相火之下。水气承之。水位之下。土气承之。土位之下。风气承之。风位之下。金气承之。金位之下。火气承之。
君火之下。阴精承之。亢则害。承乃制。制则生化。化则盛衰。害则败乱。生化大病。（六微旨大论）
此章王马滑张诸家。寻其说而不得。乃以气交之变释之。谓少阳火生。终为溽暑。不知此专气之次。非承制之的义。
夫承制者。皆元气之所本有。即其所生之理。备有生化之道。初非矫强挽回也。阴阳动静。皆涵天地之元贞。故其生物
也。贵其专精。尤忌其一往。是以阴中有阳。阳中有阴。如易卦之飞伏。飞下即伏。伏上即飞。故乾卦六阳。其下皆坤。
坤卦六阴。其下皆干。阴阳之精义。本是如此。吾故于天道之六气。各有中见。而知地节之六位。自亦有为之内者。以
为参和。是故位之下即内之义也。相火于节。主四五月。为六阳之元。而其时之水气正盛。前为谷雨。后及芒种。皆有
水泽流溢。以助调相火。是水承之义也。至于水位。则大雪冬至小寒之日矣。时当寒 。而正为物所归藏。其所以归藏
者土也。有藏而后有生。故有下起元。而得回地中之一阳。是土承之义也。若夫土生万物。而亢则有水火二至。亢于湿。
则水至而流。亢于燥。则火至而坚。苟非风木和柔之气。内居其间。何以使土脉和动。故土旺长夏。而木正向荣。是其
义也。风为春木。由甲坼条舒。以至于长茂坚成。必有金气以收之。是以榆荚之落。见于春时。亦其义也。金位兑说。
而神主蓐收。若无火气之微布。则凄冽之气。即申酉而寒 矣。乃由白露方凉。渐于寒露。暨于霜降。于时生物。及多
至于成。但火犹有存者。此知金下有火也。至若君火所承。则不曰水气。而独曰阴精。阴精者。生气之华也。地上三阴
之全气也。其火不主夏令。而首出显明。当三月之和。地气腾上。阴精所奉。莫备于此。是犹众职效用。而君自端拱也。
盖亢者专气之一往。承者相济之参和。非以其相反而相犯为制也。唯其内有以相承相济则元气足。而生生浓。故曰制。
生则化。盖生而无制则化偏。生而有制则化备也。自此而列一任加临交变。有余不足。至与未至。虽外有此列。以乘除
其间。而其本生之气。自不败不乱。故曰外列盛衰也。若专气一往而之厥所。承则本气已见败乱。安得不为生化大病乎。
相火之下，由水气来承托制约。水位之下，由土气来承托制约。土位之下，由风气来承托制约。风位之下，由金气来承托制约。金位之下，由火气来承托制约。
君火之下，由阴精来承托制约。亢盛就会造成危害，有承托制约才能维持平衡，能制约则万物生化有序，生化有序则盛衰有度；若造成危害则败坏混乱，导致严重的疾病。（出自《素问·六微旨大论》）
这一章中，王冰、马莳、滑寿、张景岳等各家学者，探寻其义却未能透彻理解，于是用“气交之变”来解释，认为少阳相火生发，最终演变为湿热酷暑。他们不知道这里讲的是气的次序规律，并非承制理论的真正含义。
所谓承制，都是元气所本有的，即事物生成的道理中，本身就具备生化的法则，起初并不是强行扭转挽回。阴阳的动静，都蕴含天地原本的贞正之气，所以它们化生万物时，贵在专精，尤其忌讳一味向前而不知返。因此阴中有阳，阳中有阴，就像易经卦象中的飞伏关系，飞下即是伏，伏上即是飞。所以乾卦六个阳爻，其下皆含坤（阴）意；坤卦六个阴爻，其下皆含乾（阳）意。阴阳的精微义理，本来就是这样的。所以我从天道的六气各有“中见”（表里配合之气），推知地节的六位，自然也有内在的机制作为参和调节。因此，“位之下”就是“内”的含义。
相火在节气上主管四、五月，是六个阳气的本源，而此时水气正旺盛。前接谷雨，后连芒种，都有水泽流溢，以助调摄相火，这就是水承托相火的含义。至于水位，则是大雪、冬至、小寒的日子，此时正当寒冷，却是万物归藏之时。万物之所以归藏，是因为有土的承载。只有先有收藏，然后才有生发，所以从地下升起元阳，得以回归地中的一阳生机，这就是土承托水位的含义。
至于土生养万物，如果亢盛就会出现水火两个极端：亢盛于湿，则水至而泛滥；亢盛于燥，则火至而坚硬。如果不是风木柔和之气，内部居于其间，怎么能使土脉和缓流动呢？所以土旺于长夏，而木气正向荣盛，就是这个道理。风对应春季木气，从种子破裂枝条舒展，以至于长得茂盛坚实，必须有金气来收敛它。所以榆荚在春天落下，也是这个原理。金位对应兑卦喜悦之象，神主蓐收（秋季肃杀之神），如果没有火气的微妙散布，凄冷之气在申酉时就已经严寒了。然而从白露开始转凉，逐渐到寒露，再到霜降，此时生物大多已经成熟，但火气仍有留存，这就知道金位之下有火气存在。
