难经七十五篇曰。经言。东方实。西方虚。泻南方。补北方。何谓也。然。金木水火土当更
相平。东方木也。西方金也。木欲实。金当平之。火欲实。水当平之。土欲实。木当平之。
金欲实。火当平之。水欲实。土当平之。东方者肝也。则知肝实。西方者肺也。则知肺虚。
泻南方火。补北方水。南方火。火者。木之子也。北方水。水者。木之母也。水胜火。子能
令母实。母能令子虚。故泻火补水。欲令金不得平木也。经曰。不能治其虚。何问其余。此
之谓也。余每读至此。未尝不叹夫越人之得经旨也。而悼夫后人之失经旨也。先哲有言。凡
读书不可先看注解。且将经文反复而详味之。待自家有新意。却以注解参校。庶乎经意昭然
。而不为他说所蔽。若先看注解。则被其说横吾胸中。自家竟无新意矣。余平生佩服此训。
所益甚多。且如难经此篇。其言周备纯正。足以为万世法。后人纷纷之论。其可凭乎。夫实
则
泻之。虚则补之。此常道也。实则泻其子。虚则补其母。亦常道也。人皆知之。今肝实肺虚
。乃不泻肝而泻心。此则人亦知之。至于不补肺补脾。而补肾。此则人不能知。惟越人知之
耳。夫子能令母实。母能令子虚。以常情观之。则曰。心火实。致肝木亦实。此子能令母实
也。脾土虚。致肺金亦虚。此母能令子虚也。心火实。固由自旺。脾土虚。乃由肝木制之。
法当泻心补脾。则肝肺皆平矣。越人则不然。其子能令母实。子谓火。母谓木。固与常情无
异。其母能令子虚。母谓水。子谓木。则与常情不同矣。故曰水者。木之母也。子能令母实
一句。言病因也。母能令子虚一句。言治法。其意盖曰。火为木之子。子助其母。使之过
分
而为病矣。今将何以处之。惟有补水泻火之治而已。夫补水者何谓也。盖水为木之母。若补
水之虚。使力可胜火。火势退。而水势亦退。此则母能虚子之义。所谓不治之治也。(此虚
字与精气
夺则虚之虚不同。彼虚谓耗其真而致虚。此虚谓抑其过而欲虚之也。
）若曰不然。则母能令子虚一句。将归之于脾肺
乎。既归于脾肺。今何不补脾乎。夫五行之道。其所畏者。畏所克耳。今火大旺。水大亏。
火何畏乎。惟其无畏。何愈旺而莫能制。苟非滋水以求胜之。孰能胜也。水胜火三字。此越
人寓意处。当细观之。勿轻忽也。虽泻火补水并言。然其要又在于补水耳。后人乃曰独泻火
。而不用补水。又曰泻火。即是补水。得不大违越人。与经之意乎。若果不用补水。经必不
言
补北方。越人必不言补水矣。虽然。水不虚。而火独暴旺者。固不必补水亦可也。若先因水
虚。而致火旺者。不补水可乎。水虚火旺。而不补水。则药至而暂息。药过而复作。将积年
累月无有穷已。安能绝其根哉。虽苦寒之药。通为抑阳扶阴。不过泻火邪而已。终非肾脏本
药。不能以滋养北方之真阴也。欲滋真阴。舍地黄黄柏之属不可也。且夫肝之实也。其因有
二。心助肝。肝实之一因也。肺不能制肝。肝实之二
因也。肺之虚也。其因亦有二。心克肺。肺虚之一因也。脾受肝克。而不能生肺。肺虚之二
因也。今补水而泻火。火退则木气削。又金不受克而制木。东方不实矣。金气得平。又土不
受克而生金。西方不虚矣。若以虚则补母言之。肺虚则当补脾。岂知肝势正盛。克土之深。
虽每日补脾。安能敌其正盛之势哉。纵使土能生金。金受火克。亦所得不偿所失矣。此所以
不补土。而补水也。或疑木旺补水。恐水生木。而木愈旺。故闻独泻火。不补水之论。欣然
而从之。殊不知木已旺矣。何待生乎。况水之虚。虽峻补尚不能复其本气。安有余力生木哉
。若能生木。则能胜火矣。或又谓。补水者。欲其不食于母也。不食于母。则金气还矣。岂
知火克金。土不生金。金之虚已极。尚不能自给。水虽欲食之。何所食乎。若如此则金虚不
由于火之克。土之不生。而由于水之食耳。岂理也哉。纵水不食金。金亦未必能复常也。金
不得平木一句。多一不字。所以泻火补水者。正欲使金得平木也。不字当删去。不能治其虚
。何问其余。虚指肺虚而言也。泻火补水。使金得平木。正所谓能治其虚。不补土。不补金
。乃泻火。补水。使金自平。此法之巧而妙者。苟不能晓此法。而不能治此虚。则不须问其
他。必是无能之人矣。故曰。不能治其虚。何问其余。若夫上文所谓金木水火土更相平之义
。不劳解而自明。兹故弗具也。夫越人亚圣也。论至于此。敢不敛衽。但恨说者之HT 蚀之
。故辨。
《难经》第七十五篇说：经文提到，东方实，西方虚，泻南方，补北方。这是什么意思呢？回答说：金、木、水、火、土五行应当互相制约平衡。东方属木，西方属金。如果木气要充实，金气应当制约它；如果火气要充实，水气应当制约它；如果土气要充实，木气应当制约它；如果金气要充实，火气应当制约它；如果水气要充实，土气应当制约它。东方对应肝脏，既然说是东方实，就知道是肝实；西方对应肺脏，既然说是西方虚，就知道是肺虚。治疗应当泻南方的心火，补北方的肾水。南方属火，火是木的子行；北方属水，水是木的母行。水能胜火，子行能使母行充实，母行能使子行虚弱。所以通过泻火补水，目的是让金气不再去制约木气（即防止金因受火克而无力制木）。经文说：“不能治疗其虚证，还问其他什么呢？”说的就是这个道理。
