伤寒之病，非比杂科，乃大方脉之首务也。其间脉理精深，艮震无常，死生反掌，甚所难明。
苟或有称治伤寒者，未免羊质虎皮，然则名节虚隆，而实德则病矣。余早年盲学，昏昏如蝇触牖，
后得汉长沙张仲景先师治法，所得石函遗着，名曰《遗芳嘉秘》，玩而诵之，以开茅塞，手足舞蹈，
不自知也。数试数验，岂不珍重哉！第恐吾老，子亦犹前之昏学，临病无措，故将遗旨，应手得心
诀法，纂以成集，名曰《伤寒证脉药截江网》，存与朝夕备览，以看省己之愚。原夫伤寒之脉，浮、
大、动、数、滑为阳，沉、涩、弱、弦、微为阴。其弦、紧、浮、滑、沉、涩六者，为残
贼之脉，故诸脉作病。春弦，夏洪，秋毛，冬石，土缓，为四季之正脉。浮、沉、迟、数为客主。
左为人迎，右为气口。呼出心肺为阳，吸入肾肝为阴。一呼一吸为一息。寸口为阳，尺泽为阴，中为
关界。阳主气，阴主血；血为荣，气为卫；寒则伤荣，风则伤卫；理自然也。所谓伤寒之病，从浅
入深，先以皮肤肌肉，次入筋骨肠胃，专以浮、中、沉、迟、数辩其阴阳寒热及表里虚实而断之矣。
诸浮为在表，轻手于皮肤之上便得之，曰浮。略重指于皮肤之下，肌肉之上，阴阳各半得之，曰中，
证属半表半里。诸沉为在里，重手于肌肉之下，筋骨之间方得之，曰沉，属阴。诸迟为在脏，属寒。
诸数为在腑，属热。阴阳、寒热、虚实，用在有力无力中分。有力者，为阳，为热，为实。无力者，
为阴，为寒，为虚。杂病以弦为阳，伤寒以弦为阴。杂病以缓为弱，伤寒以缓为和。伤寒以大为病
进，以缓为邪退。缓为胃脉，有胃气曰生，无胃气曰死。伤寒病中有神脉，如脉中有力，即为有神。
神者，气血之先也。两手无脉，曰双伏，一手无脉，曰单伏，必有正汗也。寸口阳脉中，或见沉细
者，但无力者，为阳中伏阴。尺部阴脉中，或见沉数者，为阴中伏阳。寸口数大有力，为重阳；尺
部微而无力，为重阴。寸口细微如丝，为脱阳；尺部细微无力，为脱阴。寸脉浮而有力，主寒邪
表实，宜汗。浮而无力，主风邪表虚，宜实。尺脉沉而有力，主阳邪在里，为实，宜下；无力，主
阴邪在里，为虚，宜温。寸脉弱而无力，切忌发汗。尺脉弱而无力，切忌汗下。初按来疾去迟，名
曰内虚外实；去疾来迟，名曰内实外虚。尺寸俱同，名曰缓。缓者，和而生也。汗下后脉静者，生；
燥乱身热者，死，乃邪气胜也。温之后脉来歇止者，正气脱而不复生也。纯弦之脉，名曰负。负者，
死。按之解索，名曰阴阳离。离者，死。阴病见阳脉者生，阳病见阴脉者死。
The disease of Shanghan (Cold Damage) is not comparable to other medical specialties; it is the primary concern of internal medicine (Da Fang Mai). The principles of pulse diagnosis are profound and intricate, unpredictable like the changes of Heaven and Earth, with life and death hanging in the balance, making it extremely difficult to elucidate.
If someone claims to treat Shanghan, they may merely be a sheep with tiger skin—appearing formidable but lacking substance. Thus, their reputation might be inflated, but their actual virtue and skill are flawed. In my early years, I studied blindly, confused as if a fly were bumping against a windowpane. Later, I obtained the treatment methods from my predecessor, Zhang Zhongjing, the Chancellor of Changsha during the Han Dynasty. I acquired his遗著 (legacy writings) preserved in a stone casket, titled *Yi Fang Jia Mi* (Precious Secrets Fragrant in Retrospect). I studied and recited them to clear my mental obscurity, dancing with joy without realizing it. Having tested them repeatedly with success, how could they not be cherished? However, fearing that in my old age, my descendants would still study foolishly and be at a loss when facing illness, I compiled the legacy instructions and effective techniques into a collection named *Shanghan Zheng Mai Yao Jie Jiang Wang* (The Intercepting River Net for Shanghan Symptoms, Pulses, and Medicines), to be kept for daily review, allowing me to examine and reflect upon my own ignorance.
