The term originally referred to the appearance of an artist who is concentrating on painting. It has been extended to mean an unrestrained state of mind free from external interruption when an artist is doing creative work. The book Zhuangzi describes a painter drawing freely with his clothes thrown open and legs stretching out. “To unbutton one’s clothes” is to expose one’s chest and arms; and “to sit with legs stretching out” indicates a casual posture while one is concentrating on painting. This term stresses the importance of a relaxed state and complete freedom of mind to the successful creation of quality artwork. This concept had significant influence on subsequent development of theories on calligraphy and painting in later generations.

Once when King Yuan of the State of Song was to do painting, all the painters came. Half of them, after paying him their respects, stood submissively to prepare brush-pen and ink for him. The other half were waiting outside. One painter, however, arrived late and was casual in manner. After receiving the king’s instructions, he returned to his hostel instead of standing there respectfully. The king sent somebody to check on him, and he was seen sitting there painting attentively with his chest and shoulders exposed and both legs stretching out. The king exclaimed, “Yes, that is a real painter!” (Zhuangzi)

When doing painting, one should unbutton one’s clothes, sit with legs stretching out, keep himself free from all external interruptions, and ignore spectators. That way, one is able to obtain miraculous creative power, draw inspirations from heaven, earth, and nature, go beyond the rules of previous painting masters, and freely use various painting techniques. (Yun Ge: Nantian’s Comments on Paintings)