三十八难曰∶脏惟有五，腑独有六者，何也？
然∶所谓腑有六者，谓三焦也。有原气之
别焉，主持诸气，有名而无形，其经属手少阳，此外腑也，故言腑有六焉。
三焦有形，于二十五难注中已详细言之。此论三焦为原气别使，根于命门，导引诸气，潜行
默运于一身之中，无或间断也。外腑，谓在诸脏腑之外也，三焦之形质可考，三焦之气化难见，
故曰有名而无形也。
三十九难曰∶经言腑有五，脏有六者，何也？
然∶六腑者，止有五腑也。五脏亦有六脏者，
谓肾有两脏也。其左为肾，右为命门。命门者，谓精神之所舍也，男子以藏精，女子以系胞，其气
与肾通，故言脏有六也。腑有五者，何也？
然∶五脏各一腑，三焦亦是一腑，然不属于五脏，故言腑有五焉。
经言腑五脏有六，无考，不知所出。又以三焦不附于脏，故不名为腑，虽有六腑，只五腑也。
脏亦有六者，以右肾命门，指为一脏也，然肾虽有两，而左右之气相通，实皆肾而已，恐不得
分为两脏。命门辨说，已详言三十六难注中，可参合而观之。
按∶五脏五腑，以合五行，肺合大肠，金也；肝合胆，木也；肾合膀胱，水也；心合小肠，
火也；脾合胃，土也。手厥阴，包络，即心外之衣，为心主之宫城，手少阳三焦，乃腔内脂膜，
为脏腑之郛郭，同司相火而相合，是六脏六腑，以应夫十二经脉也。若以肾分为两脏，则为七
脏矣。《灵枢·本输篇》肾合膀胱，膀胱者，津液之腑也。少阳属肾，肾上连肺，故将两脏。三
焦者，中渎之腑也，水道出焉，属膀胱，是孤之腑也。经言肾将两脏者，以肾兼主水火二气也。
少阳三焦之脉，散于胸中，而肾脉亦上连于肺，肺为天而主气，三焦之下俞，属于膀胱，而膀
胱为津液之腑，乃肾之合，三焦主相火，生于肾而游行于上下，膀胱主水，亦生于肾，盖以水
脏而领水腑也。然膀胱之气，化津化液化汗，皆三焦相火蒸腾所致。夫天一之水，地二之火，
皆肾所生，合而论之是太极，分而论之犹两仪。故本藏篇曰∶肾合三焦膀胱，三焦膀胱者，腠
理毫毛其应，即此义也。且肾虽兼将两脏，实阴阳相贯，水火互交，并主藏精，而为生气之原，
不得谓三焦无形，分肾为两脏明矣。
第三十八难问道：五脏只有五个，六腑却独有六个，这是为什么呢？
回答说：所谓六腑有六个，是指三焦。三焦是原气的别使，主持全身诸气，有名而无形，其经脉归属于手少阳经，属于外腑，所以说六腑有六个。
三焦有形体的说法，在第二十五难的注释中已经详细论述过。这里论述三焦作为原气的别使，根源于命门，引导诸气，在身体内部潜行默运，没有间断。所谓“外腑”，是指在各个脏腑之外。三焦的形质可以考证，但三焦的气化功能难以看见，所以说是“有名而无形”。
第三十九难问道：经文说五腑、六脏，这是为什么呢？
回答说：六腑实际上只有五个。五脏也有六个的说法，是指肾有两个脏器。左边的是肾，右边的是命门。命门，是精神居住的地方，男子用它来藏精，女子用它来系胞（子宫），命门的气与肾相通，所以说脏有六个。
为什么说腑只有五个呢？
回答说：五脏各配一个腑，三焦也是一个腑，但它不隶属于五脏，所以说腑只有五个。
经文说“腑有五，脏有六”，无法考证出处，不知道源自哪里。又因为三焦不依附于脏，所以不称为腑，虽然有六腑之名，实际上只有五个腑。
脏有六个的说法，是因为将右肾和命门指认为一个脏。然而肾虽然有两个，但左右之气相通，实际上都是肾罢了，恐怕不能分为两个脏。关于命门的辨析说明，已经在第三十六难的注释中详细言及，可以参考对照观看。
按语：五脏五腑，以配合五行：肺合大肠，属金；肝合胆，属木；肾合膀胱，属水；心合小肠，属火；脾合胃，属土。手厥阴心包络，就是心脏外面的衣服，是心脏主宰的宫城；手少阳三焦，则是胸腔内的脂膜，是脏腑的外廓，共同主管相火而相互配合，这就是六脏六腑，以对应十二经脉。如果把肾分为两个脏，那就变成七脏了。《灵枢·本输篇》说肾合膀胱，膀胱是津液之腑。少阳（三焦）隶属于肾，肾上连于肺，所以肾兼主两脏。三焦是中渎之腑，水道由此而出，隶属于膀胱，是孤独的腑。经文说“肾将两脏”，是因为肾兼主水火二气。手少阳三焦的经脉，散布于胸中，而肾脉也上连于肺，肺为天且主气；三焦的下俞穴，归属于膀胱，而膀胱是津液之腑，是肾的配偶，三焦主管相火，生于肾而游行于上下；膀胱主管水，也生于肾，大概是以水脏统领水腑。然而膀胱之气，化为津液、液化为汗，都是由三焦相火蒸腾所致。天一之水，地二之火，都生于肾，合起来论述就是太极，分开论述犹如两仪。所以《灵枢·本藏篇》说：“肾合三焦膀胱”，三焦和膀胱的反应体现在腠理毫毛上，就是这个道理。况且肾虽然兼主两脏，实际上是阴阳贯通，水火互交，共同主管藏精，作为生气的本源，不能因为三焦无形，就将肾分为两个脏，这已经很明白了。
Difficulty 38 states: There are only five Zang organs, yet there are uniquely six Fu organs. Why is this?