Generally speaking, the pulses of Shanghan: Fu (Floating), Da (Large), Dong (Surging), Shu (Rapid), and Hua (Slippery) belong to Yang; Chen (Deep), Se (Choppy), Ruo (Weak), Xian (Wiry), and Wei (Fine) belong to Yin. Among these, Xian (Wiry), Jin (Tight), Fu (Floating), Hua (Slippery), Chen (Deep), and Se (Choppy) are considered "destructive and harmful" pulses, causing various diseases. In Spring, the pulse is Wiry; in Summer, Surging; in Autumn, Floating (Mao); in Winter, Deep (Shi); and in the late summer/earth phase, Slow (Huan). These are the normal pulses of the four seasons. Fu, Chen, Chi (Slow), and Shu (Rapid) distinguish between pathogenic factors and healthy qi. The left wrist represents Ying (Human Welcome), and the right wrist represents Qi Kou (Qi Mouth). Exhalation relates to the Heart and Lung (Yang); inhalation relates to the Kidney and Liver (Yin). One exhalation and one inhalation constitute one breath (Xi). Cun Kou (Inch Port) is Yang, Chi Ze (Cubit Marsh) is Yin, and Guan (Pass) is the boundary between them. Yang governs Qi; Yin governs Blood. Blood is Ying (Nutritive Qi); Qi is Wei (Defensive Qi). Cold injures Ying; Wind injures Wei. This is the natural order.
The disease of Shanghan progresses from shallow to deep, initially affecting the skin and muscles, then entering the sinews, bones, intestines, and stomach. Diagnosis relies on distinguishing Yin/Yang, Cold/Heat, Exterior/Interior, and Deficiency/Excess through Fu, Zhong (Moderate), Chen, Chi, and Shu pulses.
All Fu (Floating) pulses indicate the disease is in the Exterior; felt lightly on the skin surface, it is called Fu. Felt slightly heavier below the skin but above the muscle, where Yin and Yang are equal, it is called Zhong, indicating a Half-Exterior/Half-Interior syndrome. All Chen (Deep) pulses indicate the disease is in the Interior; felt heavily below the muscle and between the sinews and bone, it is called Chen, belonging to Yin. All Chi (Slow) pulses indicate the disease is in the Zang (Organ), belonging to Cold. All Shu (Rapid) pulses indicate the disease is in the Fu (Organ), belonging to Heat. The distinctions of Yin/Yang, Cold/Heat, and Deficiency/Excess are determined by whether the pulse is Forceful or Feeble. Forceful indicates Yang, Heat, and Excess. Feeble indicates Yin, Cold, and Deficiency. In miscellaneous diseases, Wiry is Yang; in Shanghan, Wiry is Yin. In miscellaneous diseases, Slow is Weak; in Shanghan, Slow is Harmonious. In Shanghan, Large indicates disease progression; Slow indicates pathogenic retreat. Slow is the pulse of the Stomach; having Stomach Qi implies life, lacking it implies death.
In Shanghan, a "Spirit Pulse" exists; if the pulse has force, it possesses Spirit. Spirit is the precursor of Qi and Blood. If no pulse is felt in both hands, it is called Double Hidden (Shuang Fu); if no pulse is felt in one hand, it is called Single Hidden (Dan Fu). In both cases, normal sweating will occur. In the Cun Kou (Yang pulse position), if a Deep-Fine pulse is seen and is feeble, it is Yang concealing Yin. In the Chi position (Yin pulse position), if a Deep-Rapid pulse is seen, it is Yin concealing Yang. Cun Kou Rapid-Large and Forceful indicates Heavy Yang; Chi Fine-Weak and Feeble indicates Heavy Yin. Cun Kou Fine-as-silk indicates Collapse of Yang; Chi Fine-Weak and Feeble indicates Collapse of Yin.
Cun Floating and Forceful indicates Cold Pathogen in the Exterior with Excess, suitable for Sweating (Diaphoresis). Floating and Feeble indicates Wind Pathogen in the Exterior with Deficiency, suitable for Consolidating (Tonifying). Chi Deep and Forceful indicates Yang Pathogen in the Interior with Excess, suitable for Purging (Downward Drainage); Feeble indicates Yin Pathogen in the Interior with Deficiency, suitable for Warming. Cun Weak and Feeble strictly forbids Sweating. Chi Weak and Feeble strictly forbids Sweating and Purging. Upon initial palpation, if the pulse departs quickly and arrives slowly, it is called Internal Deficiency and External Excess; if it departs slowly and arrives quickly, it is called Internal Excess and External Deficiency. If Cun and Chi are identical, it is called Slow (Huan). Slow implies harmony and vitality. After Sweating or Purging, if the pulse becomes quiet, there is life; if the body is restless and hot, there is death, due to the dominance of pathogenic qi. After Warming, if the pulse shows intermittent pauses, it indicates the collapse of Healthy Qi with no recovery. A purely Wiry pulse is called Negative (Fu); Negative implies death. A pulse felt like unraveling silk is called Separation of Yin and Yang; Separation implies death. Yin diseases manifesting Yang pulses indicate life; Yang diseases manifesting Yin pulses indicate death.