It is commonly said, "Being familiar with Wang Shuhe's works is inferior to having more clinical experience." Some argue that the vital energy (Yuan Qi) of ancient and modern times differs, so ancient prescriptions cannot treat contemporary diseases. These two views have misled subsequent generations significantly. This seems to suggest that medical practitioners need not deeply investigate ancient methods, but merely seek abundant clinical experience. This is precisely why the art of medicine has been declining day by day.

One must first study books to form clear insights in mind; only then can one know how to flexibly apply prescriptions during clinical practice. If one relies solely on clinical experience without studying, what use is even abundant experience? Moreover, diseases manifest as deficiency or excess, with myriad variations; treatments involve tonification or purgation, and prescriptions should not be rigidly fixed. For instance, regarding fever, heat syndromes also differ between deficiency and excess. Some are suitable for warming or tonifying methods, while others are suitable for cooling or purging methods. Without reading, how can one distinguish which is deficiency and which is excess? It is like a master craftsman lacking a plumb line or ink line; would they not be lost and directionless?

Students must thoroughly investigate ancient laws and follow their rules, so that upon seeing a disease, they can understand its origin and achieve ease and proficiency. The intention behind the ancients' formulation of prescriptions lies in these "rules." Skill generated from rules is true skill. If one flaunts novelty to show off cleverness, such cleverness becomes clumsiness. Mencius said, "A master carpenter teaches others to follow rules but cannot teach them to be skillful." This implies that one must first master the rules before skill can emerge. I believe that learning medicine requires studying books first, followed by clinical practice; this is the principle.

The ancients said, "To recognize the false, one must first know the true." To treat diseases, it is essential to first understand the state of "pre-disease" (health). The viscera, collaterals, qi, and blood of humans originally stem from the digestion and transmission of food and drink, all following certain principles. The circulation of Ying (Nutrient) Qi and Wei (Defensive) Qi follows constant rhythms day and night. Divided by the waist, upper and lower parts distinguish clear yang from turbid yin. Among the seven orifices, the upper part receives the infusion of clear yang, while the lower part governs the transmission of turbid yin. Respiration corresponds to opening and closing, and movement and stillness distinguish yin and yang.

For example, a normal pulse beats four to five times per breath cycle. Three or two beats indicate insufficiency, signifying deficiency or cold. Six or seven beats indicate excess, signifying excess or heat. Pulse pulsation responds within the muscles. If pressing lightly does not detect the pulse, but pressing the skin surface reveals pulsation, it is a Floating Pulse (Fu Mai), indicating the pathology is at the exterior. If pressing the muscle layer fails to detect the pulse, and one must press heavily to the bone to feel it, it is a Deep Pulse (Chen Mai), indicating the pathology is at the interior. Therefore, one must first know the usual pulse to identify pathological pulses, grasp the general outline of exterior-interior and deficiency-excess, and further deduce based on location and season, carefully palpating which specific area shows unique abnormalities, thus leaving no hidden details of the disease.

Therefore, students of medicine must first read the *Neijing* (Inner Canon). The *Suwen* (Basic Questions) details the normal and changing states of viscera, Ying and Wei Qi, complexion, and pulses with meticulous precision. "Normal" refers to fixed principles; "Changing" refers to myriad mechanisms of transformation. By first knowing the fixed normal state, one can respond to myriad changes, just as sorting silk threads without confusion. Otherwise, the threads become chaotic, and one would not know where to begin.