Wu Wei is a term from Taoism and first appears in Daodejing. Wu Wei is generally translated as not-doing. It is a way of life that is also practiced in Chinese painting. The same motif is painted over and over again – for example a mountain or a tree. What could this have to do with not-doing? Doesn't it get boring to paint the same motif over and over again?
It's not primarily about the motif or the result of painting, but about the process. The artist is practicing an attitude towards life. He tries to bring his work into harmony with Tao. According to Chinese tradition Tao is called the original principle by which everything is created and kept alive. It is a higher spiritual-divine principle of order, which in its wisdom far exceeds the human, rational understanding.
The painter aligns himself with this higher principle and attunes himself to it. He no longer wants to be the doer, the painter, but Tao should be able to work through him, through his hand. He "does" and yet he does not. He stands actively in non-action. One could also call it a non-intervention, a non-intervention in the laws of Tao. The painter intuitively lets these laws work through him; he tries to unite with the creative work of Tao, to recognize and reproduce it in the motif of the picture. Through the painting process he learns to distinguish to what extent he still wants to realize his own will or can let Tao work within himself. Because Tao is in everything, without Tao is nothing.
Practice not-doing and everything will come together for the good.