BL-13 (Fei Shu) Lung Shu

What does BL-13 Fei Shu do?

Fei Shu BL-13 is the Back-Shu point of the Lungs — the place on the back where the Lung's qi is said to infuse the body surface — and it is the principal point of the back for the Lung in every one of its aspects: its qi, its yin, its heat and its relation to the exterior of the body. Sacred Lotus sources & references record that classification directly, and it is the single fact that organises everything else about this point. Where a treatment intends to reach the Lung as an organ from the back, BL-13 is the point that does it.

• Tonifies Lung qi and nourishes Lung yin — the defining action, recorded first in our own action record. It covers the weak, breathless, easily-tired presentation the tradition attributes to Lung qi deficiency, and the dry, hot, night-sweating presentation it attributes to Lung yin deficiency. That one point serves both is characteristic of the Back-Shu points: they reach the organ rather than a particular aspect of it.
• Descends and disseminates Lung qi — the action that governs breathing itself. In classical theory the Lung both spreads qi outward to the surface and sends it downward; when that downward movement fails, qi is said to rebel upward, and the result is cough and wheezing. This is the point that carries "descends rebellious Lung qi" in channel theory, by virtue of its Back-Shu classification — a phrase that circulates attached to points which have no channel basis for it, discussed under the notes below.
• Clears heat from the Lung — for the productive, hot, thick-phlegm presentations and for the recorded indications of coughing blood, tidal fever and bone-steaming heat.
• Releases the exterior — the Lung is said to govern the defensive qi at the body surface, so its Back-Shu point is used at the beginning of an external invasion as well as in chronic organ disease. This is the action BL-13 shares with its immediate neighbour Feng Men BL-12, and the two are constantly used together.
• Benefits the skin and body hair — the classical correspondence. The Lung is said to govern the skin and hair (fei zhu pi mao), which is the reasoning behind the point's long-standing use in itching, rash and chronic skin complaints as well as in respiratory ones.
• Regulates the water passages of the upper burner — the Lung is described as the "upper source of water", and BL-13 carries the recorded use for oedema of the face and upper body and for difficulty in the passage of fluids.

Why does the Back-Shu classification matter?

The Back-Shu points are the tradition's most direct route to an internal organ. Each is understood as the place where that organ's qi infuses the back, which gives them two roles: they are used to treat the organ, particularly in chronic and deficient conditions, and they are palpated in diagnosis, since tenderness, a sunken feeling or a change in the tissue at a Back-Shu point is read as a sign that its organ is involved. BL-13 is the first and highest of the twelve, and it is among the most used of the whole group — partly because respiratory complaints are common, and partly because the Lung, being the organ the tradition places closest to the exterior, is implicated in a very large share of acute illness as well as chronic.

Source: Sacred Lotus sources & references (existing action record; Back-Shu classification queried directly); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 267); Chinese Acupuncture & Moxibustion (p. 177); cross-referenced against multiple online sources.

What is BL-13 Fei Shu used for?

Fei Shu BL-13 is used above all for cough and wheezing — it is the single most frequently selected point in the published acupuncture literature on asthma — and after that for the chest, for heat and night sweating from deficiency, and for the skin. The indications carried in Sacred Lotus sources & references are cough, asthma, chest pain, spitting of blood, afternoon fever and night sweating; the standard reference literature sets them out more fully below. These describe traditional use, not proven treatment, and this point carries the pneumothorax caution set out under needling.

• Cough, chronic cough and dry cough
• Wheezing, asthma and shortness of breath
• Breathlessness on exertion and weak, shallow breathing
• Fullness or pain in the chest
• Spitting or coughing of blood
• Afternoon (tidal) fever and bone-steaming heat
• Night sweating and spontaneous sweating
• Common cold with fever, chills and body ache
• Nasal congestion and runny nose
• Sore, dry or hoarse throat and loss of voice
• Stiffness and aching of the upper back and between the shoulder blades
• Itching, rash and chronic skin complaints
• Aversion to cold and repeated susceptibility to colds
• Vomiting of foam or thin fluid, and phlegm that is hard to expel

Source: Sacred Lotus sources & references (existing indication record); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 267); Chinese Acupuncture & Moxibustion (p. 177); point-frequency data from PMID 34875661.

