Qian is yang and stands for heaven.  Kun is yin and represents earth. The union of qian and kun means the balance of yin and yang and water and fire in the human body.

    The exercises for the union of qian and kun is also known as the big zhoutian. To learn this exercise, you have to keep your mind still and peaceful, shut your eyes to all around you and listen to your inside world, and concentrate your attention on the mind and breathe slowly and evenly. Thus, fire arises from water, with the midline of back like a wheel, the four limbs like rocks, the kidneys like boiling water and the bladder like burning fire. In the twinkling of an eye, tianji (natural law) plays its part. Then direct qi gently and regulate breath consciously and slowly. Let nature take its course: l and wood blend, and water and fire rise and fall. Suddenly, something the size of a millet falls to the huangting point and proceeds to grow into an elixir. By then the mind and body will have become void and shen and qi are in harmony with nature.

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