《难经》言手心主与三焦凡八，见第八、三十一、三十六、三十八，三十九、六十二、六十六及此篇，俱当参观。
二十六难曰∶经有十二，络有十五，余三络者，是何等络也？（《灵·九针十二原篇》云∶“经脉十二，络脉十五，
凡二十七气，以上下”。）
然∶有阳络，有阴络，有脾之大络。《灵·经脉篇》∶“脾之大络，名曰大包，出渊液下三寸，布
胸中。”）阳络者，阳跷之络也。阴络者，阴跷之络也。（一跷脉详二十三难。）故络有十五焉。
二十七难曰∶脉有奇经八脉，不拘于十二经，何谓也？（奇，读如奇偶之奇，谓无手足配偶如十二经也。详下编。）
然∶有阳维，有阴维，有阳跷，有阴跷，有冲，有督，有任，有带之脉。凡此八脉者，皆不拘于经，故曰奇经八脉
也。（详
见下编。）经有十二，络有十五，凡二十七气，相随上下，（出见前篇。）何独不拘于经也？
然∶圣人图设沟渠，通利水道，
以备不然。（不然，犹言不虞也。）天雨降下，沟渠溢满，当此之时， 霈妄作，（一作行）圣人不能复图也。（此以水道
喻人身血脉之道。）此络脉满溢，诸经不能复拘也。（言血脉充盛，十二经不足以容之，则溢出而为奇经，故奇经为十二
经之别脉也。）
二十八难曰∶其奇经八脉者，既不拘于十二经，皆何起何继也？（继，续也。《脉经》作“系”。）
然∶督脉者，起于
下极之俞，（俞，即穴也。下极，即长强穴，属督脉，在脊 骨端。）并于脊里，（脊里，背脊中也。）上至风府，（风府，
属督脉，在项上入发际一寸大筋内宛宛中。）入属于脑。（《灵·经脉篇》∶“督脉之别，名曰长强，挟膂上项，散头上，下
当肩胛左右，别走太阳，入贯膂。实则脊强，虚则头重。”《素问·骨空论》∶“督脉者，起于少腹，以下骨中央，女子入
系廷孔，其孔，溺孔之端也。其络循阴器，合篡间，绕篡后，别绕臀，至少阴，与巨阳中络者合少阴上股内后廉，贯脊
属肾，与太阳起于目内 ，上额交巅上，入络脑，还出别下项。循肩膊内，侠脊，抵腰中，入循膂络肾；其男子循茎下
至篡，与女子等。其少腹直上者，贯脐中央，上贯心，入喉，上颐环唇，上系两目之下中央。此生病，从少腹上冲心而
痛，不得前后，为冲疝。其女子∶不孕，癃、痔、遗溺、嗌干。”）任脉者，起于中极之下，（中极穴，属任脉，在脐下四
寸。中极之下，盖指会阴穴也。）以上至毛际，（前阴之上。）循腹里，（即中极穴。）上关元，（关元穴在脐下三寸。）至咽
喉。（《素·骨空论》至咽喉之下，有“上颐、循面、入目”六字。《灵·经脉篇》“任脉之别，名曰尾翳，下鸠尾，散于
腹。实则腹皮痛，虚则痒搔。”）冲脉者，起于气冲，（足阳明经穴，在毛际两旁。）并足阳明之经，（《素·痿论》云∶“冲
脉者，经脉之海，主渗灌溪谷，与阳明合于宗筋，阴阳总宗筋之会，会于气冲，而阳明为长，皆属于带脉，而络于督脉。”）
侠（一作夹）脐上行，至胸中而散。（一本有也字。）
带脉者，起于季胁，（季胁，属足厥阴章门穴之分。）回身一周。（谓周身围转，如人束带之状，以束诸脉也。）《灵·经
别篇》∶“足少阴之正，至 中，别走太阳而合，上至肾，当十四椎，出属带脉。”
二十九难曰∶奇经之为病何如？
然∶阳维维于阳，（阳，阳经，身之表也。）阴维维于阴，（阴，阴经，身之里也。）
阴阳不能自相维，则怅然失志，溶溶不能自收持。（溶溶，浮荡之貌。）阳维为病苦寒热，（阳主外，阳气不和，故生寒热
也。）阴维为病苦心痛。（阴主内，心为少阴，阴气不和，故心痛也。）
《难经》中关于手厥阴心包经（手心主）与三焦经的论述共有八处，分别见于第八难、第三十一难、第三十六难、第三十八难、第三十九难、第六十二难、第六十六难以及本篇，这些内容都应当相互参照阅读。
第二十六难说：经脉有十二条，络脉有十五条，多出来的这三条络脉，是什么络脉呢？（《灵枢·九针十二原篇》中说：“经脉十二条，络脉十五条，总共二十七气，上下运行”。）
回答是：有阳跷络，有阴跷络，有脾之大络。《灵枢·经脉篇》说：“脾的大络，名叫大包，出于渊液穴下三寸，散布于胸中。”所谓的阳络，就是阳跷脉的络脉。所谓的阴络，就是阴跷脉的络脉。（跷脉的详细情况详见第二十三难。）所以络脉总共有十五条。
第二十七难说：脉象中有奇经八脉，不受十二正经的约束，这是什么意思呢？（“奇”字读音如同“奇偶”的“奇”，意思是像十二正经那样手足相配的对偶关系在这里没有。详细情况见下文编。）
回答是：有阳维脉，有阴维脉，有阳跷脉，有阴跷脉，有冲脉，有督脉，有任脉，有带脉。这八条脉，都不受正经的约束，所以称为奇经八脉。（详细情况见下文编。）经脉有十二条，络脉有十五条，总共二十七气，相随上下运行（出处见前文），为什么唯独它们不受正经的约束呢？
回答是：圣人规划设置沟渠，疏通水道，以预备意外情况的发生。（“不然”，就是说不预料到的意思。）天上降雨落下，沟渠溢满，在这个时候，大雨倾盆而下，即使是圣人也不能再重新规划了。（这是用水道比喻人身血脉的运行之道。）当络脉充满溢出时，诸条正经就不能再约束它了。（意思是血脉充盛，十二条正经不足以容纳它，就会溢出而流入奇经，所以奇经是十二正经的别脉。）
