The Ba Gua is a powerful tool used in Feng Shui to decipher the cosmic energy. It has even been used as an amulet and protection symbol in Chinese culture.
The Ba Gua is made up of eight trigrams. A trigram is a 3-tier combination of the Yin and Yang lines. It is read from the Bottom up or if found in a circle read from the inside out. The most yang or male combination, consisting of three Yang lines (solid lines) is called “Qian” or heaven. The most yin or female combination, consisting of three Yin lines (broken lines) is called “Kun” or earth.
Heaven is also known as the Father, and Earth as the Mother, together they create the other trigrams or “Children”, three sons, Zhen, Kan and Gen and three daughters, Xun, Li and Dui. These eight trigrams are placed into two different arrangements, The Early Heaven Ba Gua and the Later Heaven Ba Gua. The Early Heaven Ba Gua is the original order of the natural universe, it has the perfect balance of Yin and Yang with Heaven at the top and Earth below.

The Later Heaven Ba Gua represents the ever-changing universe; it is influenced by time and direction. It is this Later Heaven Ba Gua that is associated with world as it is now. These eight trigrams were conceived as images of all that happens in heaven and on earth. They were held to be in a state of continual transition, one changing into another, just as transition from one phenomenon to another is continually taking place in the physical world. The eight trigrams are related to certain compass directions.

Each also have an associated element and number along with other characteristics. The numbers arise from the He Tu (the river map) and the Lo Shu.