Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online.In traditional Chinese medicine and Chinese culture, yuán qì is a description of one form of qi. It is usually described as "innate" or "pre-natal" qi to distinguish it from acquired qi that a person may develop of their lifetime.Porkert describes the concept as "the metaphorical designation of the inborn constitution, the vital potential that is gradually used up in the course of life. It may be conserved but never replenished."The term has been used since at least Yuan dynasty times.