The theory of the Five Periods and Six Qi, found in chapters 66 - 71, and chapter 74 of the Huang Di Nei Jing Su Wen (The Yellow Emperor’s Inner Canon), is complex and enlightening. It offers valuable insights into the natural cycles of the universe and how these cycles manifest in the world and all living beings.

 

To fully understand the knowledge presented by this theory, one must first recognize that all living beings exist in the space between heaven and earth. Qi flows from both the heavens and the earth, influencing the manifestation of each annual season and is evident in all living beings.

 

The Five Periods (Wu Yun)

 

During ancient times, Chinese sages closely observed the movements of the Sun and Moon, as well as the rotation of the Big Dipper. They used the North Star, or Pole Star, as a constant reference point and noted that the Big Dipper moves counterclockwise across the sky. They recognized that each position of the Big Dipper's handle corresponded to different seasons and seasonal changes on Earth.

By observing and recording phenomena occurring in the sky, on Earth, and within all living beings—including themselves, their communities, their animals, and their crops—the sages confirmed that unique Qi characteristics emerged on a cyclical basis each year, season, month, and day.

 

The sky was divided into five directions: East, South, West, North, and Center, with each direction representing a distinct season and climate. They observed that as the handle of the Big Dipper moved through the sky, the seasons would manifest and change on Earth on a consistent annual basis. The Eastern direction signifies Spring and a presence of wind; in the South, it denotes Summer and ample heat; in the Center, it indicates late Summer with humidity; in the West, it marks Autumn and a dry climate; and finally, North, signifies Winter and the natural cold.

 

Furthermore, each direction and its related season were linked to one of the five personal planets: Jupiter in the East, Mars in the South, Saturn in the Center, Venus in the West, and Mercury in the North.

 

This pattern of the Five Periods and their seasonal changes establishes the foundation for the Ten Heavenly Stems and the Five Element theory. The Five Periods rotate annually; they represent the universal constants of our seasons and life on Earth.

 

In the sky, these elements appear as climatic phenomena, while on Earth, they take on distinct forms: wind represents Wood, heat symbolizes Fire, Damp corresponds to Earth, dryness signifies Metal, and cold indicates Water. Each element is linked to a season as follows:

 

Direction        Season          Climate Expression      Form on Earth

East                  Spring                         Wind                              Wood

South                Summer                     Heat                               Fire

Center              Late-Summer             Damp                             Earth

West                 Fall                             Dryness                          Metal

North                Winter                        Water                              Cold

 

The Six Qi (Liu Qi)

 

There are different contexts related to the names of the Six Qi that are pertinent to the practice of East Asian Medicine modalities. The following description specifically concerns how these energies manifest on Earth, their climatic context, and their relationship to the Twelve Earthly Branches.

 

The Five Periods above manifest as the Six (climatic) Qi on Earth as follows:

 

Jueyin                Spring                    Wind                 Wood

Shaoyin             Early Summer        Heat                  Heavenly Fire

Shaoyang          Summer                 Fire                   Earthly Fire

Taiyin                 Late Summer         Damp               Earth

Yangming          Autumn                   Dryness           Metal

Taiyang              Winter                    Cold                 Water

 

The Fire element is split into two parts to represent both its Heavenly and Earthly natures. This separation transforms the Five Periods of the universe into the Six Qi on Earth. Like the Five Periods, the Six Qi rotate annually and are linked to specific elements, seasons, and climatic characteristics.