古有离合真邪云者。盖圣人欲使其真邪相离而勿合之谓也。若邪入于真。则真受其蠹而不遂其
纯一之真。真之不遂。则其所谓真也、罹害有不可言者。真被乎邪。窃其柄而肆其横逆。邪既横逆
。则其为患。复可胜言哉。呜呼真邪之不可合也如此。胡为真。胡为邪。真之为言也、天理流行。
付与万物。万物得以为生者。皆真也。圣人保之如持盈。邪之为言也、天地间非四时五行之正气。
而差臻迭至者、皆邪也。圣人避之犹矢石。其防微杜渐之严如是。渊有旨哉。盖真立则邪远。邪厉
则真残。邪固可除。真尤宜养。养真之道。无须异求。但饮食男女。节之以限。风寒暑湿。御之以
时。复能实慈恕以爱人。虚中襟而应物。念虑必为之防。举止必为之敬。如斯内外交养周备。则吾
之生。不永生而生。不期寿而寿矣。不然。摄养少或不严。则六邪乘隙竞入。诸疾交生。众害并作
。则吾之真所能存者几希。故圣人忧之。揆度权衡机宜所在。示之以克邪之方。使屏之如沃雪拔刺
而无遗者以此。古人有云。树德务滋。除恶务本。亦此意也。然去邪之方。经旨俱存。再拜遗诠。
敬为节录。
帝问邪气在经。其病何如。取之奈何。对曰。邪之在经。如水得风。波涌陇起。其行脉中循循然。
其中手也。时大时小。动无常处。在阴与阳。不可为度。卒然逢之。早遏其路。吸则内针。无令气
忤。静以久留。无令邪市。吸则转针。以得气为故。候呼引针。呼尽乃去。大气皆出。故命曰泻。
帝曰。不足者补之奈何。必先扪而循之。切而散之。推而按之。弹而 （一作弩）之。爪而下之
。通而取之。外引其门。以闭其神。呼尽内针。静以久留。以气至为故。如待所贵。不知日暮。其
气以至。过而自缓（一作护）候吸引针。气不得出。各在其处。推阖其门。令神气存。大气留止
。故命曰补。○泻法。先以左手揣按得穴。以右手置针于穴上。令病患咳嗽一声。捻针入腠理。得
穴。令病患吸气一口。针至六分。觉针沉涩。复退至三四分。再觉沉涩。更退针一豆许。仰手转针
头向病所。以手循经络。循扪至病所。气至病已。合手回针。引气过针三寸。随呼徐徐出针。勿闭
其穴。命之曰泻。○补法。先以左手揣按得穴。以右手按之。置针于穴上。令病患咳嗽一声。捻针
入腠理。得穴。令病患呼气一口将尽。内针至八分。觉针沉紧。复退一分许。如更觉沉紧。仰手转
针头向病所。根据前循扪至病所。气至病已。随吸而疾出。针速闭其穴。命之曰补。
There was an ancient concept called "Separating True Qi from Pathogenic Factors" (Li He Zhen Xie), which means that the Sages wished for True Qi (Zhen Qi, the vital essence and defensive energy) and Pathogenic Factors (Xie Qi, disease-causing agents) to remain separate and not mix. If pathogenic factors invade True Qi, then True Qi suffers erosion and cannot maintain its pure state. If True Qi is not preserved, the harm suffered by what is called "True" is indescribable. When True Qi is occupied by pathogenic factors, these factors steal authority and act arbitrarily and violently. Once pathogenic factors act violently, the disasters they cause are beyond enumeration. Alas, True Qi and pathogenic factors must not be combined; such is the situation. What is True? What is Pathogenic? The term "True" refers to the natural flow of Heavenly Principles (Tian Li, the fundamental laws of nature), bestowed upon all things. All things that derive life from this are "True." The Sages protected it as carefully as if holding a vessel filled to the brim. The term "Pathogenic" refers to those factors in heaven and earth that deviate from the regular patterns of the Four Seasons and Five Elements, appearing erratically and alternately; these are all "Pathogenic." The Sages avoided them as one avoids arrows and stones. Their strictness in preventing subtle beginnings and stopping gradual developments was thus profound and significant. Generally, when True Qi is established, pathogenic factors stay away; when pathogenic factors are fierce, True Qi is damaged. Although pathogenic factors should certainly be eliminated, True Qi especially requires nourishment. The way to nourish True Qi requires no strange or exotic methods; simply regulate diet and sexual activity with limits, and defend against wind, cold, summer-heat, and dampness according to the seasons. Furthermore, practice compassion and forgiveness to love others, maintain an empty and receptive mind to respond to external affairs, guard against distracting thoughts, and behave with reverence. By cultivating both internally and externally in such a comprehensive manner, our life will naturally achieve longevity without seeking immortality, and age without desiring long life. Otherwise, if health preservation is slightly lax, the Six Excesses (Liu Xie, six climatic pathogens: wind, cold, summer-heat, dampness, dryness, fire) will take advantage of gaps to enter, various diseases will arise simultaneously, and multiple harms will occur together. In this case, very little of our True Qi will remain. Therefore, the Sages worried about this. They weighed and measured the critical points, demonstrating methods to overcome pathogenic factors, so that eliminating pathogens would be as thorough as melting snow or removing thorns. As the ancients said, "When cultivating virtue, strive to nurture it; when eradicating evil, strive to remove its root." This conveys the same meaning. However, the methods for expelling pathogenic factors are preserved in the classic texts. I respectfully bow to the legacy of the sages and hereby excerpt the key points.
