按仲景自序云。虽未能尽愈诸病。其留心诸病可知。故于诸病之表里阴阳。分为六经。令各得所司。清理脉症
之异同。寒热之虚实。使治病者。只在六经中下手。行汗吐下和解温补等法。而无失也。夫一身之病。俱受六经范
围者。犹周礼分六官而百职举。司天分六气而万物成耳。伤寒不过六经中一症。叔和不知仲景之六经。是经界之经。
而非经络之经。妄引内经热病论。作序例以冠仲景之书。而混其六经之政治。六经之理不明。而仲景平脉辨症。固
难尽合诸病之权衡矣。夫热病之六经。专主经脉为病。但有表里之实热。并无表里之虚寒。虽因于伤寒。而已变成
热病。故竟称热病。而不称伤寒。要知内经热病。即温病之互名。故无恶寒症。但有可汗可泄之法。并无可温可补
之例也。观温病名篇。亦称评热病论。其义可知矣。夫叔和不于病根上讲求。但于病名上分解。故序例所引内经。
既背仲景之旨。亦舛岐伯之意也。夫仲景之六经。是分六区地面。所该者广。虽以脉为经纪。而不专在经络上立说。
凡风寒温热。内伤外感。自表及里。有寒有热。有实有虚。无乎不包。故以伤寒杂病合为一症。而总名为伤寒杂病
论所以六经提纲。各立一局。不为经络所拘。勿为风寒画定也。然仲景既云。撰用素问。当于素问之六经广法之。
按皮部论云。皮有分部。脉有经纪。其生病各异。别有部分。左右上下。阴阳所在。诸经始终。此仲景创六经部位
之源。又曰。阳主外。阴主内。故仲景以三阳主外。三阴主内。又曰。在阳者主内。在阴者主出。以渗于内。故仲
景又以阳明主内。少阴亦有反发热者。故仲景于表剂中用附子。是因其渗也。又曰。少阴之阴。名曰枢儒。其入于
经也。从阳部注于经。其出者。从阴部注于骨。故仲景制麻黄附子汤。治发热脉沉无里症者。是从阳部注经之义也。
制附子汤。治身体骨节痛。手足寒。背恶寒。脉沉者。具从阴内注于骨之义也。又阴阳离合论。太阳为开。故仲景
以之主表。而以脉浮恶寒头项强痛。为提纲。立言与热论颇同。而立意自别。阳明为合。故以之主里。而以胃实为
提纲。虽目痛鼻干等症。而所主不在是。少阳为枢。少阴亦为枢。故皆在半表半里症。少阳为阳枢。归重在半表。
故以口苦咽干目眩为提纲。而不及于胸胁痛硬。少阴为阴枢。其欲寐不寐。欲吐不吐。亦半表半里症。虽有舌干口
燥等症。而不入提纲。归重在半里也。岂惟阳明主里。三阴皆主里。而阴阳异位。故所主各不同。阳明主里症之阳。
阳道实。故以胃实属阳明。太阴主里症之阴。阴道虚故以自利属太阴。太阴为开。又为阴中至阴。故主里寒而自利。
厥阴为合又为阴中之阳。故主里热而气逆。少阴为阴中之枢。故所主或寒或热之不同。或表或里之无定。与少阳相
似也。请以地理论。六经犹列国也。腰以上为三阳地面。三阳主外而本乎表。心者三阳夹界之地。内由心胸。外自
巅顶。前至头颅。后主肩背。下及于足。内合膀胱。是太阳地面。此经统领荣卫。主一身之表症。犹近边御敌之国
也。内自心胸。至胃及肠。外自额颅。犹面至腹。下及于足。是阳明地面。由心至咽。退场门颊。上耳目。斜至巅。
外自胁。内属胆。是少阳地面。比太阳差近。阳明犹京畿矣。腰以下。为三阴地面。三阴主里。而不及外腹者。三
阴夹界之地也。自腹由脾。及二肠魄门。为太阴地面。自腹至两肾。及膀胱溺道。为少阴地面。自腹由肝。上膈至
心。从胁肋。下及小腹宗筋。为厥阴地面。此经通行三焦。主一身之里症。犹近京夹辅之国矣。太阴阳明。同居异
治。犹周召分政之义。四经部位。有内外出入。上下牵引之不同。犹先王分土域民。犬牙相制之理也。若经络之经。
是六经道路。非六经地面也。六经之有正邪。客邪。合病。并病。属脾。属胃者。犹寇贼充斥。或在本境。或及邻
国。或入京师也。太阳地面最大。内临少阴。外邻阳明。故病有相关。如小便不利。本膀胱经病。少阴病。亦小便
而不利者。是邪及少阴之界也。六七日不大便。头痛身热者。是阳明热邪。侵入太阳之界也。头项为太阳之通衢。
因太阳主荣卫。心胸是荣卫之本。荣卫环周不休。犹边邑之吏民士卒。会于京畿往来不绝也。如喘而胸满者。是太
阳外邪入阳明地面而骚扰。故称为太阳阳明合病。若头不痛。项不强胸中痞硬。气上冲。咽候不得息者。此邪不自
太阳来。乃阳明热邪实结于胸中。犹乱民聚于本境而为患也。心为六经之主。故六经皆有心烦症。如不头项强痛。
则烦不属太阳。不往来寒热。则烦不属少阳。不见三阳症。则烦不属三阳矣。故心愦愦。心怵惕。心懊 。一切虚
烦。皆属阳明。以心居阳明地面也。阳明犹京师。故心腹皆居其地。邪在心而为虚烦。在腹为实热。以心为阳而属
无形。腹为阴而属有形也。夫人身之病。动关心腹。阳邪聚于心。阴邪聚于腹。肝为阴中之阳。故能使阴邪之气撞
于心。阳明主在里之阳。故能使阳邪入聚于腹耳。更请以兵法喻。兵法之要。在明地形。知贼寇所从来。知某方是
某府来路。某方是某府去路。来路是边关。三阳是也。去路是内境。三阴是也。六经来路各不同。太阳是大路。少
阴是僻路。阳明是直路。太阴近路也。少阴后路也。厥阴斜路也。客邪多从三阳来。正邪多因三阴起。由外寇自边
关至。乱民自内地生也。明六经地形。始得握百病之枢机。详六经来路。乃得操治病之规则。如以症论。伤寒。大
寇也。病从外来。中风。流寇也。病因旁及。杂病。乱民也。病由中起。既认为何等之贼。又知为何地所起。于
其发境。便御之本境。移祸邻郡。即两郡夹攻。如邪入太阳地面。即汗而散之。犹陈兵器于要害。乘其未定而击之
也。邪之轻者在卫。重者在荣。尤重者在胸膈。犹贼之浅者在关外。深者在关上。尤深者在关内也。是麻黄为关外
之师桂枝葛根为关上之师。大小青龙为关内之师矣。凡外寇不靖。内地盗贼必起而应之。因立两解法。故有大小青
