Ren in Chinese means "direction, responsibility." Ren Mai, the "Conception Vessel," has a major role in Qi circulation, monitoring and directing all of the Yin channels (plus the stomach channel). The Conception Vessel is connected to the Thrusting and Yin Linking vessels, and is able to increase the Yin energy of the body. This vessel nourishes the uterus (one of the five ancestral organs) and the whole genital system. It is said in the Nei Jing that the Conception and Thrusting vessels contain both blood and essence (Jing), and both flow up to the face and around the mouth. They contain more blood than essence in men, and thus promote the growth of the beard and body hair. Because women lose blood with their menstruation, they contain proportionately less blood and hence, no beard or body hair.
It was described in the Su Wen that both the Conception and Thrusting vessels control the life cycles every 7 years for women and every 8 years for men. It is the changes taking place in these vessels at those intervals that promote the major alterations in our lives.
In addition, the Conception vessel also controls the distribution and "dispersion" of Guardian Qi all over the abdomen and thorax via numerous small Qi branches (Luo). This vessel also plays an important role in the distribution of body fluids in the abdomen.
In Qigong society, this vessel and the Governing vessel are considered the most important among the Qi channels and vessels, and must be trained first. It is believed that there is usually no significant Qi stagnation in the Conception vessel. However, it is important to increase the amount of Qi you are able to store, which also increases your ability to regulate the Yin channels.
Just as the knowledge of the subtle channels and vital force goes back to the very beginning of Indian mystical speculation - the earliest Upanishads - so does this same knowledge go back thousands of years in ancient China. Only the names are different. Instead of "veins" or conduits (nadis) we find reference to "meridians"; instead of prana the universal life-energy is called ch'i; and instead of Ida and Pingala, solar and lunar, we have reference to yin and yang
Like the Tantric Kundalini. In ascending, the ch'i progresses through various stations, which are given exotic names like the Elixar-field, the Yellow Hall, the Heaven. These are clearly similiar to the chakras. Now comes the difference with Shakta-tantra. Reaching the top of the head, the ch'i then descends down the front of the body, down to the navel, and then around again, forming a complete circuit. This circuit is known as "The Circulation of the Light", or "The Microcosmic Orbit". Through rhythmic breathing and visualisation, the Taoist yogi can circulate the ch'i, harmonize the polarities of Yin and Yang, attain cosmic consciousness, become an immortal, and return to the Tao
Although there is no actual one on one correspondence to the chakras of Tantra (unless one consider the lower, middle, and higher tan tiens or alchemical cauldrons, which one can equate approximately with the navel, the heart, and the brow chakras), the path that the chi takes along the main acupuncture meridians as directed during the Microcosmic Orbit does correspond in part to the chakras
rear chakras
(governor channel)
ascending
central chakras
(inner being)
front chakras
(descending channel)
Guru
upper
forehead
Indu
Manas
Brow
palms of hands - fingers
Pubic genitals
behind knees
feet & big toe
beneath feet
(atavistic)