BL-24 (Qi Hai Shu) Sea of Qi Shu

What does BL-24 Qi Hai Shu do?

Qi Hai Shu BL-24 is the point on the lower back named for the "Sea of Qi" — the back counterpart of the abdominal point Qi Hai REN-06 — and its recorded work is to strengthen the lumbar region and legs and to regulate the lower burner. Sacred Lotus sources & references record both actions directly and carry the classification Sea of Qi Shu. Those two actions divide the point neatly in half: one half is structural and local, the low back and what it supports; the other half is internal, the organs and functions of the lower abdomen.

• Strengthens the lumbar region and legs — the first recorded action and the busier one in practice. BL-24 sits one and a half cun from the midline at the third lumbar vertebra, in the thickest paraspinal muscle territory on the trunk, at the level where the lumbar spine takes most of its load. Low back pain is the indication our own record lists first, and this is the action behind it. The "and legs" half matters too: the tradition treats weakness, aching and heaviness of the legs as an extension of weakness in the low back rather than as a separate problem.
• Regulates the lower burner — the second recorded action, and the one that explains why a back point carries menstrual indications. The lower burner (xia jiao) is the tradition's name for the lowest of the three divisions of the trunk, containing the bladder, the intestines below the navel and the reproductive organs. A point named for the Sea of Qi and sited over that region is understood to reach it, which is the classical reasoning behind the irregular menstruation and painful periods our own indication record carries here.
• Tonifies and gathers qi — the sense carried in the name itself rather than a separately listed action. A "sea" in this vocabulary is a place where something collects and from which it can be drawn; the abdominal Qi Hai REN-06 is one of the most used tonifying points in the repertoire, and BL-24 inherits that idea from the back. It is used for fatigue, weakness and a general lack of vigour in the same way its abdominal namesake is, and this is the honest reason its indication list stretches to asthma — breathlessness being read as qi failing to hold.

Is BL-24 a Back-Shu point?

It sits in a Back-Shu position but it is not one of the twelve organ Back-Shu points, and this library's own data say so. Queried directly, BL-24 carries the classification Sea of Qi Shu and no organ Back-Shu classification at all. The complete set of points holding one was queried in the same pass and returns exactly twelve — BL-13, BL-14, BL-15, BL-18, BL-19, BL-20, BL-21, BL-22, BL-23, BL-25, BL-27 and BL-28, for the Lungs, Pericardium, Heart, Liver, Gallbladder, Spleen, Stomach, San Jiao, Kidneys, Large Intestine, Small Intestine and Bladder respectively. BL-24 is not among them. Our BL-23 Shen Shu and BL-25 Da Chang Shu records carry that twelve-point list in full and are the place to read it; reproducing it here would imply a membership this point does not have.

What BL-24 is, is one of a small group of points on the inner Bladder line named after points on the front of the body rather than after organs. Its immediate neighbour below, Guan Yuan Shu BL-26 at L5, is the same kind of thing — queried directly, it carries the classification Gate of Origin Shu, naming it for Guan Yuan REN-04 on the abdomen, exactly as BL-24 is named for Qi Hai REN-06. Both of those abdominal points are held here and both were queried. So the run down the lower back alternates: BL-23 (Kidneys, a true Back-Shu), BL-24 (named for the Sea of Qi), BL-25 (Large Intestine, a true Back-Shu), BL-26 (named for the Gate of Origin). Our BL-25 record notes that gap in the numbering from its own side. Knowing which is which stops a reader looking for an organ behind BL-24 that was never claimed.

Source: Sacred Lotus sources & references (existing action record, reformatted here as a list; channel, the Sea of Qi Shu classification, the absence of any organ Back-Shu classification, the full twelve-point organ Back-Shu set, and the BL-26, REN-04 and REN-06 records all queried directly); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 286); Chinese Acupuncture & Moxibustion (p. 180); cross-referenced against multiple online sources.

What is BL-24 Qi Hai Shu used for?

