命门为精血之海，脾胃为水谷之海，均为五脏六腑之根。然命门为元气之本，为水火之宅，五脏之阴气
非此不能滋，五脏之阳气非此不能发。而脾胃中州待火能生，然必少阳春气始于下，则三阳从地起，而后万
物得以化生，岂非命门之阳气，正为脾胃之母乎？吾故曰∶脾胃为灌注之本，得后天之气；命门为化生之源，
得先天之气，此中本末固有先后。而东垣曰补肾不若补脾，须知可曰补脾不若补肾，可不辨而明矣。
然命门有火候，即元阳之谓也。禀赋有强弱，元气有盛衰，阴阳有胜负，病治有微甚，此火候之
所宜辨也。盖一阳之元气，必自下而升；而三焦之普护，乃各见其候。下焦之候，如地土化生之本也；中焦
之候，如灶釜水谷之炉也；上焦之候，如太虚神明之宇也。
地土有肥瘠，而出产异；山川有浓薄，而藏蓄异。聚散操权，总由阳气，得一分则有一分之用，失一
分则有一分之亏。凡寿夭勇怯，精血病治之基，无不由此，元阳之足与不足，以为消长盈缩之主，下焦火候
之谓也。
中焦如灶釜者，胃中阳气，其热如釜。饮食之滋，本于水谷，食强则体壮，食少则身衰。若灶釜之少一
炬则迟化一顷，增一炬则速化一时，火力不到则全然不化。故脾胃之化与不化，及饮食之能与不能，亦总由
阳明之气强与不强，而阴寒之邪有犯与不犯耳。及其既病，则渐痞渐长，或隔或呕，或膨聚不消，或吞酸嗳
腐，食气不变，或腹疼肚痛，终日不饥，或清浊不分，或完谷不化。盖化则无不营运，不化则无不留滞，营运
则为气为血，留滞则为积为痰。此中焦火候之谓也。
上焦如太虚者，神明根于阳气，阳气化为神灵，阳之在下则温暖，故曰相火以位；阳之在上则昭明，
故曰君火以明。是以阳长阴消，五官治而万类盛。若阳衰阴胜，而阳为阴折，聪明夺而神气减，此上焦火候之
谓也。
夫以三焦论火候，非不各有所司，惟命门实，先天真一之气藏于坎中，自下而上，与后天胃气相接，
此生生之本也。使真阳不发于渊泉，则总属无根之火矣。
火而无根，即病气也，非元气也。《易》以雷在地下而为
复，可见火之标在上，而火之本在下。若使命门阴胜，则元阳畏避，而龙火无藏身之地，游散不归而为烦
热格阳等证。善治此者，惟从其性，使阳和之气直入坎中，相求同气，虚阳归原矣。故曰甘温除大热，正
此谓也。昧者不明此理，以虚阳作实热，不思温养此火，但知寒凉可以灭火，安望其尚留生意耶？若三焦有
客热邪火，皆凡火耳，固不得不除。而除火何难，本非正气火候之谓也。
况命门有生气，即干元不息之机。
不息则惟动惟升，所以阳得生气；息则惟静惟降，所以阴得死气。故干元之气始于下而盛于上，升则向生；
坤元之气始于上而盛于下，降则向死。此阴阳之歧，相间不过毛发，而终竟远以千里，故死生之柄，惟此毫厘
升降之机耳。譬之水暖则化气，化气是升，生也；水寒则成冰，成冰是降，死也。故肾气独沉，则奉生者少
，即此生气之理也。
至若人之生气，无所不在，如脏气、颜色、声音、脉息、四肢、二便俱有生气。生气即神气，神自形生
，何不可辨？明者察之，孰者能益生气，孰者能损生气？或先攻病气以保生
气，或先固生气以御病气。使不有原始要终之明，则是寸光之流耳。
盖命门有门户，为一身巩固之关。经曰∶仓凛不藏者，是门户不要也∶水泉不止者，是膀胱不藏也。
得守者生，失守者死。又曰∶肾者胃之关也，关门不利，故聚水而从其类。又曰∶黑色通于肾，开窍于二阴
。可见北门之主总在乎肾，而肾之政令总在乎命门。
命门司阴阳之柄，阴阳和则出入有常；阴阳病则启闭无序，故有癃闭不通者，以阴竭水枯，干涸之不行
也。有滑泄不禁者，以阳虚火败，收摄之无主也。阴精既竭，非壮水必
不能行；阳气既虚，非益火必不能固，此治法也。
命门是精血汇聚的大海，脾胃是水谷精微汇聚的大海，它们都是五脏六腑的根本。然而，命门是元气的根本，也是水火（肾阴与肾阳）居住的宅邸，五脏的阴气没有它就不能滋养，五脏的阳气没有它就不能生发。而位于中焦的脾胃必须依赖火（命门之火）才能运化生成，但必须少阳春天的生气从下部开始萌发，三阳经之气才能随大地之气上升，这样万物才能得以化生，这难道不是说明命门的阳气正是脾胃的母亲吗？所以我说道：脾胃是灌注输送的根本，获得的是后天之气；命门是化生变化的源头，获得的是先天之气，这其中本末确实有先后的区别。李东垣曾说补肾不如补脾，但要知道也可以说补脾不如补肾，这一点不用分辨也就很明白了。
然而，命门中有“火候”，指的就是元阳。人的禀赋有强弱之分，元气有盛衰之别，阴阳有胜负之势，疾病治疗有轻重缓急之异，这些都需要辨别火候的适宜程度。大概一阳初生的元气，必然从下向上升发；而三焦遍布全身的护卫作用，各自显现出不同的征候。下焦的征候，就像大地土壤化生万物的根本；中焦的征候，就像锅灶炉火烹煮水谷的地方；上焦的征候，就像广阔天空神明居住的场所。
土地有肥沃贫瘠之分，出产就不同；山川有深厚浅薄之别，储藏蓄积就各异。聚散的控制权，全在于阳气，得到一分阳气就有一分的作用，失去一分阳气就有一分的亏损。凡是寿命长短、勇敢怯弱，以及精血病变治疗的根基，无不由此决定。元阳充足与否，是决定消长盈缩的主宰，这就是所说的下焦火候。
中焦像锅灶一样，胃中的阳气，其热度如同锅釜。饮食的滋养，本源于水谷，食物充足则身体强壮，食物不足则身体衰弱。如果锅灶里少一根柴火，消化一顷地的粮食就会变慢；增加一根柴火，消化一时的食物就会变快；火力达不到，就完全无法消化。所以脾胃能否运化，以及饮食能否被吸收利用，也总归取决于阳明胃气的强与不强，以及阴寒邪气是否侵犯罢了。等到已经生病，就会出现逐渐痞塞、逐渐胀大，或者膈食、呕吐，或者腹部膨隆积聚不消，或者吞酸、嗳气带有腐臭味，食物气息不变，或者腹痛肚痛，整天没有饥饿感，或者清浊不分，或者完谷不化。大概能运化的就没有不运行的，不能运化的就没有不留滞的，运行正常就成为气和血，留滞不行就成为积和痰。这就是所说的中焦火候。
上焦像广阔的天空一样，神明根源于阳气，阳气化为神灵，阳气在下则温暖，所以说相火安守其位；阳气在上则光明，所以说君火清明。因此阳气增长阴气消退，五官功能正常而万物繁盛。如果阳气衰弱阴气胜极，而阳气被阴气折损，聪明才智丧失而神气减弱，这就是所说的上焦火候。
