Sunüjing 素女經 "Book of the Immaculate Maiden" is a book on the so-called "art of the bedchamber" (fangzhong shu 房中術). It is only preserved in fragments and was first quoted by the Tang period 唐 (618-907) physicial Zhen Quan 甄權 (541?-643) in his book Gujin luyan fang 古今錄驗方 (lost), as well as in Wang Tao's 王燾 (670-755) medical encyclopaedia Waitai miyao 外臺秘要 (Waitai biyao 外臺祕要). The original text might have been compiled during the Han period 漢 (206 BCE-220 CE) or even somewhat earlier, and found its final shape during the Southern Dynasties period 南朝 (420-589).
The book itself is first mentioned in Ge Hong's 葛洪 (283-343 or 363) Baopuzi neizhuan 抱樸子內篇 (ch. Xialan 遐覽).
Parts of the text are also quoted by the Japanese physician Tamba no Yasuyori 丹波康賴 (912-995) in his book Ishimpō 医心方 (ch. Bōnai hen 房内篇). The quotations were extracted by Ye Dehui 葉德輝 (1864-1927) and assembled in his reprint series Shuangmeiying'an congshu 雙梅景[=影]闇叢書, with the name Sunüjing.
The Sunüjing was drafted as a kind of dialogue between the Yellow Emperor (Huang Di 黃帝) and the Immaculate Girl (Sunü 素女) on issues of sexual intercourse and certain behaviour according to the seasons or other conditions. Mention of the Sunü as a teacher to the Yellow Emperor occurs in the critical Han period essay collection Lunheng 論衡 (ch. Mingyi 命義).
The female "expert" warns the Yellow Emperor that to have five wives not only "entails bodily injury on father and mother", but also most seriously "affects the characters of sons and daughters" (transl. Forke). Zhang Heng 張衡 (78-139 CE) wrote a poem called Tongsheng ge 同聲歌, in which he describes the activities of the wedding night, when ten thousand prescriptions (wanfang 萬方) were carried out.
The Sunüjing explains that illness can be traced back to the violation of the proper "Way" (dao 道) in the encounter of Yin and Yang. The aim of this encounter was to produce children of a "worthy character" (xianliang 賢良) and to prolong the own and their life span (yannian yishou 延年益壽). The book therefore points out the best time to get pregnant, and the nine conditions of misfortune (jiuyang 九殃).
One prerequisite was to ejaculate not too often (mo shu xie jing 莫數泄精), but regularly—long abstinence would result in ulcers (yongju 癰疽), another one unity in love and joy (aile 愛樂) and mutual compassion and corresponding reaction (xianggan er xiangying 相感而相應). Both partners had to be ready to make love (qingyi hetong, juyou yuexin 情意合同，俱有悅心) and to avoid disharmony in the body's "essences" (jing 精, i.e. sperm and fluids) and "spirits" (qi 氣). A man had to regard his "enemy" as a tile or stone, and himself as gold or jade.
Sexual intercourse would help a man to avoid weakness and a female to prevent illness (nan zhi bu shuai, nü chu bai bing 男致不衰，女除百病).
The bibliographical chapter Jingji zhi 經籍志 in the official dynastic history Suishu 隋書 lists two books of this type, namely Sunü midao jing 素女秘道經 and Sunüfang 素女方, both with a length of one juan. Even if these books cannot be identified with the Sunüjing, they must have been related to it.
The Qing period 清 (1644-1911) scholar Sun Xingyan 孫星衍 (1753-1818) collected fragments of the Sunüfang quoted in various texts, as well as the quotations of the Sunüjing in the Waitai miyao, published in the reprint series (congshu 叢書) Pingjinguan congshu 平津館叢書.
Li Dalin 劉達臨 (1998). "Sunüjing 素女經", in Zhongguo xingkexue baike quanshu bianji weiyuanhui 《中國性科學百科全書》編輯委員會, Zhongguo da baike quanshu chubanshe she-ke-ji bianjibu 中國大百科全書出版社科技編輯部, ed. Zhongguo xingkexue baike quanshu 中國性科學百科全書 (Beijing/Shanghai: Zhongguo da baike quanshu chubanshe), 39.
Li Dalin 劉達臨 (1998). "Sunüfang 素女方", in Zhongguo xingkexue baike quanshu bianji weiyuanhui 《中國性科學百科全書》編輯委員會, Zhongguo da baike quanshu chubanshe she-ke-ji bianjibu 中國大百科全書出版社科技編輯部, ed. Zhongguo xingkexue baike quanshu 中國性科學百科全書 (Beijing/Shanghai: Zhongguo da baike quanshu chubanshe), 42.