七十五难曰∶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。东方肝也，则知肝实；
西方肺也，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。
此章诸家诠注，皆未足达越人之旨，惟徐氏《经释》庶乎近焉，今就其义而引申之。东方实，
西方虚者。东方木也，肝也，西方金也，肺也。人之五脏，应乎五行，宜平伏，不宜偏胜，若
或一脏独胜，则疾病生，须凭补泻以调之也。调之之法，而言泻南方，补北方者，南方火为木
之子，北方水为木之母也。论五行本然之道，木实金当平之，火实水当平之，土实木当平之，
金实火当平之，水实土当平之，此自然之理也。今东方肝实，西方肺虚，金虚何能平木，论治
当抑其太过，扶其不及，故曰泻南方火，补北方水，此实则泻其子也。夫火者，木之子也，水
者，木之母也，泻火则火衰，而盗泄母气，其火之势减，亦不能凌金，补水则火气愈弱，更窃
木气，故曰水胜火也。况木气即泄，金不受凌，则虚者自复，复则遂得平木之实用。水既克火，
其势益实，是以木之母水，胜木之子火也。而谓之子令母实，母令子虚者，盖木之子火，为木
之母水所克制，则火能益水之气，故曰子令母实，而水克火，能夺火之气，故曰母令子虚也。
观上下文义，则此子母两字，皆就肝木而言，抑木即所以扶金也。越人恐读者误会，更申其义
曰∶故泻火补水者，欲令金得以平木也。若不知治金虚之法，止以一经为补泻，则他病亦不能
治也。金下之不字，滑氏谓衍文宜删，极是。
按∶滑氏曰∶金不得平木，不字疑衍文。东方实，西方虚，泻南方，补北方者，木金火水，
欲更相平也。木火土金水之欲实，五行之贪胜而务权也。金水木火土之相平，以五行所胜，而
制其贪也。经曰∶一脏不平，所胜平之，东方肝也，西方肺也。东方实，则知西方虚矣，若西
不虚，则东方安得过于实耶？或泻或补，要亦抑其盛，济其不足，损过就中之道也。水能胜
火，子能令母实，母能令子虚，泻南方火者，夺子之气，使食母之有余，补北方水者，益子
之气，使不食于母也。如此，则过者退而抑者进，金得平其木，而东西方无复偏胜偏亏之患矣。
越人之意，大抵谓东方过于实，而西方之气不足，故泻火以抑其木，补水以济其金，是乃使金
得与水相停，故曰欲令金得平木也。若曰金不得平木，则前后文义窒碍，竟说不通，使肝木不
过，肺金不虚，复泻火补水，不几于实实虚虚耶？八十一难文义，正与此互相发明。九峰蔡氏
谓水火金木土，惟修取相制，以泄其过，其意亦同。故结句云∶不能治其虚，何问其余，盖为
知常而不知变者之戒也。此篇大意，在肝实肺虚，泻火补水上。或问子能令母实，母能令子虚，
当泻火补土为是，盖子有余，则不食母之气，母不足，则不能荫其子，泻南方火，乃夺子之气，
使食母之有余，补中央土，则益母之气，使得以荫其子也，今乃泻火补水何欤？曰∶此越人之
妙，一举而两得之者也。且泻火一则以夺木之气，一则以去金之克，补水一则以益金之气，一
则以制火之光，若补土则一于助金而已，不可施于两用，此所以不补土而补水也。或又问母能
令子实，子能令母虚，五行之道也。今越人乃谓子能令母实，母能令子虚，何哉？曰∶是各有
其说也。母能令子实，子能令母虚者，五行之生化。子能令母实，母能令子虚者，针家之予夺，
固不相侔也。四明陈氏曰∶仲景云∶木行乘金，名曰横。《内经》曰∶气有余，则制己所胜，
而侮所不胜，木实金虚，是木横而凌金，侮所不胜也。木实本以金平之，然以其气正强而横，
金平之，则两不相伏而战，战则实者亦伤，虚者亦败，金虚本资气于土，然其时土亦受制，未
足以资之，故取水为金之子，又为木之母，于是泻火补水，使水胜火，则火馁而取气于木，木
乃减而不复实，水为木母，此母能令子虚也。木既不实，其气乃平，平则金免木凌，而不复虚，
水为金子，此子能令母实也。所谓金不得平，木不得凌，以金平其木，必泻火补水，而旁治之，
使木金之气，自然两平耳。今按陈氏此说，亦是有理，但为不之一字所缠，未免牵强费辞，不
若直以不字为衍文尔。观八十一篇中当知金平木一语可见矣。滑氏注，于释子令母实，母令子
虚，未能明显，不若陈氏之说，较为晓畅也。然以木为火之母，水为金之子为言，其义虽通，
于越人之旨，究隔一间。
又按∶王氏曰∶余每读至此难，未尝不叹夫越人之得经旨，而悼夫后世之失经旨也。先哲有
言，凡读书不可先看注解，且将经文反复而详味之，得自家有新意，却以注解参校，庶乎经旨
昭然，而不为他说所蔽，若先看注解，则被其说横吾胸中，自家却无新意矣。余平生所佩服此
训，所益甚多。且如《难经》此篇，其言周备纯正，足为万世法，后人纷纷之论，其可凭乎？
夫实则泻之，虚则补之，此常道也，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，言治法也。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，火势退而木势亦退，此则母能
虚子之义，所谓不治之治也，若曰不然，则母能令子虚一句，将归之脾肺乎？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，则
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，细观之，勿轻
忽也。虽泻火补水并言，然其要又在补水耳。后人乃言独泻火，而不用补水。又曰泻火即是补
水，得不大违越人与经旨之意乎？若果不用补水，经不必言补北方水，越人不必言补水矣。虽
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，不能滋养北方之真阴也。欲滋真阴，舍地
黄、黄柏之属不可也。其因有二∶且夫肝之实也，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，岂知肝气正盛，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，故闻独泻火不补水论，忻然而从之，殊不知木已