龙。及桂枝麻黄加减诸方。如前军无纪。致内乱蜂起。当重内轻外。因有五苓十枣陷胸泻心抵当等汤也。邪入少阳地
面。宜杂用表里寒热攻补之品。为防御解利之法。如偏僻小路。利于短兵。不利于矛戟。利于守备。不利于战争也。
邪之轻者。入腠理。重者入募原。尤重者入脾胃。小柴胡腠理之剂也。大柴胡募原之剂也。小建中。半夏泻心。黄
芩。黄连。四方。少阳之脾剂也。柴胡加芒硝。加牡蛎二方。少阳之胃剂也。如太阳少阳。有合病并病。是一军犯
少阳矣。用柴胡桂枝汤是两路分击之师也。甚至三阳合并病。是三面受敌矣。法在独处阳明。阳明之地面整肃。则
太少两路之阳邪。不攻自解。但得内寇宁。而外寇自息。此白虎所由奏捷耳。若阳邪不战于内地。用大承气以急下
之。是攻贼以护主。若阴邪直入于中宫。用四逆汤以急救其里。是强主以逐寇也。阳明为内地。阳朝界上。即太阳
少阳地面。邪入阳明之界近太阳地面。虽不犯太阳。太阳之师不得坐视而不救。故阳明之荣卫病即假麻黄等汤以
汗之。近少阳地面。虽不入少阳。少阳之师不得高垒而无战。故阳明之腠理病。即借柴胡以解之。是知阳明之失守。
非太阳不固。即少阳无备也。所以每每两阳相合而为病也。若邪已在阳明地面。必出师奋击。以大逐其邪。不使少
留。故用栀豉瓜蒂之吐法以迅扫之。若深入内地。不可复驱则当清野千里。使无所 掠。是又白虎得力处也。若邪
在内廷。又当清宫中阴盗。此承气所由取胜。如茵陈猪苓辈。又为失纪之师立法矣。太阴亦内地。少阴厥阴地面。
是太阴之夹界也。太阴居中州。虽外通三阳。而阴阳既已殊途。心腹更有膈膜之藩蔽。故寒水之邪。从太阳外属者
轻。由少阴内授者重。风木之邪。自少阳来侵者微。因厥阴上袭者甚。如本经正邪。转属阳明而为实。犹师老势穷。
可下之而愈。如阳明实邪。转属本经而成虚。则邪盛正衰。温补挽回者甚难。盖太阴阳明。地面虽分。并无阻隔。
阳明犹受敌之通衢。甲兵所聚。四战之地也。太阴犹仓廪重地。三军所根据。亦盗贼之巢穴也。故元气有余。则邪入
阳明。元气不足。则邪入太阴。在阳明地面。则陈师鞠旅。可背城一战。取胜须臾。在太阴地面。则焚劫积蓄。仓
廪空虚。枵腹之士。无能御敌耳。厥阴之地。相火游行之区也。其本气则为少火。若风寒燥湿之邪。一入其境。悉
化为热。即是壮火。其少火为一身之生机。而壮火为一身之大患。且其地面通达三焦邪犯上焦。则气上撞心。心中
疼热。消渴口烂。咽痛喉痹。逼入中焦。即手足厥冷。脉微欲绝。饥不欲食。食即吐蛔。移祸下焦。则热利下重。
或便脓血。为害非浅。犹跋扈之师矣。仲景制乌梅丸方。寒热并用。攻补兼施。通理气血。调和三焦。为平治厥阴
之主方。犹总督内地之大帅也。其与之水以治消渴。茯苓甘草汤以治水。炙甘草汤以复脉。当归四逆以治厥。是间
出锐师。分头以救上焦之心主。而安神明也。用白虎承气辈。清胃而平中焦之热实。白头翁四逆散。清脾而止下焦之
热利。是分头以救腹中之阴。而扶胃脘之元气耳。肾为一府。而分阴阳二经。少阴一经。而兼阴阳两脏者。皆为根
本之地故也。邪有阴阳两途。藏分阴阳二气。如阳邪犯少阴之阳。反发热。心烦。咳渴。咽痛。阳邪犯少阴之阴。
则腹痛自利。或便脓血。阴邪犯少阴之阳。则身体骨节痛。手足逆冷。背恶寒。而身倦卧。阴邪犯少阴之阴。则恶
寒。呕吐。下利清谷。烦躁欲死。仲景制麻黄附子细辛。黄连阿胶。甘草桔梗。猪肤半夏苦酒等汤。御阳邪犯少阴
之阳也。其制桃花猪苓等汤。御阳邪入少阴之阴也。附子吴萸四逆等汤。御阴邪犯少阴之阳也。通脉四逆茯苓四
逆干姜附子等汤。御阴邪入少阴之阴也。少阴为六经之根本。而外通太阳。内接阳明。故初得之而反发热。与八九
日而一身手足尽热者。是少阴阳邪侵及太阳地面也。自利纯青水。心下痛。口燥舌干者。少阴阳邪侵阳明地面也。
出太阳。则用麻黄为锐师。而督以附子。入阳明。则全任大承气。而不设监制。是犹兵家用向导。与本部不同法也。
其阴邪侵入太阴。则理中四逆加人尿猪胆等法。亦犹是矣。嗟乎。不思仲景之所集。安能见病知原也。
据张仲景自序所说：“虽然不能治愈所有疾病，但他对各类疾病的用心由此可见。”因此，他将各种疾病的表里、阴阳分为六经，使各经各司其职，梳理脉象与症状的异同，辨别寒热与虚实的区别，使得治病的人只需在六经的框架下手，运用汗法、吐法、下法、和解法、温法、补法等治疗手段，就不会出现失误。
全身的疾病，都受六经范围的统摄，这就像《周礼》将官职分为六类而百官职责得以履行，司天之气分为六气而万物生长成就一样。伤寒不过是六经中的一种病症。王叔和不懂得张仲景所说的“六经”是指地理区域的界限（经界），而不是经络的循行路线（经络）。他错误地引用《内经·热病论》，撰写序例放在张仲景著作的前面，从而混淆了六经的治疗原则。如果六经的道理不明确，那么张仲景平脉辨证的理论，就难以完全符合各种疾病的权衡标准了。
《内经》中提到的热病之六经，专门主治经脉受邪导致的疾病，只有表里实热，没有表里虚寒。虽然起因可能是伤寒，但已经转化为热病，所以称为热病，而不称伤寒。要知道，《内经》的热病就是温病的别称，所以没有恶寒的症状，只有可发汗、可攻泄的方法，并没有可温补的例子。看《内经》中有《评热病论》篇，其含义也就清楚了。
王叔和不从病根上探究，只在病名上进行分解，所以他引用的《内经》内容，既违背了张仲景的宗旨，也错解了岐伯的本意。
张仲景的六经，是划分了六个区域的地面，所涵盖的内容很广。虽然以脉象为经纬，但并不专门在经络上立论。凡是风寒温热、内伤外感，从表到里，有寒有热，有实有虚，无所不包。所以将伤寒与杂病合为一书，总名为《伤寒杂病论》。因此，六经提纲各自独立成局，不被经络所拘束，不为风寒画定界限。
