SP-06 (San Yin Jiao) Three Yin Intersection

What does SP-06 San Yin Jiao do?

San Yin Jiao SP-06 is the point where the three yin channels of the leg — Spleen, Liver and Kidney — cross, and that intersection is the whole of its clinical logic. Sacred Lotus sources & references classify it as a Meeting Point of the Spleen, Liver and Kidney channels. One needle therefore reaches the organ that governs blood and the transformation of food, the organ that stores blood and moves qi, and the organ that stores essence and governs reproduction — which is why it became the workhorse point of gynaecology and of the lower abdomen.

• Tonifies the Spleen and Stomach — the Spleen-channel action proper, used for poor appetite, abdominal distension, loose stool and fatigue.
• Resolves dampness — for oedema, heaviness, urinary difficulty and damp accumulation in the lower body.
• Harmonises the Liver and tonifies the Kidneys — the action that follows directly from the crossing, and the reason SP-06 appears in patterns that are not Spleen patterns at all.
• Regulates menstruation and induces labour — recorded together in the standard sources, and the direct reason for the pregnancy contraindication set out below.
• Harmonises the lower jiao — the general regulating action on the lower abdomen and its organs.
• Regulates urination and benefits the genitals — for retention, frequency, enuresis and disorders of the external genitalia.
• Calms the spirit — the basis of its long-standing use for insomnia and restlessness, generally by nourishing blood and yin rather than by sedating.
• Invigorates blood — for stasis in the lower abdomen, painful periods and fixed lower-abdominal pain.
• Activates the channel and alleviates pain — the local action along the inner leg.

Safety reference, stated up front rather than buried: because "induces labour" is one of its documented actions, needling San Yin Jiao SP-06 is contraindicated during pregnancy in the standard reference literature. Its combination with He Gu LI-04 is the classical labour-inducing pair.

Source: Sacred Lotus sources & references (channel, Meeting Point classification and the recorded actions above); Deadman & Al-Khafaji, A Manual of Acupuncture, p. 189; Chinese Acupuncture & Moxibustion, pp. 158–159; cross-referenced against multiple online sources.

What is SP-06 San Yin Jiao used for?

San Yin Jiao SP-06 is used above all for menstrual and reproductive disorders, for the digestion, for urination, and for sleep. The indications recorded in our sources fall into four groups — gynaecological and obstetric, digestive, urogenital, and a smaller set covering the leg, the head and the spirit. These describe traditional use, not proven treatment.

• Dysmenorrhoea (painful periods)
• Irregular menstruation
• Uterine bleeding
• Morbid leukorrhoea (abnormal vaginal discharge)
• Prolapse of the uterus
• Infertility
• Delayed labour
• Abdominal pain and abdominal distension
• Borborygmus (rumbling)
• Diarrhoea
• Nocturnal emission
• Impotence
• Enuresis (bedwetting)
• Dysuria (difficult or painful urination)
• Oedema
• Hernia
• Pain in the external genitalia
• Muscular atrophy, motor impairment, paralysis and pain of the lower limb
• Headache
• Dizziness and vertigo
• Insomnia

Source: Sacred Lotus sources & references (existing indication record); Chinese Acupuncture & Moxibustion, pp. 158–159; Deadman & Al-Khafaji, A Manual of Acupuncture, p. 189.

How is SP-06 San Yin Jiao used in practice?

San Yin Jiao lies on the inner side of the lower leg, three cun above the tip of the inner ankle bone, in the hollow just behind the back edge of the shin bone. It is chosen whenever the problem sits in the lower abdomen or involves blood, and because three channels cross there, it is one of the very few points a practitioner can reach for without first deciding which of the three organs is at fault.

• With SP-10 Xue Hai — the Spleen channel's own blood pairing, used for irregular and painful menstruation; SP-10 moves and cools blood while SP-06 regulates the three yin organs behind it.
• With REN-04 Guan Yuan and REN-06 Qi Hai — the standard lower-abdominal combination for deficiency of the lower jiao, infertility, and menstrual disorders of a depleted type.
• With HT-07 Shen Men — the most-used pairing of all for insomnia, joining the Heart's Source point to the meeting point of the three leg yin channels. This is the combination on which the most informative point-specific sleep research has been done; see the research section below.
• With SP-09 Yin Ling Quan — for damp accumulation, urinary difficulty and oedema, working the Spleen channel at two levels of the same leg.
• With LIV-03 Tai Chong and BL-17 Ge Shu — for blood stasis patterns; BL-17 is the Hui-Meeting point of blood and adds a back-shu-level reach that SP-06 alone does not have.
• With BL-20 Pi Shu and BL-23 Shen Shu — the back-shu points of the two organs SP-06 most often supports, used for chronic deficiency.
• With LI-04 He Gu — the classical labour-inducing combination, and for that reason a pairing the reference literature treats as contraindicated at any other stage of pregnancy. It is recorded for delayed labour and retained placenta only.

