Huán dān zhǒu hòu jué 還丹肘後訣
Instructions on the Return-Elixir to Keep at One’s Elbow
Anonymous; late Táng to early Sòng
A handy reference-manual on the return-elixir (huán dān 還丹) in 3 juàn — “elbow-keepings” (zhǒu hòu 肘後) is a conventional Chinese title marker for compact, ready-to-hand technical manuals (cf. Gě Hóng’s Zhǒu hòu bèi jí fāng 肘後備急方). Preserved as DZ 915 / CT 915 (Dòngshén bù, Zhòng shù lèi 洞神部眾術類).
Dating. Late Táng or early Sòng (10th–11th century). Dynasty: 唐-宋.