As we mentioned in our yinyang article, the study of the five elements was originally associated with the wuxing. Wuxing refers to the properties of substances that have certain functional attributes. Water soaks and descends. Fire blazes and ascends. Wood bends and straightens. Metal holds its shape and is malleable. Earth takes seeds and give crops. Wuxing was the early Chinese attempt to work out metaphysics and a cosmology.

Since Sun Tzu's era, Chinese science and philosophy have revolved around these five classical elements, their properties, and their relationships within nature. As with the four Greek classical elements of

fire, air, earth, and water, the essence of the Chinese classical elements was understood to create the differences observed between various objects in the real world.

These elements are representative of different stages of an ongoing process of transformation. On a deeper philosophical level, these elements are seen as stages of being in a cyclical process of becoming. These transformations are driven by the dynamic interplay between complementary opposites.

In recent millennia, the "After Heaven" model of the five elements has been used in traditional Chinese science. We show it below. Sun Tzu based his system on the older "Before Heaven" model, which is still used in some martial arts. Some of the many associations with the five elements are shown.