Qi Hai Shu BL-24 is used above all for low back pain — it is one of the standard points of the lumbar region and appears in most published lumbar protocols — and after that for irregular and painful menstruation, for weakness of the legs, and for the breathlessness the tradition attributes to weak qi. The indications carried in Sacred Lotus sources & references are low back pain, irregular menstruation, dysmenorrhoea and asthma; the standard reference literature sets them out more fully below. These describe traditional use, not proven treatment. This is a lumbar point and the depth recorded for it is bounded, for the reasons set out under needling.

• Low back pain — the defining indication
• Lumbar stiffness and aching, worse for standing or sitting long
• Weakness of the low back and legs
• Pain radiating from the low back into the buttock and leg
• Lumbar disc herniation and the sciatic pain attributed to it
• Irregular menstruation
• Painful periods (dysmenorrhoea)
• Uterine bleeding and menstrual flooding
• Asthma and difficult breathing
• Fatigue, lassitude and general weakness
• Haemorrhoids
• Constipation and difficult defecation
• Abdominal distension and borborygmus
• Numbness and heaviness of the legs

Why asthma appears on a lumbar point's list, and how to read it honestly. Our own record carries asthma at BL-24, which surprises readers, and the explanation is in the name rather than in the anatomy. The Sea of Qi is where qi is said to gather; breathlessness in the classical account is often read not as a disorder of the lungs but as a failure to hold qi at the root, which is placed low in the body. Points named for the Sea of Qi therefore acquire a breathing indication by way of that reasoning. It is a classical inference, it is recorded because our sources record it, and it is not a claim that this point treats asthma. Where the reader wants the point that genuinely carries the Lung in channel terms, that is Fei Shu BL-13, the Back-Shu point of the Lungs, held here — and our BL-13 record sets out exactly why.

Source: Sacred Lotus sources & references (existing indication record, reformatted here as a list from a bare comma-run; the BL-13 record queried directly); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 286); Chinese Acupuncture & Moxibustion (p. 180); cross-referenced against multiple online sources.

Where is BL-24 Qi Hai Shu, and how is it used in practice?

Qi Hai Shu lies on the lower back, one and a half cun either side of the midline, level with the lower edge of the third lumbar vertebra. In our own words: it is a bilateral point about two fingers' width out from the spine, in the thick muscle band that runs alongside it, roughly midway between the level of the lowest ribs and the level of the top of the hip bones. Sacred Lotus sources & references hold two location records for it and they agree exactly, both giving one and a half cun lateral to the midline at the lower border of the L3 spinous process. There is no discrepancy between them to flag.

One feature of the location is worth knowing because it makes the point harder to find than its neighbours. Almost every point on the inner Bladder line is located by reference to a point on the midline directly beside it — queried directly, our own records place BL-22 beside Xuan Shu DU-05 at L1, BL-23 beside Ming Men DU-04 at L2, and BL-25 beside Yao Yang Guan DU-03 at L4. BL-24 has no such landmark: this library holds no Governing Vessel point at the L3 level, which is why our own location record for it names the Governing Vessel generically rather than a point on it. Nor is there a companion on the outer Bladder line — Zhi Shi BL-52 sits three cun out at L2 and Bao Huang BL-53 at the second sacral foramen, with nothing between them at L3. BL-24 is therefore counted down from BL-23, or found from below: the line joining the highest points of the two hip crests crosses close to the L4 spinous process, and L3 is one vertebra above it.

Which points is BL-24 combined with?

