Classification of Qi
In Chinese medicine theory, Qi is understood to take various forms within the body, each fulfilling different functions. The classification of Qi relates to its production, distribution and functional characteristics. Qi can be divided into Yin and Yang components and each of the Zang–Fu organs has its own corresponding Qi. Physiologically, Qi has six main functions:
In terms of Chinese medicine theory, the classification of Qi is broken down into:
- Yuan Qi.
- Gu Chi.
- Zong Qi.
- Zhen Qi.
- Wei Qi.
- Ying Qi.
Yuan Qi (Primordial Qi)
This type of Qi is closely related to the Essence (Jing). It has its origins in the Kidneys and is derived from the Pre-Heaven Essence, whilst being constantly replenished by the Post-Heaven Qi. The functions of Yuan Qi can be described as:
- Moving Force: – It is the dynamic force that stimulates the functional activity of all the organs and circulates throughout the body in the channels.
- Basis of Kidney-Qi: – It resides between the Kidneys, below the umbilicus at the Gate of Vitality or Ming Men. As such, it shares the role of providing the heat necessary to all the body’s functional activities.
- Facilitates Transformation of Qi: – Yuan Qi is the ‘agent of change’, transforming Zong Qi into Zhen Qi.
- Facilitates Transformation of Blood: – Yuan Qi facilitates the transformation of Gu Qi into Blood in the Heart,
- Emerges at the Source Points: – Yuan Qi originates where the Ming Men resides, and then passes through the San Jiao (Triple Burner), spreading to the organs and channels. The places where Yuan Qi emerges are known as the Source Points.
Gu Qi (Food Qi)
The second form in the classification of Qi is Gu Qi, which means ‘Qi of Grains’ or ‘Qi of Food’ and is the first stage of the transformation of Qi. Food entering the stomach is digested, or ‘rotted and ripened’ according to TCM theory, and is transformed into Gu Qi by the Spleen. At this stage it is not yet usable by the body. It must rise from the Middle Jiao to the chest and travels to the Lungs, combining with air to form Zong Qi (Gathering or Pectoral Qi). Gu Qi also rises from the Middle Jiao, through the Lungs and on to the Heart where it is transformed into Blood.
Zong Qi (Gathering Qi)
The third form in the classification of Qi is Zong Qi, referred to as either Gathering or Pectoral Qi. It is derived through the interaction of Gu Qi with air. It’s a more subtle and refined form of Qi than Gu Qi and its main functions within the body are:
- Warming and nourishing the Heart and Lungs.
- Promoting Lung function to control Qi and breathing.
- Promotes the Heart function of governing Blood and vessels and promotes circulation to the extremities.
- It is responsible for controlling speech and the voice.
As Zong Qi is the energy of the chest, the area where it gathers is sometimes referred to as the ‘Sea of Qi’ and it can be affected by emotional disturbances such as sadness and grief which deplete Lung Qi. If Zong Qi is weak or deficient, the extremities (hands and feet) can become cold and weak.
Zhen Qi (True Qi)
Zhen Qi or True Qi is the final stage of the transformation of Qi. Through the action of Zong Qi, the Yuan Qi is transformed into Zhen Qi. This is the final distillation and refinement of Qi and results in the Qi which flows through the channels.
Zhen Qi originates in the Lungs and takes on two different forms: Ying Qi (Nutritive Qi) and Wei Qi (Defensive Qi). This is the penultimate part of the classification of Qi.
Ying Qi (Nutritive Qi)
It is also known as Nourishing Qi and has the function of nourishing the Zang-Fu organs and the body as a whole. It holds a close relationship with Blood and flows through the vessels and also the channels. In the theory of Chinese medicine, this is the Qi that is activated whenever an acupuncture needle is inserted into and acupuncture point.
Wei Qi (Defensive Qi)
The final entry in the classification of Qi is Wei Qi. The word ‘Wei’ means to defend or protect. When compared to Ying Qi it is more coarse. It flows in the outer layers of the body, in skin and muscles. As it resides on the exterior, its function is to protect the body from an attack of exterior pathogenic factors such as Wind, Heat, Cold and Damp.
It also works to warm, moisten and partially nourish the skin and muscles as well as controlling the opening and closing of the pores. Through this function, it regulates both sweating and body temperature.
Like Zhen Qi, it is also under the control of the Lungs, as such, weakness or deficiency of the Lungs can result in a weakness of Wei Qi which can leave a person prone to frequent colds and/or flu.