liu Xie: The Literary Mind and the Carving of Dragons)
- 夫诗人之思，初发取境偏高，则一首举体便高；取境偏逸，则一首举体便逸。 （皎然《诗式》） （诗人刚开始构思的时候，如果取境偏于高迈，那么整首诗的意境就高迈；如果取境偏于飘逸，那么整首诗的意境就飘逸。）
When the poet starts to compose a poem, if his conception of the poem tends towards grandeur, then the aesthetic conception of the poem will be grand; if his conception of the poem is free and easy, so will the aesthetic conception of the poem be. (Jiaoran: Poetic Styles)
- 先辨体裁，引绳切墨，而后敢放言也。 （章太炎《国故论衡·文学总略》） （先辨明文章体裁，遵循文章体式所规定的要求，而后才敢放开写作。）
One should first decide on the style or form of an article, and then start writing by following the rules required by the chosen style or form for the article. (Zhang Taiyan: Overview of Traditional Chinese Scholarly Learning)