What is Ba Gua(Hexagrams,eight trigrams)?

Ba Gua is a fundamental concept in the 《I Ching》, representing the dynamic and static states of all natural phenomena.The Void (wuji) produces the Absolute (taiji). The taiji produces two forms (namely Yin and Yang). The two forms produces four phenomena: Lesser Yang, Greater Yang (taiyang also means ‘sun’), Lesser Yin, and Greater Yin (taiyin also means ‘moon’). The four phenomena produces the Bagua(eight trigrams), which generate all things。

A point ●, symbolizing the origin of all things, zero-dimensional, represents Tai Chi, the ultimate source. You can imagine it as the beginning of the universe, originating from a single explosion point.

The point transforms into a line, becoming one-dimensional. The line has both continuous (solid) and broken lines, representing Yin and Yang. It symbolizes the duality in everything—heaven and earth, male and female, positive and negative.

When the line turns into a plane, two intersecting straight lines can define a surface. Thus, Yang (─) + Yang (─) results in ✕, which represents Extreme Yang. Since it is difficult to type these special symbols on a computer, we use ─* to represent Extreme Yang. Similarly, - -* represents Extreme Yin. This gives us the Four Phenomena.

The Four Phenomena reflect the shades of gray in reality—things aren’t always black or white.

A plane becomes three-dimensional when three lines define a three-dimensional shape, which corresponds to what we commonly refer to as the length, width, and height of an object. In ancient China, there was no discipline of solid geometry, so they used three lines to describe this phenomenon. When three continuous or broken lines are combined, there are 8 possible combinations, which form the Ba Gua.

In the Ba Gua, each line is called a Yao. ─ represents a Yang Yao, and - - represents a Yin Yao.

Extreme Yang and Extreme Yin are considered rare, as extreme situations occur less frequently, which aligns with the natural order of things.

Rarity adds value, so among the three lines, the one that appears less often determines whether it is Yin or Yang. For example, in ☱, there is only one Yin Yao, so it is considered Yin.

In the I Ching, the Ba Gua correspond to the natural elements, directions, time, the human body, and more. Here is a simplified table:

These correspondences help us interpret the results of divination. For example:

While the Ba Gua represent many aspects of life, the I Ching goes further with 64 hexagrams, each formed from two trigrams. This system is often used in divination, known as 《Liu Yao Divination》.