• With Shen Shu BL-23 above and Da Chang Shu BL-25 below — its immediate neighbours on the same line, both held here and both true organ Back-Shu points. In practice the three are needled together as a run far more often than any of them is used alone, and BL-24 is the middle of that run. BL-23 is the choice when the low back is weak, chronic and cold; BL-25 when the pain is at the L4 level where lumbar strain and disc trouble concentrate; BL-24 sits between the two arguments.
• With Guan Yuan Shu BL-26 — at L5, the other point of this stretch named for an abdominal point rather than an organ. BL-24 and BL-26 are counterparts in kind as well as in position.
• With its own namesake, Qi Hai REN-06 — on the abdomen, one and a half cun below the navel, held here. Pairing a point on the back with the point on the front it is named for is the standard front-and-back structure, and at BL-24 it is built into the name. Guan Yuan REN-04 below it is the same kind of partner for BL-26.
• With Ming Men DU-04 and Yao Yang Guan DU-03 — the two Governing Vessel points on the midline that bracket BL-24 from above and below, at L2 and L4, both held here. Where the whole lower back is involved, a midline point plus the bilateral inner-line points is the usual arrangement.
• With Wei Zhong BL-40 — behind the knee, held here as a Gao Wu Command Point and a Ma Dan-yang Heavenly Star Point. The old rule that "for disorders of the low back seek Wei Zhong" makes BL-40 the standard distal partner for any lumbar point. There is a measured observation linking the two, described under research.
• With the extra points Yao Yan and Shi Qi Zhui Xia and with the Hua Tuo Jia Ji points — all held here. Yao Yan sits further out in the visible hollows of the lower back, Shi Qi Zhui Xia on the midline below L5, and the Jiaji points run in a paravertebral line half a cun from the midline; a lumbar treatment commonly combines one or more of them with the inner-line Bladder points.
• For menstrual complaints — with San Yin Jiao SP-06, Guan Yuan REN-04 and Zhong Ji REN-03. All are held here; SP-06 is the Meeting Point of the Spleen, Liver and Kidney channels and the principal distal point of gynaecological practice. BL-24 contributes the back of the lower burner where those contribute the front and the leg.
• In the published lumbar protocols. A randomised trial in 85 patients with lumbar disc herniation compared electroacupuncture at the Jiaji points with Shen Shu BL-23, Qihaishu BL-24, Guan Yuan Shu BL-26, Da Chang Shu BL-25 and Yang Ling Quan GB-34 against oral medication, reporting a higher effective rate in the electroacupuncture group (84.4 versus 65.0 per cent) and greater reduction in symptom scores (Zhongguo Zhen Jiu 2011;31(11):987–990, PMID 22136021). Every point in that prescription is held in this library and each was queried. It is a small, unblinded, single-centre trial of a six-point protocol, and nothing in the result is attributable to BL-24 alone.

Source: Sacred Lotus sources & references (both location records; the BL-22, BL-23, BL-25, BL-26, BL-40, BL-52, BL-53, DU-03, DU-04, DU-05, REN-03, REN-04, REN-06, SP-06, GB-34, Yao Yan, Shi Qi Zhui Xia and Hua Tuo Jia Ji records queried directly, together with the absence of any Governing Vessel point at the L3 level); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 286); Chinese Acupuncture & Moxibustion (p. 180); PMID 22136021 — verified resolvable and checked for retraction status before citation; cross-referenced against multiple online sources.

Where is BL-24 located?

• A Manual of Acupuncture (p. 286): 1.5 cun lateral to the lower border of the spinous process of the third lumbar vertebra (L3).
• Chinese Acupuncture and Moxibustion (p. 180): 1.5 cun lateral to the Governor Vessel (DU), at the level of the lower border of the spinous process of the third lumbar vertebra.

How is BL-24 Qi Hai Shu needled, and what lies beneath it?

