水木火土金五行生克，一阴阳升降之旋相为宫也。生为长养，即为阴升；克为制化，即
是阳降。然必阴先升而后阳乃降，亦必阳能降而后阴转升。五行不克则不生，如有妻而无夫
也。乃相生之道，人皆知之，相克之道，人多不察，请详言之。
肾主地、主阴、主水，五液亦皆主地、主阴、主水。肾中真阳之气， 煦育，
上通各脏腑之阳，而肾中真阴之气，即因肾阳蒸运，上通各脏腑之阴。阳助阴升，以养肝木
，则木气敷荣，血充而气畅矣。由是，肝得上升之阴气而养心火，则火气温润，血生而脉行
矣。由是，心得上升之阴气而养脾土，则土气健运，统血而散精矣。由是，脾得上升之阴气
而养肺金，则金有治节，调元而赞化矣。肺得上升之阴气，转降而入肾，则水精四布，五经
并行矣。此五行一气相生，始于肾，终于肺，地所以上交乎天也。
肺主天、主阳、主气，敷布阴液，以柔肝木。木得下降之阳气所制，则温柔和缓，不似
燥急难平矣。由是，木来疏土，土得下降之阳气所制，则宣松运化，不似困钝不灵矣。由是
，土来治水，水得下降之阳气所制，则知周输泄，不似汜滥无归矣。由是，水来济火，火得
上升而复下降之阳气所制，则心肾相交，不似火炎水燥矣。由是，火来暖金，金得上升而复
下降之阳气所制，则津液分布，不似金寒水冷矣。此五行一气相克，始于肺，终于肺，天所
以大包乎地也。
然则五行之生，虽五脏之阴递升而生，实肾之阳助肾之阴递升而生，阴之升，天统之而
地承之也。五行之克，虽五脏之阳递降而克，实肺之阳统肺之阴递降而克，阳之降，地承之
而天统之也。生固为生，克亦为生，生克二者，非即阴升阳降，循环而不穷者哉？
然而生克又不可太过也，太过则非真阴真阳升降以为生，而为邪水邪火升降以为害也。
木赖水生，水泛则木浮，木浮则火湿，火湿则土困，土困则金埋，金埋则水愈泛，五内有水
而无火，则泻利、肿满，诸湿病生矣。火赖水克，水盛则火灭，火灭则金寒，金寒则木湿，
木
赖木生，木盛则自焚，火焚则土燥，土燥则金枯，金枯则水涸，水涸则木愈焚，五内有火而
无水，则风、劳、蛊、膈、三消，诸燥病生矣。土赖木克，木强则土弱，土弱则水泛，水泛
则
亦亏，土无火必滥，则痞满、肿胀、泄泻诸湿病生；土无水必干，则蛊、膈、三消诸燥病又
相继而生矣。土赖火生，火炎则土燥，土燥则金熔，金熔则水亏，水亏则木炽，木炽则火愈
炎，五内有火而无水，则谵狂、膈消，诸燥病生矣。金赖火克，火炎则金燥，金燥则木炽，
木
生
困于水火，（土包五行，故多兼病），则痞满、胀痛燥湿诸病，又杂沓而生矣。水赖土克，土
燥
、窘迫、下利，诸燥病生矣。水赖金生，金寒则水冷，水冷则木滥，木滥则火湿，火湿则土
困，
克
则劳咳、咽痛、窘迫、下利，诸燥病生矣。生克一有太过，则克固为克，生亦为克。且人身真
阴真阳，只有此数，凡见太过，实由不及。太过不及，则为浊阴、为燥阳，浊阴则不为阴
而为水，燥阳则不为阳而为火。五行生克不外水火，生克太过不及为病，亦不外水火。水流
湿，火就燥。故水火二气，为五行之生成；燥湿二气，为百病之纲领。
阴阳以气言，水火以形言。坎为水，水色黑，黑属阴，然水外暗而内明，空灵活泼，实
为阴中之阳，故坎中满。离为火，火色赤，赤属阳，然火外明而内暗，且返本归根，则其色
黑，实为阳中之阴，故离中虚。以形质言，水、火质虚，木、金、土质实，是水、火又为木
、金、土之先天矣。火有形无质，必根据附于物而乃有质，水虽有质而极虚，故论五行生成之
序，则水一、火二、木三、金四、土五；论五行生克之序，则生始于水，克始于金。知五行
气质、阴阳生克，乃知天人一贯道理，玩集中各论自明。
水、木、火、土、金五行之间的相生相克，实际上是阴阳二气升降运动相互循环的表现。所谓“生”，即生长养育，对应于阴气的上升；所谓“克”，即制约化育，对应于阳气的下降。然而，必须阴气先上升，然后阳气才能下降；也必须是阳气能下降，然后阴气才能转而上升。如果五行之间只有相生而没有相克，就像有妻无夫一样，无法成立。对于相生的道理，人们大多知晓；但对于相克的道理，人们往往不加考察，下面请详细论述。
肾主大地、主阴、主水，五脏中的津液也都归属于地、归属于阴、归属于水。肾中的真阳之气，温煦繁育，向上通达各脏腑的阳气；而肾中的真阴之气，便借助肾阳的蒸腾运化，向上通达各脏腑的阴气。阳气帮助阴气上升，以滋养肝木（肝脏及其功能系统），则肝气舒展繁荣，血液充盈且气机通畅了。由此，肝得到上升的阴气来滋养心火（心脏及其功能系统），则心气温润，血液生成且脉道运行了。由此，心得到上升的阴气来滋养脾土（脾胃及其功能系统），则脾气健运，统摄血液并散布精微了。由此，脾得到上升的阴气来滋养肺金（肺脏及其功能系统），则肺气具有治理调节作用，调和元气并辅助化生了。肺得到上升的阴气，转而下降并进入肾中，则水精四布，五条经脉并行流通了。这是五行一气相生，始于肾，终于肺，是大地的阴气上交于天道的表现。
肺主天道、主阳、主气，敷布阴液，以柔润肝木。肝木得到下降的阳气的制约，则变得温柔和缓，不再像燥急难以平息那样了。由此，肝木疏泄助脾土，脾土得到下降的阳气的制约，则宣通松畅、运化正常，不再像困顿迟钝不灵敏那样了。由此，脾土制约肾水，肾水得到下降的阳气的制约，则知道周流输注与排泄，不再像泛滥无归那样了。由此，肾水济助心火，心火得到上升后又下降的阳气的制约，则心肾相交，不再像火炎上、水干燥那样了。由此，心火暖助肺金，肺金得到上升后又下降的阳气的制约，则津液分布均匀，不再像金寒水冷那样了。这是五行一气相克，始于肺，终于肺，是天道大包大揽覆盖大地的表现。
既然这样，五行的相生，虽然是五脏之阴依次上升而相生，实际上是肾之阳帮助肾之阴依次上升而相生，阴气的上升，由天道统领而地道承载。五行的相克，虽然是五脏之阳依次下降而相克，实际上是肺之阳统领肺之阴依次下降而相克，阳气的下降，由地道承载而天道统领。相生固然是生，相克也是生，相生和相克这两者，不就是阴升阳降、循环无穷的道理吗？
