Differences in Acupuncture Tonification and Reduction between Nei Jing and Nan Jing

Tonifying and reducing needling methods represent the essence of traditional acupuncture techniques. Early classical works of Chinese medicine, Nei Jing and Nan Jing, contain extensive records on this subject. This article systematically reviews and compares the discussions of tonifying and reducing needling methods in these two classics from the perspectives of their principles and theoretical connotations, as well as three key factors in clinical operation: the site of stimulation, the manipulation technique, and the timing of stimulation. Based on an objective analysis of the original texts, it is found that the accounts of tonifying and reducing needling methods in Nei Jing and Nan Jing differ markedly in all of the above aspects. This suggests that the two works may originate from different early medical schools in China, each with its own theoretical system of acupuncture tonification and reduction.

Tonifying and reducing needling was a commonly used acupuncture method in ancient times. Nei Jing provides abundant records on its principles, methods, and clinical applications, while Nan Jing also contains many discussions, although its principles and methods differ from those of Nei Jing. The modern acupuncture scholar Zhu Lian once proposed that three key factors determine the therapeutic effect of acupuncture: the site of stimulation, the method of stimulation, and the timing of stimulation. Based on the principles of tonification and reduction and these three key factors, this article explores the differences between the tonifying and reducing needling methods in Nei Jing and Nan Jing, in order to clarify and present the characteristics and evolution of acupuncture tonification–reduction theories in these two most important classical works of Chinese medicine.

1. Principles and Connotations of Acupuncture Tonification and Reduction

1.1 The Overall Principle of Tonifying Deficiency and Reducing Excess Proposed in Nei Jing

Tonifying and reducing needling is one of the various acupuncture techniques described in Nei Jing. Its guiding ideology is based on the ancient Chinese philosophical concept of reducing excess and supplementing insufficiency. Nei Jing emphasises that pulse diagnosis must be performed before applying tonifying or reducing techniques in order to determine deficiency or excess. In Ling Shu · Jiu Zhen Shi Er Yuan it is stated that before using needles, one must first examine the pulse and assess the severity or mildness of qi, and only then can treatment be applied. The same chapter further states that deficiency should be supplemented, fullness should be drained, stagnation should be removed, and when pathogenic factors prevail, deficiency should be induced.

In Ling Shu · Xiao Zhen Jie, this is explained as follows: what is meant by supplementing deficiency is that the qi at the pulse opening is deficient and should be supplemented; what is meant by draining fullness is that the qi at the pulse opening is abundant and should be reduced. Speaking of excess and deficiency as if there were something or nothing refers to the presence of qi in excess and the absence of qi in deficiency. From this it can be seen that Nei Jing mainly determines deficiency and excess through pulse diagnosis. Although Xiao Zhen Jie explains this as examining the pulse opening, it may in practice also refer to examining the pulsation points along each channel to distinguish deficiency and excess.

Nei Jing records multiple pulse diagnostic methods, such as comparative pulse diagnosis of renying and cun kou, the three regions and nine indicators method, and the root–branch pulse method.

Ling Shu · Jing Mai proposes the acupuncture treatment principle of draining when exuberant, supplementing when deficient, acting quickly in heat, retaining needles in cold, using moxibustion in sinking conditions, and selecting the channel when neither excess nor deficiency is present. Ling Shu · Jin Fu contains similar statements. The principles of draining excess and supplementing deficiency in these chapters are based on comparing the renying and cun kou pulses to assess the excess or deficiency of the twelve channels. For example, Ling Shu · Zhong Shi states that when the cun kou pulse is three times stronger, the disease is in the Foot Taiyin; when it is three times stronger and restless, it is in the Hand Taiyin. Jing Mai states that when the Lung Hand Taiyin channel is excessive, the cun kou pulse is three times larger than renying, and when deficient, it is smaller than renying. In such cases, tonification and reduction are applied simultaneously to paired interior–exterior channels. If there is no imbalance between yin and yang channels, treatment is applied only to the affected channel, as stated in Zhong Shi: one must first understand the diseases generated by the twelve channels, and only then can transmission from beginning to end be grasped; thus, when yin and yang do not shift and deficiency and excess do not incline, treatment is taken from the channel itself. This interior–exterior channel tonification–reduction represents a special case within the Nei Jing system.