然而张仲景既然说撰用《素问》，应当在《素问》六经广泛法则的基础上加以推广。按《皮部论》所说：“皮肤有分部，脉有经纪，生病各异，各有部分，左右上下，阴阳所在，诸经始终。”这是张仲景创立六经部位理论的源头。又说：“阳主外，阴主内。”所以张仲景以三阳主外，三阴主内。又说：“在阳者主内，在阴者主出，以渗于内。”所以张仲景又以阳明主内，少阴也有反发热者，所以张仲景在表剂中使用附子，是因为其能渗出的作用。又说：“少阴之阴，名叫枢儒。它进入经脉时，从阳部注入经脉；它外出时，从阴部注入骨骼。”所以张仲景制作麻黄附子汤，治疗发热、脉沉、无里证的情况，这是遵循从阳部注入经脉的道理。制作附子汤，治疗身体骨节痛、手足寒冷、背部恶寒、脉沉的情况，具备从阴内部注入骨骼的道理。
又《阴阳离合论》说：太阳为开，所以张仲景以它主管表证，并以脉浮、恶寒、头项强痛作为提纲，立言与《热论》颇为相同，但立意自有不同。阳明为合，所以以它主管里证，并以胃实作为提纲，虽然目痛、鼻干等症状存在，但不是其主要所指。少阳为枢，少阴也为枢，所以都处于半表半里的病症。少阳为阳枢，归重在半表，所以以口苦、咽干、目眩作为提纲，而不涉及胸胁痛硬。少阴为阴枢，其嗜睡或不寐、想吐或不吐，也是半表半里症，虽然有舌干、口燥等症状，但不列入提纲，归重在半里。
岂止阳明主里，三阴都主里，但因为阴阳位置不同，所以所主各不相同。阳明主里证中的阳，阳道实，所以以胃实属阳明。太阴主里证中的阴，阴道虚，所以以自利属太阴。太阴为开，又是阴中之至阴，所以主里寒而自利。厥阴为合，又是阴中之阳，所以主里热而气逆。少阴为阴中之枢，所以所主有的寒有的热，有的表有的里，没有定数，与少阳相似。
请用地理来比喻：六经就像列国。腰以上是三阳地面，三阳主外而根本在于表。心是三阳交界之地，内由心胸，外自头顶，前至头颅，后主肩背，下及于足，内合膀胱，这是太阳地面。此经统领营卫，主管一身之表证，就像靠近边境抵御敌人的国家。内自心胸，至胃及肠，外自额颅，犹如面至腹，下及于足，这是阳明地面。由心至咽，退至颊车，上达耳目，斜至头顶，外自胁肋，内属胆，这是少阳地面。比太阳稍近，阳明就像京畿之地。
腰以下是三阴地面，三阴主里，不及于外，因为腹部是三阴交界之地。自腹由脾，及大小肠肛门，为太阴地面。自腹至两肾，及膀胱尿道，为少阴地面。自腹由肝，上膈至心，从胁肋，下及小腹宗筋，为厥阴地面。此经通行三焦，主管一身之里证，就像靠近京城辅佐的国家。
太阴和阳明同居一地但治法不同，就像周公、召公分政的意义。四经的部位，有内外出入、上下牵引的不同，就像先王分封土地百姓，犬牙交错相互制约的道理。如果说是经络的经，那是六经的道路，不是六经的地面。六经的正邪、客邪、合病、并病、属脾、属胃等情况，就像寇贼充斥，或在本境，或波及邻国，或进入京师。
太阳地面最大，内临少阴，外邻阳明，所以病症有关联。如小便不利，本是膀胱经病，少阴病也有小便不利的，这是邪气波及少阴的边界。六七日不大便，头痛身热的，是阳明热邪侵入太阳的边界。头项是太阳的通衢大道，因为太阳主营卫，心胸是营卫的根本，营卫环流不休，就像边邑的官吏百姓士卒，在京畿往来不绝。如喘而胸满的，是太阳外邪进入阳明地面而骚扰，所以称为太阳阳明合病。如果头不痛，项不强，胸中痞硬，气上冲，咽喉不得呼吸的，此邪气不是从太阳来，而是阳明热邪实结于胸中，就像乱民聚集在本境而为患。
心是六经之主，所以六经都有心烦的症状。如不头项强痛，则烦不属于太阳；不往来寒热，则烦不属于少阳；不见三阳症状，则烦不属于三阳了。所以心中烦闷懊恼、心慌恐惧等一切虚烦，都属于阳明，因为心位于阳明地面。阳明像京师，所以心和腹都位于其地。邪在心而为虚烦，在腹为实热，因为心为阳而属无形，腹为阴而属有形。
人身上的疾病，动不动就关系到心腹。阳邪聚于心，阴邪聚于腹。肝为阴中之阳，所以能使阴邪之气撞击于心。阳明主在里之阳，所以能使阳邪入聚于腹。
再请用兵法比喻。兵法的要点，在于明了地形，知道贼寇从哪里来，知道哪一方是哪府的路，哪一方是哪府的去路。来路是边关，即三阳。去路是内境，即三阴。六经来路各不相同，太阳是大路，少阴是僻路，阳明是直路，太阴是近路，少阴是后路，厥阴是斜路。客邪多从三阳来，正邪多因三阴起，就像外寇从边关来到，乱民从内地产生。
明了六经地形，才能掌握百病的枢纽；详查六经来路，才能操持治病的规则。如果以症状论，伤寒是大寇，病从外来；中风是流寇，病因旁及；杂病是乱民，病由中起。既然认定为哪种贼寇，又知道是从何地而起，在其发源地就在本境防御，如果祸害移向邻郡，就两郡夹攻。如邪气进入太阳地面，就用汗法发散它，就像在要害处陈列兵器，趁其未定而攻击。邪气轻的在卫分，重的在营分，尤其重的在胸膈，就像贼寇浅的在关外，深的在关上，尤其深的在关内。所以麻黄是关外的军队，桂枝、葛根是关上的军队，大青龙、小青龙是关内的军队。
凡是外寇不安定，内地盗贼必定起来响应，因此设立两解法，所以有大青龙、小青龙及桂枝麻黄加减诸方。如果前军无纪律，导致内乱蜂起，应当重内轻外，因此有五苓散、十枣汤、陷胸汤、泻心汤、抵当汤等方剂。
