灵枢经·卫气行 Discourse on the Circulation of Defensive Qi

Huangdi asked Qibo: "I wish to hear how the defensive qi circulates, and how its emergence and entry correspond to the body — how does this work?" Qibo replied: "The year has twelve months, and the day has twelve double-hours; zi and wu form the warp, and mao and you form the weft. Heaven's circuit comprises twenty-eight lunar lodges, seven stars to each of the four quarters, four sevens making twenty-eight stars in all. Fang and Mao form the weft, while Xu and Zhang form the warp. Thus, from the lodge Fang to the lodge Bi is yang, and from the lodge Mao to the lodge Xin is yin; yang governs the daytime, and yin governs the night. Therefore the circulation of the defensive qi, over the course of one day and one night, makes fifty circuits of the body: during the daytime it travels through the yang for twenty-five circuits, and during the night it travels through the yin for twenty-five circuits, circulating through the five viscera."

Thus, at dawn, when yin is exhausted, the yang qi emerges from the eyes; when the eyes open, the qi ascends to the head, follows the nape, and descends along the Foot Taiyang channel, following the back down to the tip of the little toe. A branch of it separates at the outer canthus of the eye and descends along the Hand Taiyang channel, down to the outer side, between the little finger and the hand. Another branch separates at the outer canthus and descends along the Foot Shaoyang channel, pouring into the space between the fourth and little toes. It then ascends and follows the lateral aspect of the Hand Shaoyang channel, descending to the space between the fingers. A separate branch ascends to a point in front of the ear, joins with the mandibular vessel, and pours into the Foot Yangming channel, descending to the instep and entering the space between the toes. A branch of it descends from below the ear along the Hand Yangming channel, entering the space between the thumb and index finger, and into the palm. When the qi reaches the foot, it enters the sole, emerges at the medial malleolus, travels downward through the yin portion of the leg, and once again joins with the eyes — thus completing one circuit.

Thus, when the sun travels one lodge, the human qi makes one circuit of the body plus eight-tenths of a circuit; when the sun travels two lodges, the human qi makes three circuits of the body plus six-tenths; when the sun travels three lodges, the human qi makes five circuits of the body plus four-tenths; when the sun travels four lodges, the human qi makes seven circuits of the body plus two-tenths; when the sun travels five lodges, the human qi makes nine circuits of the body; when the sun travels six lodges, the human qi makes ten circuits of the body plus eight-tenths; when the sun travels seven lodges, the human qi makes twelve circuits of the body plus six-tenths; when the sun travels fourteen lodges, the human qi makes twenty-five circuits of the body with a remaining fraction of two-tenths — at this point yang is exhausted and passes into yin, and yin then receives the qi. When the qi first enters yin, it always proceeds from the Foot Shaoyin channel and pours into the kidney; the kidney pours into the heart, the heart pours into the lung, the lung pours into the liver, the liver pours into the spleen, and the spleen once again pours into the kidney, completing one circuit. Thus, in the course of the night, for each lodge the sun would travel, the human qi makes one circuit through the yin viscera plus eight-tenths of a circuit, just as in its daytime passage through yang it makes twenty-five circuits, and then once again joins with the eyes. Combining the yang and yin circuits of a single day and night, there remains a fraction of four-tenths of a bodily circuit and two-tenths of a visceral circuit; this is the reason that the time at which people fall asleep and awaken varies, being sometimes early and sometimes late — because this remaining fraction never divides evenly.

Huangdi said: "Since the defensive qi, as it moves through the body, travels up and down without a fixed schedule, how does one wait for the proper moment of qi in order to needle it?" Bogao replied: "The divisions of day and night have their greater and lesser portions, and the days have their longer and shorter lengths; in spring, autumn, winter, and summer, each has its own proportional pattern. Nevertheless, one should always take dawn as the starting point of reckoning, and the end of night as the beginning. Thus, over the course of one day and one night, the water clock drips down a hundred markings (ke); twenty-five markings constitute the measure of half a day. This pattern holds constantly without exception, ending when the sun sets; one reckons according to the varying length of the day and needles accordingly. If one carefully observes the proper timing, the disease can be anticipated and treated in step with it; but if one misses the timing and goes against the proper observation, the hundred diseases cannot be cured. Hence it is said: in needling excess, one needles as the qi is arriving; in needling deficiency, one needles as the qi is departing. This refers to the timing of the qi's presence or absence, by which one observes deficiency and excess and needles accordingly. Thus one must carefully observe where the qi is located and needle it there — this is called 'meeting the proper time.' When the disease is in the three yang channels, one must wait until the qi is in the yang before needling; when the disease is in the three yin channels, one must wait until the qi is in the yin portion before needling."

When the water clock has dripped down one marking, the human qi is in Taiyang; at two markings, the human qi is in Shaoyang; at three markings, the human qi is in Yangming; at four markings, the human qi is in the yin portion. At five markings, the human qi is in Taiyang; at six markings, in Shaoyang; at seven markings, in Yangming; at eight markings, in the yin portion. At nine markings, the human qi is in Taiyang; at ten markings, in Shaoyang; at eleven markings, in Yangming; at twelve markings, in the yin portion. At thirteen markings, the human qi is in Taiyang; at fourteen markings, in Shaoyang; at fifteen markings, in Yangming; at sixteen markings, in the yin portion. At seventeen markings, the human qi is in Taiyang; at eighteen markings, in Shaoyang; at nineteen markings, in Yangming; at twenty markings, in the yin portion. At twenty-one markings, the human qi is in Taiyang; at twenty-two markings, in Shaoyang; at twenty-three markings, in Yangming; at twenty-four markings, in the yin portion. At twenty-five markings, the human qi is in Taiyang — this is the measure of half a day. From the lodge Fang to the lodge Bi is fourteen lodges, corresponding to fifty markings of the water clock, during which the sun travels half of its circuit, returning through one lodge for every three markings and four-sevenths of a marking. The essential rule states: whenever the sun arrives at a given lodge, the human qi is in Taiyang; thus, as the sun travels one lodge, the human qi travels through the three yang channels and the yin portion. This pattern continues constantly without ever ceasing; Heaven and Earth share the same reckoning, moving on in endless succession, ending only to begin again — over the course of one day and one night, the water clock drips down a hundred markings, and the cycle is complete.