KI-10 (Yin Gu) Yin Valley

What does KI-10 Yin Gu do?

Yin Gu KI-10 is the He-Sea and Water point of the Kidney Channel of Foot Shao Yin, at the inner end of the knee crease, and its recorded work is to clear damp-heat out of the lower part of the body while benefiting the Kidneys. Its indication list is dominated by the genito-urinary region — impotence, hernia, uterine bleeding, difficult urination — which is what a He-Sea point on the Kidney channel would be expected to reach.

• Clears damp-heat from the lower jiao — the primary recorded action, and the basis of its use in difficult, painful or scanty urination and in genital swelling, itching or pain.
• Benefits the Kidneys — the channel action, applied to impotence, to uterine bleeding and to the deficiency presentations the Kidney governs.
• Activates the channel and alleviates pain — the local action at the knee, for pain in the knee and in the hollow behind it, and for pain along the inner thigh where the channel runs.
• Regulates the lower abdomen — the extension of the same action upward along the channel, and the recorded basis for its classical listing under hernia and lower abdominal pain.
• Calms the spirit — recorded in the standard literature in connection with mania and disordered mental states, an indication carried at several Kidney-channel points and understood through the Kidney's relationship with the will.

Source: Sacred Lotus sources & references (channel, He-Sea and Water classification, existing action record); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 350); Chinese Acupuncture & Moxibustion (p. 194); cross-referenced against multiple online sources.

What is KI-10 Yin Gu used for?

Yin Gu KI-10 is used mainly for genito-urinary complaints — impotence, hernia, uterine bleeding and difficult urination — and locally for pain at the inner side and back of the knee. The indications below are those carried in Sacred Lotus sources & references together with those set out in the standard reference literature. They describe traditional use, not proven treatment.

• Impotence
• Hernia and lower abdominal pain
• Uterine bleeding
• Difficult, painful or scanty urination
• Genital itching, pain or swelling
• Vaginal discharge
• Pain in the knee and in the popliteal fossa — the hollow behind the knee
• Pain along the inner side of the thigh
• Mental-emotional disturbance and mania

Source: Sacred Lotus sources & references (existing indication record); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 350); Chinese Acupuncture & Moxibustion (p. 194).

Where is KI-10 Yin Gu, and how is it used in practice?

Yin Gu lies at the inner end of the crease behind the knee, in the gap between the two hamstring tendons that stand out there — the semitendinosus and the semimembranosus — level with Wei Zhong BL-40 at the middle of the same crease. Both of our location records say the knee should be slightly bent when the point is found, because that is what makes the two tendons stand up and the gap between them findable.

Which points is KI-10 combined with?

• With Qu Quan LIV-08 — the pairing that defines this point in teaching. LIV-08 is the Liver's He-Sea and Water point and sits at the inner end of the front of the same knee crease; KI-10 is the Kidney's, at the inner end of the back. Two He-Sea and Water points, on the two yin channels most concerned with the genito-urinary region, within a couple of inches of each other. They are combined for genital and urinary complaints and are compared constantly.
• With Zhong Ji REN-03 and San Yin Jiao SP-06 — the standard lower-abdominal pairing for urinary difficulty and for damp-heat in the lower burner, adding the Front-Mu point of the Bladder and the meeting point of the three leg yin channels.
• With Tai Xi KI-03 and Shen Shu BL-23 — where the presentation is read as Kidney deficiency rather than damp-heat, adding the channel's Yuan-Source point and its Back-Shu point.
• With Wei Zhong BL-40 and Wei Yang BL-39 — for knee and popliteal pain, taking the medial, central and lateral points of the same crease together.
• With Xue Hai SP-10 — for uterine bleeding, adding the point whose name is "Sea of Blood"; the two also turn out to be neighbours in the sensitisation data described below.
• Method — Sacred Lotus sources & references record moxibustion as applicable at this point.

Where does KI-10 sit among its category peers?