至于君火所承托的，不称为水气，而独称阴精。阴精，是生气的精华，是地上三阴的全备之气。君火不主宰夏季，而是首先显现光明，当三月温和之时，地气升腾，阴精所奉养，没有比这更完备的了。这就像众职各司其职效力，而君主端坐拱手无为而治一样。
所谓“亢”，是专气的一味向前；所谓“承”，是相互济助的参和调节。并不是因为相反相犯才叫制约。正因为内部有相互承托济助，元气才充足，生生之机才浓厚。所以叫“制”。有生则有化，如果生而没有制约，则化就偏颇；生而有制约，则化就完备。从此以后，无论加临交变如何，有余还是不足，至与未至，虽然外在有此列变化，以此乘除其间，但其本生的元气，自然不会败坏混乱。所以说外在表现为盛衰的变化。如果专气一味向前到达其极点，承托的本气已经出现败乱，怎么能不成为生化的大病呢？
Below the Fire of Minister (Xianghuo), the Qi of Water (Shuiqi) acts as its support and restraint. Below the position of Water, the Qi of Earth (Tuqi) acts as its support and restraint. Below the position of Earth, the Qi of Wind (Fengqi) acts as its support and restraint. Below the position of Wind, the Qi of Metal (Jinqi) acts as its support and restraint. Below the position of Metal, the Qi of Fire (Huoji) acts as its support and restraint.
Below the Fire of Sovereign (Junhuo), the Yin Essence (Yinjing) acts as its support and restraint. When in a state of hyperactivity (Kang), harm ensues; only with support and restraint (Chengzhi) is balance maintained. With restraint, transformation and generation (Shenghua) occur orderly; with orderly transformation, there is measure in waxing and waning. If harm occurs, chaos and disorder prevail, leading to severe diseases. (From *Suwen: Chapter 21, Discussion on the Six Subtle Principles*)
In this chapter, scholars such as Wang Bing, Ma Shi, Hua Shou, and Zhang Jingyue sought its meaning but failed to grasp it thoroughly. They interpreted it through the concept of "changes at the intersection of Qi," arguing that the generation of Shaoyang Fire eventually manifests as humid heat and summer heat. They did not realize that this passage specifically discusses the sequence of Qi, which is not the precise meaning of the theory of support and restraint.
