（《素问·六元正纪大论》）
帝曰∶天地之数，终始奈何？（司天在泉各有所主之数。）岐伯曰∶悉乎哉问也！是明道也。数之始，起于上而终于
下，（司天在前，在泉在后，司天主上，在泉主下，故起于上而终于下。）岁半之前，天气主之，岁半之后，地气主之，（岁
半之前，始于大寒，终于小暑也。岁半之后，始于大暑，终于小寒也。《至真要大论》 曰∶初气终三气，天气主之；四
气尽终气，地气主之。）上下交互，气交主之，岁纪毕矣。（交互者，天气地气，互合为用也。气交主之，即三气四气之
际，乃天地气交之时。详义见本类前九。）故曰位明，气月可知乎，所谓气也。（上下左右之位既明，则气之有六，月之
有十二，其终始移易之数，皆可知矣，此即所谓天地之气。）帝曰∶余司其事，则而行之，不合其数何也？（不合其数，
谓以上中下运气之数，推其岁候，其有不能相合者也。）岐伯曰∶气用有多少，化洽有盛衰，衰盛多少，同其化也。（洽，
合也。气用有多少，化洽有盛衰，言一岁之上下左右、主客运气必有所合，若以多合多，则盛者愈盛，以少合少，则衰
者愈衰，故盛衰之化，各有所从，则各同其化也。洽，爻甲切。）帝曰∶愿闻同化何如？岐伯曰∶风温春化同，热曛昏火
夏化同，胜与复同，（凡四时气化，有见风温者，皆木气也，故与春化同。有见热曛昏火者，皆火气也，故与夏化同。胜
与复同者，言初气终三气，胜之常也；四气尽终气，复之常也。凡此同化之气，所遇皆然，而无分乎四时也。下文燥清
烟露等化亦然。）燥清烟露秋化同，（皆金气之同化也。）云雨昏暝埃长夏化同，（皆土气之同化也。）寒 气霜雪冰冬化同，
（皆水气之同化也。）此天地五运六气之化，更用盛衰之常也。（运气更用则化有盛衰，盛衰有常变，故难合于数也。此
篇下文言同天化、同地化者，详本类前七。）
(From "Suwen: Chapter 66, Grand Treatise on the Correct Principles of the Six Qi")
The Yellow Emperor asked: What are the beginning and end of the numerical laws governing Heaven and Earth? (Si Tian [Heavenly Sovereign] and Zai Quan [Earthly Ruler] each have their respective governing numbers.)
Qibo replied: Your question is indeed thorough! It elucidates the Great Dao. The number begins from above and ends below. (Si Tian is in front, Zai Quan is behind; Si Tian governs the upper part, and Zai Quan governs the lower part; thus, it begins from above and ends below.) In the first half of the year, the Qi of Heaven dominates; in the second half of the year, the Qi of Earth dominates. (The first half of the year starts from Da Han [Great Cold] and ends at Xiao Shu [Minor Heat]. The second half starts from Da Shu [Major Heat] and ends at Xiao Han [Minor Cold]. As stated in "Zhi Zhen Yao Da Lun": From Chu Qi [Initial Qi] to the end of San Qi [Third Qi], the Qi of Heaven dominates; from the start of Si Qi [Fourth Qi] to the end of Zhong Qi [Final Qi], the Qi of Earth dominates.] Heaven and Earth interact, governed by the Qi Intersection (Qi Jiao), completing the annual cycle. (Interaction refers to the mutual cooperation of Heavenly Qi and Earthly Qi. The Qi Intersection governs, specifically referring to the period between San Qi and Si Qi, which is the time when Heaven and Earth Qi intersect. For detailed meaning, see Item 9 in this category earlier.) Therefore, it is said that if positions are clear, the Qi of each month can be known; this is what is meant by "Qi". (If the positions of up, down, left, and right are clarified, then the numbers regarding the six transformations of Qi and the twelve cycles of months, including their beginnings, endings, and shifts, can all be deduced; this is the so-called Qi of Heaven and Earth.)
The Yellow Emperor asked: I am responsible for implementing matters according to these principles. If my actions do not align with the numbers, why is this? (Not aligning with the numbers refers to situations where the numerical calculations of Upper, Middle, and Lower Yun [Five Movements] fail to perfectly match the climatic conditions of the year.)
Qibo replied: The application of Qi varies in abundance and scarcity, and its transformation has periods of prosperity and decline. Prosperity, decline, abundance, and scarcity all conform to the transformation. (Qia means convergence. The variation in Qi application and the convergence of transformation imply that the ruling and traveling Qi of the year must converge. If abundant meets abundant, the prosperous becomes more prosperous; if scarce meets scarce, the declining becomes more declining. Thus, the transformations of prosperity and decline follow specific patterns, each conforming to its own transformation. Qia is pronounced 'yao jia'.)
The Yellow Emperor said: I wish to hear about what constitutes Tong Hua [Conformable Transformation].
Qibo said: Wind and warmth conform to the transformation of Spring; heat, haze, turbidity, and fire conform to the transformation of Summer; Sheng [Victory/Excess] and Fu [Revenge/Reaction] also conform. (Whenever wind and warmth appear in the four seasons, they are Wood Qi, thus conforming to Spring transformation. Whenever heat, haze, turbidity, and fire appear, they are Fire Qi, thus conforming to Summer transformation. Regarding Sheng and Fu conforming: from Chu Qi to the end of San Qi, Sheng [excessive influence] is common; from Si Qi to Zhong Qi, Fu [reactive influence] is common. All such conformable Qi encounters are consistent regardless of the season. The same applies to Dryness, Coolness, Smoke, and Dew mentioned later.) Dryness, coolness, smoke, and dew conform to the transformation of Autumn (all are Conformations of Metal Qi). Clouds, rain, dusk, and dust conform to the transformation of Chang Xia [Long Summer] (all are Conformations of Earth Qi). Cold air, frost, snow, and ice conform to the transformation of Winter (all are Conformations of Water Qi). These are the normal patterns of transformation for the Five Movements and Six Qi of Heaven and Earth, alternating in use with regularities of prosperity and decline. (When Yun alternates, transformation has prosperity and decline; prosperity and decline have constants and variations, making them difficult to fit perfectly into numerical schemes. The subsequent text in this chapter discusses Tong Tian Hua [Conforming to Heaven] and Tong Di Hua [Conforming to Earth]; see Item 7 in this category earlier for details.)