我每次读到此处，无不感叹越人（秦越人）对经旨的理解精妙，同时也哀叹后世之人误解了经旨。先哲有句话说：凡是读书，不要先看注解。先把经文反复诵读并细细品味，等到自己有了新的心得体会后，再用注解来参考校对，这样经文的本意才能清晰显现，而不被他人的学说所蒙蔽。如果先看注解，就会被别人的说法横亘在心中，自己就再也产生不了新的见解了。我平生非常佩服这句教诲，受益良多。就拿《难经》这一篇来说，它的论述周全纯正，足以成为万世的典范。后人纷纷议论的那些观点，哪里值得相信呢？
一般来说，“实证用泻法，虚证用补法”，这是常规法则。“实则泻其子，虚则补其母”，这也是常规法则。人们都知道这些。现在肝实肺虚，却不泻肝而泻心，这一点人们也知道。至于不补肺而补脾，反而补肾，这一点人们就不能理解了，只有越人知道其中的奥妙。所谓“子能令母实，母能令子虚”，从常理来看，会说：心火实，导致肝木也实，这是子能令母实；脾土虚，导致肺金也虚，这是母能令子虚。心火实，固然由自身旺盛引起；脾土虚，是因为被肝木克制所致。按照常理应当泻心火、补脾土，这样肝和肺都能平衡了。但越人不是这样认为的。他说“子能令母实”，这里的子指火，母指木，这与常理无异；但他所说的“母能令子虚”，这里的母指水，子指木，这就与常理不同了。所以说“水是木的母行”。其中“子能令母实”一句，讲的是病因；“母能令子虚”一句，讲的是治法。其大意是说：火是木的子行，子行助长母行，使其过分而为病。那么现在该如何处理呢？只有采用补水泻火的治法罢了。
什么叫补水呢？因为水是木的母行，如果补水的不足，使水的力量能够胜过火，火势退却，而水势也会随之退却（指水不再被火耗伤，得以恢复以制约木），这就是“母能令子虚”的含义，也就是所谓的“不治之治”（此处“虚”字与《内经》“精气夺则虚”中的虚不同，彼处的虚是指耗损真阴导致的虚弱，此处的虚是指抑制过亢之气使其归于平和）。如果说不是这样，那么“母能令子虚”这一句，难道要归结到脾肺吗？既然归结到脾肺，现在为什么不补脾呢？五行的规律中，其所畏惧的，是其所不胜（即克制它的那一行）。现在火大旺，水大亏，火还畏惧谁呢？正因为无所畏惧，所以越发旺盛而无法制约。如果不滋补肾水以求战胜它，谁能战胜它呢？“水胜火”这三个字，是越人寓意的关键所在，应当仔细观察，不可轻视。虽然文中同时提到了泻火和补水，但其重点在于补水。后人却说只泻火，不用补水；又说泻火就是补水，这岂不是大大违背了越人和经文的原意吗？如果果然不用补水，经文必定不会说“补北方”，越人也必定不会说“补水”了。
话虽如此，如果水不虚，只是火单独暴旺，固然是可以不补水的。但如果是因为先有水虚，才导致火旺，能不补水吗？水虚火旺，如果不补水，药物到达时症状暂时平息，药力过后又会复发，长年累月没有穷尽，怎么能断绝病根呢？即使是苦寒的药物，通常也是用来抑阳扶阴，不过只是泻火邪而已，终究不是肾脏的本药，不能滋养北方的真阴。想要滋补肾的真阴，除了地黄、黄柏这类药物外别无他选。
况且肝实的成因有两个：一是心火助长肝木，这是肝实的一个原因；二是肺金不能制约肝木，这是肝实的第二个原因。肺虚的成因也有两个：一是心火克制肺金，这是肺虚的一个原因；二是脾土受到肝木克制，不能生养肺金，这是肺虚的第二个原因。现在通过补水泻火，火势退却，木气就会削弱；接着金气不受火克，就能制约木气，东方（肝）就不实了；金气得平，土气不受木克，就能生养金气，西方（肺）就不虚了。如果按照“虚则补其母”的说法，肺虚应当补脾。岂不知肝势正盛，深克脾土，即使每天补脾，怎能抵挡肝木正盛之势呢？纵使土能生金，但金受火克，也是所得不足以补偿所失。这就是为什么不补土而补水的原因。
有人怀疑：木旺而补水，恐怕水生木，导致木更旺，所以听到“独泻火，不补水”的理论，便欣然接受。殊不知木已经旺了，何须再靠水生呢？况且水本身已虚，即使峻补尚且不能恢复其本气，哪有余力去生木呢？如果能生木，那就能胜火了。又有人说：补水，是为了让水不去消耗金（母）的能量。水不食金，金气就能恢复。岂知火克金，土不生金，金的虚弱已经到了极点，尚且不能自给自足，水虽然想“食”（这里指相生关系中的资源分配或比喻性的消耗，原文逻辑稍显晦涩，意指水若强则可能反侮或竞争，但在五行相生中水为金之母，此处作者反驳的是“补水会导致金更虚”的错误观点，或者是指水虚不能生金，若强行补水若无源亦无益，作者核心论点是补水是为了制火以救金），它能从哪里获取资源呢？如果像那样，金虚就不是由于火的克制、土的不生，而是由于水的“食”造成的，这哪有道理呢？纵然水不“食”金，金也未必能恢复正常。