Stated plainly and with the level specified, because at this point the level is the whole answer: BL-24 sits at the third lumbar vertebra, one and a half cun from the midline. The kidneys are retroperitoneal — behind the abdominal cavity, in front of the lumbar muscles — spanning roughly the twelfth thoracic to the third lumbar vertebral levels. BL-24 is therefore at the lower edge of the renal span: the standard kidney-region framing applies here with less force than at Shen Shu BL-23 at L2, and with more force than at Da Chang Shu BL-25 at L4, which our record for that point correctly places below the usual span altogether. Everything below is recorded as neutral reference data describing what the textbooks and the published imaging 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 perpendicular insertion of 0.8 to 1.2 inches, with moxibustion applicable. That is a comparatively generous figure by the standards of this library, and the reason is the tissue rather than the absence of anything below: the lumbar paraspinal muscle mass is the thickest on the trunk.
• Deadman & Al-Khafaji (p. 286) and Chinese Acupuncture & Moxibustion (p. 180) record a comparable bounded perpendicular range with oblique options directed toward the spine.
• For comparison within our own holdings. Queried directly, our thoracic Back-Shu points such as Fei Shu BL-13 carry markedly tighter figures with an explicit oblique direction, because the lung lies beneath them. The lumbar points carry deeper figures because muscle does. Depth figures in this literature track the structure underneath, not the size of the region.
• Moxibustion is recorded as applicable here and is common at the lumbar points, the low back being one of the regions where warmth is most used.

What actually lies beneath

• The tissue in order. At L3, one and a half cun from the midline, a perpendicular needle passes through skin and the thoracolumbar fascia into the erector spinae muscle mass, and deeper still toward quadratus lumborum and the transverse process region. This is thick, forgiving territory, and it is why the reference depth here is greater than at most points on the body.
• The kidney, and where its lower pole reaches. The renal span of roughly T12 to L3 is an average. The right kidney sits slightly lower than the left because of the liver above it, so the lower pole of the right kidney is the part that reaches furthest down; normal variation extends further still, and a ptotic or congenitally low-lying kidney lower again. The accurate framing at BL-24 is therefore that it lies at the boundary of the kidney region rather than clearly inside or clearly outside it — which is precisely why the depth recorded in the texts is bounded and why direction matters.
• The transverse process of L3 is the longest of the lumbar transverse processes and lies deep to this region; the syndrome named after it is a recognised cause of one-sided low back pain and has its own small acupuncture literature at this level.
• The lumbar nerve roots emerge segmentally beside the vertebrae, and the pain patterns for which this point is used follow them.

The measured evidence — and exactly whose point it measured

• The kidney-region MRI study did not measure BL-24, and we say so rather than borrow it. An MRI study of 61 healthy subjects measured both the "dangerous depth" and the effective safe depth of perpendicular and oblique needling at the acupoints of the kidney region. The points it measured were Wei Shu BL-21, San Jiao Shu BL-22, Shen Shu BL-23, Wei Cang BL-50, Huang Men BL-51 and Zhi Shi BL-52 — not BL-24. Its finding was that dangerous and effective safe depths were significantly greater in overweight subjects than in moderate-weight ones, and greater again than in underweight subjects, in whom the authors concluded that direction and depth must be restricted (Chen GT et al., Zhongguo Zhen Jiu 2022;42(9):1006–1010, PMID 36075596). It is cited here because it is the best-quantified evidence that safe depth in the lumbar region is a function of the individual body rather than a fixed number — and expressly not as a measurement of this point. The six points it did measure all lie at L1, L2 or T12, that is, higher up the same span; none is at L3.
• Two general facts about depth. Two systematic reviews of the safe-depth literature — 33 studies in the first, 47 in the second, by MRI, CT, ultrasound and cadaveric dissection — both concluded that measured depths for the same point vary greatly between subject groups and measuring methods, and that "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). Neither reports a figure for this point.
• Where the serious events of acupuncture actually cluster. Systematic reviews of the Chinese case literature place them over the chest, the abdomen, the neck and the orbit, attributed chiefly to improper technique (He W et al., PMID 22967282; Zhang J et al., Bull World Health Organ 2010;88(12):915–921C, PMID 21124716, PMC2995190). The lumbar region is not among the leading sites; the recorded concern here is specifically about depth and direction over the kidney region rather than about the region as a whole.
• Risk in proportion. A meta-analysis of prospective clinical studies estimated serious adverse events in acupuncture at approximately 1 per 10,000 patients and about 8 per million treatments, with roughly half of all recorded events being bleeding, pain or flare at the needle site (Bäumler P et al., BMJ Open 2021;11:e045961, PMID 34489268). A 2024 review of acupuncture safety reaches the same conclusion (Am J Chin Med 2024;52(6):1555–1587, PMID 39460372).
• Honest limit. We could not locate any published case report naming BL-24 specifically in connection with an organ injury, and none is asserted. What is recorded here instead is what is documented: a bounded depth in the reference texts, the point's position at the lower edge of the renal span, and the named study that measured six neighbouring points but not this one.