第二十八难说：那奇经八脉，既然不受十二正经的约束，它们都是从哪里起始、到哪里接续的呢？（“继”，就是接续的意思。《脉经》中写作“系”。）
回答是：督脉，起始于下极之俞（俞，就是穴位。下极，就是长强穴，属于督脉，位于脊椎末端），并行于脊柱内部（脊里，即背脊中间），向上到达风府穴（风府穴，属于督脉，在项部入发际一寸大筋内的凹陷处），进入并归属于脑。（《灵枢·经脉篇》说：“督脉的别络，名叫长强，挟行脊柱两旁上行至项部，散布于头部，下行至肩胛左右，别走太阳经，进入贯穿脊柱。实证表现为脊柱强直，虚证表现为头重。”《素问·骨空论》说：“督脉，起于小腹内，向下出于会阴部，女子联系廷孔，这个孔就是尿道口的一端。其络脉循行于阴器，合于篡间，环绕篡后，别绕臀部，至少阴经，与巨阳经的中络汇合，少阴经沿大腿内侧后缘上行，贯穿脊柱，归属于肾；与太阳经起于目内眦，上额交巅顶，入络于脑，复出别向下行于项部。循行于肩膊内，夹脊柱，抵于腰中，进入贯穿脊柱联络肾脏；男子循阴茎下行至会阴，与女子相同。其从小腹直上的分支，贯穿脐中央，向上贯穿心，进入喉部，上颐部环绕嘴唇，上系于两目之下的中央。此脉生病，从少腹上冲心而痛，大小便不通，称为冲疝。女子则表现为不孕、癃闭、痔疮、遗尿、咽喉干燥。”）任脉，起始于中极穴之下（中极穴，属于任脉，在脐下四寸。中极之下，大概是指会阴穴），向上到达毛际（前阴之上），循行于腹部里面（即中极穴所在之处），向上经过关元穴（关元穴在脐下三寸），到达咽喉。（《素问·骨空论》在“至咽喉”之下，有“上颐、循面、入目”六个字。《灵枢·经脉篇》说：“任脉的别络，名叫尾翳，向下至鸠尾穴，散布于腹部。实证表现为腹皮疼痛，虚证表现为瘙痒搔抓。”）冲脉，起始于气冲穴（足阳明胃经穴位，在毛际两旁），并足阳明经而行（《素问·痿论》说：“冲脉，是经脉的海，主要渗透灌溉溪谷，与阳明经会合于宗筋，阴阳总汇于宗筋，会合于气冲穴，而阳明经为主导，都隶属于带脉，而联络于督脉。”），挟脐上行，到达胸中而散开。（另一版本有“也”字。）
带脉，起始于季胁（季胁，属于足厥阴肝经章门穴的范围），回身一周（谓周身围转，像人束带一样，用来约束诸条经脉）。《灵枢·经别篇》说：“足少阴经的正经，至腘窝中，别走太阳经而汇合，向上至肾，当第十四椎处，出而属连带脉。”
第二十九难说：奇经发生病变会怎样呢？
回答是：阳维脉维系诸阳经（阳，指阳经，即身体的体表部分），阴维脉维系诸阴经（阴，指阴经，即身体的体内部分），如果阴阳不能互相维系，就会感到惆怅失意，身体浮荡而不能自我控制。（溶溶，形容浮荡的样子。）阳维脉发病，苦于寒热往来（阳主外，阳气不和，所以产生寒热症状），阴维脉发病，苦于心痛（阴主内，心属少阴，阴气不和，所以产生心痛症状）。
The *Nan Jing* (Classic of Difficult Issues) mentions the Pericardium (Hand Jueyin) and Sanjiao (Triple Energizer) a total of eight times, appearing in Difficulties 8, 31, 36, 38, 39, 62, 66, and this chapter. All these passages should be consulted cross-referentially.
Difficulty 26 states: There are twelve meridians (Jing Mai) and fifteen collaterals (Luo Mai). What are the three extra collaterals? (*Ling Shu · Nine Needles and Twelve Origins Chapter* states: "There are twelve meridians and fifteen collaterals, totaling twenty-seven Qi pathways moving up and down.")
The answer is: There are the collateral of Yang Qiao, the collateral of Yin Qiao, and the great collateral of the Spleen. (*Ling Shu · Meridians Chapter*: "The great collateral of the Spleen is named Da Bao, originating three cun below Yuan Ye, spreading across the chest.") The so-called Yang collateral refers to the collateral of the Yang Qiao vessel. The so-called Yin collateral refers to the collateral of the Yin Qiao vessel. (For details on the Qiao vessels, see Difficulty 23.) Thus, there are fifteen collaterals in total.