关于“金不得平木”一句，多了一个“不”字。之所以泻火补水，正是为了让金能够平抑木气。这个“不”字应当删去。“不能治其虚，何问其余”，这里的“虚”指的是肺虚。泻火补水，使金能够平抑木气，这正是所谓“能治其虚”。不补土，不补金，而是泻火、补水，使金气自然平和，这是方法巧妙精妙的地方。如果不能理解这种方法，就不能治疗这种虚证，那就无需问及其他，必然是无能之人了。所以说：“不能治其虚，何问其余。”至于上文所说的金木水火土互相制约平衡的道理，不需要解释自然就明白了，所以这里不再赘述。越人是亚圣般的人物，论述达到这种境界，怎敢不恭敬致敬？只是痛恨那些解说者歪曲了原意，所以进行辨析。
Chapter 75 of the *Nan Jing* (Classic of Difficult Issues) states: The classic says, "The East is excess, the West is deficiency; drain the South, tonify the North." What does this mean? The answer is: Metal, Wood, Water, Fire, and Earth should mutually regulate and balance each other. The East corresponds to Wood, and the West to Metal. If Wood qi tends to become excessive, Metal should regulate it; if Fire qi tends to become excessive, Water should regulate it; if Earth qi tends to become excessive, Wood should regulate it; if Metal qi tends to become excessive, Fire should regulate it; if Water qi tends to become excessive, Earth should regulate it. The East corresponds to the Liver (*Gan*), so knowing the East is excess implies Liver excess. The West corresponds to the Lung (*Fei*), so knowing the West is deficiency implies Lung deficiency. The treatment should be to drain the Fire of the South (Heart) and tonify the Water of the North (Kidney). The South corresponds to Fire, which is the "son" element of Wood. The North corresponds to Water, which is the "mother" element of Wood. Water overcomes Fire. The son can make the mother full, and the mother can make the son empty. Therefore, by draining Fire and tonifying Water, the intention is to prevent Metal from regulating Wood (specifically, to prevent Metal from being weakened by Fire's attack, thereby allowing Metal to regain its ability to control Wood). The classic says, "If one cannot treat the deficiency, what need is there to ask about anything else?" This refers to this principle.