The Yellow Emperor asked: When pathogenic factors are in the meridians, what are the symptoms? How should acupuncture be applied? The response was: When pathogenic factors are in the meridians, it is like water encountering wind, causing waves to surge and ridges to rise. It moves within the vessels in a progressive manner. When needle sensation arrives, it varies in size, sometimes large, sometimes small, moving without a fixed location, wandering between Yin and Yang meridians, making it impossible to measure regularly. Upon sudden encounter, one must block its path early. Insert the needle during the patient's inhalation, ensuring that the healthy Qi does not become disordered. Leave the needle quietly for a long time, preventing the pathogenic factor from gathering. Rotate the needle during exhalation, aiming for De Qi (arrival of needle sensation). Withdraw the needle while the patient is exhaling, removing it completely only after exhalation ends. At this point, the major Qi (pathogenic Qi) is expelled, hence this is called the Reducing Method (Xie Fa).
The Yellow Emperor said: For conditions of deficiency, how is tonification performed? First, palpate and stroke along the meridian, press and scatter stagnation, push and press the acupoint, tap the area, use fingernails to press down, unblock the channel, and select the point. Pull open the gate of the acupoint externally to close the Shen (Spirit/Energy). Insert the needle at the end of exhalation, leave it quietly for a long time, taking the arrival of Qi as the goal. Wait as if expecting a honored guest, unaware of the passing day. When Qi arrives, if it is excessive, allow it to slow down naturally. Withdraw the needle during inhalation so that Qi does not escape, remaining in place. Push and close the acupoint gate, allowing the Shen Qi to remain and the major Qi to stay inside and stop leaking out. Hence, this is called the Tonifying Method (Bu Fa). ○ Reducing Method Operation: First, use the left hand to palpate and locate the acupoint. Place the needle on the acupoint with the right hand. Ask the patient to cough once, then twist the needle into the subcutaneous tissue (Cou Li) until De Qi is obtained. Ask the patient to inhale once, insert the needle 6 cun deep. When a heavy and resistant sensation is felt, withdraw the needle to 3-4 cun. When the heavy sensation is felt again, withdraw the needle further by approximately one bean's width. Turn the needle head upward toward the diseased area. Use the hand to stroke and press along the meridian until the sensation reaches the diseased area. When Qi arrives, the illness resolves. Turn the hand downward to return the needle, guiding the Qi three inches past the needle tip. Withdraw the needle slowly during exhalation, do not close the acupoint immediately. This is called the Reducing Method. ○ Tonifying Method Operation: First, use the left hand to palpate and locate the acupoint. Press the area with the right hand, place the needle on the acupoint. Ask the patient to cough once, then twist the needle into the subcutaneous tissue until De Qi is obtained. Ask the patient to exhale fully. Insert the needle 8 fen deep. When a heavy and tight sensation is felt, withdraw the needle by about 1 fen. If the heavy and tight sensation persists, turn the needle head upward toward the diseased area. Follow the previous method of stroking and pressing along the meridian until the sensation reaches the diseased area. When Qi arrives, the illness resolves. Withdraw the needle quickly during inhalation, and rapidly close the acupoint. This is called the Tonifying Method.