旺矣，何待生乎！况水之虚，虽峻补不能复其本气，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，则金还矣。岂知火克金，土不生金，金之虚已极，
尚不能自给，水虽食之，何所食乎！若然，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，不解而自明，兹故弗具也。夫越人，亚圣也，论至
于此，敢不敛衽。但说者之 蚀，故辨之。
愚按∶伯仁受针法于东平高洞阳，故专以针法补泻
注，安道不习针，故以用药论，若越人则一以贯之，学人习玩斯篇，于补泻之法，获益非浅。
第七十五难说：医经上讲，东方（肝木）实证，西方（肺金）虚证，应当泻南方（心火），补北方（肾水），这是什么意思呢？
回答说：金、木、水、火、土五行，应当相互平衡。
东方属木，西方属金。木气想要充实，金气应当制约它；火气想要充实，水气应当制约它；土气想要充实，木气应当制约它；金气想要充实，火气应当制约它；水气想要充实，土气应当制约它。东方对应肝脏，所以知道是肝实；西方对应肺脏，所以知道是肺虚。治疗应当泻南方心火，补北方肾水。南方属火，火是木之子；北方属水，水是木之母。水能胜火，子能令母实，母能令子虚，所以泻火补水，是为了让金气能够制约木气。医经说：不能治疗其虚损，还问其他什么呢？说的就是这个道理。
这一章各家注解，都不足以阐明越人（秦越人，即扁鹊）的本意，只有徐氏的《经释》比较接近，现在依据他的义理加以引申。所谓东方实、西方虚，是指东方属木，对应肝脏；西方属金，对应肺脏。人的五脏对应五行，适宜平伏，不适宜偏盛，如果某一脏单独偏盛，疾病就会产生，必须依靠补泻来调节。调节的方法，说要泻南方、补北方，是因为南方火是木之子，北方水是木之母。从五行本然的道理来说，木实则金当平之，火实则水当平之，土实则木当平之，金实则火当平之，水实则土当平之，这是自然的道理。如今东方肝实，西方肺虚，金气虚弱怎能制约木气？论治应当抑制太过，扶持不及，所以说泻南方火，补北方水，这就是“实则泻其子”的道理。火是木之子，水是木之母，泻火则火衰，从而盗泄母气（木气），火势减弱，也不能欺凌金气；补水则火气更弱，又窃取木气，所以说水胜火。况且木气既然泄了，金不受欺凌，那么虚者自然恢复，恢复了就能起到制约木气的作用。水既克制火，其势更加充实，所以是木之母水，胜过木之子火。而所谓“子令母实，母令子虚”，大概是因为木之子火，被木之母水所克制，火就能增益水之气，所以叫“子令母实”；而水克火，能夺取火之气，所以叫“母令子虚”。纵观上下文义，这里的“子”、“母”两字，都是就肝木而言，抑制木就是扶持金。越人恐怕读者误解，进一步申述其义说：所以泻火补水，是想让金得以制约木。如果不知道治疗金虚的方法，只针对一经进行补泻，那么其他病也就不能治了。关于“金不得平木”中的“不”字，滑寿认为衍文宜删，非常正确。
按：滑寿说：“金不得平木”，“不”字疑为衍文。东方实，西方虚，泻南方，补北方，是指木、金、火、水，想要相互平衡。木、火、土、金、水想要充实，是五行贪胜而务求权位的表现。金、水、木、火、土相互平衡，是用五行相胜的关系来制约这种贪婪。医经说：一脏不平，由所胜之脏来平复它。东方是肝，西方是肺。东方实，就知道西方虚了，如果西方不虚，东方怎么会过于实呢？或泻或补，大抵是抑制其盛，济助其不足，这是损过就中的道理。水能胜火，子能令母实，母能令子虚，泻南方火，是夺取子气，使其食用母的有余；补北方水，是益子气，使其不食于母。这样，过者退而抑者进，金得以平其木，东西方不再有偏胜偏亏的祸患了。越人的意思，大体是说东方过于实，而西方之气不足，所以泻火以抑制木，补水以济助金，这是为了让金能与水相停，所以说“想令金得平木”。如果说“金不得平木”，则前后文义窒碍，说不通，假如肝木不过，肺金不虚，再泻火补水，岂不是实其实、虚其虚吗？第八十一难的文义，正与此互相发明。九峰蔡氏说水火金木土，只有修取相制，以泄其过，其意思也相同。所以结句说：不能治其虚，何问其余，这是给那些知常不知变的人的警告。这篇大意，在于肝实肺虚，泻火补水。有人问：子能令母实，母能令子虚，应当泻火补土才对，因为子有余，就不食母之气，母不足，就不能荫庇其子，泻南方火，是夺子之气，使食母之有余，补中央土，则是益母之气，使得以荫其子，如今却泻火补水为什么呢？回答说：这是越人的妙处，一举两得。且泻火一则夺木之气，二则去金之克；补水一则益金之气，二则制火之光。若补土则仅助金而已，不可施于两用，这就是不补土而补水的原因。又有人问：母能令子实，子能令母虚，是五行的道理。如今越人说子能令母实，母能令子虚，为什么？回答说：这各有说法。母能令子实，子能令母虚，是五行的生化规律；子能令母实，母能令子虚，是针灸家的予夺之法，本来就不一样。四明陈氏说：仲景说：木行乘金，名叫横。《内经》说：气有余，则制己所胜，而侮所不胜。木实金虚，是木横而凌金，侮所不胜。木实本应由金平之，但因其气正强而横，金平之，则两不相伏而战，战则实者亦伤，虚者亦败。金虚本资气于土，然此时土亦受制，不足以资之，故取水为金之子，又为木之母，于是泻火补水，使水胜火，则火馁而取气于木，木乃减而不复实，水为木母，此母能令子虚也。木既不实，其气乃平，平则金免木凌，而不复虚，水为金子，此子能令母实也。所谓金不得平，木不得凌，以金平其木，必泻火补水，而旁治之，使木金之气，自然两平耳。如今看陈氏此说，也是有理，但被“不”之一字缠绕，未免牵强费辞，不如直接将“不”字视为衍文。观第八十一篇中可知“金平木”一语可见矣。滑氏注，在解释子令母实，母令子虚时，未能明显，不如陈氏之说较为晓畅。然而以木为火之母，水为金之子来论述，其义虽通，对于越人的本意，终究隔了一层。
