Library

Adjust one's own breath, wait for the respiration to stabilize. Four to five pulsations per respiratory cycle constitute the standard of a harmonious pulse. Three pulsations per cycle is termed *Chi* (Slow) pulse, which indicates cold syndromes; six pulsations per cycle is termed *Shu* (Rapid) pulse, which indicates heat syndromes. A shift from slow to rapid implies a transition from cold to heat; a shift from rapid to slow implies a transition from heat to cold.

Having clarified the distinction between slow and rapid pulses, one must then differentiate between floating (*Fu*) and sinking (*Chen*) pulses. This elucidates the method of pulse diagnosis, emphasizing the necessity of grasping its fundamental principles. When a physician arrives at the patient's residence, they should first sit quietly for a moment, regulating their own breathing until it is even, before proceeding to palpate the patient's pulse. The criterion is based on the physician's own respiration: if the patient's pulse beats four to five times per cycle, it is considered a harmonious pulse, indicating health or, if disease is present, that it is extremely mild and superficial, as the pulse has not undergone pathological change. If the pulse beats only three times per cycle, falling short of four, it is named a *Chi* (Slow) pulse. A *Chi* pulse signifies cold qi and sluggish circulation, thus indicating cold diseases. If the pulse beats six times per cycle, exceeding four or five, it is named a *Shu* (Rapid) pulse. A *Shu* pulse signifies hot qi and swift circulation, thus indicating heat diseases. A further slowing to less than three beats indicates intensified cold; a further acceleration to more than six beats indicates intensified heat. This demonstrates the correspondence between *Chi/Shu* pulses and pathological conditions.

Once slow and rapid are understood, cold and heat are determined. To ascertain the location of cold or heat, one must further distinguish between floating and sinking.

Differentiating Floating, Sinking, Slow, and Rapid to Identify Internal and External Etiologies: External etiologies originate from Heaven (Nature), while internal etiologies originate from Humans. Heaven possesses Yin and Yang, wind, rain, darkness, and brightness; humans possess joy, anger, worry, thought, sorrow, fear, and fright. External pathogens manifesting in the exterior result in a floating pulse and exterior syndromes; those in the interior result in a sinking pulse. A slow pulse belongs to Yin, while a rapid pulse indicates Yang excess. Regarding internal factors, a floating pulse is often caused by deficient wind, a sinking pulse by Qi stagnation, a slow pulse by cold, and a rapid pulse by heat—what doubt could there be? A floating-rapid pulse indicates exterior heat; a sinking-rapid pulse indicates interior heat; a floating-slow pulse indicates exterior deficiency; a sinking-slow pulse indicates cold accumulation. By differentiating exterior-interior, Yin-Yang, wind-qi, and cold-heat, one distinguishes internal and external causes.

Pulse and symptoms are analyzed together to discern pulse principles. Although pulse theory is vast, it can be summarized into four categories: floating, sinking, slow, and rapid. Having grasped this outline, one can extend knowledge through analogy. Here, these four pulses are collectively described as the纲领 (guiding principle) of pulse taking, used to differentiate the etiology of internal and external infections. Exterior locations correspond to floating pulses; interior locations correspond to sinking pulses; slow indicates cold; rapid indicates heat. This is an immutable principle. However, there are two types of etiology, necessitating the distinction between internal and external causes.

External contraction of the Six Excesses (Liu Yin) arises from Heavenly factors; internal injury from the Seven Emotions (Qi Qing) arises from Human factors. The Six Excesses refer to the Yin and Yang, wind, rain, darkness, and brightness of nature. "Excess" (Yin) refers to overflowing, biased dominance, and prolonged persistence without recovery. As stated by Yi He in the *Zuo Zhuan*: Yin excess causes cold diseases; Yang excess causes heat diseases; Wind excess causes diseases of the extremities; Rain excess causes abdominal diseases; Darkness (obscurity) excess causes disorders of confusion; Brightness (excessive light) excess causes heart diseases. The Seven Emotions refer to human joy, anger, worry, thought, sorrow, fear, and fright. These are also known as the "Seven Qi." As described in Chao Yuanfang's *Zhu Bing Yuan Hou Lun*: Joy relaxes Qi; Anger causes Qi to ascend; Sorrow dissipates Qi; Fear causes Qi to descend; Worry disrupts Qi; Fatigue consumes Qi; Thought causes Qi to knot; Fright scatters Qi.

External pathogens enter from the exterior and remain in the exterior. When the healthy Qi responds, the pulse must be floating. If a sinking pulse is observed, it indicates the pathogen has left the exterior and entered the interior. If the pulse rate is less than four beats per cycle, it is called *Chi* (Slow), indicating the pathogen is in the Yin aspect, primarily causing cold. If it exceeds four beats, it is called *Shu* (Rapid), indicating the pathogen is in the Yang aspect, primarily causing heat.

Internal pathogens arise from within. For instance, sudden great joy, abrupt fright, or violent anger cause Yang Qi to float outward, resulting in a floating pulse, yet underlying deficiency exists. Such cases include fainting or collapsing due to anger, fainting due to fright, or stooping pain due to excessive joy, resembling stroke but not caused by external wind; this is termed "deficient wind." Conversely, prolonged accumulation of worry, thought, sorrow, and fear leads to depression, causing the pulse to sink. Since there is no floating wind manifestation, it is directly attributed to Qi. A slow pulse indicates cold; regardless of the specific Qi involved, a slow pulse primarily indicates cold. A rapid pulse indicates heat; regardless of the specific Qi involved, a rapid pulse primarily indicates heat.

If the pulse is rapid and indicates heat: if obtained via superficial palpation (floating), the heat is in the exterior, regardless of the cause; if obtained via deep palpation (sinking), the heat is in the interior. If the pulse is slow and indicates cold: if obtained via superficial palpation, the cold is in the exterior and associated with deficiency; if obtained via deep palpation, the cold is in the interior and associated with accumulation. External factors involve exterior-interior and Yin-Yang distinctions; internal factors involve wind-qi and cold-heat distinctions. Without pulse diagnosis, these cannot be differentiated. Although pulse theory is extensive, grasping the general principles allows for detailed analysis. By focusing on the four pulses—floating, sinking, slow, and rapid—and applying analogical reasoning, one can use one case to verify another and one principle to exemplify another. In this way, the profound essence of pulse diagnosis becomes largely comprehensible.