This refers to the situation or trend in the development of things. The formation, existence and change of a situation hinges on how things are organized, their relative strength, and how they interact with each other. It also refers to topography, such as occupying a commanding position at a high location. It may also refer to how people behave as influenced by their social positions. In terms of literary work, a trend refers to a particular force running through a literary work arising from its structure and style. The impact of a tendency upon people and social affairs gives rise to laws governing nature and social development. One can accomplish great things by following and gaining a good command of social trends. Under certain conditions, one changes the developmental course of things by creating trends.

Topography decides where and how water flows. Similarly, the strategy to win a war should be made based on an understanding of the situation in the enemy’s camp. So, just as there is no fixed form of flowing water, there is no fixed strategy in commanding an army. Those who win the war by changing their strategy in response to changes in the enemy’s situation are truly master of warfare. (The Art of War)

With power to dictate the trend, a sovereign can ensure that his orders and prohibitions are enforced. Power means control over the life and death of others, while the ability to dictate a trend is the means to govern the general public. (Hanfeizi)

With different temperaments and tastes, different writers have different approaches to writing, and they will use different literary styles according to what they want to write about. In doing so, they create a particular literary force.

(Liu Xie: The Literary Mind and the Carving of Dragons)