I. The Principle of Moxibustion Sensation When moxibustion is applied, the body's Qi within the meridians is stimulated and activated by the warmth of the mugwort. As the Qi circulates, it confronts the pathogenic factors at the site of the illness. Once the Qi overcomes these factors, they are expelled, leading to a range of sensations associated with moxibustion. The presence or absence of these sensations is directly related to the effectiveness of the moxibustion treatment. II. Types of Moxibustion Sensations There are seven types of moxibustion sensations: 1. Penetrating Heat: The heat from the moxibustion penetrates directly from the skin surface at the application point into deeper tissues, and may even reach the organs in the chest and abdominal cavity. 2. Radiating Heat: The heat from the moxibustion spreads around the application point. 3. Conducting Heat: The heat from the moxibustion starts at the application point and follows the meridians to distant areas, potentially reaching the site of the disease. 4. Local Coolness (or Mild Warmth) with Distant Heat: The application area is not warm (or only mildly warm), but areas far from the application point feel very hot. 5. Surface Coolness with Internal Heat: The surface is not warm (or only mildly warm), but deeper tissues under the skin, and even organs in the chest and abdominal cavity, feel very hot. 6. Sensations at the Application Point or Distant Areas: The application point or areas far from the application point may experience sensations of sourness, swelling, numbness, heaviness, pain, cold, etc., which are non-heat sensations. 7. Deep Penetration and Distant Transmission at the Application Point: The aforementioned sensations are transmitted to areas where the disease is alleviated. The heat, swelling, pain, and other sensations at the application point are deeply penetrating and transmitted to distant areas, and the disease is alleviated wherever they arrive. These seven types of sensations deepen in sequence during the moxibustion process. The sixth and seventh sensations indicate that the pure Yang Qi of moxibustion is being conducted along the meridians, and the moxibustion has achieved the expected therapeutic effect. Sensations are not limited to the application area but are conducted along the meridians. The strength of the sensations generally represents the degree of blockage in the meridians. The presence of strong sensations indicates that the meridians are unobstructed, and the effects are immediate; the absence of sensations indicates severe stagnation of pathogenic factors in the meridians, requiring time to disperse and unblock, hence the effects are slower. Among normal people, sensations vary with time, place, and individual. Generally, the stronger the stimulation, the longer the time, and the more frequent the stimulation, the easier the sensations appear; "meridian-sensitive people" have relatively strong sensations; in a warm and quiet environment, and when the skin is moist and the mind is focused, sensations are more likely to occur and are transmitted more quickly. Conversely, short moxibustion time, few stimulations, cold and noisy indoor environments, dry skin, and insensitivity of the meridians will result in dull or imperceptible sensations. Different Stages of Sensations: 1. Moxibustion Fire Following the Meridians Warmth is the dynamic sensation that appears in the first stage of moxibustion, a benign reaction where the moxibustion fire automatically follows the meridians, promoting the warming and circulation of Qi and blood. 2. Struggle Between Health and Pathogenic Qi Numbness, swelling, sourness, heaviness, and pain are the static sensations that appear in the second stage of moxibustion, a normal reaction to the body's healthy Qi fighting against pathogenic factors. 3. Expulsion of Pathogenic Qi Wind, coolness, and cold are the dynamic sensations that appear in the third stage of moxibustion, a benign reaction indicating that the body's healthy Qi is strong and the pathogenic factors are weak, and they are being expelled from the body.