邪气进入少阳地面，宜杂用表里寒热攻补的药物，作为防御和解的方法。就像偏僻小路，利于短兵相接，不利于矛戟长兵；利于守备，不利于战争。邪气轻的，进入腠理；重的，进入募原；尤其重的，进入脾胃。小柴胡汤是治疗腠理的药剂，大柴胡汤是治疗募原的药剂，小建中汤、半夏泻心汤、黄芩、黄连四方，是少阳的脾剂；柴胡加芒硝、加牡蛎二方，是少阳的胃剂。如太阳少阳有合病并病，是一军侵犯少阳，用柴胡桂枝汤是两路分击的军队。甚至三阳合并病，是三面受敌，方法在于独治阳明。阳明地面整肃，则太阳、少阳两路的阳邪，不攻自解。只要内寇安宁，外寇自然平息，这就是白虎汤奏捷的原因。
如果阳邪不在内地交战，用大承气汤急下之，这是攻贼以护主。如果阴邪直接侵入中宫，用四逆汤急救其里，这是强主以逐寇。阳明是内地，阳气朝于界上，即太阳、少阳地面。邪气进入阳明边界，接近太阳地面，虽然没有侵犯太阳，但太阳的军队不能坐视不救，所以阳明营卫病就借用麻黄等汤发汗。接近少阳地面，虽然没有进入少阳，但少阳的军队不能高垒不战，所以阳明腠理病就借柴胡汤和解。由此可知，阳明的失守，要么是不固，要么是少阳无备。所以常常两阳相合而发病。
如果邪气已经在阳明地面，必须出兵奋击，大力驱逐邪气，不让少留，所以用栀子豉汤、瓜蒂散的吐法来迅速清扫。如果深入内地，不可再驱赶，则应当清野千里，使其无处掠夺，这又是白虎汤得力之处。如果邪气在内廷，又应当清除宫中的阴盗，这就是承气汤取胜的原因。如茵陈、猪苓之类，又是为失去纪律的军队立法。
太阴也是内地，少阴、厥阴地面，是太阴的夹界之地。太阴居中州，虽然外通三阳，但阴阳已殊途，心腹更有膈膜的屏障。所以寒水之邪，从太阳外属的较轻，由少阴内授的较重。风木之邪，自少阳来侵的轻微，因厥阴上袭的严重。如本经正邪，转属阳明而为实，就像军队疲惫势穷，可用下法治愈。如阳明实邪，转属本经而成虚，则邪盛正衰，用温补挽回很难。
盖太阴和阳明，地面虽分开，并无阻隔。阳明像受敌的通衢大道，甲兵聚集，四战之地。太阴像仓廪重地，三军依靠，也是盗贼的巢穴。所以元气有余，则邪入阳明；元气不足，则邪入太阴。在阳明地面，则陈列军队，可以背城一战，顷刻取胜。在太阴地面，则焚烧劫掠积蓄，仓廪空虚，空腹的士兵，无法御敌。
厥阴之地，是相火游行的区域。其本气则为少火，如果风寒燥湿之邪一入其境，全部化为热，即是壮火。少火是一身的生机，而壮火是一身的大患。且其地面通达三焦，邪犯上焦，则气上撞心，心中疼热，消渴，口烂，咽痛喉痹；逼入中焦，即手足厥冷，脉微欲绝，饥不欲食，食即吐蛔；移祸下焦，则热利下重，或便脓血，为害非浅，就像跋扈的军队。
张仲景制作乌梅丸方，寒热并用，攻补兼施，通理气血，调和三焦，是平治厥阴的主方，就像总督内地的大帅。给他水以治消渴，茯苓甘草汤以治水，炙甘草汤以复脉，当归四逆汤以治厥，这是间出精锐部队，分头救援上焦的心主，而安神明。用白虎、承气辈，清胃而平中焦的热实；白头翁、四逆散，清脾而止下焦的热利，是分头救援腹中之阴，而扶胃脘的元气。
肾是一个府，而分阴阳二经。少阴一经，而兼阴阳两脏，都是根本之地。所以邪有阴阳两途，藏分阴阳二气。如阳邪犯少阴之阳，反发热，心烦，咳渴，咽痛；阳邪犯少阴之阴，则腹痛自利，或便脓血；阴邪犯少阴之阳，则身体骨节痛，手足逆冷，背恶寒，而身倦卧；阴邪犯少阴之阴，则恶寒，呕吐，下利清谷，烦躁欲死。
张仲景制作麻黄附子细辛汤、黄连阿胶汤、甘草桔梗汤、猪肤汤、半夏苦酒汤等，抵御阳邪侵犯少阴之阳。其制作桃花汤、猪苓汤等，抵御阳邪进入少阴之阴。附子汤、吴茱萸汤、四逆汤等，抵御阴邪侵犯少阴之阳。通脉四逆汤、茯苓四逆汤、干姜附子汤等，抵御阴邪进入少阴之阴。
少阴是六经的根本，而外通太阳，内接阳明。所以初得病而反发热，与八九日而一身手足尽热的，是少阴阳邪侵及太阳地面。自利纯青水，心下痛，口燥舌干的，是少阴阳邪侵及阳明地面。出太阳，则用麻黄为锐师，而督以附子；入阳明，则全任大承气，而不设监制，这就像兵家用向导，与本部不同法。其阴邪侵入太阴，则理中汤、四逆加人尿猪胆汁等法，也是如此。
唉！如果不思考张仲景所集成的学问，怎么能见病知原呢？
According to Zhang Zhongjing's preface: "Although [I] could not cure all diseases, one can see his dedication to various illnesses." Therefore, he divided the exterior-interior and yin-yang of various diseases into six channels (Jing), allowing each to perform its own functions, clarifying the similarities and differences in pulse and symptoms, and distinguishing between cold-heat and deficiency-excess. This enables physicians to treat diseases within the framework of the six channels, employing methods such as sweating (Han), vomiting (Tu), purging (Xia), harmonizing (Hejie), warming (Wen), and tonifying (Bu), without making errors.