Every channel has a He-Sea point, and on the yin channels the He-Sea point is always the Water point. Sacred Lotus sources & references hold the yin-channel set complete, and reading it together is the quickest way to see what KI-10 is: LU-05 Chi Ze (Lung, and the Lung's sedation point), HT-03 Shao Hai (Heart), P-03 Qu Ze (Pericardium), SP-09 Yin Ling Quan (Spleen, the great damp-draining point), LIV-08 Qu Quan (Liver, and the Liver's tonification point) and KI-10 Yin Gu (Kidney). Within its own channel KI-10 completes the five-shu series: KI-01 Yong Quan (Jing-Well, Wood), KI-02 Ran Gu (Ying-Spring, Fire), KI-03 Tai Xi (Shu-Stream, Earth, and the Yuan-Source point), KI-07 Fu Liu (Jing-River, Metal) and KI-10 Yin Gu (He-Sea, Water).

Source: Sacred Lotus sources & references (both location records, five-shu and element classifications, and the complete Kidney five-shu series together with the LU-05, HT-03, P-03, SP-09, LIV-08, BL-39, BL-40, BL-23, SP-06, SP-10 and REN-03 records queried directly in the live point records); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 350); Chinese Acupuncture & Moxibustion (p. 194); cross-referenced against multiple online sources.

Where is KI-10 located?

• A Manual of Acupuncture (p. 350): At the medial end of the popliteal crease, between the semitendinosus and semimembranosus tendons. Locate and needle with the knee slightly flexed.
• Chinese Acupuncture and Moxibustion (p. 194): When the knee is flexed, the point is on the medial side of the popliteal fossa, between the tendons of m. semitendinosus and semimembranosus, at the level with Weizhong (BL-40).

How is KI-10 Yin Gu needled in the textbooks?

Reference record only — this documents what the standard texts state, not instruction for a reader. Sacred Lotus sources & references record perpendicular insertion of 0.8 to 1.0 inch at KI-10, with moxibustion noted as applicable. Deadman & Al-Khafaji record a comparable perpendicular range and note that the point is both located and needled with the knee slightly flexed.

• Angle documented: perpendicular.
• Depth documented: approximately 0.8–1.0 cun — deeper than the ankle points of the same channel, because there is more tissue at the knee.
• Position documented: knee slightly flexed, which opens the interval between the two tendons.
• Moxibustion: documented as applicable.

What lies beneath the point

This is a low-hazard point, and it is worth saying so directly rather than attaching a generic warning. KI-10 lies in the gap between the semitendinosus and semimembranosus tendons at the inner end of the knee crease — that is, at the medial corner of the popliteal fossa rather than in the middle of it. There is no lung, no body cavity and no viscus anywhere near it. The structures that matter are the popliteal vessels and the tibial nerve, which run through the centre of the fossa, closer to Wei Zhong BL-40 than to KI-10; the standard references attach no special prohibition to this point, and the tendons on either side are what keep the needle path away from the midline of the hollow. A comparative dissection study that marked and dissected the Kidney-channel points in animals described the needle path at Yin Gu as passing through skin, superficial and deep fascia to the gracilis aponeurosis, adductor magnus and the medial head of gastrocnemius (Zhen Ci Yan Jiu 2020;45(11):929–35, PMID 33269839).

Location is the honest caveat at this point, not danger. That same study graded how reliably each Kidney point could be identified from surface landmarks and electrical measurement, and Yin Gu KI-10 came out as the least reliable of the six tested — a low-reliability point, where KI-03, KI-05, KI-07 and KI-09 at the ankle were graded high. That finding is about animal work and should not be over-read, but it matches what practitioners report: the inner end of the knee crease is a softer, less landmarked target than the inner ankle, which is exactly why both our location records specify flexing the knee first.

