Black and white colors,
represent the yin and yang, the heaven and earth;
the boundary between black and white
is the human realm that divides the heaven and earth, and yin and yang.
A black dot in the white
represents yin within yang,
and a white dot in the black
represents yang within yin.

The Tai Chi diagram is said to have been passed down by the Daoist master Chen Tuan of the Song Dynasty, originally called "The Wuji Diagram." The Tai Chi diagram is an important image for studying the principles of the Yi Jing (Book of Changes). "Tai" means the ultimate; "Ji" means the limit, meaning reaching the limit, without any equal. It includes the ultimate truth as well as the extreme limits of time and space. When expanded, it fills the universe, and when folded, it is stored within the heart. It can be larger than any quantity but cannot exceed the circumference and space, and it can be smaller than any quantity but not equal to zero or nothing. These are the meanings of the term "Tai Chi."

The saying "the Dao gives rise to one, one gives rise to two, two gives rise to three, and three gives rise to myriad things" means that Wuji gives rise to Tai Chi, and Tai Chi gives rise to the Two Instruments (Yin and Yang). Yin and Yang combine to create all things.

The universe is infinite, hence it is called Tai Chi, but the universe is also tangible, having substantial content. According to the view of Yi Jing, tangible things come from intangible ones, so Wuji gives rise to Tai Chi. This Tai Chi entity is continuously active, meaning the universe is in motion. Motion generates yang energy, and when motion reaches a certain point, it turns into relative stillness, which generates yin energy. Thus, one motion and one stillness, the energies of yin and yang are mutually the root of each other, circulating endlessly.

The natural world is also like this. Yin and Yang, cold and heat, the four seasons' growth, transformation, storage, and harvest—these are the laws of the growth of all things, all containing yin-yang and the Five Elements. Regarding the human realm's yin and yang, "the way of heaven forms the male, and the way of earth forms the female." When yin and yang combine, they give rise to all things, and all things continue to change according to this law, thus producing endless changes. These contents propose the three fundamental principles: the way of heaven, the way of earth, and the way of humanity, known as the Three Talents. As stated, "the movement of the six lines embodies the three poles."