三十八难曰。脏唯有五腑独有六者。何也。然。所以腑有六者。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。
丁曰。其言五脏六腑者。谓五脏应地之五行。其六腑应天之六气。其言天之六气。谓三焦为相火。属手少阳。故言
腑独有六也。杨曰。三焦无内腑。惟有经脉名手少阳。故曰。外腑也。
三十九难曰。经言腑有五。脏有六者。何也。然。六腑者。正有五腑也。然五脏亦有六脏者。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。
丁曰。五脏正有五腑。今曰三焦。是为一腑。配心包络为脏。即脏腑皆有六焉。其二经俱是相火。相行君命。故曰
命门也。杨曰。五脏六腑皆五。有五六之数。或俱五。或俱六。或一五。或一六。并应天地之数也。若以正脏腑言之。
则脏腑俱有五也。脏五以应地之五岳。腑五以应天之五星。若以俱六言之、则脏六以应六律。腑六以应干数。若以脏五
腑六言之。则脏五以应五行。腑六以法六气。若以腑五脏六言之。则脏六以法六阴。腑五以法五常。所以脏腑俱五者。
手心主非脏。三焦非腑也。脏腑俱六者。合手心主及三焦也。其余例可知也。虞曰。天以六气司下。地以五行奉上。天
地交泰。五六之数而成也。人法三才。所以脏腑以法五六之数。谓人头圆象天。足方象地。以脏腑五六之数以象人。则
三才备矣。十一之数。相因而成。故不离于五六也。汉书云。五六乃天地之中数也。
第三十八难问：五脏只有五个，而六腑却独有六个，这是为什么呢？回答说：之所以说六腑有六个，是因为包括了“三焦”。三焦是原气的别道，主持全身之气，有名而无形。它的经脉归属于手少阳经，因此被称为“外腑”，所以说六腑有六个。
丁氏说：文中所说的“五脏六腑”，是指五脏对应大地的五行，六腑对应上天的六气。所谓上天的六气，是指三焦为相火，归属于手少阳经，所以说六腑独有六个。杨氏说：三焦没有对应的内脏实体，只有名为“手少阳”的经脉，所以称为“外腑”。
第三十九难问：经文说“五腑、六脏”，这是为什么呢？回答说：所谓的六腑，实际上正只有五个腑。但是五脏也有六个脏的说法，这是因为肾脏有两个部分。左边称为肾，右边称为命门。命门，是指精神藏舍的地方。男子通过它贮藏精气，女子通过它维系子宫（胞宫）。命门的气与肾相通，所以说脏有六个。那为什么说腑只有五个呢？回答说：五脏各配一个腑，三焦虽然也是一个腑，但它不直接隶属于某一特定的脏，所以说腑有五个。
丁氏说：五脏正配五个腑，现在加上三焦，作为一个腑，配合心包络作为脏，这样脏腑就都有六个了。这两条经脉都属于相火，相火执行君火的命令，所以称为命门。杨氏说：五脏六腑在数量上既有五也有六，或者都是五，或者都是六，或者一个是五、一个是六，这都是为了顺应天地之数。如果从正统的脏腑来看，那么脏腑都只有五个。五脏之五对应大地的五岳，五腑之五对应上天的五星。如果从都是六个来说，那么六脏对应六律，六腑对应天干之数。如果从脏五腑六来说，那么脏五对应五行，腑六效法六气。如果从腑五脏六来说，那么脏六效法六阴，腑五效法五常。之所以说脏腑都只有五个，是因为手心主（心包）不算独立的脏，三焦不算独立的腑。之所以说脏腑都有六个，是因为合用心包和三焦。其余的情况可以类推。虞氏说：天以六气主管下方，地以五行奉献上方，天地交泰，五六之数由此形成。人效法天、地、人三才，所以脏腑效法五六之数。人的头圆象天，脚方象地，用脏腑五六之数来象征人，那么三才就齐备了。十一这个数，是相生而成的，所以离不开五六。《汉书》中说：五六是天地的中间之数。
Chapter 38 asks: 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 is due to the Sanjiao (Triple Burner). It serves as a distinct pathway for Yuan Qi (Original Qi), governing all Qi in the body; it has a name but no physical form. Its meridian belongs to the Hand-Shaoyang (Hand-Taiyang) channel. Therefore, it is referred to as an "External Fu Organ," hence the statement that there are six Fu organs.
