The tongue is the sprout of the Heart (Xin). It is where the Qi of the Great Master of the Zang-Fu organs (Zang-Fu) communicates and where its orifice opens. Examining the diagrams of the Zang-Fu, the Spleen (Pi), Lung (Fei), Liver (Gan), and Kidney (Shen) all have their roots in the Heart. Investigating the meridians and collaterals (Jing-Luo), and examining the Yin and Yang of the hand and foot, there is no meridian that does not connect to the tongue. Thus, it can be known that diseases of the meridians and Zang-Fu are not limited to Shanghan (Cold Damage) with fever presenting a coating for verification; even all internal and external miscellaneous diseases present their forms and colors on the tongue. Therefore, the method of inspecting the tongue cannot be neglected by clinicians. Why did previous famous physicians omit this, recording it only in *Jin Jing* (Golden Mirror) regarding Shanghan? Since my adulthood, I respectfully inherited my family's learning, dedicating myself to medical principles. I occasionally experienced the thirty-six tongues from *Jin Jing*, finding many methods unsuitable, and questioned my late father about them. My father said: "Has Dongzhuang not said that the thirty-six tongues in *Jin Jing* should be understood in spirit rather than adhered to rigidly? There are conditions beyond these thirty-six tongues that must be comprehended through insight." Following my father's instruction, I reflected on why the spirit should be grasped and the methods not rigidly followed, realizing that what Dongzhuang said truly resonated with my mind. Thus, in clinical practice, when inspecting the tongue, one must observe its form and examine its color, combining this with pulse and symptoms, thereby gaining secret insights. Based on the tongue, distinguishing between Xu (Deficiency) and Shi (Excess) ensures accuracy; based on the tongue, distinguishing Yin and Yang prevents error; based on the tongue, identifying Zang-Fu and prescribing main formulas ensures correct organ localization and formula selection. In critical and difficult cases, where symptoms offer little reference and pulses are hard to palpate, the tongue serves as the sole criterion; in diseases of women and children, where breath sounds are absent and complaints are silent, the tongue remains the only verifiable sign. Thus, Yin and Yang, Xu and Shi, are perceived truly; tonifying and draining, warming and clearing, yield miraculous responses. People see that observation is always true and treatment always effective, invariably praising it as extraordinary. Yet they do not know that among the Four Diagnostic Methods (Si Zhen), I possess a unique secret regarding tongue diagnosis. However, what is this unique secret? It is merely the shared principle. If clinicians study deeply and comprehend, then analyzing separately, each Zang-Fu has its own Yin and Yang, and each Yin and Yang has its own Xu and Shi; with complete principles and precise methods, one can supplement what *Jin Jing* omitted, extending beyond just thirty-six tongues. Synthesizing them, all Zang-Fu share this Yin and Yang, and this Yin and Yang shares this Xu and Shi; with round principles and flexible methods, one can correct what *Jin Jing* failed to fit, without being bound to thirty-six tongues. Analyzing separately, the methods do not exceed the Five Elements (Wu Xing); synthesizing together, the principle originates from the Taiji (Supreme Ultimate). Applying this to clinical practice, although disease manifestations may be as numerous as ten thousand leaves and thousand branches, a single glance with divine clarity allows one to trace the root and extract the source. How could there be creating illness where none exists, or exacerbating illness where it exists, thereby inviting pathogenic factors, losing righteous Qi, and cutting short life? Herein, I detail the various methods of tongue inspection for the reference of knowledgeable practitioners.