Acupuncture and Point Location
Location is proportional, not absolute
Use anatomical landmarks plus proportional cun. Key spans: elbow crease to wrist crease 12 cun; axilla to elbow 9 cun; popliteal crease to lateral malleolus 16 cun; umbilicus to pubic symphysis 5 cun; umbilicus to xiphisternum 8 cun; nipple to nipple 8 cun. Then subtract for landmarks, for example ST25 is 2 cun lateral to the umbilicus and ST36 is 3 cun below ST35, one fingerbreadth lateral to the tibial crest.
Point categories tested constantly
Yuan-source points (yuan-source = source), luo-connecting (on the limb, opposite the yuan), xi-cleft (acute, painful, blood stasis), front-mu (on chest/abdomen, yin organs), back-shu (paraspinal, 1.5 cun lateral), five-shu (jing-well, ying-spring, shu-stream, jing-river, he-sea). Five-shu element order differs: yin channels run wood, fire, earth, metal, water; yang channels run metal, water, wood, fire, earth. This reversal is a classic trap.
Danger points
Memorize points where depth causes harm: ST1, BL1, GB21 (also contraindicated in pregnancy), LU1, KI27, CV17, CV22, ST9, SP21, and the posterior cervical and upper thoracic region generally. Any question that pairs a needle depth greater than about 0.5 cun at these sites should be flagged as unsafe.
Worked example
A stem asks for the point 3 cun above the wrist crease on the radial side. On the lung channel, LU7 (xi-cleft and luo) is 1.5 cun; LU6 (xi-cleft) is 7 cun; LU5 (he-sea) is at the elbow crease. Careful: LU6 is the xi-cleft at 7 cun, LU7 the luo at 1.5 cun. Count proximal from the wrist crease and check the channel's own measured distances.