Ding stated: When referring to "Five Zang and Six Fu," it means the Five Zang correspond to the Five Elements of the Earth, and the Six Fu correspond to the Six Qi of Heaven. Regarding the Six Qi of Heaven, it refers to the Sanjiao being Xiang Huo (Ministerial Fire), which belongs to the Hand-Shaoyang channel. Thus, it is said that there are uniquely six Fu organs. Yang stated: The Sanjiao lacks an internal organ entity; it possesses only the meridian named Hand-Shaoyang. Hence, it is called an "External Fu Organ."
Chapter 39 asks: The classics state "Five Fu and Six Zang." Why is this? The answer is: The so-called Six Fu actually consist of just five proper Fu organs. However, there is also a concept of Six Zang organs because the Kidney comprises two parts. The left side is called the Kidney, and the right side is called the Mingmen (Gate of Life). The Mingmen is where the Spirit (Shen) and Essence (Jing) reside. In men, it stores Jing (Essence); in women, it connects to the Baoguo (Uterus/Womb). Its Qi communicates with the Kidney, hence it is said there are six Zang organs. Why then are there only five Fu organs? The answer is: Each of the Five Zang corresponds to one Fu. Although the Sanjiao is also a Fu organ, it does not belong directly to any specific Zang organ. Therefore, it is said there are five Fu organs.
Ding stated: The Five Zang properly correspond to five Fu organs. Now, adding the Sanjiao as one Fu, paired with the Xinbao Luo (Pericardium/Luo) as a Zang, results in both Zang and Fu having six. These two meridians both belong to Ministerial Fire (Xiang Huo), which executes the commands of Sovereign Fire (Jun Huo), hence it is called the Mingmen. Yang stated: The Five Zang and Six Fu involve numbers of both five and six; they may be both five, both six, or one five and one six. This aligns with the numbers of Heaven and Earth. If speaking of orthodox Zang and Fu, then both Zang and Fu number five. The five Zang correspond to the Five Great Mountains (Wuyue) of the Earth, and the five Fu correspond to the Five Stars (Wuxing) of Heaven. If speaking of them all being six, then the six Zang correspond to the Six Pitch-pipes (Liulü), and the six Fu correspond to the Heavenly Stems (Tiangan). If speaking of five Zang and six Fu, then the five Zang correspond to the Five Elements (Wuxing), and the six Fu emulate the Six Qi (Liuqi). If speaking of five Fu and six Zang, then the six Zang emulate the Six Yin, and the five Fu emulate the Five Constants (Wuchang). The reason Zang and Fu are considered five is that the Heart-Master (Xin Zhuzhi/Pericardium) is not a distinct Zang, and the Sanjiao is not a distinct Fu. The reason Zang and Fu are considered six is by including the Pericardium and the Sanjiao. Other cases can be understood by analogy. Yu stated: Heaven governs below with the Six Qi, and Earth offers above with the Five Elements. Heaven and Earth interact harmoniously, forming the numbers of five and six. Humans emulate the Three Powers (Sancai: Heaven, Earth, Humanity). Therefore, the Zang and Fu emulate the numbers of five and six. The human head is round like Heaven, and the feet are square like Earth. Using the numbers of five and six for Zang and Fu to symbolize humanity completes the Three Powers. The number eleven arises from their interaction, thus remaining inseparable from five and six. The Book of Han states: Five and Six are the central numbers of Heaven and Earth.