司天运气。仲景不言，非忽也。上古圣人。欲通天之纪。从地之理。以调民之气。五运者即
金木水火土营运之数。六气者即寒暑燥湿风火临御之化。因按十二辰纪岁以明其气。太阳寒水
。阳明燥金。少阳相火。太阴湿土。少阴君火。厥阴风木。子午之岁。上少阴火。下阳明金
丑未之岁。上太阴土。下太阳水。寅申之岁。上少阳相火。下厥阴木。卯酉之岁。上阳明金
。下少阴火。辰戌之岁。上太阳水。下太阴土。巳亥之岁。上厥阴木。下少阳相火。此天地
之气。营运旋转。以是绾定上下。分别司天在泉。其次可按岁而纪。然上下旋转。虽有定位
。而其中所乘之运。又按岁上所临之天干。分别异运。且六气皆有左右间。一岁之间。分别
循环作主。此外又有天符岁会三命之不齐。南政北政之易位。与夫气之胜与不胜。脉之应与不应。
以及初终胜复。气至先后。自非通天彻地参赞位育之圣人。焉能知化穷神。洞烛无间。乃今
人开口辄言司天运气。置一切精义于不讲。但言本年何气司天。是年之民。当生何病。此种
耳食之谈。殊堪喷饭。且必按司天运气以言民病。则岁不一气。民不一病。转使学人无着实
下手工夫。故仲景但就人身上三阴三阳。谛实病因。而天之五运六气。即已范围于莫能外。
经云善言天者必有验于人。内经所言天人合一之学。仲景所言尽人合天之学。医之有仲景。
犹儒之有孔子。试观四子书中所言皆日用伦常之事。虽极参天地赞化育之功能。总在伦常日
用上做起。端木子曰。夫子之文章。可得而闻也。夫子之言性与天道。不可得而闻也。此诚悟道之言也。
司天运气（指每年主岁的六气变化规律）的理论，张仲景在《伤寒论》中并未直接论述，这并不是因为他疏忽了。上古的圣人，想要通晓天道的纲纪，顺应地理的规律，以此来调和百姓的气机。所谓“五运”，就是金、木、水、火、土五行运行变化的数理；所谓“六气”，就是寒、暑、燥、湿、风、火六种气候临御化育的作用。于是按照十二地支来纪年，以明确其气运。太阳寒水（子午之年对应的在泉之气等），阳明燥金，少阳相火，太阴湿土，少阴君火，厥阴风木。
子年和午年，上为少阴君火司天，下为阳明燥金在泉；
丑年和未年，上为太阴湿土司天，下为太阳寒水在泉；
寅年和申年，上为少阳相火司天，下为厥阴风木在泉；
卯年和酉年，上为阳明燥金司天，下为少阴君火在泉；
辰年和戌年，上为太阳寒水司天，下为太阴湿土在泉；
巳年和亥年，上为厥阴风木司天，下为少阳相火在泉。
这就是天地之气的运行旋转，以此确定上下位置，分别司天和在泉的方位。其次可以按年份来记录。然而上下旋转虽然有其固定的位置，但其中所乘的运数，又根据每年所临的天干，分为不同的异运。而且六气都有左右间气，一年之间，分别循环作为主气。此外还有天符、岁会、三命等不同情况，以及南政、北政位置的变换，还有气的胜与不胜，脉象的应与不应，以及初终阶段的胜复之气，气至的先后顺序。如果不是能够通天彻地、参赞天地化育的圣人，怎么能知晓气化穷尽神妙，洞察细微无间呢？
如今的人开口就谈论司天运气，却置一切精微义理于不讲求，只说本年是何气司天，这一年的百姓应当生什么病。这种道听途说的言论，实在令人喷饭。而且如果一定要按照司天运气来论述百姓的疾病，那么每年气不同，百姓的病也不同，反而使学医之人没有切实下手的功夫。所以张仲景只是针对人体上的三阴三阳，仔细审察病因，而天上的五运六气，就已经包含在其中，无法逃脱其范围。
经典说：善于谈论天道的人，一定能在人身验证。《内经》所言的是天人合一的学问，张仲景所言的是尽人合天的学问。医学中有张仲景，就像儒家有孔子一样。试看《四书》中所言的都是日常伦理常情之事，虽然极尽参赞天地化育的功能，总还是在伦理日用上做起。端木赐（子贡）说：夫子关于文献典籍的知识，我们可以听到；夫子关于性与天道的言论，我们听不到。这确实是领悟大道的言语。
The theory of Si Tian Yun Qi (Annual Dominant Six-Qi Changes) is not explicitly discussed by Zhang Zhongjing in the *Shanghan Lun* (Treatise on Cold Pathogenic Diseases), not because he overlooked it. The sages of antiquity sought to comprehend the principles of Heaven and conform to the laws of Earth, thereby regulating the Qi of the people. "Wu Yun" (Five Movements) refers to the numerical patterns of the operation and transformation of Metal, Wood, Water, Fire, and Earth. "Liu Qi" (Six Qis) refers to the transformative influences of Cold, Heat, Dryness, Dampness, Wind, and Fire. Thus, they utilized the Twelve Earthly Branches to record years to clarify these Qi movements.
