Sun Xi Kun on Daoism: Authentic Cultivation of Daoism
The essence of cultivation is to understand the methods for realizing (enlightening) the heart-mind and one’s essential nature. Empty prattle about cultivating the Way (Dao) will not lead to real awakening to truth. Buddhism’s empty, obstinate sitting cultivates Xing, but does not cultivate Ming. In Daoism, both Xing and Ming are cultivated.  But, few people can get authentic instruction. I have heard that the path to immortality has no fixed methods and no fixed phases (time period). Careless sitting can easily cause illness. If attachment to the bonds of the world is unfinished, one cannot research deeply. Those who study the Dao are as numerous as hairs on an ox, but those who reach attainment are as rare as a Qilin.  Those who believe and practice sincerely and painstakingly are few, and those who boast and seek fame are numerous. Coming in through the side door, one can go astray.
Of course in cultivating the Dao, there are those who cultivate movement (Dong) and those who cultivate stillness (Jing). For those who cultivate Daoism from motion, it is first necessary to strengthen Wai Dan (external elixir)  by first refining grain into essence (Jing) and cultivating a Pine Resin (Song Jiao) body, [4[ and then training Nei Dan (internal elixir).  For those who cultivate tranquility, one must first realize one’s inner nature and then cultivate Nei Dan. The training methods are different, but the achievements are same. The real principle is to first nourish Post-Heaven (Hou Tian) and then return to Pre-Heaven (Xian Tian). Without the strong body of an Arhat  how can there possibly be an immortal baby Buddha that is vigorous and perceptive?
People today fail to understand and cultivate the Dao. Three Key Points must be understood: longevity (Shou), achievement (Gong) and Dao (the Way). These three are interrelated. The first stage of cultivation is to prevent disease and prolong life. The second stage in cultivating the Tai Gong (great achievement) is to lay a foundation by collecting the medicines  that forge Dan (elixir) so as to consolidate the San Bao (Three Treasures).  Then one can begin to talk about the Dao. In human life the bones and sinews change after sixty years. At that point the functioning of the internal organs has decayed. Even if one is able to prolong life, one is already half-dead. The ancients say that once a sixty-year cycle has passed, one has passed over the gate of hell. Therefore, people should accelerate their cultivation before becoming old and weak and maintain the health of their bodies.
Although there are three thousand and six hundred side doors and seventy-two heterodox paths.  they are nothing more than just refining grain to transform into Jing (essence), cultivating and transforming essence into Qi, cultivating and transforming Qi into Shen (spirit) and then refining spirit so it can return to emptiness. One who cultivates only their nature does not cultivate life. Even if they see through the vanity of human affairs and discipline their temperament, sitting still, worshipping Buddha and chanting scriptures – they are cultivating Xing, but not Ming.  Obstinate empty sitting only dries up the cooking pot in an attempt to eliminate illness and prolong life. All of these methods deviate from the true instruction that is passed down. If the true doctrine of the Great Dao is sought, one must return to true awakening. Xing and Ming must be cultivated simultaneously. Because the root of the heart is the spirit, and the spirit resides in the heart and life. Ming [resides] in the kidney, essence (Jing) is Yuan Qi. Refined essence is transformed into Qi and refined. Qi is transformed into spirit and refined spirit returns to emptiness. Nourishing Pre-Heaven is based upon this. Therefore Xing is cultivated in death and Ming cultivates life. After Xing Gong is realized there are no distracted thoughts in the heart. Then one can begin to cultivate Ming Gong.  Nevertheless, Xing Gong and Ming Gong progress together simultaneously. This is exactly what simultaneous cultivation of Nature and Life means.
The heart belongs to the fire and resides in the south, a manifestation of the trigram Li. The kidney belongs to the water and resides in the north, a manifestation of the trigram of Kan. In Daoist cultivation, the principle is to use fire to boil water so that water transforms into Qi. Qi transforms spirit and spirit transforms into emptiness. The Dan (elixir) Classic says to “subdue the dragon and vanquish the tiger” [12} The dragon is Xing and the tiger is Ming. A calm heart is the dragon returning to the sea. Letting go of emotion is the tiger hiding in the mountain. This is the cultivation of both Xing and Ming. There are three steps in Daoist cultivation: (1) prevent disease and prolong life; (2) seek immortality; (3) cultivate the Great Dao. Therefore, those who cultivate the Dao, regardless of what situations they encounter, should avoid the pull of material desires. Upon encountering things they desire, they should withdraw the heart-mind - their conscious perception (awareness). From conscious perception to no perception to true (realized) perception. This is cultivation of the Li [trigram] palace. For one who attains the true Way, yin-shen (invisible spirit) appears. Yang-shen (visible spirit) does not appear, especially a ghost being. 
Both in ancient times and today, for those who cultivated the Dao, it is difficult to cut off the Licentious Root. Longevity is impossible, unless Ma Yin Zang Xiang (Penis Hidden in the Abdomen) is trained.  Female Daoist practitioners should first cut off the Red Dragon.  Male Daoist Practitioners should first subdue the White Tiger.  Women can cultivate the Dao faster than men, because the woman’s body is the offspring of pure yang. Only the lower private parts belong to yin. A man‘s body is the offspring of pure yin. Only the lower private parts belong to yang. The so-called Red Dragon is between the two breasts. When the breasts are trained to emptiness, the Red Dragon is cut off. Therefore, women train form and men train Qi. Ren Mai arises from Hui Yang which is located slightly in front of Huiyin (CV 1), inside the root of the kidney (external genitalia), and ends at Chengjiang (CV 24) below the lower lip. Du Mai arises from Huiyin (CV 1) and ends at Renzhong (GV 26), in the groove above the upper lip. Shenqi  starts here and flows between the two mai without stopping. This is the Heavenly Circle achievement (Zhou Tian Gong). 