Su Wen · San Bu Jiu Hou Lun records the three regions and nine indicators pulse method, which examines pulsations on the head and face, upper limbs, and lower limbs. It states that humans have three regions, each with three indicators, by which life and death are determined, all diseases are managed, deficiency and excess are regulated, and pathogenic factors are eliminated. The text further explains that disease location is identified by observing abnormalities such as isolated smallness, largeness, rapidity, slowness, heat, cold, or sinking of pulses. Su Wen · Ba Zheng Shen Ming Lun also states that one should know the diseased pulse sites of the three regions and nine indicators and treat them accordingly, while Su Wen · Li He Zhen Xie Lun emphasises careful palpation of their excess and deficiency for regulation.

Thus, Su Wen places greater emphasis on the three regions and nine indicators pulse method, using it to diagnose disease and guide treatment based on supplementing deficiency and draining excess. Overall, Nei Jing establishes pulse diagnosis as the primary means of determining deficiency and excess and proposes the general therapeutic principle of tonifying deficiency and reducing excess, which forms its fundamental theoretical basis.

1.2 The Advocacy of the Mother–Child Tonification and Reduction Method in Nan Jing

Nan Jing proposes the method of exclusively taking the cun kou pulse, stating that the cun kou is where the five zang and six fu begin and end, and thus pulse diagnosis should be taken there. It further explains that by palpating the cun kou pulse and observing its deficiency or excess, one can determine the affected zang or fu organ. In addition to pulse-based assessment, Nan Jing also judges deficiency and excess through clinical manifestations and sensations such as pain and itching during diagnosis. Forty-Eight Difficult Issues describes three types of deficiency and excess: those of the pulse, of the disease, and of diagnosis itself, each with detailed criteria.

After determining deficiency or excess, Nan Jing further applies the principles of correspondence between the five zang organs and the five elements, transforming the tonification–reduction principle into the method of supplementing the mother in deficiency and draining the child in excess.

Forty-Nine Difficult Issues distinguishes between diseases arising from the proper channels themselves and those caused by the invasion of the five pathogenic factors, detailing how different emotional and environmental factors damage specific organs. Sixty-Nine Difficult Issues explains that supplementing deficiency means supplementing the mother, draining excess means draining the child, and when neither deficiency nor excess is present, treatment is taken from the affected channel itself.

Commentaries such as Nan Jing Ji Zhu by Yang Xuancao and Nan Jing Jing Shi by Xu Lingtai further elucidate these principles using the five-element generation and control relationships. According to these explanations, selecting channels and points for tonification and reduction based on mother–child relationships differs fundamentally from the interior–exterior channel method described in Ling Shu.

In addition to selecting channels according to the mother–child principle, Nan Jing also assigns the five shu points of each channel to the five elements and applies the same principle to select specific points for tonification and reduction.

2. Selection of Sites for Acupuncture Tonification and Reduction

2.1 Selection of Five Shu Points, Pulsation Sites, or Blood Collaterals in Nei Jing

Various chapters of Ling Shu record specific stimulation sites for tonifying and reducing needling, though not in a systematic manner. When these passages are examined collectively, it becomes clear that the five shu points below the elbows and knees are most commonly used. Classical passages describe selecting jing, ying, shu, jing, and he points, as well as treating through distal channel points and organ-associated points. These points are described as gateways of qi, locations where original qi enters and exits, and thus are closely related to the zang and fu organs and suitable for regulating deficiency and excess.

In addition, Nei Jing also describes treating directly at pathological pulse sites, representing an earlier form of acupuncture. The three regions and nine indicators method involves needling directly at diseased pulse sites. Ling Shu · Zhong Shi describes palpating pulsations between the big toe to determine deficiency or excess and applying rapid reduction or slow tonification accordingly. Other passages explain that sudden pulsations indicate the presence of pathogenic qi and justify needling at these sites.

