Lóng hǔ huán dān jué 龍虎還丹訣

Instructions on the Dragon-Tiger Return-Elixir

by 金陵子 (Jīn líng zǐ) — early Northern-Sòng Daoist alchemist

A Northern-Sòng alchemical instruction-text on the dragon-tiger return-elixir (lóng hǔ huán dān 龍虎還丹) — the coupling of lead (tiger, yīn) and mercury (dragon, yáng). Dated 1042 (Qìng lì 2). Preserved as DZ 909 / CT 909 (Dòngshén bù, Zhòng shù lèi 洞神部眾術類) in 2 juàn.