Taiyang Han Shui (Cold Water of Taiyang), Yangming Zao Jin (Dry Metal of Yangming), Shaoyang Xiang Huo (Ministerial Fire of Shaoyang), Taiyin Shi Tu (Damp Earth of Taiyin), Shaoyin Jun Huo (Ruler's Fire of Shaoyin), Jueyin Feng Mu (Wind-Wood of Jueyin).
In years of Zi and Wu, Shaoyin Jun Huo (Ruler's Fire of Shaoyin) governs above (Si Tian / Governing Heaven), and Yangming Zao Jin (Dry Metal of Yangming) governs below (Zai Quan / In-spring).
In years of Chou and Wei, Taiyin Shi Tu (Damp Earth of Taiyin) governs above, and Taiyang Han Shui (Cold Water of Taiyang) governs below.
In years of Yin and Shen, Shaoyang Xiang Huo (Ministerial Fire of Shaoyang) governs above, and Jueyin Feng Mu (Wind-Wood of Jueyin) governs below.
In years of Mao and You, Yangming Zao Jin (Dry Metal of Yangming) governs above, and Shaoyin Jun Huo (Ruler's Fire of Shaoyin) governs below.
In years of Chen and Xu, Taiyang Han Shui (Cold Water of Taiyang) governs above, and Taiyin Shi Tu (Damp Earth of Taiyin) governs below.
In years of Si and Hai, Jueyin Feng Mu (Wind-Wood of Jueyin) governs above, and Shaoyang Xiang Huo (Ministerial Fire of Shaoyang) governs below.
These are the movements and rotations of the Qi of Heaven and Earth, which determine the positions of above and below, distinguishing between Si Tian (Governing Heaven) and Zai Quan (In-spring). Subsequently, one can record them according to the year. However, although the rotation of above and below has fixed positions, the Yun (Movement) prevailing within them varies according to the Heavenly Stem associated with each year, resulting in different Yun variations. Furthermore, each of the Six Qis has left and right interstitial Qi, which cycle sequentially throughout the year to act as the main Qi. Additionally, there are irregularities such as Tian Fu (Heavenly符), Sui Hui (Year Meeting), and San Ming (Three Destinies), as well as positional changes between Nan Zheng (Southern Administration) and Bei Zheng (Northern Administration). There are also considerations of Qi exceeding or failing to exceed, pulse response or non-response, the victory and revenge of Qi at the beginning and end, and the sequence of Qi arrival. Unless one is a sage capable of comprehending Heaven and Earth and assisting in their creative transformation, how could one know the profound mysteries of Qi transformation and perceive without any gap?
Today, people readily discuss Si Tian Yun Qi but neglect all its subtle meanings, merely stating which Qi governs Heaven in a given year and what diseases the populace should expect. Such hearsay is laughable. Moreover, if one must diagnose public diseases strictly according to Si Tian Yun Qi, then since the Qi differs each year, the diseases differ for the people, leaving students of medicine without a solid foundation for practical application. Therefore, Zhang Zhongjing focuses solely on the Three Yin and Three Yang of the human body, carefully examining the etiology, while the Wu Yun Liu Qi of Heaven are already encompassed within this framework, unable to escape it.
The Classics state: "One who speaks well of Heaven must have verification in humanity." What the *Neijing* (Inner Canon) discusses is the unity of Heaven and Humanity; what Zhang Zhongjing discusses is the integration of humanity with Heaven. In medicine, Zhang Zhongjing is like Confucius in Confucianism. Observe that the teachings in the *Four Books* concern daily ethical relations. Although they fully embody the function of assisting Heaven and Earth in their creative processes, they always begin from daily ethics and routines. Duanmu Ci (Zigong) said: "The literary achievements of our Master may be heard; his words on Human Nature and the Way of Heaven cannot be heard." This is indeed a statement reflecting the understanding of the Great Dao.