Diseases of the whole body are encompassed by the scope of the six channels, just as the *Rites of Zhou* divided official duties into six categories so that hundreds of responsibilities were fulfilled, or as the Heavenly Stems divided into six Qi allowed all things to mature. Cold damage (Shanghan) is merely one type of condition within the six channels. Wang Shuhe did not understand that Zhang Zhongjing's "six channels" referred to geographical boundaries (Jingjie) rather than meridian pathways (Jingluo). He erroneously cited the *Neijing*'s "Treatise on Heat Diseases" (*Rebing Lun*) and wrote a preface for Zhang Zhongjing's book, thereby confusing the therapeutic principles of the six channels. If the principles of the six channels are unclear, then Zhang Zhongjing's methods of differentiating pulses and symptoms will hardly align with the standards for treating all diseases.
The six channels mentioned in the *Neijing* specifically refer to diseases of the meridians, involving only excess heat in the exterior and interior, with no deficiency-cold. Although originating from cold damage, it has transformed into a heat disease; thus, it is called heat disease, not cold damage. It should be known that the heat disease in the *Neijing* is synonymous with warm disease (Wenbing); therefore, there are no aversion-to-cold symptoms, only methods for inducing sweating or purging, with no examples of warming or tonifying. The existence of the chapter "Evaluation of Heat Diseases" (*Ping Rebing Lun*) in the *Neijing* makes this clear.
Wang Shuhe did not investigate the root of diseases but merely analyzed them by name. Thus, the *Neijing* citations in his preface both contradict Zhang Zhongjing's intent and misinterpret Qibo's meaning.
Zhang Zhongjing's six channels divide the body into six regional territories, covering a broad scope. Although using pulses as coordinates, he did not base his theory solely on meridians. Whether wind-cold, wind-heat, internal injury, or external contraction, whether from exterior to interior, cold or heat, deficiency or excess—all are included. Hence, he combined cold damage and miscellaneous diseases into one work, titled *Treatise on Cold Damage and Miscellaneous Diseases*. Consequently, the outlines of the six channels stand independently, unconstrained by meridians, and not fixed by wind-cold.