Where is BL-13 Fei Shu, and how is it used in practice?

Fei Shu lies high on the upper back, one and a half cun either side of the midline, level with the lower border of the spinous process of the third thoracic vertebra — that is, level with Shen Zhu DU-12 on the spine itself. Sacred Lotus sources & references give it in both terms. It is a bilateral point, needled on both sides, and it sits in the muscle mass beside the spine at the level of the upper part of the shoulder blades, high in the band of the back that lies directly over the lung.

In practice BL-13 is used in two registers that are worth keeping apart. As a Back-Shu point it is reached for in chronic Lung patterns — deficiency of qi or yin, lingering cough, wheezing that returns every winter — usually with its Front-Mu point on the chest and a distal Lung-channel point. As an exterior-releasing point it is used at the onset of a cold or an asthma attack, in company with Feng Men BL-12 above it and Da Zhui DU-14 on the midline. It is also one of the points most often treated without a needle at all: moxibustion, cupping and the summer herbal plaster tradition all centre on this part of the back.

Which points is BL-13 combined with?

• With Zhong Fu LU-01 — the Front-Mu point of the Lungs, on the upper chest below the outer end of the collarbone. Back-Shu with Front-Mu is the classical Shu-Mu pairing for reaching an organ from front and back at once, and this is its Lung instance. Both points are held in this library, and both lie over the thorax and carry the same family of depth considerations.
• With Tai Yuan LU-09 — the Yuan-Source point of the Lung channel at the wrist, and additionally the Hui-Meeting point of the vessels. Back-Shu with Yuan-Source is the classical pairing for supplementing an organ.
• With Feng Men BL-12 — one level above at T2, the "Wind Gate". BL-12 is chosen when a pathogen is arriving; BL-13 addresses the Lung itself. In practice the two are needled together so routinely that they function almost as a single point.
• With Ding Chuan and Da Zhui DU-14 — the upper-back grouping for wheezing. A data-mining analysis of 183 controlled clinical trials of acupuncture for asthma found Feishu BL-13 to be the most frequently used point of all, ahead of Dingchuan, Dazhui, Shenshu BL-23, Pishu BL-20 and Fengmen BL-12, and identified BL-13, BL-12 and Ding Chuan as the central nodes of the combination network (Shang PP et al., Complement Med Res 2022;29(2):136–146, PMID 34875661).
• With Pi Shu BL-20 and Shen Shu BL-23 — the classical three-organ structure for chronic wheezing: free the Lung qi while supporting Spleen and Kidney, treating the symptom and the root together. The same data-mining analysis flagged this exact grouping as a priority combination, and it is the protocol used in the summer point-application tradition.
• With Gao Huang Shu BL-43 — three cun lateral and one level below on the outer Bladder line, the great point of the upper back for chronic depletion. BL-13 with BL-43 is the standard pairing for long-standing Lung deficiency and was the pairing used in the experimental work on pulmonary fibrosis noted under the BL-43 record.
• With Lie Que LU-07 and He Gu LI-04 — the distal pair for releasing the exterior, added at the onset of a cold.
• With Chi Ze LU-05 and Kong Zui LU-06 — the He-Sea and Xi-Cleft points of the Lung channel on the forearm, for acute cough and for coughing blood respectively.
• With Po Hu BL-42 — "Po Door", on the outer Bladder line three cun lateral at the same T3 level, the outer companion of BL-13 and the point associated with the po, the corporeal soul the Lung is said to house.

Where does BL-13 sit among the Back-Shu points?

