Discourse on the Distinction of Yin and Yang

The Yellow Emperor asked: "Man has four meridians and twelve associates—what does this mean?" Qi Bo replied: "The four meridians correspond to the four seasons; the twelve associates correspond to the twelve months, and the twelve months correspond to the twelve vessels. Vessels have yin and yang differentiation. Understanding yang vessels enables understanding of yin vessels; understanding yin vessels enables understanding of yang vessels. There are five types of yang vessels, and five times five makes twenty-five types of yang vessels. What are called yin vessels are the true visceral vessels; when this pulse pattern appears, it indicates that the righteous qi is failing, and failure inevitably leads to death. What are called yang vessels are the yang qi of the stomach duct. To distinguish yang vessels is to know where the disease lies; to distinguish yin vessels is to know the day of death or survival. The three yang channels are located in the head, and the three yin channels in the hand—their principle is the same. To distinguish yang vessels is to know the seasonal prohibitions of disease; to distinguish yin vessels is to know the date of death or survival. Carefully and diligently familiarize yourself with yin and yang pulse patterns, and do not consult with others. As for yin and yang, when the pulse departs, it is yin; when it arrives, it is yang. When it is quiet, it is yin; when it is agitated, it is yang. When it is slow, it is yin; when it is rapid, it is yang. In all cases where a true visceral pulse is obtained: if the liver pulse appears suspended and extremely tense, death occurs in eighteen days; if the heart pulse appears suspended and extreme, death occurs in nine days; if the lung pulse appears suspended and extreme, death occurs in twelve days; if the kidney pulse appears suspended and extreme, death occurs in seven days; if the spleen pulse appears suspended and extreme, death occurs in four days."

Question: "In disease of the two yang, occurring in the heart and spleen, there may be cases where one cannot express hidden feelings; in women this leads to irregular menstruation. If it transmits and transforms into wind consumption, and further transmits into dyspnea with fullness, it becomes untreatable and results in death." Question: "In disease of the three yang, there is alternating cold and heat, swelling and abscesses in the lower parts, as well as atrophy, reversal, and soreness of the lower legs; it transmits into withered skin, and further transmits into hernia with swelling." Question: "In disease of the one yang, there is shortness of breath, tendency to cough, and tendency to diarrhea; it transmits into pulling pain in the heart, and further transmits into dysphagia." When the two yang and one yin are diseased, the main symptoms are fright, back pain, tendency to belch, and tendency to yawn; the disease is called wind reversal. When the two yin and one yang are diseased, there is tendency to abdominal distension, fullness in the heart, and tendency to sigh. When the three yang and three yin are diseased, it manifests as hemiplegia, atrophy and weakness, and inability to move the four limbs.

When the pulse is stirred by one yang, it is called a hook pulse; when stirred by one yin, it is called a hairy pulse; when stirred by excessive and rapid yang pulse, it is called a string pulse; when stirred by the arrival of yang pulse that suddenly breaks off, it is called a stone pulse; when yin and yang interact with each other, it is called a slippery pulse. When yin qi contends internally and yang qi disturbs externally, sweat cannot be retained, and coldness of the four limbs rushes upward; rushing upward scorches the lung, causing the person to wheeze audibly. The generation of yin qi takes fundamental harmony as its balance. Therefore, if hardness combines with hardness, yang qi will scatter and break, and yin qi will also vanish. If yin qi is excessive, then hardness and softness are not harmonized, and channel qi will be severed. For those belonging to death yin, death occurs within three days; for those belonging to life yang, death occurs within four days. What is meant by life yang and death yin: when the liver transmits to the heart, it is called life yang; when the heart transmits to the lung, it is called death yin; when the lung transmits to the kidney, it is called double yin; when the kidney transmits to the spleen, it is called destructive yin, untreatable and resulting in death. When yang qi is constrained, the four limbs swell. When yin qi is constrained, there is bloody stool of one sheng; with a second constraint, bloody stool of two sheng; with a third constraint, bloody stool of three sheng. When both yin and yang are constrained and lean to one side, with more yin and less yang, it is called stone water, with swelling of the lower abdomen. Constraint of the two yang is called wasting-thirst; constraint of the three yang is called dysphagia; constraint of the three yin is called edema; constraint of one yin and one yang is called throat obstruction. When the yin pulse is strong and forceful, and the yang pulse is distinct from it, it indicates pregnancy. When both yin and yang are deficient and there is dysentery, death occurs. When the yang pulse overlies the yin pulse, it is called sweating. When the yin pulse is deficient and the yang pulse is strong and forceful, it is called uterine bleeding. When all three yin pulses are forceful, death occurs at midnight on the twentieth day. When all two yin pulses are forceful, death occurs at dusk on the thirteenth day. When all one yin pulses are forceful, death occurs on the tenth day. When all three yang pulses are forceful and stirring, death occurs on the third day. When all three yin and three yang pulses are forceful, there is distension and fullness of the heart and abdomen. When the condition reaches an extreme and hidden feelings cannot be expressed, death occurs on the fifth day. When all two yang pulses are forceful, the disease is warm febrile, untreatable, and death occurs within no more than ten days.