However, since Zhang Zhongjing stated he used the *Suwen*, he should have expanded upon the broad principles of the six channels in the *Suwen*. According to the "Treatise on Skin Regions" (*Pibu Lun*): "Skin has divisions, vessels have networks; diseases differ, each having specific parts, left/right, upper/lower, locations of yin/yang, and the beginning/end of all meridians." This is the source of Zhang Zhongjing's creation of the six-channel regions. It also states: "Yang governs the exterior, Yin governs the interior." Thus, Zhang Zhongjing assigned the Three Yang to the exterior and the Three Yin to the interior. It further says: "What is in Yang governs entering inward; what is in Yin governs exiting outward, seeping into the interior." Therefore, Zhang Zhongjing associated Yangming with the interior. Shaoyin may present with fever; thus, Zhang Zhongjing uses Fuzi (Aconiti Lateralis Radix Praeparata) in exterior-releasing formulas because of its ability to seep/penetrate. It also states: "Shaoyin's Yin is named Shuru. When entering the meridians, it flows from the Yang aspect into the meridians; when exiting, it flows from the Yin aspect into the bones." Thus, Zhang Zhongjing formulated Mahuang Fuzi Tang (Ephedra and Prepared Aconite Decoction) to treat fever, deep pulse, and absence of interior symptoms, following the principle of flowing from the Yang aspect into the meridians. He formulated Fuzi Tang (Prepared Aconite Decoction) to treat body and joint pain, cold hands and feet, aversion-to-cold on the back, and deep pulse, embodying the principle of flowing from the Yin interior into the bones.
Furthermore, the "Treatise on Separation and Union of Yin and Yang" states: "Taiyang is Kai (Opening)," so Zhang Zhongjing uses it to govern exterior syndromes, taking floating pulse, aversion-to-cold, and stiffness/pain of the head and neck as the outline. His wording resembles the *Rebing Lun*, but his intent differs. "Yangming is He (Closing)," so he uses it to govern interior syndromes, taking stomach excess (Wei Shi) as the outline. Although eye pain and nasal dryness exist, they are not the primary focus. "Shaoyang is Shu (Pivot)," and "Shaoyin is also Shu," so both belong to half-exterior/half-interior syndromes. Shaoyang is the Yang Pivot, focusing on the half-exterior, so bitter taste, dry throat, and vertigo are the outline, excluding chest/flank pain/stiffness. Shaoyin is the Yin Pivot; lethargy or insomnia, desire to vomit but unable, are also half-exterior/half-interior syndromes. Although dry tongue and mouth exist, they are not in the outline, focusing instead on the half-interior.
Does Yangming alone govern the interior? No, all Three Yin govern the interior, but due to different yin-yang positions, their focuses differ. Yangming governs the Yang aspect of interior syndromes; the Yang path is solid, so stomach excess belongs to Yangming. Taiyin governs the Yin aspect of interior syndromes; the Yin path is deficient, so spontaneous diarrhea belongs to Taiyin. Taiyin is Kai and the most Yin within Yin, so it governs interior cold and spontaneous diarrhea. Jueyin is He and Yang within Yin, so it governs interior heat and rebellious Qi. Shaoyin is the pivot within Yin, so its governance varies—sometimes cold, sometimes heat, sometimes exterior, sometimes interior, without fixed rules, similar to Shaoyang.
Let us use geography as an analogy: The six channels are like states. Above the waist is the territory of the Three Yang, governing the exterior based on the surface. The Heart is the borderland of the Three Yang: internally from the chest/heart, externally from the vertex, anteriorly to the head, posteriorly to the shoulders/back, inferiorly to the feet, internally connecting to the Bladder. This is the Taiyang territory. This channel governs Ying and Wei, managing exterior syndromes of the body, like a border state defending against enemies. Internally from the chest/heart to the stomach/intestines, externally from the forehead/skull (like face to abdomen), inferiorly to the feet, this is the Yangming territory. From the heart to the pharynx, retreating to the cheekbones, ascending to eyes/ears, diagonally to the vertex, externally from the flanks, internally belonging to the Gallbladder, this is the Shaoyang territory. Closer than Taiyang, Yangming is like the capital region.
Below the waist is the territory of the Three Yin, governing the interior, not extending to the exterior, as the abdomen is the borderland of the Three Yin. From the abdomen via the Spleen to the intestines and anus, this is the Taiyin territory. From the abdomen to the kidneys and bladder/urethra, this is the Shaoyin territory. From the abdomen via the Liver, ascending through the diaphragm to the heart, along the flanks, descending to the lower abdomen and sinews, this is the Jueyin territory. This channel circulates through the Sanjiao, governing interior syndromes of the body, like a state assisting the capital.
Taiyin and Yangming share the same location but have different treatments, akin to the division of governance by Duke Zhou and Duke Shao. The four channels' locations differ in interior/exterior entry-exit and upper/lower traction, like the ancient kings dividing land and people, interlocking like dog's teeth. If referring to meridians as Jing, these are the roads of the six channels, not the territories. The Zheng (regular), Ke (invading), Hebing (combined), Bingbing (concurrent) pathogens, or those belonging to Spleen/Stomach, are like bandits filling the land—in their own territory, neighboring states, or the capital.
Taiyang territory is largest, adjacent to Shaoyin internally and Yangming externally, so diseases relate. For example, difficulty urinating is originally a Bladder channel disease; Shaoyin disease also presents with difficulty urinating, indicating the pathogen has reached the boundary of Shaoyin. Constipation for 6-7 days, headache, and fever indicate Yangming heat invading Taiyang's boundary. The head and neck are the thoroughfares of Taiyang. Since Taiyang governs Ying and Wei, and the chest/heart is the root of Ying and Wei, which circulate endlessly, it is like border officials and soldiers constantly traveling to the capital. Wheezing and chest fullness indicate Taiyang exterior pathogens entering Yangming territory and causing disturbance, hence called Taiyang-Yangming Combined Disease. If no headache or neck stiffness, but chest oppression/stiffness, rising Qi, and inability to breathe through the throat, this pathogen did not come from Taiyang but is Yangming heat-solid binding in the chest, like rebels causing trouble in their own territory.
