《黄帝内经·素问·六元正纪大论》
岐伯说；首先要确立纪年的天干，明了主岁之气与金木水火土五运值年之数；然后根据地支，明了司天、在泉之气的寒暑燥湿风火六气的加临情况，这样自然界的变化规律就可以显露出来，人们就可以根据天道的规律调养身体，阴阳之气盛衰的道理也就浅近易知，不再疑惑。
岐伯曰：先立其年以明其气，金木水火土运行之数，寒暑燥湿风火临御之化，则天道可见，民气可调，阴阳卷舒，近而无惑，数之可数者，请遂言之。
Qi Bo said: Firstly, we should determine the Heavenly Stems of the years, and find out the annual Qi of the current year and the annual number of the five transports of Metal, Wood, Water, Fire and Earth; then in accordance with Earthly Branches, we should find out the influences of six Qi of cold, heat, drought, wetness, wind and fire of the primary ruler of the sky and that of the springs, so the changing rule of the world may show up, and people may keep their bodies in good health according to the rule of the heavenly way, and the principles of the growing and declining of Yang and Yin Qi will be easy to understand and no more doubts.