又按：王氏说：我每次读到这里，未尝不感叹越人得经旨，而哀悼后世失经旨。先哲有言，凡读书不可先看注解，且将经文反复详味，得自家有新意，再以注解参校，庶乎经旨昭然，而不为他说所蔽。若先看注解，则被其说横亘胸中，自家却无新意了。我平生佩服此训，受益甚多。且如《难经》此篇，其言周备纯正，足为万世法，后人纷纷之论，岂可凭信？夫实则泻之，虚则补之，这是常道，人皆知之。今肝实肺虚，却不泻肝而泻心，这也是人皆知的，至于不补肺补脾而补肾，则人不能知，只有越人知之罢了。从常情看，“子能令母实”，指心火实，致肝木亦实，这是子能令母实。“母能令子虚”，指脾土虚，致肺金亦虚，这是母能令子虚。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。所以说“水者木之母也”。“子能令母实”一句，言病因也。“母能令子虚”一句，言治法也。其意大概是：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，火势退而木势亦退，此则母能虚子之义，所谓不治之治也。若曰不然，则“母能令子虚”一句，将归之脾肺乎？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，则愈旺而莫能制，苟非滋水以求胜之，孰能胜也。“水胜火”三字，此越人寓意处，细观之，勿轻忽也。虽泻火补水并言，然其要又在补水耳。后人乃言独泻火，而不用补水。又曰泻火即是补水，得不大违越人与经旨之意乎？若果不用补水，经不必言补北方水，越人不必言补水矣。虽水不虚，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，不能滋养北方之真阴也。欲滋真阴，舍地黄、黄柏之属不可也。其因有二：且夫肝之实也，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，岂知肝气正盛，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，故闻独泻火不补水论，忻然而从之，殊不知木已旺矣，何待生乎！况水之虚，虽峻补不能复其本气，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，则金还矣。岂知火克金，土不生金，金之虚已极，尚不能自给，水虽食之，何所食乎！若然，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，不解而自明，兹故弗具也。夫越人，亚圣也，论至此，敢不敛衽。但说者之蚀，故辨之。
愚按：伯仁受针法于东平高洞阳，故专以针法补泻注，安道不习针，故以用药论，若越人则一以贯之，学人习玩斯篇，于补泻之法，获益非浅。
Chapter 75 states: The classics say, "When the East is excess and the West is deficiency, drain the South and tonify the North." What does this mean?
The response is: Metal, Wood, Water, Fire, and Earth should balance each other.
The East corresponds to Wood, and the West to Metal. If Wood desires to be excessive, Metal should restrain it; if Fire desires to be excessive, Water should restrain it; if Earth desires to be excessive, Wood should restrain it; if Metal desires to be excessive, Fire should restrain it; if Water desires to be excessive, Earth should restrain it. The East corresponds to the Liver (Gan), indicating Liver excess; the West corresponds to the Lung (Fei), indicating Lung deficiency. Treatment involves draining the South (Heart/Fire) and tonifying the North (Kidney/Water). The South belongs to Fire, which is the son of Wood; the North belongs to Water, which is the mother of Wood. Water overcomes Fire. The son can make the mother full, and the mother can make the son empty. Therefore, draining Fire and tonifying Water aims to allow Metal to restrain Wood. The classics state: "If one cannot treat the deficiency, what need is there to ask about the rest?" This refers to this principle.
