🕮 Daode jing, sec. 6: The gate of the Mysterious-Female is called the root of Heaven and Earth. 玄牝之門，是謂天地根。
① The point of conjunction of Yin (the “Female”) and Yang (“Heaven”) before their separation, and of their reconjunction after their separation. Equivalent to Spirit of Valley (gushen).
⊛ The Mysterious is Yang and Heaven, the Female is Yin and Earth. 元 (玄) 者，陽也，天也。牝者，陰也，地也。 (Bai Yuchan, "Essay on 'The Spirit of the Valley does not Die'", trans. in Taoist Internal Alchemy: An Anthology of Neidan Texts, p. 118)
⊛ The Mysterious is the Yang Qian ☰, the virtue of firmness and strength. The Female is the Yin Kun ☷, the virtue of yieldingness and compliance. 玄者，乾陽，剛健之德。牝者，坤陰，柔順之德。 (Awakening to Reality, "Cut-off Lines", poem 40, Comm. Liu Yiming)
② An image of the Center as the place of conjunction of Yin and Yang.
⊛ The Gate of the Mysterious-Female is the Central Palace. 〔中宮：〕玄牝之門。 (Weng Baoguang, "Model Images of the Golden Elixir", trans. in Taoist Internal Alchemy: An Anthology of Neidan Texts, p. 135)
③ A synonym of One Opening of the Mysterious Barrier (xuanguan yiqiao).
⊛ You must know the One Opening at the center of the person, which is called the Mysterious-Female. 要須知夫身中一竅，名曰玄牝。 (Four Hundred Words on the Golden Elixir, Preface)
④ⓐ Mouth and nose (nostrils), the breathing organs through which the human being communicates with the Breath (qi) of Heaven and Earth.
⊛ What is the Gate of the Mysterious-Female? The nose communicates with the Breath of Heaven and is called the Mysterious Gate. The mouth communicates with the Breath of the Earth and is called the Female Door. Therefore the mouth and the nose are called the Gate and Door of the Mysterious and the Female. 問曰，何謂玄牝之門。答曰，鼻通天氣，曰玄門，口通地氣，曰牝戶，口鼻乃玄牝門戶也。 (Xiao Tingzhi, Questions and Answers on the Golden Elixir, trans. in Taoist Internal Alchemy: An Anthology of Neidan Texts, p. 145)
④ⓑ This view is disapproved in several Neidan works.
⊛ Few in the world know the Gate of the Mysterious-Female: stop fiddling around with your mouth and your nose. 玄牝之門世罕知，休將口鼻妄施為。 (Awakening to Reality, "Cut-off Lines", poem 40, trans. in Taoist Internal Alchemy: An Anthology of Neidan Texts, p. 83)
⊛ Someone refers to the mouth and the nose, but this is wrong. 或指口鼻者，非也。 (Li Daochun, The Harmony of the Center: An Anthology, chap. 3)