The Back-Shu points run down the inner Bladder line, one and a half cun either side of the spine, one for each organ, in roughly the order the organs sit in the trunk. Sacred Lotus sources & references hold the complete set of twelve, and they are worth seeing together because the arrangement is the point:

• Fei Shu BL-13 — Lungs
• Jue Yin Shu BL-14 — Pericardium
• Xin Shu BL-15 — Heart
• Gan Shu BL-18 — Liver
• Dan Shu BL-19 — Gallbladder
• Pi Shu BL-20 — Spleen
• Wei Shu BL-21 — Stomach
• San Jiao Shu BL-22 — San Jiao
• Shen Shu BL-23 — Kidneys
• Da Chang Shu BL-25 — Large Intestine
• Xiao Chang Shu BL-27 — Small Intestine
• Pang Guang Shu BL-28 — Bladder

BL-13 is the highest of the twelve, which matches the position of the organ: the Lung sits at the top of the trunk and the tradition calls it the "canopy" over the other organs. Each Back-Shu point pairs with its organ's Front-Mu point on the front of the trunk, and the full set of twelve Front-Mu points is held here as well:

• Zhong Fu LU-01 — Lungs
• Shan Zhong REN-17 — Pericardium
• Ju Que REN-14 — Heart
• Qi Men LIV-14 — Liver
• Ri Yue GB-24 — Gallbladder
• Zhang Men LIV-13 — Spleen
• Zhong Wan REN-12 — Stomach
• Shi Men REN-05 — San Jiao
• Jing Men GB-25 — Kidneys
• Tian Shu ST-25 — Large Intestine
• Guan Yuan REN-04 — Small Intestine
• Zhong Ji REN-03 — Bladder

The Lungs are one of the few organs whose Front-Mu point sits on its own channel: Zhong Fu LU-01 is both the Lung's Front-Mu point and the first point of the Lung channel. That is not the rule — our own records show the Kidneys' Front-Mu on the Gall Bladder channel at Jing Men GB-25, the Spleen's at Zhang Men LIV-13 on the Liver channel, and the Pericardium's at Shan Zhong REN-17 on the Conception Vessel — which makes the Lung pairing the easiest of the twelve to learn and the one most often used to teach the Shu-Mu structure.

Source: Sacred Lotus sources & references (BL-13 record; the full twelve-point Back-Shu set and the twelve Front-Mu points queried directly, and reproduced here identically to the sets carried in the BL-23 and BL-18 records); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 267); Chinese Acupuncture & Moxibustion (p. 177); PMID 34875661; cross-referenced against multiple online sources.

Where is BL-13 located?

• A Manual of Acupuncture (p. 267): 1.5 cun lateral to the lower border of the spinous process of the third thoracic vertebra (T3).
• Chinese Acupuncture and Moxibustion (p. 177): 1.5 cun lateral to Shenzhu (DU-12), at the level of the lower border of the spinous process of the third thoracic vertebra.

How is BL-13 Fei Shu needled, and what is the pneumothorax risk?

Stated plainly: BL-13 lies over the thorax beside the third thoracic vertebra, with the upper lobe of the lung directly beneath it, and pneumothorax — a punctured lung — is the documented hazard at this point and at every point in the band it belongs to. The reference texts do not record a perpendicular insertion here. Our own record specifies oblique insertion of 0.5 to 0.7 inch, and the angle is the substance of the record, not a stylistic detail. Everything below is recorded as neutral reference data describing what the textbooks and the published anatomical studies state. It is not instruction, this page does not teach technique, and needling is carried out only by a qualified, licensed practitioner.

