The microcosmic orbit (小周天), also known as the Self Winding Wheel of the Law, is a Taoist qigong energy cultivation technique. It involves deep breathing exercises in conjunction with meditation and concentration techniques which aim to develop the flow of qi along certain pathways of energy in the human body which may be familiar to those who are studying traditional Chinese medicine, qigong, tai chi, Neidan and Chinese alchemy. The exercise can be performed usually at first in a sitting position, but it can also be practiced standing as in Zhan zhuang or with movements included as with tai chi.

The clear understanding of the microcosmic orbit technique is very important not only because of its historical context in the story of Chinese alchemy but because it is at the heart of many Taoist forms of exercise performed throughout the world by many millions of people today.

The history of the microcosmic orbit dates back to prehistoric times in China, and the underlying principles can be found in the I Ching which according to legend was written by the Emperor Fu Xi approximately five thousand years ago or at least two centuries before the time of the Yellow Emperor. For example, the Chinese character for the I Ching hexagram number 5, Waiting, depicts a person sitting in meditation and the commentary pertains to the flow of energy from one of the psychic energy channels to another during meditation:

The commentary on the Image for hexagram 5 reveals the entire process of meditation. "The clouds rise up to heaven" symbolizes the meditator's energy rising upward as it evaporates into the head, where it is distilled into a saliva like nectar (referred to in the phrase "the superior man eats and drinks"), which returns to the abdomen. " It furthers one to cross the great water" alludes to crossing the great water of the abdomen and mouth.

An 1886 stone carving in the White Cloud Temple in Beijing contains a pictorial representation of some of the symbols which describe the processes involved in the microcosmic orbit meditation technique. These particular techniques are derived from the Taoist Patriarch Lü Dongbin who was born in 798 AD. Lü Dongbin was one of the Eight Immortals.

Lü Dongbin and his teacher, Chung-li Ch'üan, were two of the "Eight Immortals”, pa-hsien. While a fugitive after an abortive Chinese military expedition against Tibet, Chung-li Ch'uan encountered Master Tung-hua. He "earnestly begged for the secrets of immortality. Master Tung-hua thereupon imparted to him not only an infallible magic process for attaining longevity, but also the method to produce the Philosopher's Stone."

The exercise itself usually begins with preparation designed to relax the physical body and develop the ability to concentrate. Students may indeed be encouraged to practice Taoist Yoga exercises or tai chi as a way of building enough energy to begin performing the microcosmic orbit exercise as it can induce a strain on the nervous system and cause energy depletion if practiced without adequate preparation.

To begin with the student is encouraged to develop deep abdominal breathing into the primary dantian or Taoist energy centre to develop heat and pressure in the lower abdomen or "Golden Stove". A preparatory exercise known by some as the Lesser Heavenly circulation involves moving energy between two areas known as the seat of fire near the heart or the solar plexus where a psychic centre symbolised by the trigram Li from the I Ching is located, and the seat of water in the area of the kidneys where a psychic centre symbolised by the trigram kan is located.