用三焦来论述火候，并非各不负责，只有命门实际上藏有先天真一之气于坎卦之中，从下向上，与后天的胃气相接，这是生生不息的根本。假如真阳不从深渊泉源发出，那就总属于无根之火。
火如果没有根，就是病气，而不是元气。《易经》以雷在地下象征复卦，可见火的表象在上，而火的根本在下。如果使命门阴气胜极，那么元阳就会畏缩回避，龙火无处藏身，游散不归而出现烦热、格阳等证候。善于治疗这种情况的人，只顺从其本性，使温和的阳气直接进入坎中，寻求同类之气，虚浮的阳气就能回归本源。所以说甘温药物可以消除大热，正是这个意思。愚昧的人不明白这个道理，把虚阳当作实热，不想着温养这团火，只知道用寒凉药可以灭火，哪里还指望它能保留生机呢？如果三焦有客居的热邪之火，那都是凡火，固然不得不除去。而除去这种火并不难，因为它们本来就不是正气火候所指的范畴。
况且命门具有生气，也就是乾元不息的机理。不息就表现为动和升，所以阳气获得生气；息就表现为静和降，所以阴气获得死气。因此乾元之气始于下部而盛于上部，上升趋向于生；坤元之气始于上部而盛于下部，下降趋向于死。这是阴阳的分歧，相差不过毫毛细微，但最终相距千里之遥，所以生死的权柄，就在于这毫厘之间的升降之机罢了。譬如水暖则化为气，化气是上升，代表生；水寒则结成冰，成冰是下降，代表死。所以肾气独沉，奉养生机的力量就少，就是这个生气的道理。
至于人的生气，无处不在，如脏气、面色、声音、脉象呼吸、四肢、大小便都体现出生气。生气就是神气，神从形体产生，有什么不可辨别的呢？明智的人观察它，谁能增益生气，谁能损害生气？是先攻治病气以保护生气，还是先巩固生气以抵御病气。假使没有追溯本源、究察终始的明察，那就是目光短浅之辈了。
大概命门有门户，是一身巩固的关键关口。医经说：“粮仓不储藏东西，是因为门户把守不严；泉水不止流出，是因为膀胱不能固藏。”能够守住根本的就生存，失去守御的就死亡。又说：“肾脏是胃的关口，关门不利，所以积水并伴随类似性质的病理产物聚集。”又说：“黑色通应于肾，开窍于前后二阴。”由此可见，北门（北方/下部）的主宰总在于肾，而肾的政令总在于命门。
命门掌管阴阳的权柄，阴阳调和则出入有常规；阴阳失调则开闭无序，所以有的出现小便癃闭不通，是因为阴竭水枯，干涸而不能通行；有的出现滑泄不禁，是因为阳虚火败，收摄没有主宰。阴精既然枯竭，不壮水之源一定不能通行；阳气既然虚弱，不益火之源一定不能固摄，这就是治疗方法。
The Mingmen (Gate of Life) is the sea of essence and blood, and the Spleen and Stomach are the sea of water and grain; both serve as the root of the five zang organs and six fu organs. However, the Mingmen is the root of Yuan Qi (Primordial Qi), and the residence of Water and Fire (Kidney Yin and Kidney Yang). The Yin Qi of the five zang organs cannot nourish without it, and the Yang Qi of the five zang organs cannot emerge without it. The Spleen and Stomach, located in the central jiao (Middle Burner), rely on Fire to generate, but it must be that the Spring Qi of Shaoyang (Lesser Yang) begins to rise from below, so that the Three Yang channels rise with the earth's qi, allowing all things to be transformed and generated. Is this not proof that the Yang Qi of the Mingmen is indeed the mother of the Spleen and Stomach? Therefore, I say: The Spleen and Stomach are the root of infusion and distribution, obtaining Post-Heaven Qi; the Mingmen is the source of transformation and generation, obtaining Pre-Heaven Qi. There is inherently a sequence of origin and branch between them. Li Dongyuan stated that tonifying the Kidney is inferior to tonifying the Spleen, but one should know that it can also be said that tonifying the Spleen is inferior to tonifying the Kidney; this is clear without needing further debate.
