Following Part 1 (Authentic Cultivation of Daoism), Part 2 (True Formula of the Dao Elixir Secret Treasure), and Part 3 (The Method of Quiet Sitting), we continue with Sun Xi Kun on Daoism with the General Discussion of the Medicine Collecting Method. These articles on Daoism are excerpted from The True Transmission of Ba Gua Zhang 八卦拳真传 Ba Gua Zhang Zhen Chuan by Sun Xi Kun 孙锡 堃
“Medicine” means Pre Heaven One Qi. What is Pre-Heaven One Qi? Before Heaven and Earth, there was no Heaven and Earth; this qi appeared naturally in the Hun Dun (primordial undifferentiated state). The root of yin is the root of Wu Ji (no-limit) and then Tai Ji (great limit). Then Tai Ji, gave birth to yin and yang. This qi spreads and moves (prevails), giving birth to human beings and all living things.The fetus in the mother’s belly is Pre-Heaven. After the mother gives birth [to the fetus} it gradually suffers loss, becoming Post-Heaven jing, qi and shen. Because they wither, only one who does not die can see this. By using the method of refining and cultivating like a child ascetic, the True Yang des not leak and is consolidated. As for the middle-aged and old people, using the pure Qian (Heaven; the Creative) diagram – yang going through to the pure Kun (Earth; the receptive) diagram, Qian transforms into Li (Fire; Clinging) and Kun transforms into Kan (Water; The Abyss). When the foundation is refined (trained), [one] takes from Kan to fill in Li, especially as one waits for the medicine to form. 
When does the medicine form? Inner reflection through drooping the eyelids and clenching the fists like a great mountain,  the heart is still like water. Internally observe the heart. There is heart without heart.  In the outside appearance and form, there is form without form. In looking at things from afar, there is no thing within things (no objective within the objective).
If these three things are realized, only emptiness is seen; emptiness without emptiness. Then the heart (heart-mind) is bright and clear, existing in the center of great emptiness, dark and undifferentiated, like a baby inside its mother’s belly, not knowing, not recognizing, without others and without self. The center of emptiness gives birth to tranquility and to its polar opposite movement.  This [movement] is True Yang. The Zi time period (1st Earthly Branch: 11pm to 1 am) is the firing time. Collect the medicine immediately and be sure not to let the intention wander. Da Mo said “rein in the yang pass and regulate the external medicine through Er Hou Cai Mo (two steps to perceive the essence)  and treasure sword joins the three roads”.  Master Huang taught him the method of reversing the flow of water. The normal flow gives birth to sons, while reversing the flow gives birth to the elixir. For longevity, one must return (turn back) essence to nourish the brain. In this way qi is returned to the stove and refined. Through the firing times it is cooked and refined to become the elixir, the priceless treasure of the body.
 In the post heaven configuration of the Yi Jing Diagrams, Qian-Heaven is replaced by Li-Fire and Kun-Earth is replaced by Kan-Water. Li and Kan, then become emblematic of yang and yin in cyclical temporal movement of living things through the seasons and in the post-heaven progression from conception and birth to aging and death. In Daoist meditation the trigram Kan represents the Kidneys and Dantian. Kan is full in the middle (it has a solid yang line in the middle). The yang line in the center indicates that there is a true yang-fire within yin-water. Li represents the heart and chest. Li is empty in the middle. This symbolizes the hidden true yin-water within yang-fire. Normally, fire is light and rises to the chest and water is heavy and sinks to Dantian. This is the post-heaven state whose trigram configuration moves temporally from birth to death. However if fire is brought beneath water, they mutually restrain each other and interact. This creates steam and condensation which is a rarefied energy. Then the middle lines of the trigrams switch places and the Qian trigram and Kun trigrams (Hexagram 11: Tai) are formed creating the original pre-heaven state, which in Daoist beliefs leads to stopping of the temporal movement and therefore “immortality”.
 Great Mountain, (Tai Shan 太山): can also refer to Mount Tai Shan.
 Although this phrase 心无其心 (Xin Wu Qi Wu) may literally mean “heart without its heart” or “no heart within the heart”. In context it means that there is emptiness inside the heart or “no mind within the mind”, “no intention within intention”.
 In this sentence Zhong 中 “center” or “middle”, can also mean “between the two extremes”, between the two poles of the Tai Ji , the ultimate division or supreme polarity. From emptiness comes tranquility and automatically its opposite – movement.
 Er Hou Cai Mo Ni 二候采摩尼： one step to contain the essence through intention after the medicine is produced, and another step to return the medicine to the stove for consolidation.
 The Chinese Sword (jian) was viewed by Daoists a sacred implement that could embody the primordial energy and act as a microcosm of the human body. Here the treasure sword and the three roads probably refers to the three treasures co-mingling and inter-transforming.