Source: Sacred Lotus sources & references (existing needling record and both location records; the BL-13, BL-21, BL-22, BL-23, BL-25, BL-50, BL-51 and BL-52 records queried directly); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 286); Chinese Acupuncture & Moxibustion (p. 180); PMID 36075596 (measuring BL-21, BL-22, BL-23, BL-50, BL-51 and BL-52, not BL-24); PMID 21417806; PMID 23935678; PMID 22967282; PMID 21124716 (PMC2995190); PMID 34489268; PMID 39460372 — each verified resolvable and checked for retraction status before citation.

What does the name Qi Hai Shu mean?

Qi Hai Shu means "Sea of Qi Shu" — qi, the vital energy of the body; hai, a sea; and shu, a transport point. Sacred Lotus sources & references translate it exactly that way. The character shu carries the sense of conveying or transporting, and it names the whole class of points on the inner Bladder line where something is said to be conveyed to the body surface — which is why every one of them, organ point or not, ends in shu. The first two characters are the interesting part: this point is named for Qi Hai REN-06, the "Sea of Qi", one and a half cun below the navel on the front of the body, held here and queried. A "sea" in this vocabulary is a reservoir — a place where something gathers and from which it can be drawn — and REN-06 is among the most used tonifying points in the repertoire. BL-24 is that reservoir approached from the back.

The name is therefore a statement of what the point is not, as much as what it is. Read the run of names down the lower back and the pattern is obvious once seen: Shen Shu — Kidney Shu; Qi Hai Shu — Sea of Qi Shu; Da Chang Shu — Large Intestine Shu; Guan Yuan Shu — Gate of Origin Shu. The first and third name organs. The second and fourth name points on the abdomen. That single observation is the clearest way to see why BL-24 sits in a Back-Shu position without being one of the twelve.

How is BL-24 different from the points around it?

Shen Shu BL-23 lies one level above at L2 and is the Back-Shu point of the Kidneys — the choice when the low back is weak, chronic and cold rather than acutely strained, and the point that genuinely carries the "tonifies the Kidneys" action. Our Yao Yan record had a Kidney-tonifying claim removed during review and names BL-23 as the real carrier; the same applies here, and BL-24 should not be read as a Kidney point merely because it is next door to one. Da Chang Shu BL-25 lies one level below at L4 and is the Back-Shu point of the Large Intestine, and is also the point of this stretch that sits in the middle of the segment where lumbar disc herniation and lumbar strain occur. Guan Yuan Shu BL-26 at L5 is BL-24's counterpart in kind, named for Guan Yuan REN-04. Zhi Shi BL-52, three cun out at L2, is on the outer Bladder line — and, as noted under practice, there is no companion to BL-24 on that outer line at all. The extra point Yao Yan sits further out in the visible hollows of the lower back, and Shi Qi Zhui Xia on the midline below. Ming Men DU-04 at L2 and Yao Yang Guan DU-03 at L4 are the Governing Vessel points that bracket this level from above and below. And Wei Zhong BL-40 behind the knee is BL-24's constant distal partner and the Command point of the back. All of these are held in this library and all were queried.

Is there research on BL-24 Qi Hai Shu?

Yes — and unusually for a point of this kind, some of it genuinely measures something at BL-24 by name rather than merely including it in a prescription. It is a small literature of observational and physiological studies rather than trials, and that is exactly how it is presented here.