然而，相生相克又不可太过。太过就不是真阴真阳的升降来产生生机，而是邪水邪火的升降来造成危害了。木依赖水生，水泛滥则木漂浮，木漂浮则火湿滞，火湿滞则土困顿，土困顿则金埋没，金埋没则水更加泛滥，五脏内有水而无火，就会产生腹泻、水肿胀满等各种湿病。火依赖水来克制，水盛则火灭，火灭则金寒，金寒则木湿，木湿则……（原文此处似有脱漏或语意连贯问题，依文意理解为木受湿困），木依赖木生（此处原文逻辑稍显混乱，通常指木盛自焚，结合下文“木盛则自焚”理解），木盛则自焚，火焚烧则土干燥，土干燥则金枯槁，金枯槁则水枯竭，水枯竭则木更加焚烧，五脏内有火而无水，就会产生风证、劳损、蛊胀、膈噎、三消等各种燥病。土依赖木来克制，木强则土弱，土弱则水泛滥，水泛滥则……（原文缺字，推测为土亦亏或相关脏腑受损），土无火必泛滥，就会产生痞满、肿胀、泄泻等各种湿病；土无水必干燥，就会产生蛊胀、膈噎、三消等各种燥病相继而生。土依赖火来滋生，火炎则土燥，土燥则金熔毁，金熔毁则水亏虚，水亏虚则木炽盛，木炽盛则火更炎，五脏内有火而无水，就会产生谵语狂乱、膈消等各种燥病。金依赖火来克制，火炎则金燥，金燥则木炽盛，木炽盛则……（原文此处逻辑跳跃，接下文“困于水火”），木困于水火之中（土包五行，故多兼夹病症），就会产生痞满、胀痛、燥湿等各种杂病交织而生。水依赖土来克制，土燥则水……（原文缺字，结合下文“窘迫”等，意指水被约束或枯竭），水被约束则出现劳咳、咽痛、窘迫、下利等各种燥病。水依赖金来滋生，金寒则水冷，水冷则木泛滥，木泛滥则火湿滞，火湿滞则土困顿，土困顿则……（原文缺字，结合上文逻辑），若土受制则劳咳、咽痛、窘迫、下利等各种燥病产生。相生相克一旦有过度的情况，那么相克固然是克，相生也成了克。况且人身体的真阴真阳数量是有限的，凡是见到太过，实际上是由于不及造成的。太过和不及，就会变成浊阴、变成燥阳，浊阴就不再是阴而变成了水邪，燥阳就不再是阳而变成了火邪。五行的生克不外乎水和火，生克的太过和不及导致疾病，也不外乎水和火。水往湿润处流，火向干燥处就。所以水和火二气，是五行生成的根本；燥和湿二气，是百病的纲领。
从气的角度说叫阴阳，从形的角度说叫水火。坎卦代表水，水色黑，黑色属阴，然而水外表昏暗而内部光明，空灵活泼，实则是阴中之阳，所以坎卦中间是实线（中满）。离卦代表火，火色赤，红色属阳，然而火外表明亮而内部昏暗，并且返本归根时其色变黑，实则是阳中之阴，所以离卦中间是虚线（中虚）。从形质来说，水、火的质地虚空，木、金、土的质地坚实，所以水、火又是木、金、土的先天本源了。火有形但没有实体，必须依附于物体才有实体；水虽然有实体但极其虚空，所以在论述五行生成的次序时，是水一、火二、木三、金四、土五；在论述五行生克的次序时，则是生始于水，克始于金。了解了五行的气质、阴阳的生克关系，就能明白天人合一的道理，研读书中的其他论述自然明了。
The mutual generation and restriction among the Five Elements—Water, Wood, Fire, Earth, and Metal—are essentially a cyclic rotation of Yin ascending and Yang descending. "Generation" (Sheng) refers to nourishment and growth, corresponding to the ascent of Yin; "Restriction" (Ke) refers to control and transformation, corresponding to the descent of Yang. However, it is necessary for Yin to ascend first before Yang can descend; similarly, it is necessary for Yang to descend effectively before Yin can turn and ascend again. If the Five Elements only generate without restricting, it would be like having a wife but no husband, which is untenable. While people generally understand the principle of generation, they often overlook the principle of restriction; let us discuss this in detail.
The Kidney governs the Earth, Yin, and Water; the five body fluids also belong to Earth, Yin, and Water. The True Yang Qi within the Kidney warms and nurtures, connecting upward to the Yang Qi of all other Zang-Fu organs. Meanwhile, the True Yin Qi within the Kidney, facilitated by the steaming and movement of Kidney Yang, connects upward to the Yin Qi of all other Zang-Fu organs. Yang assists Yin in ascending to nourish Liver Wood, causing Liver Qi to spread and flourish, resulting in abundant blood and smooth Qi flow. Consequently, the Liver receives ascending Yin to nourish Heart Fire, making Heart Qi warm and