This concept refers to those calligraphic works, poems, essays, and other literary and artistic works that are natural, leisurely and simple in style but have profound implications. A natural and leisurely style rejects excessive embellishment and is not bound by any particular forms. Created by Su Shi (1037–1101) in the Song Dynasty as a term of literary and art criticism, this concept had great influence on literary and artistic works in the Ming and Qing dynasties. Based on the thought of Zhuangzi （369？-286 BC） and including the thinking of the Chan Sect, this concept stresses the need to be leisurely and simple and the need to avoid being opinionated, to break free from the fetters of rules and regulations and to take things as they come to ensure that an artistic work embodies the beauty of leisure, simplicity, freedom, and naturalness.

I once talked about calligraphy, and I said that the calligraphic works of Zhong Yao and Wang Xizhi were natural, leisurely, simple，yet profound and their artistic appeal went far beyond the calligraphic works themselves. In the Tang Dynasty, Yan Zhenqing and Liu Gongquan drew on all the calligraphic styles of previous times to develop their own calligraphic styles. It is fair to say that Yan and Liu reached the zenith of calligraphic art, and they were unanimously regarded as the great calligraphic masters. In contrast, the influence of Zhong Yao and Wang Xizhi is on the decline. The same is true with poetry. (Su Shi: Postscript to the Selected Poems of Huang Zisi)

Xie Tiao’s poems were more neatly done than his predecessors’, but as a result such poems became less natural and leisurely，and one begins to see a distinctive feature of Tang poems in them. (Tang Geng: Postscript to Poems of Xie Lingyun, Xie Huilian, and Xie Tiao)