Among its category peers, SP-06 is the best known of the points where several channels meet, and the only crossing point most practitioners use daily. SP-12 Chong Men, held here, is another meeting point of the Spleen and Liver channels, but with the Yin Linking vessel rather than the Kidney, and it is a far more specialised choice.

Source: Sacred Lotus sources & references (location and point categories); Deadman & Al-Khafaji, A Manual of Acupuncture, p. 189; Chinese Acupuncture & Moxibustion, pp. 158–159; cross-referenced against multiple online sources.

Where is SP-06 located?

• A Manual of Acupuncture (p. 189): On the medial side of the lower leg, 3 cun superior to the prominence of the medial malleolus, in a depression close to the medial crest of the tibia.
• Chinese Acupuncture and Moxibustion (p. 158-159): 3 cun directly above the tip of the medial malleolus, posterior to the medial border of the tibia.

How is SP-06 San Yin Jiao needled, and when is it contraindicated?

Reference fact, stated plainly and first: the standard acupuncture literature records that needling San Yin Jiao SP-06 is CONTRAINDICATED IN PREGNANCY. The reason is explicit in the point's own recorded actions — "regulates menstruation and induces labour" — and SP-06 together with He Gu LI-04 is the classical labour-inducing combination, the pair the tradition names when a birth is to be brought on and therefore forbids while a pregnancy is to be maintained. Everything below records what the textbooks document; it is not instruction, and this page does not teach technique.

The angle and depth the texts record

• Chinese Acupuncture & Moxibustion records perpendicular insertion of 0.5–1.0 cun, with moxibustion noted as applicable, and states the pregnancy contraindication explicitly.
• Deadman & Al-Khafaji record a comparable perpendicular range at the same site, close to the rear edge of the tibia, and note the same contraindication.
• Moxibustion: documented as applicable — and, notably, moxibustion at SP-06 rather than needling is what several of the labour studies below actually used.

Anatomy documented at the point

SP-06 lies just behind the shin bone in the muscle of the inner calf, in a region that carries the great saphenous vein superficially and the posterior tibial vessels and tibial nerve more deeply. The standard references note that bruising is the ordinarily documented occurrence here and that the point is often markedly tender, particularly in menstrual and urinary disorders — a tenderness the classical literature reads diagnostically.

Why this contraindication is treated as a real one

It is not only a textual tradition. An experiment in late-pregnancy rats studied electroacupuncture at LI-04 and SP-06 explicitly as "a traditional acupuncture formula that induces labor" and reported increased amplitude, frequency and duration of uterine contraction waves (PMID 21227039). Whatever one concludes about clinical efficacy, that is direct evidence the pairing acts on uterine contractility, which is the material fact behind the prohibition. In general proportion, a meta-analysis of prospective clinical studies estimated serious acupuncture-related adverse events at roughly 1 per 10,000 patients (PMID 34489268). Acupuncture is performed by qualified practitioners; this record documents the literature.

Source: Chinese Acupuncture & Moxibustion, pp. 158–159 (including the recorded pregnancy contraindication); Deadman & Al-Khafaji, A Manual of Acupuncture, p. 189; Sacred Lotus sources & references (existing needling record, which also carries the pregnancy contraindication); PubMed PMID 21227039, 34489268, each checked as active and not retracted.

What does the name San Yin Jiao mean?

San Yin Jiao means "Three Yin Intersection" — san yin, the three yin, and jiao, to cross or intersect. The name is a literal statement of anatomy in channel terms: the Spleen, Liver and Kidney channels of the leg all pass through this one spot on the inner lower leg, three cun above the inner ankle bone. It is one of the clearest cases in the point nomenclature of a name that is also a complete explanation — everything the point is used for follows from the crossing it is named after.

Why does the Meeting Point classification matter at SP-06?

A Meeting Point belongs to more than one channel, and treating it treats all of them. Because the three channels crossing here are precisely the three yin organs of the lower body — Spleen governing blood and transformation, Liver storing blood and coursing qi, Kidney storing essence and governing reproduction — SP-06 covers between them almost the whole traditional territory of menstruation, fertility, urination and the lower abdomen. That breadth is also its limitation: it is a general point, not a precise one, and where a single organ is clearly at fault the tradition often reaches for that channel's own points instead.

