Sahasrara, meaning thousand, is the “Lotus of the Thousand Petals” located four finger-breadths above the crown of the head. Sahasrara chakra is the upper terminal point of Sushumna nadi, the central channel. From Saharara the nectar of immortality (Amrita) flows in a constant stream.
Sahasrara chakra is the seat of the parabindu (supreme bindu). It is the location of the merging of Kundalini Shakti and Shiva. By this union the adept attains liberation while living which is considered in Indian life to be the highest experience: an union of the individual with the universe.
Sahasrara chakra is located above Brahma-randhra, “the cave of Brahma”. It is a hole in the crown of the head through which the soul is said to escape at death. When the Yogi separates himself from the physical body at the time of death, this Brahma-randhra bursts open and the soul comes out through this opening (Kapala Moksha). This opening is also called the ‘Door to Pure Consciousness’ or door of liberation.
Once the Kundalini Shakti, also called “Serpent Power”, has ascended through Sushumna to Sahasrara, it is made to reverse its course and return to rest in the base center again. Immortality is achieved within Sahasrara Chakra. Before attaining to this chakra the yogi is unable to reach the unconscious conscious state called asama-prajnata-samadhi. In this state there is no activity of the mind and no knower, no knowledge, nothing to be known: knowledge, knower, and known all become unified and liberated.
When the Kundalini is raised up to Sahasrara chakra, the illusion of individual self is dissolved. The yogi becomes realized, one with the cosmic principles that govern the entire universe within the body. One is no longer subjected to birth or death.
Samadhi is the pure bliss of total inactivity. Up to the sixth chakra the yogi may enter a trance in which activity or form still remains within the consciousness.
In Sahasrara Chakra the prana moves upward and reaches the highest point. The mind establishes itself in the pure void of Shunya Mandala, the space between the hemispheres.
At this time all feelings, emotions and desires, which are the activities of the mind, are dissolved into their primary cause. The union is achieved. The yogi is sat-chit-ananda, truth-being-bliss.
He is his own real self, and as long as he stays in his physical body he retains nondual consciousness, enjoying the play of lila without becoming troubled by pleasure and pain, honors and humiliations.