The trigram Li: sun, fire, the lucid, the Clinging, plays a great role in this religion of light. It dwells in the eyes, forms the protecting circle, and brings about rebirth… The trigram K’an: water, the Abysmal, is the opposite of Li, as is already shown in its outer structure. It represents the region of eros, while Li stands for logos. Li is the sun, K’an the moon. The marriage of K’an and Li is the secret magical process which produces the child, the new man…

AFTER COMPLETION
BEFORE COMPLETION

Man’s heart stands under the fire sign. ^1)↓ The flames of the fire press upward. When both eyes are looking at things of the world it is with vision directed outward. Now if one closes the eyes and, reversing the glance, directs it inward and looks at the room of the ancestors, that is the backward-flowing method. The energy of the kidneys is under the water sign. When the desires are stirred, it runs downward, is directed outward, and creates children. If, in the moment of release, it is not allowed to flow outward, but is led back by the energy of thought so that it penetrates the crucible of the Creative, and refreshes heart and body and nourishes them, that also is the backward-flowing method. Therefore it is said, The Way of the Elixir of Life depends entirely on the backward-flowing method.
 
If one wants to penetrate the more subtle regions by this method, one must first see to it that body and heart are completely controlled, that one is quite free and at peace, letting go of all entanglements, untroubled by the slightest excitement, and with the heavenly heart exactly in the middle. Then let one lower the lids of the two eyes as if one received a holy edict, a summons to become the minister. Who would dare disobey? Then with both eyes one illumines the house of the Abysmal (water, K’an). Wherever the Golden Flower goes, the true light of polarity comes forth to meet it. The Clinging (brightness, Li) is bright outside and dark within; this is the body of the Creative. The one dark [line] enters and becomes master. The result is that the heart (consciousness) develops in dependence on things, is directed outward, and is tossed about on the stream. When the rotating light shines towards what is within, it does not develop in dependence on things, the energy of the dark is fixed, and the Golden Flower shines concentratedly. This is then the collected light of polarity. Related things attract each other. Thus the polarized light-line of the Abysmal presses upward. It is not only the light in the abyss, but it is creative light which meets creative light. As soon as these two substances meet each other, they unite inseparably, and there develops an unceasing life; it comes and goes, rises and falls of itself, in the house of the primal energy. One is aware of effulgence and infinity. The whole body feels light and would like to fly. This is the state of which it is said: Clouds fill the thousand mountains. Gradually it goes to and fro quite softly; it rises and falls imperceptibly. The pulse stands still and breathing stops. This is the moment of true creative union, the state of which it is said: The moon gathers up the ten thousand waters. In the midst of this darkness, the heavenly heart suddenly begins a movement. This is the return of the one light, the time when the child comes to life.

In the Elixir of Life symbols are used for the most part, and in them the fire of the Clinging (Li) is frequently compared to a bride, and the water of the Abyss to the boy (puer aeternus). From this arose the misunderstanding about Master P’eng ^2)↓ having restored his virility through women. These are errors that have forced their way in later.
 But adepts can use the means of overthrowing the Abysmal (K’an) and the Clinging (Li) only when they have sincere intention in the work, otherwise a pure mixture cannot be produced. The true purpose is subject to the earth; the colour of the earth is yellow, therefore in books on the Elixir of Life it is symbolized by the yellow germ. When the Abysmal and the Clinging (Li) unite, the Golden Flower appears; the golden colour is white, and therefore white snow is used as a symbol. But worldly people who do not understand the secret words of the Book of the Elixir of Life have misunderstood the yellow and white there in that they have taken it as a means of making gold out of stones. Is not that foolish?

When the Elixir is completed, spirit and energy are pure and clear; the heart is empty, human nature (hsing) manifest, and the light of consciousness transforms itself into the light of human nature. If one continues to hold firmly the light of human nature, the Abysmal and the Clinging (fire, Li) have intercourse spontaneously. When the Abysmal and the Clinging commingle, the holy fruit is borne.
 FROM „THE SECRET OF THE GOLDEN FLOWER”