Difficulty 27 states: Among the pulses, there are the Eight Extraordinary Vessels (Qi Jing Ba Mai), which are not constrained by the Twelve Regular Meridians. What does this mean? ("Qi" is pronounced like "odd" in "odd-even," meaning they lack the paired hand-foot relationship found in the Twelve Regular Meridians. See the lower section for details.)
The answer is: There are the Yang Wei, Yin Wei, Yang Qiao, Yin Qiao, Chong, Du, Ren, and Dai vessels. These eight vessels are all unconstrained by the regular meridians; hence they are called the Eight Extraordinary Vessels. (See the lower section for details.) There are twelve meridians and fifteen collaterals, totaling twenty-seven Qi pathways moving up and down together (as mentioned in previous chapters). Why are these specifically unconstrained by the regular meridians?
The answer is: Sages planned and dug channels to facilitate water flow, preparing for unforeseen circumstances. ("Bu Ran" means unexpected events.) When rain falls from heaven and channels overflow, during such times when heavy rains pour down, even a sage cannot redesign them. (This uses water channels as a metaphor for the pathways of blood and vessels in the human body.) When the collaterals become full and overflow, the regular meridians can no longer constrain them. (This means that when blood and Qi are abundant, the twelve regular meridians cannot contain them, so they overflow into the extraordinary vessels; thus, the extraordinary vessels are the branch vessels of the twelve regular meridians.)
Difficulty 28 states: Since the Eight Extraordinary Vessels are not constrained by the Twelve Regular Meridians, where do they originate and where do they connect? ("Ji" means to continue or succeed. *Mai Jing* writes it as "Xi".)