• Pressure sensitivity measured at BL-24 by name — with the finding stated in full. Thirty patients with chronic non-specific low back pain of varying duration underwent pressure-sensitive point detection with an algometer over a defined lumbar area, 50 points tested per patient, each scored for pain; the positions were extracted and the proportion of pressure-sensitive points falling within a Euclidean-distance threshold of each traditional acupoint was calculated. Under the study's constraint conditions, the proportions at Qihaishu BL-24 and at Dachangshu BL-25 were positively correlated with duration of illness (r = 0.55, P < 0.01) (Lin D et al., Zhongguo Zhen Jiu 2025;45(12):1743–1750, PMID 41397724). The honest part is the part usually left out: the study's own conclusion favoured the BL-23 with BL-25 combination, on the basis of the factor and silhouette analyses, and BL-24 does not appear in that recommendation. The paper measured this point and reported a real association for it, but did not end by recommending it.
• Skin temperature measured at BL-24 by name. Infrared thermography compared 50 patients with low back pain from lumbar disc herniation against 45 healthy subjects, measuring surface temperature over the lumbosacral region and bilaterally at BL-22, BL-23, BL-24, BL-25, BL-26, BL-27 and BL-28. The left-right temperature differences at Shen Shu BL-23, Qihaishu BL-24, Dachangshu BL-25, Guanyuanshu BL-26 and Xiaochangshu BL-27 were all greater in the patients than in the controls; comparing the affected with the unaffected side within the patient group, however, the elevation reached significance only at BL-23 and BL-25, and the authors concluded that those two showed relative specificity (Yuan X et al., Zhongguo Zhen Jiu 2024;44(4):423–427, PMID 38621730). Two things are worth flagging. First, the result at BL-24 is real but secondary — the specificity finding belongs to its neighbours. Second, that paper describes all seven of those points as "back-shu points"; this library's own data classify only BL-23, BL-25, BL-27 and BL-28 of them as organ Back-Shu points, with BL-22 the San Jiao Shu, and BL-24 and BL-26 named for abdominal points instead. The looser usage is common in the literature and is noted here so that a reader is not misled by it.
• Blood perfusion measured at BL-24 by name — the most unexpected finding. Ten healthy volunteers had the region of Wei Zhong BL-40 behind the knee scraped (gua sha) with a horn plate for five minutes until the skin flushed, and cutaneous blood perfusion was then measured by laser Doppler flowmetry both there and at the region of Qihaishu BL-24 on the same side of the back. Perfusion rose significantly at the scraped site at 0, 15, 60 and 90 minutes, and also rose significantly at the distant BL-24 region at 15, 60 and 90 minutes, with a positive correlation between the two (Xu QY et al., Zhen Ci Yan Jiu 2013;38(1):52–56, PMID 23650801). The limits are severe: ten healthy volunteers, no control site reported in the abstract, no blinding, and a measurement of skin blood flow rather than of any clinical outcome. It is recorded because it is one of very few published measurements made at this point by name, and because it tests, in a small way, exactly the BL-40-to-lower-back relationship the tradition asserts.
• The trials it appears in are protocol trials. The electroacupuncture trial for lumbar disc herniation described under practice (PMID 22136021) uses BL-24 as one of six points, as does most of the lumbar literature. Nothing in those results is attributable to this point alone.
• What is not here. There is no randomised trial of BL-24 on its own, no sham-controlled study of it, and no imaging or cadaveric measurement at it. Its menstrual and respiratory indications in particular rest entirely on the classical record and the reference literature, with no clinical evidence of any kind. That is stated flatly rather than filled in with lumbar-protocol trials.

Source: Sacred Lotus sources & references (name, translation, channel, the Sea of Qi Shu classification, the absence of any organ Back-Shu classification and the full twelve-point organ Back-Shu set queried directly; the BL-22, BL-23, BL-25, BL-26, BL-27, BL-28, BL-40, BL-52, DU-03, DU-04, REN-04, REN-06, Yao Yan and Shi Qi Zhui Xia records queried directly); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 286); Chinese Acupuncture & Moxibustion (p. 180); PMID 41397724; PMID 38621730; PMID 23650801; PMID 22136021 — each verified resolvable and checked for retraction status before citation; cross-referenced against multiple online sources.