The answer is: The reason there are six Fu organs refers to the Sanjiao (Triple Burner). It is a distinct branch of Yuanqi (Original Qi), governing all Qi in the body. It has a name but no form. Its meridian belongs to the Hand-Shaoyang (Lesser Yang) channel, and it is considered an external Fu organ; therefore, it is said that there are six Fu organs.
The physical form of the Sanjiao has been discussed in detail in the commentary on Difficulty 25. Here, the discussion posits the Sanjiao as the special envoy of Yuanqi, rooted in the Mingmen (Gate of Life), guiding various Qi, moving silently within the body without interruption. "External Fu" means situated outside the other Zang and Fu organs. The physical structure of the Sanjiao can be examined, but its functional transformation (Qi-hua) is difficult to see; thus, it is described as having a name but no form.
Difficulty 39 states: The classics mention five Fu organs and six Zang organs. Why is this?
The answer is: Among the Fu organs, there are actually only five. Among the Zang organs, there is also the concept of six, referring to the fact that the Kidneys consist of two organs. The left one is the Kidney, and the right one is the Mingmen (Gate of Life). The Mingmen is where the Shen (Spirit) resides; in men, it stores Jing (Essence), and in women, it anchors the Bao (Uterus). Its Qi connects with the Kidney; therefore, it is said that there are six Zang organs.
Why are there only five Fu organs?
The answer is: Each of the five Zang organs corresponds to one Fu organ. The Sanjiao is also a Fu organ, but it does not belong to any of the five Zang organs; therefore, it is said that there are five Fu organs.
The statement in the classics regarding "five Fu and six Zang" cannot be verified, and its origin is unknown. Furthermore, because the Sanjiao does not attach to a specific Zang organ, it is not named as a standard Fu organ; although there is the term "six Fu," there are only five actual Fu organs.
The idea that there are six Zang organs arises from identifying the right Kidney and the Mingmen as separate entities. However, although there are two kidneys, their Qi on the left and right communicates, so they are essentially just the Kidney; it is doubtful that they should be divided into two separate Zang organs. The detailed discussion on the Mingmen can be found in the commentary on Difficulty 36, which readers may consult for reference.
Commentary: The five Zang and five Fu organs correspond to the Five Elements: the Lung pairs with the Large Intestine (Metal); the Liver pairs with the Gallbladder (Wood); the Kidney pairs with the Bladder (Water); the Heart pairs with the Small Intestine (Fire); the Spleen pairs with the Stomach (Earth). The Pericardium (Xinbao), belonging to the Hand-Jueyin channel, is like the outer garment of the Heart, serving as the palace city governed by the Heart. The Sanjiao, belonging to the Hand-Shaoyang channel, is the fatty membrane within the cavity, acting as the outer wall of the Zang and Fu organs. They jointly govern Xianghuo (Ministerial Fire) and correspond to each other, forming the six Zang and six Fu organs to correspond to the twelve meridians. If the Kidney were divided into two Zang organs, there would be seven Zang organs. The *Ling Shu · Ben Shu* chapter states that the Kidney pairs with the Bladder, and the Bladder is the Fu organ of Jin Ye (Body Fluids). Shaoyang (Sanjiao) attaches to the Kidney, and the Kidney connects upward to the Lung; thus, the Kidney governs two Zang organs. The Sanjiao is the Fu organ of middle channels, through which water pathways exit; it attaches to the Bladder and is the solitary Fu organ. When the classic says "the Kidney governs two Zang organs," it means the Kidney governs both Water and Fire Qi. The meridian of the Hand-Shaoyang Sanjiao scatters in the chest, while the Kidney meridian also connects upward to the Lung. The Lung represents Heaven and governs Qi. The lower shu points of the Sanjiao belong to the Bladder, which is the Fu organ of Jin Ye and the partner of the Kidney. The Sanjiao governs Ministerial Fire, which originates in the Kidney and circulates up and down; the Bladder governs Water, which also originates in the Kidney. Thus, the Water Zang organ leads the Water Fu organ. However, the Qi of the Bladder transforms into Jin Ye, fluids, and sweat, all caused by the steaming action of the Sanjiao's Ministerial Fire. Tianyi (Heaven One) Water and Dier (Earth Two) Fire are both generated by the Kidney. Discussed together, they represent Taiji (Supreme Ultimate); discussed separately, they resemble Liangyi (Two Polarities). Therefore, the *Ben Cang* chapter states: "The Kidney pairs with the Sanjiao and Bladder." The reactions of the Sanjiao and Bladder manifest in the couli (interstices) and body hair, which illustrates this principle. Moreover, although the Kidney jointly governs two Zang organs, it is essentially characterized by the interconnection of Yin and Yang and the mutual interaction of Water and Fire, jointly governing the storage of Essence and serving as the source of Sheng Qi (Vital Qi). It is clear that one cannot divide the Kidney into two Zang organs simply because the Sanjiao has no form.