The answer is: The Du vessel originates at Xia Ji Shu (Shu refers to an acupoint. Xia Ji refers to the Chang Qiang point, belonging to the Du vessel, located at the end of the spine), runs parallel within the spinal column (Spinal interior, i.e., the center of the back), ascends to Feng Fu (Feng Fu belongs to the Du vessel, located one cun above the hairline in the depression within the large tendons at the nape), and enters to connect with the brain. (*Ling Shu · Meridians Chapter*: "The divergent branch of the Du vessel is named Chang Qiang, flanking the spine ascending to the neck, scattering over the head, descending below the shoulder blades on both sides, departing to join the Taiyang vessel, entering and piercing the spine. Excess manifests as stiff spine; deficiency manifests as heavy head." *Su Wen · Bone Empty Theory*: "The Du vessel originates in the lower abdomen, exiting below the central bone. In women, it connects to the Ting Kong, which is the opening of the urethra. Its collateral circulates around the genitalia, meeting at the perineum, encircling the anus posteriorly, diverting around the buttocks to reach the Shaoyin vessel, combining with the middle collateral of the Juyang vessel. The Shaoyin vessel ascends along the posterior medial aspect of the thigh, pierces the spine, and connects to the Kidney. Joining the Taiyang vessel which starts at the inner canthus, it crosses the vertex, enters the brain, emerges again to descend separately along the neck. It follows the interior of the shoulder blades, flanks the spine, reaches the loins, enters to follow the spine and connect to the Kidney; in men, it follows the penis down to the perineum, same as in women. The branch rising straight from the lower abdomen pierces the center of the umbilicus, ascends through the heart, enters the throat, rises to the chin, circles the lips, and connects to the center below both eyes. Diseases of this vessel include pain rushing up from the lower abdomen to the heart, inability to pass stool or urine, known as Chong Hernia. In women, it causes infertility, strangury, hemorrhoids, urinary incontinence, and dryness of the throat.") The Ren vessel originates below Zhong Ji (Zhong Ji belongs to the Ren vessel, four cun below the umbilicus. Below Zhong Ji likely refers to the Hui Yin point), ascends to the pubic region (above the external genitalia), follows the interior of the abdomen (the location of Zhong Ji), ascends through Guan Yuan (Guan Yuan is three cun below the umbilicus), and reaches the throat. (*Su Wen · Bone Empty Theory* adds six characters after "reaches the throat": "ascends to the chin, follows the face, enters the eyes." *Ling Shu · Meridians Chapter*: "The divergent branch of the Ren vessel is named Wei Yi, descending from Jiu Wei, scattering in the abdomen. Excess manifests as pain in the abdominal skin; deficiency manifests as itching.") The Chong vessel originates at Qi Chong (an acupoint of the Foot Yangming Stomach channel, located on both sides of the pubic region), runs alongside the Foot Yangming channel (*Su Wen · Flaccidity Theory* states: "The Chong vessel is the sea of the meridians, primarily infiltrating and irrigating the muscle valleys. It combines with the Yangming at the Zong Jin. The Yin and Yang converge at the Zong Jin, meeting at Qi Chong, with Yangming as the leader, all subordinate to the Dai vessel and connected to the Du vessel."), ascends flanking the umbilicus, and disperses in the chest. (Another version includes the character "Ye".)
The Dai vessel originates at Ji Xie (Ji Xie falls under the distribution of Zhang Men, an acupoint of the Foot Jueyin Liver channel), circling the body once (meaning it encircles the entire body like a belt worn by a person, thereby binding the various vessels). (*Ling Shu · Divergent Channels Chapter*: "The proper pathway of the Foot Shaoyin vessel reaches the popliteal fossa, departs to join the Taiyang and merges, ascending to the Kidney, at the level of the fourteenth vertebra, emerging to connect to the Dai vessel.")
Difficulty 29 states: How do diseases manifest in the Extraordinary Vessels?
The answer is: The Yang Wei vessel maintains the Yang vessels (Yang refers to Yang meridians, which are on the exterior of the body). The Yin Wei vessel maintains the Yin vessels (Yin refers to Yin meridians, which are on the interior of the body). If Yin and Yang cannot mutually maintain each other, one feels despondent and lost, with a floating sensation unable to control oneself. ("Rong Rong" describes a floating or wavering appearance.) Disease of the Yang Wei vessel involves suffering from aversion to cold and fever (Yang governs the exterior; disharmony of Yang Qi generates cold and fever). Disease of the Yin Wei vessel involves suffering from heart pain (Yin governs the interior; the Heart belongs to Shaoyin; disharmony of Yin Qi generates heart pain).