However, there is "fire intensity" (Huo Hou) in the Mingmen, which refers to Yuan Yang (Primordial Yang). Constitution varies in strength, Yuan Qi varies in abundance or decline, Yin and Yang have dominance or subordination, and disease treatment has severity or mildness; these require discernment of appropriate fire intensity. Generally, the Primordial Yang Qi arises from below and ascends; the protective function of the San Jiao (Triple Burner) manifests differently in each region. The manifestation of the Lower Burner is like the earth and soil, the root of transformation and generation; the manifestation of the Middle Burner is like a stove or cauldron, the furnace for cooking water and grain; the manifestation of the Upper Burner is like the vast sky, the dwelling place of divine spirit.
Soil varies in fertility, leading to different produce; mountains and rivers vary in depth and thickness, leading to different storage capacities. The control of gathering and dispersing lies entirely with Yang Qi. Gaining one part of Yang yields one part of utility; losing one part of Yang results in one part of deficiency. Longevity or brevity of life, courage or timidity, and the foundation of treating diseases involving essence and blood all stem from this. Whether Yuan Yang is sufficient or insufficient serves as the master of increase, decrease, fullness, and emptiness; this is what is meant by the fire intensity of the Lower Burner.
The Middle Burner is like a stove or cauldron; the Yang Qi in the Stomach generates heat like a pot. Nourishment from food and drink originates from water and grain. Abundant food leads to a strong body; scarce food leads to physical decline. If a stove lacks even one torch, digesting a large amount takes longer; adding one torch speeds up digestion. If firepower does not reach, nothing is digested at all. Thus, whether the Spleen and Stomach can transform and whether food can be utilized depends entirely on whether the Yang Qi of the Yangming (Stomach Channel) is strong or weak, and whether pathogenic cold-yin invades or not. Once illness occurs, symptoms may include gradual bloating and distension, dysphagia or vomiting, abdominal swelling and accumulation that does not resolve, acid regurgitation or belching with rotten smells, unchanged food odor, abdominal pain, lack of hunger all day, failure to separate clear and turbid, or undigested food in stool. Generally, if transformation occurs, there is no stagnation; if transformation fails, there is retention. Proper operation becomes Qi and Blood; retention becomes Accumulation and Phlegm. This is what is meant by the fire intensity of the Middle Burner.