Is there research on SP-06 San Yin Jiao?

SP-06 has an unusually large point-specific literature by acupuncture standards, because it is one of the few points regularly studied alone, often as acupressure, which makes single-point trials easy to run. The quality of that literature is another matter — many of the trials are small, use a light-touch control rather than a credible sham, and come from a narrow set of research groups.

• Primary dysmenorrhoea. A systematic review with meta-analysis of SP-06 acupressure pooled six studies and 461 participants and reported a significant reduction in pain immediately after intervention (effect size −0.72) persisting to three hours (−0.98), while stating plainly that the included studies were generally of low quality with a high risk of bias (PMID 27863617). An earlier meta-analysis of acupuncture or acupressure at SP-06 for the same condition reached a similar conclusion (PMID 23533489), and individual trials of SP-06 acupressure report comparable short-term effects (PMID 20347835). Set against the wider field, a Bayesian network meta-analysis of 33 trials of non-pharmacological treatments for primary dysmenorrhoea found acupuncture among the interventions probably reducing pain intensity, while calling for larger and better-designed research (PMID 38242565).
• Labour pain and labour duration. This is the point's most-tested traditional claim. A randomised trial of 75 women in labour compared 30 minutes of SP-06 acupressure against touch at the same point and reported lower pain scores at every measured time and a shorter total labour (PMID 15673989). A systematic review and meta-analysis of SP-06 and LI-04 acupressure reported less pain immediately after SP-06 intervention (standardised mean difference −0.56, 95% CI −0.77 to −0.36) and shorter labour, again against touch controls in small studies (PMID 29344038). A controlled study of moxibustion rather than needling at SP-06 in first-time mothers reported effects on the first stage of labour and on contraction pain (PMID 21660681).
• What the pooled evidence actually shows. The Cochrane review of acupuncture or acupressure for pain management in labour included 28 trials and 3960 women and concluded that no study was at low risk of bias on all domains; acupuncture may increase satisfaction with pain relief and probably reduces use of pharmacological analgesia against sham, but for most comparisons the certainty of evidence was low or very low (PMID 32032444). The companion Cochrane review on induction of labour, 22 trials and 3456 women, found no clear benefit in reducing caesarean section (PMID 29036756). The fair summary is that SP-06 stimulation plausibly helps with pain in the short term, that the labour-shortening findings come from small trials with weak controls, and that the pooled evidence does not establish that it induces labour.
• Insomnia. A randomised trial in 90 people with insomnia compared electroacupuncture at HT-07 alone, SP-06 alone, and the two combined; all three improved sleep measures, the combination outperformed HT-07 alone, and SP-06 alone also outperformed HT-07 alone on several measures, the authors concluding that SP-06 was the larger contributor to the pairing (PMID 35880281). This is reported the same way on the HT-07 record in this library: the best point-specific human evidence available does not support HT-07 being the most active component of its own most famous combination. Remaining sleep work is animal-model mechanism research on SP-06 with HT-07 or DU-20 (for example PMID 30945498, PMID 36636219), which does not transfer directly to clinical practice.

Taken together, SP-06 is better studied as an isolated point than almost any other, and the results are consistently modest, consistently short-term, and consistently limited by trial quality. That is worth saying plainly rather than presenting the volume of publication as though it were weight of evidence.

How does San Yin Jiao differ from the points near it?

SP-09 Yin Ling Quan, the He-Sea and Water point of the same channel, lies higher on the same inner leg and is the more specifically damp-resolving and urinary point; SP-06 is the broader gynaecological one. SP-08 Di Ji, the Xi-Cleft point of the Spleen, sits between them and is the acute-pain choice for severe dysmenorrhoea, where SP-06 is the regulating one. KI-03 Tai Xi and LIV-03 Tai Chong are the Source points of two of the three channels crossing at SP-06 and are used when one of those organs is clearly the problem rather than all three. On the opposite side of the same leg, KI-07 Fu Liu shares the sweating and oedema territory from the Kidney channel. All are held in this library.

Source: Sacred Lotus sources & references (name, categories and cross-referenced point records); Deadman & Al-Khafaji, A Manual of Acupuncture, p. 189; Chinese Acupuncture & Moxibustion, pp. 158–159; PubMed PMID 27863617, 23533489, 20347835, 38242565, 15673989, 29344038, 21660681, 32032444, 29036756, 35880281, 30945498, 36636219, each checked as active and not retracted; cross-referenced against multiple online sources.