Whenever I read this passage, I cannot help but sigh at Yue Ren (Qin Yueren)'s profound understanding of the classic's intent, while also lamenting that later generations have misunderstood it. An ancient sage said: When studying books, do not look at the annotations first. Instead, repeatedly recite the original text and savor its meaning carefully. Only after you have formed your own new insights should you use the annotations for reference and verification. In this way, the true meaning of the classic will become clear, and you will not be obscured by others' theories. If you look at the annotations first, their arguments will dominate your mind, and you will never generate new insights yourself. I have admired this advice throughout my life and have benefited greatly from it. Take this chapter of the *Nan Jing* as an example: its discussion is comprehensive and pure, sufficient to serve as a model for all generations. How reliable are the numerous debates of later scholars? Generally speaking, "excess conditions are treated with draining methods, and deficiency conditions are treated with tonifying methods"; this is the constant path. "Drain the son in excess conditions, tonify the mother in deficiency conditions"; this is also a constant path. Everyone knows this. Now, given Liver excess and Lung deficiency, one does not drain the Liver but drains the Heart. This point is known to people. However, regarding not tonifying the Lung or the Spleen, but instead tonifying the Kidney, most people cannot understand this; only Yue Ren knows.
The phrase "the son can make the mother full, and the mother can make the son empty," viewed from common sense, might be interpreted as: Heart Fire excess causes Liver Wood to become excess; this is "the son makes the mother full." Spleen Earth deficiency causes Lung Metal to become deficient; this is "the mother makes the son empty." Heart Fire excess is indeed due to its own flourishing. Spleen Earth deficiency is caused by Liver Wood overcoming it. According to standard methods, one should drain Heart Fire and tonify Spleen Earth, so that both Liver and Lung would be balanced. But Yue Ren did not think so. When he said "the son makes the mother full," the son refers to Fire and the mother to Wood, which aligns with common sense. However, when he said "the mother makes the son empty," the mother refers to Water and the son to Wood, which differs from common sense. Thus, "Water is the mother of Wood." The sentence "the son makes the mother full" explains the etiology (cause of disease), while "the mother makes the son empty" explains the therapeutic method. The implication is: Fire is the son of Wood. The son assists the mother, causing her to become excessive and pathological. So how should we handle this? There is only the treatment of tonifying Water and draining Fire.
What does tonifying Water mean? Since Water is the mother of Wood, if we tonify the deficiency of Water, enabling its strength to overcome Fire, the Fire qi will retreat, and consequently, the Water qi will also stabilize (meaning Water is no longer consumed by Fire and can thus function to restrain Wood). This is the meaning of "the mother makes the son empty," also known as "treating without treating" (here, the character "empty/deficient" differs from the "deficiency" in *Nei Jing*'s "when essence and qi are depleted, it is deficiency." That deficiency refers to depletion of true Yin leading to weakness; this deficiency refers to suppressing excessiveness to restore balance). If one argues otherwise, then to which organs should "the mother makes the son empty" be attributed? To the Spleen and Lung? If attributed to them, why not tonify the Spleen now? In the Dao of the Five Elements, what is feared is being overcome. Now, Fire is excessively strong, and Water is severely depleted. Who does Fire fear? Precisely because it fears nothing, it becomes more vigorous and uncontrolled. Unless we nourish Water to seek victory over it, who can prevail? The three characters "Water overcomes Fire" contain Yue Ren's key寓意 (implied meaning) and should be observed carefully, not taken lightly. Although both draining Fire and tonifying Water are mentioned, the crux lies in tonifying Water. Later scholars claimed that only Fire should be drained, without tonifying Water; or they argued that draining Fire is equivalent to tonifying Water. Does this not greatly deviate from the intentions of Yue Ren and the classic? If tonifying Water were truly unnecessary, the classic would not say "tonify the North," nor would Yue Ren mention tonifying Water.
