Within the classical understanding of Qi, the vital energy of the body is seen as differentiated into several interrelated forms, each with its own origin, location, and function. At the deepest level lies Yuan Qi, often described as Original or Source Qi, inherited from one’s parents and rooted in the Kidneys; it provides the constitutional foundation for growth, development, and vitality. From daily life arise other forms: Gu Qi, the Qi derived from food and drink, and Kong Qi, the Qi drawn from the air through breathing. These two mingle in the chest to form Zong Qi, or Gathering Qi, which concentrates in the region of the Heart and Lungs and supports respiration and circulation. In this way, the body is seen as a meeting place of ancestral endowment and present nourishment.

From these sources emerges Zhen Qi, sometimes called True Qi, the refined, functional Qi that circulates through the meridians and sustains the organs and tissues. Zhen Qi itself is understood to manifest in two primary modes. Ying Qi, or Nutritive Qi, flows within the meridians and blood vessels, closely associated with Blood, and nourishes the internal organs and all bodily structures. Wei Qi, or Defensive Qi, moves more on the exterior, beneath the skin and outside the main channels, guarding the body against external influences and helping to regulate the opening of pores and body temperature. Together, these aspects of Qi reflect both the inner nourishment and the outer protection that sustain embodied life.

Qi is also spoken of in terms of its specific expressions within the organs and the larger system. Each organ possesses its own Zang-Fu Qi—such as Heart Qi, Lung Qi, Liver Qi, Spleen Qi, and Kidney Qi—governing the characteristic functions attributed to that organ system. Jing Qi, or Essence Qi, represents a more refined, long-term form of energy associated with Essence, supporting growth, reproduction, bone marrow, and the brain, and is closely linked with the Kidney storehouse. On a broader level, Zheng Qi, or Upright Qi, names the totality of the body’s healthy, protective energies—especially Yuan Qi and Wei Qi—that stand in opposition to harmful influences. In this vision, the many types of Qi are not separate substances, but different faces of a single living current, viewed from the angles of origin, function, and depth.