三十难曰∶荣气之行，常与卫气相随不？
然∶经言人受气于谷，谷入于胃，乃传于五脏六腑，
五脏六腑，皆受于气。其清者为荣，浊者为卫，荣行脉中，卫行脉外，荣周不息，五十而复大会。
阴阳相贯，如环之无端，故知荣卫相随也。
荣卫循行之义，已详一难中。此言荣卫相随不息之原，起于胃之谷气，其清者为荣，即谷味
之精，乃阳中之阴也。血为荣，行于脉中，其浊者为卫，即谷味之气，乃阴中之阳，即所谓阳明悍
气也，化气为卫，以卫护于脉外。《素问·痹论》云∶营者，水谷之精气也，和调于五脏，洒陈于
六腑，乃能入于脉也。卫者，水谷之悍气也，其气 疾滑利，不能入于脉也。亦即此义。但此节
乃《灵枢·营卫生会篇》中语。惟《灵枢》作谷入于胃，以传于肺，五脏六腑皆以受气，为少殊耳。
然胃中水谷之精，为微丝液管吸至颈会管，过肺入心，化赤为血，以荣五脏六腑。经脉之中，删
去（以传于肺）四字，便乖脏腑传道之义，关系匪轻，不可缺也。
三十一难曰∶三焦者，何禀何生？何始何终？其治常当何许，可晓以不？
然∶
三焦者，水谷之道路，气之所终始也。上焦者，在心下，下膈，在胃上口，主内而不出，其治在膻
中，玉堂下一寸六分，直两乳间陷者是。中焦者，在胃中脘，不上不下，主腐熟水谷，其治在脐旁。
下焦者，当膀胱上口，主分别清浊，主出而不内。以传道也，其治在脐下一寸。故名曰三焦，其府
在气街。
前节举五脏六腑，禀水谷荣卫之气而相资养，为论脏腑之首条。此因三焦之气化，论其发用
之理也。夫三焦者，禀元气以资始，合胃气以资生，上达胸中而为用，往来通贯，宣布无穷，造化
出纳，作水谷之道路，为气之所终始也。上焦在膈膜之下者，以其上层与膈膜下层粘属也。其气自
下而上，散于胸中，分布薰蒸于皮肤腠理，故在胃上口，主纳而不令出，其治在膻中穴，属任脉，
在玉堂下同身寸之一寸六分陷者中，任脉气所发也。中焦在胃中脘，以其包肝裹胃也，其治在脐旁
之天枢，胃脉之穴也，其用在胃之中脘，中脘者，乃十二经所起所会，阴阳肉完之处，故曰脘也。
下焦者，当膀胱上口，乃阑门之分，盖由此清者入于膀胱而为气为溺，浊者入于大肠而为滓为秽，
故主出而不纳，以传道也，其治在脐下任脉之阴交穴。《素问·灵兰秘典论》曰∶三焦者，决渎之
官，水道出焉，即指此也。其所在气街者，气街在毛际两旁，足阳明经穴，乃三焦之根，原气所之
处，即由肾系所生之脂膜也。夫三焦属相火之宅，火之性自下而
上，故《素问·经脉别论》曰∶饮入于胃，游溢精气，上输于脾，此指中焦也。脾气散精，上
归于肺，此指上焦也。通调水道，下输膀胱，此指下焦也。然论上中下三焦之气，何以独重乎饮，
不知气乃水之所化也。膀胱之水，借吸入之天阳，引心火至下焦，薰蒸化而为气以上达，为津为
液为汗，此火交于水化气之理，即干阳入坤阴，随阳气上腾而为云为雨之义也。若夫三焦之形质，
详见于二十五难，可参互观之。
Chapter 30 asks: Does the movement of Ying Qi (Nutritive Qi) always accompany Wei Qi (Defensive Qi)?
The answer is: The classics state that humans derive Qi from food. When food enters the stomach, it is transmitted to the Zang and Fu organs. All Zang and Fu organs receive this Qi. The clear and light portion becomes Ying Qi (Nutritive Qi), while the turbid and heavy portion becomes Wei Qi (Defensive Qi). Ying Qi circulates within the vessels, while Wei Qi circulates outside the vessels. Ying Qi flows ceaselessly, completing fifty cycles before reuniting at the Lung Meridian of Hand-Taiyin. The Yin and Yang meridians interconnect like a circle without beginning or end; thus, we know that Ying Qi and Wei Qi move in concert.