The Heart is the master of the six channels, so all six channels can present with vexation. If no head/neck stiffness, vexation does not belong to Taiyang; if no alternating chills/fever, vexation does not belong to Shaoyang; if no Three Yang symptoms, vexation does not belong to the Three Yang. Thus, mental restlessness, palpitations, and inner embarrassment—all deficiency vexations—belong to Yangming, because the Heart resides in the Yangming territory. Yangming is like the capital, so both Heart and Abdomen are within its domain. Pathogen in the Heart causes deficiency vexation; in the Abdomen, excess heat. The Heart is Yang and formless; the Abdomen is Yin and formed.
Diseases of the human body often involve the Heart and Abdomen. Yang pathogens gather in the Heart; Yin pathogens gather in the Abdomen. The Liver is Yang within Yin, so it can cause Yin pathogenic Qi to strike the Heart. Yangming governs interior Yang, so it can cause Yang pathogens to gather in the Abdomen.
Again, let us use military strategy as an analogy. The essence of strategy is knowing terrain and where bandits come from. Knowing which direction leads to which prefecture. The incoming route is the border pass (Three Yang); the outgoing route is the interior (Three Yin). The six channels' incoming routes differ: Taiyang is the main road, Shaoyin is the remote path, Yangming is the direct road, Taiyin is the nearby road, Shaoyin is the rear road, Jueyin is the diagonal road. Invading pathogens mostly come from the Three Yang; regular pathogens often arise from the Three Yin, like foreign invaders coming from borders or rebels arising from the interior.
Understanding the terrain of the six channels allows one to grasp the pivot of all diseases; detailing the incoming routes allows one to control the rules of treatment. By symptom: Cold damage is a major invader, disease from outside; Wind strike is a roaming bandit, disease spreading from sides; Miscellaneous disease is a rebel, disease arising from within. Once identified as a certain type of bandit and known origin, defend at the source. If disaster spreads to neighboring counties, attack from two sides. If pathogen enters Taiyang territory, release via sweating, like deploying troops at key points and striking before they settle. Light pathogens are in the Wei (Defensive) level; heavy in the Ying (Nutritive) level; especially heavy in the chest/diaphragm, like bandits shallow outside the pass, deep at the pass, deepest inside. Thus, Mahuang (Ephedrae Herba) represents troops outside the pass; Guizhi (Cinnamomi Ramulus) and Gegen (Puerariae Lobatae Radix) represent troops at the pass; Da Qinglong Tang (Major Blue-Green Dragon Decoction) and Xiao Qinglong Tang (Minor Blue-Green Dragon Decoction) represent troops inside the pass.
When external invaders are unstable, internal thieves rise in response, hence the method of dual resolution, leading to formulas like Da/Xiao Qinglong Tang and modified Guizhi/Mahuang formulas. If the vanguard lacks discipline causing internal chaos, prioritize interior over exterior, hence Wuling San (Five-Ling Powder), Shizao Tang (Ten-Jujube Decoction), Xianxiong Tang (Trap-Chest Decoction), Xiexin Tang (Drain-Epigastric Decoction), Didang Tang (Eliminate-Accumulation Decoction).
If pathogen enters Shaoyang territory, mix exterior/interior, cold/heat, attacking/tonifying agents for defense and resolution. Like narrow paths favoring short weapons over spears, and defense over offense. Light pathogens enter Couli (pores); heavy enter Muyuan (fascial spaces); especially heavy enter Spleen/Stomach. Xiao Chaihu Tang (Minor Bupleurum Decoction) treats Couli; Da Chaihu Tang (Major Bupleurum Decoction) treats Muyuan; Xiao Jianzhong Tang (Minor Construct the Middle Decoction), Banxia Xiexin Tang (Pinellia Drain Epigastric Decoction), Huangqin (Scutellariae Radix), Huanglian (Coptidis Rhizoma) are Shaoyang Spleen agents; Chaihu Jia Mangxiao Tang (Bupleurum Plus Gypsum Decoction) and Chaihu Jia Muli Tang (Bupleurum Plus Oyster Shell Decoction) are Shaoyang Stomach agents. If Taiyang-Shaoyang Combined/Concurrent disease occurs, it is one army invading Shaoyang; Chaihu Guizhi Tang (Bupleurum and Cinnamon Twig Decoction) is a two-pronged attack. If all Three Yang combine, it is three-sided enemy attack; the method is to isolate Yangming. If Yangming territory is secured, Yang pathogens from Taiyang/Shaoyang resolve spontaneously. If internal rebels calm, external invaders cease; this is why Baihu Tang (White Tiger Decoction) succeeds.
If Yang pathogens do not fight in the interior, use Dachengqi Tang (Major Order the Qi Decoction) for urgent purging, attacking bandits to protect the lord. If Yin pathogens directly invade the Central Palace, use Sini Tang (Frigid Extremities Decoction) to urgently rescue the interior, strengthening the lord to expel bandits. Yangming is the interior, with Yang facing the border (Taiyang/Shaoyang). If pathogen enters Yangming near Taiyang, though not invading Taiyang, Taiyang troops cannot ignore it; thus, Yangming Ying/Wei diseases borrow Mahuang-type formulas for sweating. Near Shaoyang, though not entering Shaoyang, Shaoyang troops cannot remain passive; thus, Yangming Couli diseases borrow Chaihu for resolution. Thus, Yangming's failure to hold implies either Taiyang insecurity or Shaoyang unpreparedness. Hence, Two Yangs often combine to cause disease.