In cultivating the Dao and training Dan (the elixir),  it is necessary to collect the medicine to put on the stove, in order to nourish Dan to pass through the barrier, and to conceive the fetus to give birth to the spirit.  After that one is free and unfettered and can become a contented immortal.
Cultivating the Dao occurs in the human body; the outside body is not the Dao. It is divided into three passes (San Guan), respectively in the front and in the back. Namely: upper Dantian, also termed Shang Huang Ting (Upper Yellow Court), i.e. the brain; the middle Dantian, also termed Zhong Huang Ting (Middle Yellow Court), i.e. the spleen, located 1.2 cun below the umbilicus, and the Lower Dantian, Xia Huang Ting (Lower Yellow Court), i.e. the lower abdomen. The posterior three passes are the Yu Zhen (Jade Pillow), i.e. the occipital bone, Jia Ji Pass, i.e. the spine, and Wei Lu Pass, i.e. the coccyx. Those are the barriers that must be passed through in refining and transforming Qi.
It is said in the Dan Classics that after going through the three mountains (three passes), one can attain immortal spirit. If those who cultivate the Dao want to understand the true way, they must seek out the wise.
Notes: This comparison of Xing 性: inner nature; character; disposition; property; quality and Ming 命: vital force or life, refers to two methods or “schools” of Daoist cultivation: Xing Gong and Ming Gong. Xing Gong refers to self-cultivation which employs quiet seated meditation to cultivate the mind, while Ming Gong trains the body through Qi cultivation exercises. These two methods or schools are complimentary. Xing and Ming are the Qi/Breath and the Shen (spirit). Xing relates to Earth and Ming to Heaven. Xing and Ming must circulate and unite.
 The Qilin is often equated to a unicorn. However, the Qilin (Kirin, in Japanese) is a mythical animal with the head of a dragon, the horns and body of a deer , the hooves of a horse and the tail of an ox. Other descriptions depict the Qilin with the scales of a carp, the hooves of an ox, the tail of a lion, and the head of a dragon. In some depictions the Qilin has two horns and in others, only one.
 Wai Dan (Outer Elixir): External exercises in which Qi is built up externally, usually through movement, and then led internally.
 This may be an oblique reference to Bigu (辟谷), which literally means avoiding grains. Bigu is a Daoist fasting technique associated with achieving transcendence or immortality. It is sometimes understood as not eating certain foods or in other cases as not eating any foods and subsisting on the breath and various herbs, one of which is pine resin.
 Nei Dan (Inner Elixir): Internal exercises, often involving stillness or tranquility, in which qi is accumulated internally and then led externally. Part of Nei Dan involves cultivating the Three Treasures (Jing, Qi/Breath and Shen) and refining and transforming them into the “internal elixir” (Nei Dan).
 In Buddhism, an Arhat is a practitioner whose spiritual practice is advanced and has attained liberation.
 The “medicines” or “herbs” refer to Qi and Jing (essence) which must be gathered like herbs in order to be refined (“cooked”) internally by a process of extraction and transformation. This “cooking” of the “medicinal substances” is a metaphor for cultivation of the internal elixir – Nei Dan practice.
 The San Bao 三宝 are Jing (essence), Qi (Qi-Breath) and Shen (spirit). In Nei Dan self-cultivation practices, Jing, Qi/Breath and Shen transmute and inter-transform in order to return to the Pre-Heaven state of emptiness.
 In effect: many methods and unorthodox doctrines.
 see footnote #1
 See footnote #1.
 降龙伏虎 Xiang Long Pu Hu. Literally: lower; descend or subdue the dragon and hide; lie down or tame the tiger. Can also mean to overcome powerful adversaries, or in Daoism – ”to conquer one’s passions.”
 This seems to refer to Yang Shen (yang spirit) and Yin Shen (yin spirit). These are projections of the spirit out of the body. Some Daoists say that the Yang Shen is a sign of achievement in meditation, while others posit that Yin Shen is the sign of achievement
 This seems to refer to a Daoist practice in which a man’s “outside yang” (penis) shrinks so that jing (essence) is not lost and therefore qi can be refined internally.
 The “red dragon” refers to menstruation. Sun Xi Kun references Daoist practices that aim to stop menstruation so that female practitioners stop the monthly loss of blood which impacts on their essence (Jing).
 Subduing the White Tiger refers to techniques of sexual neigong or inner alchemy in which semen (Jing) is transmuted into Qi.
 Shenqi 神气: qi and spirit ; the aspect of qi that transforms into spirit.
 小周天 Xiao Zhou Tian: “Small Heavenly Circulation” or the “Micro-cosmic Orbit.” Internal transformation of the Three Treasures practiced by Daoists and martial arts practitioners, in which qi is circulated through the Ren and Du Meridians. Part of Nei Gong practices and Daoist inner alchemy.
 Lian Dan 炼丹: “Refining the elixir”; “concocting pills of immortality”. In Neidan practices this means creating a “pill” inside the body by refining Jing, Qi/Breath and Shen.
 This again refers to refining Jing to Qi/Breath so that the Qi/Breath can move through the three barriers (San Guan) in the Du Mai and transmute into spirit. Then in passing through Ren Mai, spirit replenishes Jing forming a “fetus” inside the body which in turn gives birth to spirit.