The angle and depth the texts record

• Sacred Lotus sources & references record oblique insertion of 0.5 to 0.7 inch, with moxibustion applicable — the same bounded figure our records give for Feng Men BL-12 above it, for Ge Shu BL-17 below it and for Pi Shu BL-20 further down the same line.
• Deadman & Al-Khafaji (p. 267) and Chinese Acupuncture & Moxibustion (p. 177) record oblique insertion directed medially, toward the spine, in a comparable range, and both attach an explicit caution against deep or laterally angled insertion at the thoracic Shu points because of the lung beneath. Angling toward the vertebral column keeps the needle in the muscle mass with bone behind it; angling outward points it at the intercostal space and the pleura behind that.
• Moxibustion, cupping and herbal point application are all recorded at this point and are extremely common at it. None of them carries the pneumothorax hazard, which is one reason the upper back is so often treated without needles at all — and why the largest body of clinical research on BL-13 concerns plasters and moxa rather than needling.
• For comparison within our own records: the 0.5–0.7 inch recorded at BL-13 is bounded in the same way as the 0.3–0.5 inch given for GB-21 over the apex of the lung, and considerably shallower than the 1–1.2 inch given for BL-23 in the lumbar region below the ribs. Depth figures in this literature track the structure underneath, not the size of the region.

The measured anatomy — and what each study actually measured

• A CT study that measured BL-13 itself. This is the point-specific finding. A retrospective study measured, directly from chest CT images, the safe needling depth at 23 upper-back acupoints in 319 patients aged 4 to 18 (205 boys, 114 girls), defining safe depth as the distance from the skin surface of the point to the pleura. The 23 points were DU-09 to DU-14, BL-11 to BL-17, BL-41 to BL-46, SI-14, SI-15, GB-21 and SP-21. The measured depth at Fei Shu BL-13 was 28.54 ± 7.08 mm in boys and 26.41 ± 5.38 mm in girls, a difference that was significant at this point (P = 0.003). Across the five age bands the depth at BL-13 rose from 24.82 ± 2.74 mm at ages 4 to 6 to 30.68 ± 8.04 mm at ages 16 to 18 (P < 0.001), and it rose with body size as well — from 26.25 ± 4.70 mm in the lightest weight band to 33.51 ± 12.84 mm in the heaviest, and from 26.09 ± 4.78 mm in the underweight body-mass-index group to 33.22 ± 12.10 mm in the obese one. Multiple regression identified weight as the single most important determinant at all 23 points (Ma YC et al., BMC Complement Altern Med 2016;16:85, PMID 26922245, PMC4769822, DOI 10.1186/s12906-016-1060-x). State the limits precisely: these are children and adolescents drawn from a single Taiwanese hospital population, all of them patients rather than healthy children, and the figure is the distance at which the pleura is reached — not a recommended needling depth.
• Why that figure is worth reading twice. Two and a half to three centimetres, in a child, is the entire margin, and a standard deviation of seven millimetres in boys means individual children differed from one another by more than the whole textbook insertion range. BL-13 was also one of the points at which boys and girls did differ significantly — unlike the lateral points on the same list — which is consistent with the depth here tracking the paravertebral muscle mass rather than the tissue over the shoulder blade.
• Honest limit on the adult figure. No imaging study measuring a safe needling depth at BL-13 in adults could be located, and none is quoted. For adults, what is recorded here is the bounded depth and specified angle the reference texts give, together with the measured anatomy of the surrounding region — with every measurement attributed to the point at which it was actually made.
• Cadaveric mapping of the pleural dome. A dissection study of 46 adult bodies mapped the dome of the pleura against the commonly used points around it, naming Da Zhu BL-11 — the Bladder-channel point two levels above Fei Shu, in the same band — explicitly alongside Tian Tu REN-22, Jian Jing GB-21, Qi She ST-11 and Ding Chuan EX-B1. The projection of the pleural dome varied widely between individuals, extending beyond the medial third of the clavicle in almost 60 per cent of bodies. The authors' conclusion is the operative one: when a point is located and angled as the standard describes the pleura is not reached, but exceeding the recorded depth breaches the pleural membrane (Chen Y et al., Zhongguo Zhen Jiu 2006;26(5):346–8, PMID 16739850). That study named BL-11, not BL-13; the two sit two vertebral levels apart on the same line, and the finding is cited for the region rather than as a measurement of this point.
• How thin the tissue actually is over the lung apex. The nearest directly measured figure in this region comes from Jian Jing GB-21, a short distance laterally on the shoulder: ultrasonography in 101 adults measured the depth from skin to the pleural line at 17.4 mm in men and 14.6 mm in women on average, increasing with weight, height and body mass index (Lin S-K et al., J Acupunct Meridian Stud 2018;11(6):355–360, PMID 29936338, DOI 10.1016/j.jams.2018.06.004). That figure is for GB-21, not for Fei Shu, and it is offered as the measured scale of the region rather than as a number for this point — but it makes the essential fact concrete: over the shoulder girdle and upper back, a centimetre and a half can be the whole of the margin.
• Adult back depths, measured as a region. A CT study of 120 patients, grouped by weight, height and sex, measured the distance from the skin of the back to the thoracic pleura at the relevant acupuncture locations and defined that distance as the safe depth. Depths did not differ significantly between the sexes but differed highly significantly between body-size groups (P < 0.01) (Zhong Xi Yi Jie He Za Zhi 1991;11(1):10–13, PMID 2054884), with a companion study doing the same for the chest (Zhonghua Yi Xue Za Zhi (Taipei) 1992;50(5):388–99, PMID 1338010). Neither abstract names BL-13 among the points measured.
• No single agreed safe depth exists for any point. Two systematic reviews of the safe-depth literature — 33 studies in the first, 47 in the second, measured by MRI, CT, ultrasound and cadaveric dissection — both concluded that depths measured for the same point differ greatly between subject groups and measuring methods, and that the definition of "safe depth" has never been standardised (J Altern Complement Med 2011;17(3):199–206, PMID 21417806; Evid Based Complement Alternat Med 2013;2013:740508, PMID 23935678). A textbook depth figure describes an average body, not a constant.
• What lies beneath, in plain terms. At the T3 level the needle passes through skin, subcutaneous tissue, trapezius and rhomboid, then the erector spinae mass beside the vertebra. In front of those lie the third and fourth ribs and, between them, the intercostal space with the parietal pleura and the upper lobe of the lung immediately behind it. There is no bony floor here in the way there is over the scapula or the occiput. That is the whole anatomical reason for the recorded medial angle and shallow depth.