moist, leading to blood generation and pulse circulation. Subsequently, the Heart receives ascending Yin to nourish Spleen Earth, strengthening Spleen Qi's transportation and transformation, enabling it to control blood and distribute essence. Then, the Spleen receives ascending Yin to nourish Lung Metal, granting Lung Metal its regulatory function, harmonizing Yuan Qi, and assisting in metabolic transformation. Finally, Lung Metal receives ascending Yin, turns downward, and enters the Kidney, allowing water essence to distribute throughout the body and the five meridians to circulate together. This represents the mutual generation of the Five Elements as one Qi, starting from the Kidney and ending at the Lung, symbolizing the Earth's Yin ascending to unite with Heaven.
The Lung governs Heaven, Yang, and Qi, distributing Yin fluids to soften Liver Wood. When Liver Wood is controlled by descending Yang, it becomes gentle and mild, no longer dry and urgent. Consequently, Liver Wood soothes Spleen Earth; when Spleen Earth is controlled by descending Yang, it becomes loose and functional, no longer sluggish and dull. Then, Spleen Earth controls Kidney Water; when Kidney Water is controlled by descending Yang, it knows how to circulate and excrete properly, no longer flooding aimlessly. Next, Kidney Water assists Heart Fire; when Heart Fire is controlled by Yang that has ascended and then descended, Heart and Kidney interact harmoniously, no longer suffering from flaming fire and dry water. Furthermore, Heart Fire warms Lung Metal; when Lung Metal is controlled by Yang that has ascended and then descended, body fluids are distributed evenly, no longer cold and dry like metal and water. This represents the mutual restriction of the Five Elements as one Qi, starting from the Lung and ending at the Lung, symbolizing Heaven's comprehensive coverage of Earth.
Thus, although the generation of the Five Elements involves the sequential ascent of Yin in the five Zang organs, it is actually Kidney Yang assisting Kidney Yin in ascending sequentially. The ascent of Yin is led by Heaven and supported by Earth. Although the restriction of the Five Elements involves the sequential descent of Yang in the five Zang organs, it is actually Lung Yang leading Lung Yin in descending sequentially. The descent of Yang is supported by Earth and led by Heaven. Generation is indeed generation, and restriction is also generation; are not generation and restriction simply the endless cycle of Yin ascending and Yang descending?