No pregnancy contraindication is recorded for KI-10 in our sources or in the standard reference literature; on the same leg that caution attaches to SP-06 San Yin Jiao. Standard clean-needle practice applies. For context rather than alarm: a meta-analysis of prospective clinical studies estimated serious adverse events from acupuncture at approximately 1 per 10,000 patients and around 8 per million treatments, and concluded that acupuncture is among the safer treatments in medicine (Bäumler P et al., BMJ Open 2021;11:e045961, PMID 34489268). Those events cluster at a small number of anatomically exposed points, and KI-10 is not among them.

Source: Sacred Lotus sources & references (existing needling record, both location records); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 350); Chinese Acupuncture & Moxibustion (p. 194); PMID 33269839; PMID 34489268 — each verified resolvable and checked for retraction status before citation.

What does the name Yin Gu mean?

Yin Gu means "Yin Valley" — yin, the shaded, inner, lower aspect, and gu, a valley. Both halves are literally descriptive. The point is on the yin — the inner — side of the leg, on a yin channel, at the inner end of the knee; and it sits in a valley, the trough between the two hamstring tendons that stand up when the knee is bent. The valley image also belongs to the five-shu water scheme, in which channel qi rises as a well at the toe and grows as it flows inward. But note that at KI-10 the water has passed the valley stage: this is the He-Sea point, where the classics say the qi finally enters the deep like a river reaching the sea. The name describes the terrain, not the stage.

Why is KI-10 called the horary point of the Kidney channel?

Because it is the Water point of a Water channel — the one point on the Kidney channel whose element is the channel's own element. Sacred Lotus sources & references record KI-10 as the He-Sea and Water point, and on yin channels the five-shu run Wood – Fire – Earth – Metal – Water from the toe upward, so the He-Sea point of a yin channel is always its Water point. The Kidney is the yin Water channel. Water on Water is therefore what the tradition calls the horary point.

The term comes from the classical clock. Each of the twelve channels is assigned a two-hour period of the day at which its qi is said to be at its height — for the Kidney, the late afternoon — and the horary point is the point at which channel and element coincide. In five-element styles of practice it is used at that hour to reinforce the channel most directly, and more generally it is understood as the point that expresses the channel's own nature without borrowing from another phase.

It follows that KI-10 is neither the tonification nor the sedation point. Under the mother-child rule you supplement through the mother and drain through the child, and neither can be an element identical to the channel's own. On the Kidney channel:

• Tonification (mother) point — KI-07 Fu Liu, the Jing-River and Metal point. Metal produces Water.
• Sedation (child) point — KI-01 Yong Quan, the Jing-Well and Wood point. Water produces Wood.
• Horary point — KI-10 Yin Gu, the He-Sea and Water point. Water on Water, neither mother nor child.

The pattern repeats on every channel, and the other horary points held in this library make it plain. On the yin channels, where the elements run Wood – Fire – Earth – Metal – Water from the extremity inward: HT-08 Shao Fu is Fire on the Heart's Fire channel and P-08 Lao Gong Fire on the Pericardium's, both at the Ying-Spring position; SP-03 Tai Bai is Earth on the Spleen's Earth channel at the Shu-Stream position; LU-08 Jing Qu is Metal on the Lung's Metal channel at the Jing-River position; and KI-10 is Water on Water at the He-Sea position. On the yang channels, where the elements run Metal – Water – Wood – Fire – Earth: LI-01 Shang Yang is Metal on the Large Intestine's Metal channel, BL-66 Tong Gu Water on the Bladder's Water channel, GB-41 Zu Lin Qi Wood on the Gall Bladder's Wood channel, SI-05 Yang Gu and SJ-06 Zhi Gou Fire on the two Fire channels, and ST-36 Zu San Li Earth on the Stomach's Earth channel. The horary point therefore sits at a different five-shu position on almost every channel — which is why it has to be worked out from the elements rather than memorised as a position.

How does KI-10 compare with LIV-08 Qu Quan?

