The relationship between the five elements, wood, fire, water, metal and earth are a fundamental part of Chinese philosophy. Each element is in control of another element and is dependent upon another element, thus fostering an environment where each element is of equal strength.
Metal holds Water;
Water grows plants, thus creating wood;
Wood is burned, thus creating Fire;
Fire reduces to ash, thus settling into the Earth;
Earth is where from where metal is extracted.
This five year cyclical pattern is followed by the assignment of an element to a year, thus producing sixty possible sign combinations with a finer level of granularity to the analysis.
Through the Four Pillar analysis of our personalities, we discover that we are composed of a combination of 12 elements. It is this combination, coupled with our four signs that provide us the level of detail needed to fully understand ourselves.