Nei Jing also records bloodletting techniques at collateral vessels to regulate deficiency and excess, consistent with earlier medical texts such as the Zhangjiashan Han bamboo manuscripts. These methods involve bleeding congested vessels to expel pathogenic factors and restore balance.

There is a close relationship between acupuncture points and pulses. Many acupuncture points evolved from pulse sites, and the first point of each channel originated from its corresponding pulse opening. In early times, pulse diagnostic sites at the wrists and ankles also served as treatment sites, functioning both diagnostically and therapeutically.

Because Nei Jing incorporates materials from multiple early sources, its descriptions of tonification–reduction sites vary, including pulse sites, blood collaterals, and five shu points. Over time, the five shu points became the most commonly used sites due to their strong distal therapeutic effects and their ability to treat internal organ disorders.

2.2 Selection of Five Shu Points Based on Five-Element Theory in Nan Jing

Nan Jing places great emphasis on the five shu points and original points, and the sites selected for tonification and reduction are primarily these points, making its approach more concise than that of Nei Jing. It assigns the five shu points of yin and yang channels to the five elements according to generation principles, with yin channels corresponding in the order of wood, fire, earth, metal, and water, and yang channels in the order of metal, water, wood, fire, and earth.

Specific passages describe these correspondences and explain how tonifying the mother and draining the child are achieved by selecting appropriate shu points. Thus, Nan Jing clearly establishes point selection for tonification and reduction based on the mother–child principle. In this way, the therapeutic intention of supplementing deficiency and draining excess is partially realised before needle manipulation even begins.

This integration of five-element theory with acupuncture point selection is not found in Nei Jing and represents one of the key conceptual differences between the two classics.

3. Determination of the Timing of Tonification and Reduction Operations

3.1 Waiting for Respiration or for the Arrival of Qi in Nei Jing

The timing of needle insertion and withdrawal is a crucial factor influencing the effect of tonification and reduction. Nei Jing records two methods for determining timing: observing respiration and waiting for the arrival of qi under the needle. The former is mainly found in Su Wen, while the latter appears in both Ling Shu and Su Wen.

Su Wen · Li He Zhen Xie Lun describes inserting and withdrawing the needle in coordination with inhalation and exhalation, defining reduction as inserting on inhalation and withdrawing on exhalation, and tonification as the reverse. Other chapters such as Ba Zheng Shen Ming Lun and Tiao Jing Lun further elaborate on adjusting needling according to the fullness or emptiness of qi during respiration.

In contrast, Ling Shu emphasises waiting for the arrival of qi beneath the needle. Jiu Zhen Shi Er Yuan explains that mastery lies in recognising subtle changes in qi movement and accurately timing needle manipulation. Commentaries clarify that once qi is obtained under the needle, it must be carefully maintained, as this moment determines therapeutic success.

Ling Shu · Guan Neng provides a detailed account of how needle manipulation corresponds to qi movement, describing reduction as rapid insertion and slow withdrawal to expel pathogenic qi, and tonification as slow insertion and rapid withdrawal to preserve true qi. Taken together, these passages show that Ling Shu places particular importance on waiting for the arrival of qi as the basis for determining tonification and reduction timing.

3.2 Waiting for Qi with the Left Hand in Nan Jing

Nan Jing makes a clear choice between the two timing methods described in Nei Jing and introduces its own distinctive approach. It states that tonification and reduction do not necessarily depend on respiration. Instead, emphasis is placed on using the left hand to stimulate and sense the arrival of qi before needle insertion. When qi arrives under the left hand, resembling arterial movement, the needle is inserted accordingly. Tonification is achieved by advancing the needle after qi arrives, while reduction is achieved by lifting and extending it.

Commentaries explain that this method prioritises the left hand in inducing and sensing qi, with the right hand performing needle manipulation. In Nan Jing, obtaining qi is the prerequisite for tonification and reduction, whereas in Nei Jing, the arrival of qi often serves as an indicator for needle withdrawal. By elevating the role of the left hand and emphasising coordinated bilateral manipulation, Nan Jing exerted a profound influence on the development of complex tonification–reduction techniques in later Yuan, Ming, and Qing dynasty acupuncture practice.