Fifty Circuits

The Yellow Emperor said: I would like to hear about the fifty circulations—what is their significance? Qi Bo replied: The celestial cycle encompasses twenty-eight lunar mansions, each separated by a distance of thirty-six fen. The qi of the human body’s channels circulates through a total length of one thousand and eight fen in one complete circuit, corresponding to the sun’s traversal of the twenty-eight mansions in a single day. The human body has twenty-eight channels—upper and lower, left and right, front and back—with a total length of sixteen zhang and two chi, corresponding to the twenty-eight mansions. Day and night are marked by the dripping of a clepsydra, with one hundred ke marking the full cycle. Thus, with one exhalation, the pulse beats twice and the channel qi moves three cun; with one inhalation, the pulse also beats twice and the channel qi moves three cun. One exhalation and one inhalation together constitute one breath, during which the channel qi moves a total of six cun. After ten breaths, the channel qi moves six chi, and the sun moves two fen. After two hundred and seventy breaths, the channel qi moves sixteen zhang and two chi, completing one full circuit through the body where the qi converges and interflows. At this point, the clepsydra has dripped two ke of water, and the sun has moved twenty-five fen. After five hundred and forty breaths, the channel qi completes two full circuits through the body, the clepsydra has dripped four ke, and the sun has moved forty fen. After two thousand seven hundred breaths, the channel qi completes ten full circuits, the clepsydra has dripped twenty ke, and the sun has moved five mansions plus twenty fen. After thirteen thousand five hundred breaths, the channel qi completes fifty full circuits through the body, the clepsydra has dripped one hundred ke, and the sun has traversed the twenty-eight mansions. When the water in the clepsydra is exhausted, the qi in the channels has also completed its circulation. What is called “interflow” (jiaotong) means that the channel qi moves concurrently through the same number of circuits. Therefore, when the fifty circulations are complete, a person can fully enjoy the natural lifespan bestowed by Heaven and Earth, and the total length of channel qi movement is eight hundred and ten zhang.