The Bagua, Pakua or Palgwae are eight symbols used in Taoist cosmology to represent the fundamental principles of reality, seen as a range of eight interrelated concepts. Each consists of three lines, each line either "broken" or "unbroken", respectively representing yin or yang, 0 or 1 forming binary numbers 000-111 (0 to 7). Due to their tripartite structure, they are often referred to as Eight Trigrams in English.

The trigrams are related to Taiji or Taegeuk philosophy, Taijiquan and the Wuxing, or "five elements".[1] The relationships between the trigrams are represented in two arrangements, the Primordial (先天八卦), "Earlier Heaven"[2] or "Fu Xi" bagua (伏羲八卦), and the Manifested (後天八卦), "Later Heaven,"[2] or "King Wen" bagua. The trigrams have correspondences in astronomy, astrology, geography, geomancy, anatomy, the family, martial arts and elsewhere.[3][4]

The ancient Chinese classic, I Ching (Pinyin: Yi Jing), consists of the 64 pairwise permutations of trigrams, referred to as "hexagrams", along with commentary on each one.

There are two possible sources of bagua. The first is from traditional Yin and Yang philosophy. This is explained by Fuxi in the following way:

Another possible source of bagua is the following, attributed to King Wen of Zhou Dynasty: "When the world began, there was heaven and earth. Heaven mated with the earth and gave birth to everything in the world. Heaven is Qian-gua, and the Earth is Kun-gua. The remaining six guas are their sons and daughters".

The trigrams are related to the five elements of Wu Xing, used by Feng Shui practitioners and in Traditional Chinese Medicine. Those five elements are Water, Wood, Fire, Earth and Metal. The Water (Kan) and Fire (Li) trigrams correspond directly with the Water and Fire elements. The element of Earth corresponds with both the trigrams of Earth (Kun) and Mountain (Gen). The element of Wood corresponds with the trigrams of Wind (Xun) (as a gentle but inexorable force that can erode and penetrate stone) and Thunder (Zhen). The element of Metal corresponds with the trigrams of Heaven (Qian) and Lake (Dui).

There are eight possible combinations to render the various trigrams (八卦 bāguà):

This is also known as the "binary sequence" or Shao Yong sequence. A binary interpretation of each hexagram is made by interpreting yin as "0" and yang as "1", and reading the leading "digit" from the inside of the diagram, so the hexagram kūn is interpreted as 0, and gèn as 1. The hexagrams are in binary order when read up from the bottom around on the right, then up again on the left to the top.[clarification needed][citation needed]

Cycles of elements in this chart: (Generative/Counter-clockwise), (Destructive/Clockwise)

Fire brings water, water feeds wood, wood brings metal, metal brings fire

Fire melts metal, metal chops wood, wood drains water, water quenches fire

Cycles of elements in this chart: (Generative/Counter-clockwise),(Destructive/Clockwise)

Water feeds wood, wood brings metal, metal brings fire, fire brings water

Water quenches fire, fire melts metal, metal chops wood, wood drains water

Earth is now contest in element. Wood, Fire, Metal and Water is contest.

The Bagua is an essential tool in the majority of Feng Shui schools. The Bagua used in Feng shui can appear in two different versions: the Earlier Heaven Bagua, used for burial sites, and the Later Heaven Bagua, used for the residences.

In the Chinese orthodoxy culture, five elements does not exist. In the ancient China, Chinese people created four elements theory as the earliest theory of Bagua. Historian expert from Hong Kong discovered the genuine versions of eight trigram should be follow the rule of clockwise Gold (Spring), Wood (Summer), Water (Autumn), Fire (Winter). Another Bagua must following Spring (Fire), Summer (Gold), Autumn (Wood), Winter (Water). Both Xiantian Bagua and Houtian Bagua were counterfeited versions promoted by Confucianisms.[7]

In Xiantian Bagua, also known as Fu Xi Bagua or Earlier Heaven Bagua, the Heaven is in the higher part and the Earth is in the lower part. The trigram Qian (Heaven) is at the top, the trigram Kun (Earth) is at the bottom (in the past, the South was located at the top in Chinese maps). The trigram Li (Fire) is located on the left and opposite to it is the trigram Kan (Water). Zhen (Thunder) and Xun (Wind) form another pair, while being one opposite the other, the first on the bottom left next to Li while the second is next to Qian on the top right of the Bagua. Gen (Mountain) and Dui (Lake) form the last pair, one opposite the other, both in balance and harmony. The adjustment of the trigrams is symmetrical by forming exact contrary pairs. They symbolize the opposite forces of Yin and Yang and represent an ideal state, when everything is in balance.

The sequence of the trigrams in Houtian Bagua, also known as the Bagua of King Wen or Later Heaven Bagua, describes the patterns of the environmental changes. Kan is placed downwards and Li at the top, Zhen in the East and Dui in the West. Contrary to the Earlier Heaven Bagua, this one is a dynamic Bagua where energies and the aspects of each trigram flow towards the following. It is the sequence used by the Luo Pan compass which is used in Feng Shui to analyze the movement of the Qi that allegedly affects us.

Feng shui was made very popular in the Occident thanks to the Bagua of the eight aspirations. Each trigram corresponds to an aspect of life which, in its turn, corresponds to one of the cardinal directions. Applying feng shui using the Bagua of the eight aspirations (or Bagua map for short) made it possible to simplify feng shui and to bring it within the reach of everyone. Western Bagua focuses more heavily on the power of intention than the traditional forms of feng shui.[8]

Masters of traditional feng shui disregard this approach,[9] for its simplicity, because it does not take into account the forms of the landscape or the temporal influence or the annual cycles. The Bagua of the eight aspirations is divided into two branches: the first, which uses the compass and cardinal directions, and the second, which uses the Bagua by using the main door. It is clear that, not taking into account the cardinal directions, the second is even more simplified.

A bagua map is a tool used in Western forms of feng shui to map a room or location and see how the different sections correspond to different aspects in one's life. These sections are believed to relate to every area or aspect of life and are divided into such categories as: fame, relationships/marriage, children/creativity, helpful people/travel, career, inner knowledge, family/ancestors/health, and wealth/blessings.

In this system, the map is intended to be used over the land, one's home, office or desk to find areas lacking good chi, and to show where there are negative or missing spaces that may need rectifying or enhancing in life or the environment.

For example, if the bagua grid is placed over the entire house plan and it shows the toilet, bathroom, laundry, or kitchen in the wealth/blessings area it would be considered that the money coming into that particular environment would disappear very fast, as if to be 'going down the drain.'

In Peking Opera, a role that has Taoist technique or military strategy wears a costume decorated with Taiji and Bagua.

Baguazhang and Taijiquan are two Chinese martial arts based on principles derived from bagua.