This is the comparison worth learning, because the two points are structurally identical and functionally different. Both are the He-Sea and Water point of a yin leg channel; both sit at the inner end of the knee; and the two are within a couple of inches of one another. What separates them:

• Position. Qu Quan LIV-08 is at the medial end of the crease on the front of the bent knee, above the end of the crease, level with the inner edge of the kneecap area. Yin Gu KI-10 is at the medial end of the crease behind the knee, between the two hamstring tendons.
• Five-element role. The Liver is a Wood channel, and Water is the mother of Wood — so LIV-08, a Water point on a Wood channel, is the Liver's tonification point. The Kidney is a Water channel — so KI-10, a Water point on a Water channel, is the Kidney's horary point and is neither mother nor child. Identical five-shu position, identical element, entirely different office.
• Emphasis. LIV-08 is reached for when Liver blood and Liver yin are judged depleted; KI-10 is reached for when damp-heat has settled in the lower burner. Their indication lists overlap most in the genito-urinary region, which is where they are combined.

Is there research on KI-10 Yin Gu?

There is no clinical trial that isolates KI-10, and this record does not pretend otherwise. What does exist is one large and genuinely relevant observational finding about the point's location, and one anatomical study.

• Point sensitisation at the knee — the one substantial finding. A study of 916 patients with knee osteoarthritis palpated the knee for tender points and measured both their distance from the nearest classical point and their pressure-pain threshold. A total of 3,618 tender points were mapped, of which 3,338 met the criterion for sensitisation; they fell on average 1.26 cun from the nearest classical point, and 48.7 per cent of them clustered around three points — Yin Gu KI-10, Qu Quan LIV-08 and Xue Hai SP-10, all on the medial side of the knee. The number and degree of sensitisation correlated with the patients' pain scores (Zhongguo Zhen Jiu 2020;40(11):1198–1201, PMID 33788488). This is an observational mapping study rather than a treatment trial, and it says nothing about whether needling KI-10 helps. What it does say is that in a large sample of a common knee condition, the tender territory of the medial knee is centred on KI-10 and its two neighbours — which is a measured finding about where this point sits, and it is notable that the two points it clusters with are the ones the tradition already pairs it with.
• Anatomy and location reliability. The comparative dissection and skin-potential study described under needling located, dissected and graded KI-10 by name (PMID 33269839), grading it the least reliably identifiable of the six Kidney points it examined.

What is missing should be said plainly: none of KI-10's traditional indications — impotence, hernia, uterine bleeding, urinary difficulty — has been tested at this point in a randomised trial we have been able to locate. Where KI-10 appears in the modern trial literature it is one point inside a multi-point protocol, and this site does not present such trials as though they were about this point.

How does KI-10 compare with the points around it?

Wei Zhong BL-40 lies at the middle of the same crease and is the He-Sea point of the Bladder, one of the four Command points, and the great point for the lower back — a far busier point than KI-10, and the one whose depth caution matters, because the popliteal vessels and tibial nerve pass beneath it. Wei Yang BL-39 is at the lateral end of the same crease and is the Lower He-Sea point of the Sanjiao, with its own water and urinary indications. Qu Quan LIV-08 is the structural twin discussed above. Yin Ling Quan SP-09 lies a little below on the inner shin and is the Spleen's He-Sea and Water point, the principal point for draining damp — the third member of the medial-knee water group, and the one usually chosen ahead of KI-10 when the problem is damp rather than Kidney. Zhu Bin KI-09 is the next Kidney point down, on the line from KI-03 up to KI-10.

Source: Sacred Lotus sources & references (name, translation, element and five-shu classifications, the complete Kidney five-shu series and the horary-point set, and the LIV-08, SP-09, BL-39, BL-40, KI-09, SP-10, HT-08, P-08, GB-41, SI-05, LU-08, SP-03 and ST-36 records queried directly in the live point records); Deadman & Al-Khafaji, A Manual of Acupuncture (p. 350); Chinese Acupuncture & Moxibustion (p. 194); Nan Jing (Classic of Difficulties), on the five-shu indications; PMID 33788488; PMID 33269839 — each verified resolvable and checked for retraction status before citation; cross-referenced against multiple online sources.