Various commentaries on this chapter have failed to fully elucidate Yuèrén's (Bian Que) intent. Only Xu's *Jing Shi* comes close. I will now elaborate on its meaning. "East excess, West deficiency" means the East is Wood corresponding to the Liver, and the West is Metal corresponding to the Lung. The five Zang organs correspond to the Five Elements and should remain balanced, not biased towards excess. If one organ becomes excessively strong, disease arises, requiring supplementation and drainage for regulation. The method of regulation mentions draining the South and tonifying the North because Southern Fire is the son of Wood, and Northern Water is the mother of Wood. According to the natural way of the Five Elements, if Wood is excessive, Metal should restrain it; if Fire is excessive, Water should restrain it; if Earth is excessive, Wood should restrain it; if Metal is excessive, Fire should restrain it; if Water is excessive, Earth should restrain it. This is natural logic. Currently, the Eastern Liver is excessive, and the Western Lung is deficient. How can deficient Metal restrain Wood? Treatment should suppress the excessive and support the deficient. Thus, we drain Southern Fire and tonify Northern Water, which is "draining the son when the parent is excessive." Fire is the son of Wood, and Water is the mother of Wood. Draining Fire weakens Fire, thereby depleting the mother's Qi (Wood), reducing Fire's momentum so it cannot oppress Metal. Tonifying Water further weakens Fire and consumes Wood's Qi, hence "Water overcomes Fire." Since Wood's Qi is drained, Metal is not oppressed, and the deficient state naturally recovers, allowing Metal to function in restraining Wood. Since Water controls Fire, its power increases, making Wood's mother (Water) overcome Wood's son (Fire). The phrases "son makes mother full" and "mother makes son empty" imply that since Wood's son (Fire) is controlled by Wood's mother (Water), Fire benefits Water's Qi ("son makes mother full"), while Water controlling Fire deprives Fire of Qi ("mother makes son empty"). Contextually, these terms refer to Liver Wood. Suppressing Wood supports Metal. Yuèrén feared misunderstanding and clarified: draining Fire and tonifying Water allows Metal to restrain Wood. If one does not know how to treat Lung deficiency and only treats one meridian, other diseases cannot be cured. Regarding the phrase "Metal cannot restrain Wood," Hua Shi argued the character "bu" (not) is a superfluous character and should be deleted, which is correct.