The concept of support and restraint is inherent in Yuan Qi (Primal Qi); it is the principle of generation itself, containing within it the path of transformation and generation. It is not initially about forcing a reversal or recovery. The movement and stillness of Yin and Yang both contain the primal integrity of Heaven and Earth. Therefore, when they generate all things, they value specialization and focus, and particularly avoid proceeding blindly without return. Thus, Yin contains Yang, and Yang contains Yin. This is like the flying and hiding (Feifu) in I Ching hexagrams: what flies down hides, and what hides up flies. In the Qian Hexagram (Pure Yang), below the six Yang lines lies the essence of Kun (Yin); in the Kun Hexagram (Pure Yin), below the six Yin lines lies the essence of Qian (Yang). The profound meaning of Yin and Yang is inherently thus.
Therefore, regarding the Six Qi of Heaven's Dao, each has a "Zhongjian" (Middle Manifestation/Interior-Exterior pairing). Knowing this, we understand that the Six Positions of Earth's Jie (Solar Terms) also have internal mechanisms acting as parameters for harmony. Hence, "below the position" implies an "internal" meaning.
Minister Fire governs the fourth and fifth months in the solar terms. It is the origin of the six Yang phases. At this time, the Qi of Water is vigorous. Preceded by Guyu (Grain Rain) and followed by Mangzhong (Grain in Ear), water marshes overflow, assisting in regulating Minister Fire. This illustrates the meaning of Water supporting Minister Fire. As for the position of Water, it corresponds to the days of Daxue (Major Snow), Dongzhi (Winter Solstice), and Xiaohan (Minor Cold). The weather is cold, yet it is precisely when all things return to storage. The reason for this storage is Earth. Only after storage can there be generation; thus, the primal Yang rises from underground, recovering the one Yang within the earth. This illustrates the meaning of Earth supporting Water.
As for Earth generating all things, if it becomes hyperactive, two extremes appear: Water and Fire. Hyperactivity in dampness leads to water overflowing; hyperactivity in dryness leads to fire hardening. Unless the soft and gentle Qi of Wind-Wood resides internally between them, how could the Earth pulse remain harmonious and mobile? Therefore, Earth prospers in Late Summer, while Wood Qi is towards flourishing. This is the underlying principle.
Wind corresponds to Spring Wood. From the cracking of seeds and stretching of branches to lush growth and firm formation, there must be Metal Qi to harvest and restrain. Thus, the falling of elm pods in spring also follows this principle. The position of Metal corresponds to the Dui Hexagram (Joy), and its spirit governs "Rushou" (Autumn Harvest/Slaughter). Without the subtle distribution of Fire Qi, the chilling air would become severely cold during Shen and You hours (3 PM - 7 PM). However, from Bailu (White Dew) bringing coolness, gradually to Hanlu (Cold Dew) and Shuangjiang (Frost Descent), living things mostly reach maturity. Yet, some Fire Qi remains. This indicates that Fire exists below Metal.
Regarding what supports Sovereign Fire, it is not called Water Qi, but exclusively Yin Essence. Yin Essence is the essence of Sheng Qi (Vital Qi) and the complete Qi of the three Yin levels on Earth. Sovereign Fire does not govern Summer; rather, it first appears brightly. During the harmony of the third month, Earth Qi ascends. The offering of Yin Essence is most complete here. This is akin to various officials performing their duties while the Sovereign sits upright and governs without action (Wuwei).
"Hyperactivity" (Kang) refers to the blind forward progress of exclusive Qi. "Support" (Cheng) refers to mutual assistance and harmonization. It is not about restraint through opposition and conflict. Precisely because internally there is mutual support and assistance, Yuan Qi becomes sufficient, and the generative process becomes dense. Hence, it is called "restraint." Generation leads to transformation. If there is generation without restraint, transformation becomes biased; if there is generation with restraint, transformation becomes complete. From this point on, regardless of the superimposed changes, whether excess or deficiency, arrival or non-arrival, although external manifestations exist to multiply and divide within these processes, the original generative Qi itself will not decay or become chaotic. Hence, it is said that externally, waxing and waning are displayed. If exclusive Qi proceeds blindly to its extremity, and the supporting original Qi shows signs of decay and chaos, how can it not result in major diseases of transformation and generation?