wǔ háng xiàng shēng 五行相生
The Five Elements, Each in Turn Producing the Next
This refers to the concept of the five basic elements, each in turn giving rise to the next. The five basic elements are: wood, fire, earth, metal, and water. All things in the world are composed of these five elements or possess their properties. According to this concept, wood produces fire; fire produces earth; earth produces metal; metal produces water; and water produces wood. Similarly, things with the properties of these five elements also have similar relations between themselves.
The five elements are comparable to five official positions. Adjacent things come into being in certain sequences. If things do not emerge in order, each will check the next. This principle also applies to the governance of a state and all social affairs. Chaos grows if the order of the five elements is disrupted; peace prevails if the five elements are in good order. (Dong Zhongshu: Luxuriant Gems of The Spring and Autumn Annals)