The principles of Ying and Wei circulation were detailed in Chapter 1. This chapter discusses the origin of their ceaseless accompanying movement, which arises from the Grain Qi in the stomach. The clear portion is Ying Qi, the essence of grain flavors, belonging to Yin within Yang. Blood belongs to Ying Qi and moves within the vessels. The turbid portion is Wei Qi, the Qi of grain flavors, belonging to Yang within Yin, also known as the vigorous Qi of Yangming. It transforms into Wei Qi to protect the exterior of the vessels. *Su Wen: Pi Lun* states: "Ying Qi is the essence of water and grain, harmonizing with the five Zang organs and spreading to the six Fu organs, thereby entering the vessels." "Wei Qi is the vigorous Qi of water and grain; its nature is swift and slippery, unable to enter the vessels." This conveys the same meaning. However, this section originates from *Ling Shu: Ying Wei Sheng Hui Pian*. The only slight difference is that *Ling Shu* reads "grain enters the stomach and is transmitted to the lungs," allowing all Zang and Fu organs to receive Qi. Nevertheless, the essence of water and grain in the stomach is absorbed by capillary lymphatic vessels, transported to the jugular convergence, passes through the lungs to enter the heart, turns red to become blood, and nourishes the five Zang and six Fu organs. If the four characters "transmitted to the lungs" are omitted from the meridian text, it violates the principle of Zang-Fu transmission, a matter of significant consequence that cannot be omitted.
Chapter 31 asks: What does the San Jiao (Triple Burner) inherit for its origin? Where does it begin and end? Where is its treatment site usually located? Can this be explained?
The answer is:
The San Jiao (Triple Burner) is the pathway for water and grain and the starting and ending point of Qi. The Upper Jiao (Upper Burner) is located below the heart, beneath the diaphragm, and above the upper opening of the stomach. Its primary function is reception without discharge. Its treatment site is at Danzhong (CV-17), one cun and six fen below Yutang (CV-19), in the depression between the two breasts. The Middle Jiao (Middle Burner) is located at Zhongwan (CV-12) within the stomach, neither high nor low. Its primary function is the rotting and ripening of water and grain. Its treatment site is beside the umbilicus. The Lower Jiao (Lower Burner) is located at the upper opening of the bladder. Its primary function is separating the clear from the turbid, discharging waste without receiving new intake, serving as a conduit. Its treatment site is one cun below the umbilicus. Hence it is called the San Jiao (Triple Burner), and its fu organ connection is at Qijie (Stomach Channel points near the groin).
The previous section listed the five Zang and six Fu organs, which rely on the Nutritive and Defensive Qi derived from water and grain for mutual support; this was the first principle discussed regarding Zang and Fu organs. Here, due to the Qi transformation of the San Jiao (Triple Burner), the principle of its functional manifestation is discussed. The San Jiao (Triple Burner) inherits Yuan Qi (Original Qi) as its beginning and combines with Stomach Qi as its source of generation. It ascends to the chest to exert its function, flowing freely and unceasingly, announcing boundless changes, acting as the passage for water and grain and the cycle of Qi. The Upper Jiao is below the diaphragm because its upper layer adheres to the lower layer of the diaphragm. Its Qi rises from below, disperses in the chest, and distributes via steaming to the skin and interstices. Therefore, it is at the upper opening of the stomach, governing intake without allowing exit. Its treatment site is at Danzhong (CV-17), belonging to the Ren Mai (Conception Vessel), located in the depression one cun and six fen below Yutang (CV-19), where the Qi of the Ren Mai emerges. The Middle Jiao is at Zhongwan (CV-12) within the stomach because it envelops the Liver and Stomach. Its treatment site is Tian Shu (ST-25) beside the umbilicus, an acupoint of the Stomach Meridian. Its function lies in the middle of the stomach; Zhongwan (CV-12) is where the twelve meridians originate and converge, a place of complete Yin and Yang flesh, hence called "Wan" (cavity). The Lower Jiao is at the upper opening of the bladder, specifically the boundary of the Lanmen (Gate of Filth). Presumably, the clear part enters the bladder to become Qi and urine, while the turbid part enters the large intestine to become dregs and feces. Thus, it governs discharge without reception, serving as a conduit. Its treatment site is Yinjiao (CV-7) of the Ren Mai, one cun below the umbilicus. *Su Wen: Ling Lan Mi Dian Lun* states: "The San Jiao (Triple Burner) is the official of drainage; the water pathways emerge from it," referring to this. The location referred to as Qijie is on both sides of the pubic hairline, acupoints of the Foot-Yangming Meridian. It is the root of the San Jiao (Triple Burner) and the destination of Yuan Qi (Original Qi), essentially the fatty membrane generated from the kidney system. The San Jiao (Triple Burner) is the residence of Minister Fire. Since the nature of fire rises from below, *Su Wen: Jing Mai Bie Lun* states: "When drink enters the stomach, its essence overflows and is transported upward to the spleen." This refers to the Middle Jiao. "The Spleen scatters the essence upward to return to the lungs." This refers to the Upper Jiao. "Regulating the water pathways, transporting downward to the bladder." This refers to the Lower Jiao. However, when discussing the Qi of the Upper, Middle, and Lower Jiao, why is emphasis placed solely on water? One must not fail to realize that Qi is transformed from water. Water in the bladder, aided by the Heavenly Yang Qi inhaled, draws Heart Fire down to the Lower Jiao, where steaming transforms it into Qi to ascend, becoming Jin Ye (Body Fluids) and sweat. This is the principle of Fire and Water interacting to transform Qi, analogous to Dryness entering Earth's Yin, rising with Yang Qi to become clouds and rain. As for the physical form of the San Jiao (Triple Burner), it is detailed in Chapter 25 and can be cross-referenced.