What is documented, and how often

Pneumothorax is the second most frequently reported serious adverse event in acupuncture. A systematic review of the Chinese case-report literature from 1956 to 2010 identified 1,038 adverse-event cases across 167 articles, of which 307 were pneumothorax — behind only fainting. Thirty-five deaths were recorded across the whole series, and the authors attributed the events chiefly to improper technique, concluding that most were avoidable through standardised training (He W et al., J Altern Complement Med 2012;18(10):892–901, PMID 22967282). A companion systematic review of 115 Chinese-language articles reporting 479 adverse events including 14 deaths reached the same conclusion about traumatic complications (Zhang J et al., Bull World Health Organ 2010;88(12):915–921C, PMID 21124716, PMC2995190). The presentation is not always immediate: an emergency-medicine case report describes a healthy 38-year-old woman who developed pleuritic chest pain the day after dry needling of the back, with bedside ultrasound showing absent lung sliding and a lung point on the right (Cureus 2021;13(3):e14207, PMID 33948398, PMC8086747). Fatal cases exist: an autopsy report describes bilateral pneumothoraces following electroacupuncture, the authors noting that electrical pulses and the muscle contraction they cause may draw needles deeper than the depth at which they were inserted (J Forensic Sci 2022;67(1):377–383, PMID 34435369). A pneumothorax after needling over the thorax or upper back may declare itself hours later, with sudden chest pain, breathlessness or a persistent dry cough; it is a medical emergency requiring immediate assessment.

The proportion of the risk

A meta-analysis of prospective clinical studies estimated serious adverse events in acupuncture at approximately 1 per 10,000 patients and around 8 per million treatments, with about half of all recorded events being bleeding, pain or flare at the needle site, placing acupuncture among the safer treatments in medicine (Bäumler P et al., BMJ Open 2021;11:e045961, PMID 34489268, DOI 10.1136/bmjopen-2020-045961). Both facts belong together: the overall rate is low, and the events that do occur concentrate in the small band of points over the lung to which Fei Shu belongs. The bounded oblique depth exists to keep it that way.