Hua Shi notes: "Metal cannot restrain Wood" likely contains a superfluous "not". East excess, West deficiency, draining South, tonifying North implies Wood, Metal, Fire, Water seeking mutual balance. The desire for Wood, Fire, Earth, Metal, Water to be full represents the Five Elements' greed for dominance. Their mutual balance uses overcoming relationships to curb this greed. The classics say: "If one Zang is unbalanced, the element that overcomes it balances it." East is Liver, West is Lung. If East is excessive, West must be deficient; otherwise, how could East be overly excessive? Drain or tonify, the goal is to suppress excess and aid deficiency, following the path of moderation. Water overcomes Fire. Draining Southern Fire takes the son's Qi, making it consume the mother's surplus. Tonifying Northern Water benefits the son's Qi, preventing it from consuming the mother. Thus, excess retreats, suppression advances, Metal restrains Wood, and East/West no longer suffer bias. Yuèrén's intent is that East is overly excessive and West is deficient. Draining Fire suppresses Wood; tonifying Water aids Metal, allowing Metal to equilibrate with Water, hence "allowing Metal to restrain Wood." If "Metal cannot restrain Wood," the text becomes contradictory. If Liver Wood is not excessive and Lung Metal is not deficient, draining Fire and tonifying Water would exacerbate excess and deficiency (making excess more excess and deficiency more deficient). Chapter 81 clarifies this. Cai Jiufeng agrees that mutual control泄s excess. The conclusion "If one cannot treat the deficiency, what need is there to ask about the rest" warns against those who know constants but not variations. The main point is Liver excess and Lung deficiency, treated by draining Fire and tonifying Water.
A question arises: "Son makes mother full, mother makes son empty." Shouldn't we drain Fire and tonify Earth? Because if the son has surplus, it doesn't consume the mother's Qi; if the mother is deficient, it cannot nourish the son. Draining Fire takes the son's Qi to consume the mother's surplus; tonifying Central Earth benefits the mother's Qi to nourish the son. Why drain Fire and tonify Water? Answer: This is Yuèrén's brilliance, achieving two goals at once. Draining Fire reduces Wood's Qi and removes Metal's oppression. Tonifying Water benefits Metal's Qi and controls Fire's brightness. Tonifying Earth only aids Metal, lacking dual utility. Hence, Water is tonified instead of Earth.
Another question: "Mother makes son full, son makes mother empty" is the Way of Five Elements. Why does Yuèrén say "son makes mother full, mother makes son empty"? Answer: These are different theories. "Mother makes son full, son makes mother empty" refers to Five Element generation/production. "Son makes mother full, mother makes son empty" refers to acupuncture manipulation (giving/taking). Chen Siming cites Zhang Zhongjing: "Wood attacking Metal is called Heng (Horizontal)." The *Neijing* says: "Excess Qi controls what it overcomes and insults what it cannot overcome." Liver excess and Lung deficiency represent Wood insulting Metal. Normally Metal restrains Wood, but if Wood is too strong, Metal's attempt leads to conflict, harming both. Lung deficiency relies on Earth, but Earth is also controlled by Wood. Thus, Water is chosen as Metal's son and Wood's mother. Draining Fire and tonifying Water makes Water overcome Fire. Fire becomes weak and draws Qi from Wood, reducing Wood. Water, as Wood's mother, makes the son (Wood) empty. Wood becomes balanced, relieving Metal's oppression, restoring Metal. Water, as Fire's son, makes the mother (Fire) full. Chen's theory is logical but constrained by the word "not," making it forced. Deleting "not" aligns better with Chapter 81. Hua Shi's explanation is less clear than Chen's. However, viewing Wood as Fire's mother and Water as Metal's son fits logically but misses Yuèrén's deeper intent.
