There are six gates on the way leading to the origin of Kundalini power. Or, it may be said that this path is locked by six locks. Human soul can reach the inner energy centers by opening these gates or locks. These six obstructions are called Shat-Chakras in spiritual language.
These six Chakras are related to Brahamnadi which is one og the three nadis situated in the inner most part of the Sushumna. They can also be compared to lotus flowers strung into the thread of a garland. Readers will be able to see in the picture where a particular Chakra is located in the body. Mooladhar chakra lies in the genital region; Swadhisthan chakra in the portion between the navel and the pubic region; Manipur chakra in the umbilicus region; Anahat chakra near the heart; Vishudakhya chakra near the neck; Agya chakra in the middle of both the eye-brows; and above all lies Sahasrar.
Sukshumna and three nadis encased within it namely, Vajra, chitrani and brahmanadi are so subtle that they can not be seen by naked eye. The corresponding chakras are still more subtle. Any attempt to operate upon the body to locate shat chakras will be ridiculous and futile because the power of vision of human eye is very much limited. Sound waves, atoms of air, germs of diseases cannot be seen by the naked eye, still their existence cannot be denied. Yogis have seen these chakras by their yogic vision and have gained miraculous knowledge, insights and powers through investigations of the inner being of man. They have given a well-organized scientific description of such investigations and presented it before those who are interested in the subject.
Shat chakras are like subtle knots (granthis) formed in the passage of Brahmanadi. When a Sadhak concentrates his mind on these chakras he unusual experiences of subtle conditions prevailing there. These knots (granthis) are not circular but angular like petals of a flower. These petals are called Padma-dal. They are like a bunch of fibers.
These chakras are of different hues because of energies of varying potencies of elements dominant in different Granthis. This also affects the quantity and color of the blood of that region. The color changes to pink, blue, red and smoky according to the prominence of the elements of earth, water, fire, air and sky respectively. The mixture of these elements changes the color of each chakra.
When a weevil (wood-worm) cuts through wood, the cut portion assumes different shapes. When vital breath (pran-vayu) passes through these chakras, its passage becomes slightly zigzagged according to the position of the Granthi. It takes different shapes similar to the shape of some letters of devnagri script and they are called letters of that particular chakra.
In a fast flowing river, whirlpools of different shapes are formed at several points. When the vital breath of Sushumna flows rapidly through these chakras, subtle whirlpools are formed, which are quadrangular, triangular, hexagonal, circular, semi-circular and phallus-like in shape. The flame of rising fire is thick at the bottom and thin at the top. Thus an irregular triangle is formed when the chakras are pierced. Different shapes are thus formed by the flow of vital breath; these are known as yantras of chakras.