The Sanskrit word bindu means 'drop' or 'point'. But the name of the centre we are talking about is actually bindu visarga which literally means 'falling of the drop'. The drop referred to is amrit, the immortalizing nectar. It is this particular secretion which maintains the life of yogis who undertake such feats as being buried alive for forty days without food, water or oxygen. It controls all possible process of metabolism, produces nutrition and the required quantity of oxygen. Bindu is the seat of this nectar.
The location point for bindu is at the top back of the head, where Brahmins have a tuft of hair. Today Brahmins only keep this tuft of hair to show that they are Brahmins, but traditionally the tuft of hair was pulled tight and twisted, creating tension right on the centre of bindu. This was the best method of gaining awareness of bindu which incidentally has no kshetram. Bindu is directly connected with vishuddhi by a particular network of nerves which flow through the interior portion of the nasal orifice passing through lalana (a minor chakra which is responsible for storing and secreting amrit). Lalana is not a centre of awakening, nor is bindu. When awakening takes place in vishuddhi it also occurs in bindu and lalana.
Bindu is a centre of nada yoga. There is not one particular sound in bindu, but many, many sounds. When practising nada yoga one should concentrate on bindu.
Symbolically bindu is represented by both a full moon and a crescent moon. The full moon is the infinitesimally small drop of nectar and the crescent moon is associated with the phases of the moon. In the same way that the moon is progressively revealed during the period from new moon to full moon, so immensity of sahasrara behind the bindu can be gradually unveiled through yogic sadhana. The bindu is drawn on the background of the night sky indicating that the basis of the bindu, the saharasrara, is infinite. For the awakening of bindu there are no specific practices. Once vishudhi becomes active it will have a consequential influence on bindu.
The Sanskrit word sahasrara means 'one thousand'. Although sahasrara is represented by a lotus with one thousand petals, the 'one thousand' literally implies that its magnitude and significance is vast, in fact, unlimited. Sahasrara is shoonya, the void. It is difficult to discuss sahasrara for its transcends concepts and words and is beyond experience, for the experience, the experienced and the experiencer are one and the same. Sahasrara is the merging of consciousness and prana. It is culmination of yoga, it is yoga itself, the perfect union. When one gains mastery over sahasrara he becomes free in all states; he becomes rooted in happiness and free from grief and bondage. With the blossoming of sahasrara the yogi is said to acquire various psychic powers but if he can free himself from attachment to such powers, he may then become the knower of the supreme and acquire every kind of knowledge.
SADHANA FOR ALL CHAKRAS
Once you have become familiar with the exact location of each chakra, you can start to practise the two advanced techniques which follows:
This is one of the first kriya yoga practices which, in english can be translated as 'search for the chakras'. In this kriya and in other kriyas you are required to move your awareness through two psychic passages called the arohan and the awarohan. The path of these passage is as follows:
Arohan is the ascending psychic passage which starts from mooladhara chakra, travel forward to swadhisthana kshetram in the public area, then travels upward through the kshetrams of manipura, anahata and vishuddhi, then in a straight line to bindu at the back of the head.
Awarohan is the descending passage which starts at bindu, travels forward to ajna chakra, then down through sushumna in the spine, passing through all the chakra points in turn to finally terminate at mooladhara.
These two passage ways join at bindu and mooladhara. They are widely known through the world, especially in mystical circles and healing systems such as acupuncture in which arohan is yang and awarohan is yin.
Sit in a comfortable meditative posture, preferably siddhasana or siddha yoni asana. Make the spine erect, relax the whole body and close the yes.
Breathing normally, focus your awareness at mooladhara chakra.
Now ascend your awareness through the arohan passage way passing in turn through swadhisthana, manipura, anahata, vishuddhi, until it reaches bindu. As you pass through each kshetram, mentally say the name of the centre.
When you reach bindu, immediately let your awareness descend through the awarohan passage to mooladhara. Mentally repeat the name of each chakra as your awareness passes through it: ajna, vishuddhi, anahata, manipura, swadhishthana, mooladhara.
This completes one round or circuit of awareness. You should immediately start a second round by moving your awareness upwards through the arohan passage, again mentally repeating the name of each centre as you pass through it.
Do not make tense efforts to locate the chakra and shetram points. Let your awareness flow through the centres without effort. Imagine that each centre is a railway station, and that your awareness is like a train that passes through them without stopping.
The centres should be regarded as though they are part of the psychic scenery. Alternatively, you can visualize your awareness as a thin silver serpent travelling an elliptical path within the body. Practice 3 rounds and gradually icnrease to a amximum of 9 rounds.
Sit in a comfortable cross-legged meditative posture. Your body should be relaxed but erect, with your head, neck and chest in a straight line. Eyes closed.
Take your awareness to mooladhara chakra and visualize an altar of fire there. It is triangular in shape with the flames forming the upper point of the triangle.
You can see the flames rising from the altar and illuminating the whole of the spinal column. Practise ujjayi pranayma with kchechari mudra for a few minutes.
Now as you inhale, visualize the flames shooting up through sushumna nadi and momentarily illuminating and warming each chakra, then finally passing out of the body through sahasrara.
You must try to hear the steady sounds of the fire. As you exhale you should try to see and hear the arousal of the flames in mooladhara.
Practise 3 rounds.
Then with each exhalation, either mentally or aloud, and in harmonization with the sounds of the fire, chant the mantra Om.
Notice how it causes the fire to burn brighter.
Prefer a maximum of 7 rounds with the feeling that you are being absorbed in the altar of fire.
Source: Excerpts from the book on "Sure-ways of Self Realization" by Swami Satyananda Saraswati.