Wang remarks: Reading this, I sigh at Yuèrén grasping the classics while lamenting later generations losing them. Ancients said: Do not read commentaries first. Savor the text yourself to find new insights, then compare with commentaries. Otherwise, preconceived notions block true understanding. I admire this advice. This chapter is perfect. Later debates are unreliable. "Excess drains, deficiency tonifies" is common knowledge. Everyone knows to drain Heart (Fire) for Liver (Wood) excess. Few know to tonify Kidney (Water) instead of Spleen (Earth) for Lung (Metal) deficiency. Only Yuèrén knew this. Common sense suggests Heart Fire excess causes Liver Wood excess ("son makes mother full") and Spleen Earth deficiency causes Lung Metal deficiency ("mother makes son empty"). Standard treatment would drain Heart and tonify Spleen. Yuèrén differs: "Son makes mother full" refers to Fire (son) and Wood (mother), consistent with common sense. But "Mother makes son empty" refers to Water (mother) and Wood (son), differing from common sense. "Son makes mother full" explains etiology (Fire assists Wood, causing excess). "Mother makes son empty" explains treatment (Tonify Water to drain Fire). Tonifying Water strengthens Water to overcome Fire; as Fire declines, Wood declines. This is "mother making son empty," a form of non-treatment. If applied to Spleen/Lung, why not tonify Spleen? Fire fears Water. With Fire strong and Water weak, Fire is unafraid and uncontrollable. Only by nourishing Water can it be overcome. "Water overcomes Fire" is key. Although both draining Fire and tonifying Water are mentioned, tonifying Water is crucial. Later scholars claim only draining Fire is needed, or that draining Fire equals tonifying Water, contradicting Yuèrén. If tonifying Water were unnecessary, the text wouldn't mention it. If Water is not deficient but Fire is suddenly hyperactive, tonifying Water might not be needed. But if Fire hyperactivity stems from Water deficiency, not tonifying Water is wrong. Without tonifying Water, symptoms temporarily subside but return, becoming chronic. Bitter-cold drugs only drain Fire邪 (evil) but do not nourish Kidney True Yin. To nourish True Yin, Rehmanniae Radix (Dihuang) and Phellodendri Cortex (Huangbai) are essential. Reasons: Liver excess is caused by Heart assisting Liver and Lung failing to control Liver. Lung deficiency is caused by Heart controlling Lung and Spleen failing to generate Lung due to Liver control. Draining Fire and tonifying Water reduces Wood, allowing Metal to control Wood (East not excessive). Metal balances, allowing Earth to generate Metal (West not deficient). If we followed "tonify mother for deficiency," we would tonify Spleen for Lung deficiency. But Liver is strong and controls Earth deeply. Daily Spleen tonification cannot counteract strong Liver. Even if Earth generates Metal, Metal is controlled by Fire, resulting in net loss. Hence, Water is tonified, not Earth. Some worry tonifying Water feeds Wood, increasing Wood. They prefer draining Fire alone. But Wood is already excessive; it doesn't need feeding. Moreover, severe Water deficiency cannot be quickly restored to generate Wood. If it could generate Wood, it would overcome Fire. Others argue tonifying Water prevents it from consuming the mother, thus saving Metal. But Metal is extremely deficient due to Fire control and Earth failure, unable to sustain itself. How can it be consumed by Water? If Lung deficiency were due to Water consumption, that would be absurd. Even if Water doesn't consume Metal, Metal may not recover. The "not" in "Metal cannot restrain Wood" should be deleted. Draining Fire and tonifying Water allows Metal to restrain Wood. "Cannot treat deficiency" refers to Lung deficiency. This method cleverly restores Metal without directly tonifying Earth or Metal. Those who don't understand this cannot treat deficiency and are incompetent. Hence, "If one cannot treat the deficiency, what need is there to ask about the rest?" The earlier concept of mutual balancing is self-evident. Yuèrén is a near-sage; his words deserve respect. I clarify here to correct misunderstandings.
Note: Bo Ren learned acupuncture from Gao Dongyang, focusing on needle techniques. Andao focused on herbal medicine. Yuèrén integrated both. Students studying this chapter gain much insight into supplementation and drainage methods.