Source: Sacred Lotus sources & references (existing needling record); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 267); Chinese Acupuncture & Moxibustion (p. 177); PMID 16739850; PMID 29936338; PMID 26922245 (PMC4769822); PMID 2054884; PMID 1338010; PMID 21417806; PMID 23935678; PMID 22967282; PMID 21124716 (PMC2995190); PMID 33948398 (PMC8086747); PMID 34435369; PMID 34489268 — each verified resolvable and checked for retraction status before citation.

What does the name Fei Shu mean?

Fei Shu means "Lung Shu" — fei, the Lungs, and shu, a transport point. The character shu carries the sense of conveying or transporting, and the Back-Shu points are named for exactly that: the places on the back where each organ's qi is said to be transported to the body surface. Sacred Lotus sources & references translate the name as Lung Shu and classify the point as the Back-Shu of the Lungs. The name is a description of the point's function rather than a metaphor, which sets the twelve Back-Shu points apart from most of the repertoire and makes them among the easiest names in acupuncture to learn.

Is BL-13 the point that "descends rebellious Lung qi"?

Yes — and it is worth saying so explicitly, because the phrase attaches itself to other points that have no channel basis for it. "Descends rebellious Lung qi" is a statement of channel and organ theory: it asserts that a point acts on the Lung organ and on the direction of its qi. Only a point with a channel or classification relationship to the Lung can carry it. The extra point Ding Chuan, beside Da Zhui on the upper back, is the clearest case of the phrase circulating where it does not belong: Ding Chuan is a genuinely useful and heavily used point for wheezing, but it lies on no channel, holds no five-shu, yuan, luo, xi-cleft, back-shu or front-mu classification, and has no channel connection to the Lung organ. Our own record for Ding Chuan previously carried the claim and it has been removed; the action belongs to BL-13 Fei Shu, whose Back-Shu classification is precisely a statement that it reaches the Lung organ. This page is the other half of that correction. What Ding Chuan's sources actually document is the clinical result — wheezing calmed — and that is what its record now says. A reader who arrived searching for "the point that descends rebellious Lung qi" has arrived at the right one.

Is there research on BL-13 Fei Shu?

BL-13 is the most frequently selected point in the published acupuncture literature on asthma, and it is one of the very few points at which a physiological measurement has been taken at the point itself and correlated with organ disease. The honest summary is that the point-specific research is measurement research and point-selection research rather than efficacy research: no adequately powered sham-controlled trial isolates BL-13.