That said, if Water is not deficient and Fire alone is violently excessive, it is indeed possible to proceed without tonifying Water. But if the Fire excess was caused initially by Water deficiency, can we avoid tonifying Water? If Water is deficient and Fire is excessive, and we do not tonify Water, symptoms may temporarily subside when medicine arrives, but will recur once the medicinal effect wears off. This will continue indefinitely year after year. How can the root cause be eradicated? Even bitter-cold herbs, generally used to suppress Yang and support Yin, merely drain Fire pathogenic factors. They are ultimately not the specific herbs for the Kidney and cannot nourish the True Yin of the North. To nourish True Yin, there is no alternative but herbs like *Rehmanniae Radix* (Dihuang) and *Phellodendri Cortex* (Huangbai).
Furthermore, there are two reasons for Liver excess: First, Heart aids Liver, causing one aspect of Liver excess. Second, Lung fails to control Liver, causing the second aspect. There are also two reasons for Lung deficiency: First, Heart overcomes Lung, causing one aspect of Lung deficiency. Second, Spleen is overcome by Liver and thus fails to generate Lung, causing the second aspect. Now, by tonifying Water and draining Fire, Fire retreats, and Wood qi is diminished. Then, Metal is not overcome by Fire and can control Wood, so the East (Liver) will not be excessive. With Metal qi balanced, Earth is not overcome by Wood and can generate Metal, so the West (Lung) will not be deficient. If we spoke according to "tonify the mother in deficiency," Lung deficiency should be treated by tonifying the Spleen. But isn't it known that Liver qi is currently very strong and deeply overcomes Earth? Even if the Spleen were tonified daily, how could it resist the strong force of Liver? Even if Earth could generate Metal, Metal is still overcome by Fire, so the gain would not compensate for the loss. This is why we do not tonify Earth but instead tonify Water.
Some doubt: Tonifying Water when Wood is already excessive might cause Water to generate Wood, making Wood even more excessive. Hence, they happily accept the theory of "draining Fire only, without tonifying Water." Little do they know that Wood is already excessive; why wait for generation? Moreover, Water itself is deficient; even with potent tonification, it may struggle to restore its original qi, let alone have surplus energy to generate Wood. If it could generate Wood, it would be able to overcome Fire. Others argue: Tonifying Water is intended to prevent Water from consuming its mother (Metal). If Water does not consume Metal, Metal qi will return. But don't they realize that Fire overcomes Metal, and Earth fails to generate Metal, leaving Metal extremely deficient and unable to sustain itself? Even if Water wanted to "consume" (in the context of resource allocation or interaction), where would it get resources? If this were the case, Metal's deficiency would not be due to Fire's overcoming or Earth's failure to generate, but due to Water's consumption. Is this logical? Even if Water does not consume Metal, Metal may not necessarily recover to normal.
Regarding the phrase "Metal cannot regulate Wood," the character "not" (bu) seems superfluous or misplaced in interpretation. The reason for draining Fire and tonifying Water is precisely to enable Metal to regulate Wood. The "not" should be understood differently or removed in this specific logical context to affirm that Metal *can* regulate Wood. "If one cannot treat the deficiency, what need is there to ask about anything else?" Here, "deficiency" refers to Lung deficiency. Draining Fire and tonifying Water enables Metal to regulate Wood, which is exactly what is meant by "being able to treat the deficiency." Not tonifying Earth or Metal, but rather draining Fire and tonifying Water to allow Metal to naturally balance, is a clever and subtle method. If one cannot comprehend this method, one cannot treat this deficiency, and thus there is no need to ask about other matters; such a person must be incompetent. Hence, "If one cannot treat the deficiency, what need is there to ask about anything else?" As for the meaning of Metal, Wood, Water, Fire, and Earth mutually regulating each other mentioned earlier, it is self-evident and requires no explanation, so it is not detailed here. Yue Ren is akin to a Second Sage. His discourse reaches such a level; how dare I not show reverence? I only regret that commentators have distorted the meaning, which is why I have written this clarification.