The Ba Gua, alternatively known as Pa Kua or Bagua, is an octagonal Taoist symbol that was first presented in the I-Ching, a philosophical and cosmological text which originated within China around 4000 BCE. http://www.sacred-texts.com/time/timeline.htm The outer part of the Bagua diagram contains eight (ba) trigrams (guas) which are symbolic of various attributes, energies, seasons, colors, directions and more. The inner part of the diagram contains the Tai chi symbol, representing constant interplay of the yin and yang energies. http://www.thespiritualfengshui.com/feng-shui-bagua.php http://www.goldenelixir.com/taoism/table_bagua.html

The Ba Gua is a fundamental part of the practice of Feng Shui, the art of the placement of objects. In the art of Black Hat Sect Feng Shui, the Ba Gua acts as a template or map that can be superimposed on living spaces to evaluate energy flow in a place and how it relates to areas of your life. Each space is divided up into 9 sections, including the center tai chi symbol. Optimal arrangements, colors, and directions are evaluated for each space. http://www.thespiritualfengshui.com/feng-shui-bagua.php

There is also a martial art called Ba Gua Zhang, or bagua zhang, with ever-changing circular, twisting, coiling and spiraling movements that are based on the energies that are expressed in the Ba Gua symbol. This martial art was developed in China during the 19th century. The techniques for changing patterns follow the different characteristics assigned to each of the eight trigrams found in the ba gua symbol: heaven, earth, thunder, wind, fire, water, mountain and lake. http://www.energyarts.com/Articles/Contributors/Excerpts-from-Whirling-Circles-of-Ba-Gua-Zhang-Part-II-of-II.html

The eight trigrams contained within the Ba Gua diagram are images that represent tendencies to change a state of being. Each of the symbols are not static representations; they undergo change ad infinitum. The movement and changes are characterized by the qualities given by the image associated with the symbol. Thus, the symbols represent a type, or a quality, of change. http://www.iging.com/intro/introduc.htm

Some have categorized the eight symbols represented by the trigrams into three different categories:

1. Ominous Situations (Chen = earthquake or tremor, K'an = pit, and Li = bird or omen)
2. Human Actions (Sun = kneeling, K'en = opposition and Tui = mediator)
3. Philosophical Abstractions of Sacredness (Ch'en = Heaven and K'un = Earth).

This symbolism is believed to represent a cosmological view represented by the wu xing, or five element theory, held during the middle of the Zhou dynasty. http://www.fengshuigate.com/bagua.html

In the application of the Ba Gua for Feng Shui, it can be used to find areas of living space where there are problems that may require changes. There are various "cures" for overcoming problems, including rearrangement of furniture, or the judicious placement of mirrors, pictures, plants, or art. These can correct imbalance and create a more positive environment, which will help bring about positive life changes. http://www.thespiritualfengshui.com/feng-shui-bagua.php