However, generation and restriction must not be excessive. Excess means that instead of True Yin and True Yang generating life through their ascent and descent, pathogenic Water and Fire cause harm through theirs. Wood relies on Water for generation; if Water floods, Wood floats; if Wood floats, Fire becomes damp; if Fire is damp, Earth is trapped; if Earth is trapped, Metal is buried; if Metal is buried, Water floods further. With excess Water and lack of Fire in the interior, diarrhea, edema, and fullness arise, along with various damp diseases. Fire relies on Water for restriction; if Water is excessive, Fire extinguishes; if Fire extinguishes, Metal becomes cold; if Metal is cold, Wood becomes damp; if Wood is damp... [Note: Text implies Wood stagnation]. Wood generates itself; if Wood is excessive, it burns itself; if Fire burns, Earth dries; if Earth is dry, Metal withers; if Metal withers, Water dries up; if Water dries up, Wood burns more fiercely. With excess Fire and lack of Water in the interior, wind disorders, consumption, Gu distension, Ge dysphagia, and Sanxiao (Three Wasting-Thirsting) arise, along with various dry diseases. Earth relies on Wood for restriction; if Wood is strong, Earth is weak; if Earth is weak, Water floods; if Water floods... [Text implies Earth deficiency]; without Fire, Earth floods, causing chest stuffiness, swelling, and diarrhea (damp diseases); without Water, Earth dries, causing Gu distension, Ge dysphagia, and Sanxiao (dry diseases). Earth relies on Fire for generation; if Fire flares, Earth dries; if Earth is dry, Metal melts; if Metal melts, Water is deficient; if Water is deficient, Wood is vigorous; if Wood is vigorous, Fire flares more. With excess Fire and lack of Water, delirium, mania, and Ge Xiao arise. Metal relies on Fire for restriction; if Fire flares, Metal dries; if Metal dries, Wood is vigorous; if Wood is vigorous... [Text transitions to Wood trapped between Water and Fire], Wood is trapped between Water and Fire (Earth encompasses the Five Elements, so diseases often combine), causing chest stuffiness, distending pain, and mixed dry/damp diseases. Water relies on Earth for restriction; if Earth is dry... [Text implies Water constraint], leading to labor cough, sore throat, distress, and diarrhea (dry diseases). Water relies on Metal for generation; if Metal is cold, Water is cold; if Water is cold, Wood floods; if Wood floods, Fire becomes damp; if Fire is damp, Earth is trapped; if Earth is trapped... [Text repeats previous pattern] leads to labor cough, sore throat, distress, and diarrhea. If generation or restriction is excessive, restriction becomes restriction, and generation also becomes restriction. Moreover, the amount of True Yin and True Yang in the human body is fixed. Any appearance of excess is actually due to insufficiency. Excess and insufficiency transform into Turbid Yin and Dry Yang. Turbid Yin ceases to be Yin and becomes Pathogenic Water; Dry Yang ceases to be Yang and becomes Pathogenic Fire. The generation and restriction of the Five Elements revolve around Water and Fire; diseases caused by excess or insufficiency in generation and restriction also revolve around Water and Fire. Water flows toward moisture; Fire moves toward dryness. Therefore, Water and Fire are the foundation of the Five Elements' formation; Dryness and Dampness are the guidelines for all diseases.
Yin and Yang refer to Qi (energy/function), while Water and Fire refer to Form (substance/structure). Kan (☵) represents Water; Water is black, and black belongs to Yin. However, Water appears dark externally but bright internally, being empty and lively, thus representing Yang within Yin, hence Kan is solid in the middle (one solid line). Li (☲) represents Fire; Fire is red, and red belongs to Yang. However, Fire appears bright externally but dark internally, and returning to its root makes it black, thus representing Yin within Yang, hence Li is hollow in the middle (one broken line). From the perspective of substance, Water and Fire have void qualities, while Wood, Metal, and Earth have solid qualities. Thus, Water and Fire are the prenatal origins of Wood, Metal, and Earth. Fire has form but no substantial mass, requiring attachment to objects to manifest substance; Water has substance but is extremely void. Therefore, in discussing the order of Five Elements generation, it is Water 1, Fire 2, Wood 3, Metal 4, Earth 5; in discussing the order of Five Elements restriction, generation starts with Water, and restriction starts with Metal. Understanding the Qi and nature of the Five Elements, and the generation and restriction of Yin and Yang, reveals the principle of unity between Heaven and Humanity. Studying the other treatises in this collection will make this clear.