If pathogen is already in Yangming territory, must send troops to vigorously drive it out, leaving none behind; hence use Zhizi Chi Tang (Gardenia and Fermented Soybean Decoction) and Gua Di San (Melon Tip Powder) for vomiting to sweep quickly. If deeply penetrating the interior, cannot drive out, then scorched earth policy (clear fields for a thousand li) deprives them of plunder; this is where Baihu Tang excels. If pathogen is in the inner court, must clear internal Yin thieves; this is how Chengqi formulas win. Agents like Yinchen (Artemisiae Scopariae Herba) and Zhuling (Polyporus) legislate for undisciplined armies.
Taiyin is also interior; Shaoyin/Jueyin territories are Taiyin's borderlands. Taiyin occupies the Central Plain, connecting externally to Three Yang, but Yin/Yang paths diverge, with diaphragm barriers between Heart/Abdomen. Thus, Cold-Water pathogens from Taiyang exterior invasion are light; from Shaoyin interior transmission are heavy. Wind-Wood pathogens from Shaoyang invasion are slight; from Jueyin upward assault are severe. If original pathogen transfers to Yangming becoming excess, like exhausted troops, purging cures it. If Yangming excess transfers to original channel becoming deficiency, pathogen strong/deficiency weak, warming/tonifying recovery is difficult.
Though Taiyin and Yangming territories are separate, there is no barrier. Yangming is a thoroughfare for enemies, gathering troops, a four-battle ground. Taiyin is a granary, relied upon by armies, also a bandit nest. If Yuan Qi is sufficient, pathogen enters Yangming; if insufficient, enters Taiyin. In Yangming territory, deploy troops for a decisive battle, winning quickly. In Taiyin territory, granaries burned/looted, empty stores, starving soldiers cannot resist.
Jueyin territory is the zone of Ministerial Fire circulation. Its original Qi is Minor Fire; if wind-cold-dryness-dampness enters, it transforms entirely into Heat, i.e., Major Fire. Minor Fire is the life force of the body; Major Fire is the great disaster. Its territory connects to Sanjiao. Pathogen attacking Upper Jiao causes Qi rushing to Heart, burning pain in Heart, thirst, oral ulcers, sore throat/obstruction. Pressing into Middle Jiao causes cold extremities, faint pulse, hunger without desire to eat, vomiting roundworms after eating. Moving to Lower Jiao causes dysentery with heaviness, or pus/blood in stool, causing deep harm, like a rebellious army.
Zhang Zhongjing formulated Wu Mei Wan (Mume Pill), using cold/heat together, attacking/tonifying simultaneously, regulating Qi/Blood, harmonizing Sanjiao, as the main formula for pacifying Jueyin, like a Grand Commander of the interior. Giving water for thirst, Fuling Gancao Tang (Poria and Licorice Decoction) for water retention, Zhigancao Tang (Processed Licorice Decoction) for restoring pulse, Danggui Sini Tang (Angelica Frigid Extremities Decoction) for cold extremities—these are elite troops sent separately to rescue the Heart Master in Upper Jiao and calm the Spirit. Using Baihu/Chengqi types clears Stomach and calms Middle Jiao heat-excess; Baitouweng Tang (Pulsatillae Decoction) and Sini San (Frigid Extremities Powder) clear Spleen and stop Lower Jiao heat-dysentery, rescuing Yin in the Abdomen and supporting Stomach Qi.
Kidney is one Fu organ but divides into Yin/Yang channels. Shaoyin is one channel but combines Yin/Yang Zang, being the root. Thus, pathogens have Yin/Yang paths; Zang divides Yin/Yang Qi. If Yang pathogen attacks Shaoyin-Yang, reverse fever, vexation, cough/thirst, sore throat. If Yang pathogen attacks Shaoyin-Yin, abdominal pain, spontaneous diarrhea, or pus/blood in stool. If Yin pathogen attacks Shaoyin-Yang, body/joint pain, cold extremities, back aversion-to-cold, lethargy. If Yin pathogen attacks Shaoyin-Yin, aversion-to-cold, vomiting, clear grain diarrhea, restlessness desiring death.
Zhang Zhongjing formulated Mahuang Fuzi Xixin Tang (Ephedra, Prepared Aconite, and Asarum Decoction), Huanglian Ejiao Tang (Coptis and Donkey-Hide Gelatin Decoction), Gancao Jiegeng Tang (Licorice and Platycodon Decoction), Zhufu Tang (Pig Skin Decoction), Banxia Kujiu Tang (Pinellia and Vinegar Decoction) to defend against Yang pathogens attacking Shaoyin-Yang. He formulated Taohua Tang (Peach Blossom Decoction) and Zhuling Tang (Polyporus Decoction) to defend against Yang pathogens entering Shaoyin-Yin. Fuzi Tang, Wuyu Tang (Evodia Decoction), Sini Tang defend against Yin pathogens attacking Shaoyin-Yang. Tongmai Sini Tang (Pulse-Restoring Frigid Extremities Decoction), Fuling Sini Tang, Ganjiang Fuzi Tang defend against Yin pathogens entering Shaoyin-Yin.
Shaoyin is the root of six channels, connecting externally to Taiyang and internally to Yangming. Thus, initial reverse fever and fever of whole body/extremities after 8-9 days indicate Shaoyin-Yang pathogen invading Taiyang territory. Spontaneous diarrhea of pure green water, epigastric pain, dry mouth/tongue indicate Shaoyin-Yang pathogen invading Yangming territory. Exiting Taiyang, use Mahuang as vanguard supervised by Fuziu; entering Yangming, rely fully on Dachengqi without supervision, like using guides differently from main troops. Yin pathogens invading Taiyin use Lizhong Tang (Regulate the Middle Decoction) and Sini plus Human Urine/Pig Bile, similarly.
Alas! Without pondering Zhang Zhongjing's compilation, how can one see the disease and know its origin?