• Blood perfusion measured at BL-13 itself. In a rat model of chronic obstructive pulmonary disease, blood perfusion at the body surface was measured at Feishu BL-13 and compared with control non-acupoints and with Taichong LIV-03, Yanglingquan GB-34 and Zusanli ST-36 through the onset, establishment and recovery of the disease. Perfusion at BL-13 rose as the disease progressed and fell as it recovered, and it correlated more closely with the lung pathology — mean linear intercept, bronchitis score, interleukin-1β and interleukin-6 — than perfusion at any of the comparison points. The authors propose it as a possible early-warning marker (Yang HM et al., J Integr Med 2026;24(2):238–252, PMID 40713362, DOI 10.1016/j.joim.2025.07.003). It is an animal study, but the design is unusual and directly relevant: it tests the classical claim that a Back-Shu point reflects its organ, and it tests it against other points rather than against nothing.
• Skin temperature at BL-13 in human asthma. Sixty-one patients with chronic persistent asthma were divided by lung-function level, and the skin surface temperature was measured at bilateral Feishu BL-13, Geshu BL-17, Pishu BL-20 and Shenshu BL-23. Temperature at all four points was higher in the reduced-lung-function group and was negatively correlated with forced vital capacity, forced expiratory volume in one second, the FEV1/FVC ratio and peak expiratory flow, all expressed as percentages of predicted (Zhongguo Zhen Jiu 2025;45(3):274–279, PMID 40097207). Sixty-one people and an observational design — but again a direct test of the diagnostic half of the Back-Shu idea, in humans, at this point.
• Point-selection analysis, where BL-13 comes first. A data-mining study of 183 controlled clinical trials of acupuncture for asthma found Feishu BL-13 the most frequently prescribed point, ahead of Dingchuan, Dazhui, Shenshu, Pishu and Fengmen, with BL-13 among the central nodes of the point-combination network; cluster analysis recovered the treatment principle of freeing the Lung qi while supporting Spleen and Kidney (Shang PP et al., Complement Med Res 2022;29(2):136–146, PMID 34875661, DOI 10.1159/000521346). This measures what practitioners and trialists have chosen, not whether it worked.
• The largest trial in which the point is a variable. Four hundred and fifty-six patients with asthma were randomised to three different point prescriptions for summer herbal point application over the years 2015 to 2019, one of which used Feishu BL-13, Xinshu BL-15 and Geshu BL-17. Attack frequency and total serum IgE fell in all three groups; two of the three prescriptions outperformed the third, and the authors' conclusion was that which points were chosen, and not how long the plaster was left on, determined the effect (J Tradit Chin Med 2023;43(1):146–153, PMID 36640006, PMC9924751). A large study, and one of the few that varies the point selection deliberately — but it compares prescriptions against each other rather than against a sham.
• Preclinical mechanism work. A rat study applied a mustard-seed-based ointment at Feishu BL-13, Pishu BL-20 and Shenshu BL-23 in an ovalbumin asthma model and traced the anti-inflammatory effect to suppression of autophagy through the AMPK/mTOR pathway, confirmed by blocking AMPK (J Asthma 2026;63(1):15–25, PMID 40920042). A three-point animal protocol, recorded for completeness rather than as evidence about the point in humans.

What is missing should be said plainly: there is no sham-controlled randomised trial of BL-13 alone for asthma, cough or any other of its principal uses. Every clinical study that names it uses it inside a prescription, so the results describe the prescription. The point's standing rests on the classical record, on its overwhelming frequency of selection, and on a small amount of measurement taken at the point itself.

How does BL-13 compare with the points around it?

Feng Men BL-12 lies one level above at T2 and is the exterior point — chosen when a pathogen is arriving — while Fei Shu addresses the Lung organ itself. The two are constantly used together and are the pair most often confused. Jue Yin Shu BL-14 at T4 and Xin Shu BL-15 at T5 continue the line below, for the Pericardium and the Heart. Da Zhu BL-11 sits two levels above at T1, is the Hui-Meeting point of the bones, and is directed at bone and the upper spine rather than at the Lung. Po Hu BL-42 is BL-13's outer companion three cun lateral at the same level, associated with the corporeal soul the Lung is said to house. Gao Huang Shu BL-43 lies just below it on that outer line and is the great point of the upper back for chronic depletion; where BL-13 addresses the Lung, BL-43 addresses depletion in general. Zhong Fu LU-01 on the upper chest is BL-13's Front-Mu counterpart, and Tai Yuan LU-09 at the wrist its distal Yuan-Source partner. And Ding Chuan, the extra point beside Da Zhui, is the symptomatic wheezing point of the same region — genuinely useful, but not a Lung-organ point, which is the distinction set out above. Every point in this band shares the pneumothorax caution recorded under needling.

Source: Deadman & Al-Khafaji, A Manual of Acupuncture (p. 267); Chinese Acupuncture & Moxibustion (p. 177); Sacred Lotus sources & references (BL-13 record; Back-Shu and Front-Mu point sets, the neighbouring points and the Ding Chuan extra-point record queried directly); PMID 40713362; PMID 40097207; PMID 34875661; PMID 36640006 (PMC9924751); PMID 40920042 — each verified resolvable and checked for retraction status before citation; cross-referenced against multiple online sources.