The Upper Burner is like the vast sky; divine spirit is rooted in Yang Qi, and Yang Qi transforms into spiritual awareness. When Yang is below, it provides warmth, hence it is said that Minister Fire (Xiang Huo) resides in its proper position. When Yang is above, it provides brightness, hence it is said that Sovereign Fire (Jun Huo) is clear. Therefore, when Yang grows and Yin declines, the five sense organs function properly and all species flourish. If Yang declines and Yin prevails, crushing Yang, intelligence is lost and divine spirit diminishes; this is what is meant by the fire intensity of the Upper Burner.
Discussing fire intensity via the San Jiao implies that each has its specific functions, but only the Mingmen actually stores the Pre-Heaven True One Qi within Kan (Water trigram). From below upwards, it connects with Post-Heaven Stomach Qi, forming the root of life. If True Yang does not emit from the abyssal spring, it remains merely unrooted fire.
Fire without a root is pathogenic Qi, not Yuan Qi. The *I Ching* uses Thunder under the Earth to symbolize Fu (Return), showing that the manifestation of fire is above, while its root is below. If Mingmen Yin prevails, Yuan Yang retreats in fear, leaving Dragon Fire (Long Huo) with no place to hide. It wanders and scatters, causing syndromes such as vexing heat or floating Yang (Ge Yang). Those skilled in treating this follow its nature, allowing harmonious Yang Qi to enter Kan directly, seeking its kindred energy, so that floating Yang returns to its origin. Hence, sweet-warm herbs can eliminate great heat, which is precisely what this means. Ignorant people fail to understand this principle, mistaking floating Yang for excess heat. Instead of warming and nourishing this fire, they only know that cold-cool herbs extinguish fire, expecting it to retain vitality? If there are guest heat or pathogenic fire in the San Jiao, these are ordinary fires and must indeed be removed. Removing such fire is not difficult, as they do not belong to the righteous Qi fire intensity.
Moreover, the Mingpossession of Sheng Qi (Vital Qi) is the mechanism of endless movement in Qian Yuan (Heavenly Primal Qi). Endless movement implies activity and ascent, thus Yang obtains vital Qi. Rest implies stillness and descent, thus Yin obtains death Qi. Therefore, Qian Yuan Qi begins below and peaks above; ascending leads to life. Kun Yuan (Earthly Primal Qi) begins above and peaks below; descending leads to death. This divergence of Yin and Yang differs by less than a hair but results in a distance of a thousand miles. Thus, the handle of life and death lies in this minute mechanism of ascent and descent. For example, warm water transforms into vapor; vaporization is ascent, representing life. Cold water forms ice; freezing is descent, representing death. Therefore, if Kidney Qi sinks alone, the force supporting life is reduced, illustrating the principle of vital Qi.
As for human vital Qi, it is everywhere: in Zang Qi, complexion, voice, pulse and respiration, limbs, and urination and defecation. Vital Qi is Divine Spirit (Shen); Shen arises from form, so how can it not be discernible? Wise individuals observe it: who can enhance vital Qi, and who can damage it? Should one first attack pathogenic Qi to protect vital Qi, or first consolidate vital Qi to resist pathogenic Qi? Without clarity on tracing origins and examining endings, one is merely short-sighted.
Generally, the Mingmen has gates, serving as the critical pass for consolidating the whole body. The Classics state: "If the granaries do not store, it is because the gates are not secured; if spring waters do not stop, it is because the Bladder does not store." Retaining security brings life; losing security brings death. It is also said: "The Kidneys are the gate of the Stomach; if the gate is obstructed, water accumulates following its kind." It is also said: "Black corresponds to the Kidney, opening into the two yin orifices." Thus, the master of the North (Lower Body) lies in the Kidney, and the administration of the Kidney lies in the Mingmen.
The Mingmen holds the authority over Yin and Yang. When Yin and Yang are harmonious, entry and exit follow regular patterns; when Yin and Yang are diseased, opening and closing are disordered. Thus, some experience urinary retention (Long Bi) due to exhaustion of Yin and drying of fluids, where dryness prevents flow. Others experience involuntary slipping or leakage due to Yang deficiency and fire failure, where retention lacks mastery. If Yin Essence is exhausted, strengthening Water (nourishing Yin) is necessary for flow; if Yang Qi is deficient, benefiting Fire (tonifying Yang) is necessary for consolidation. These are the therapeutic methods.