Svecchamrityu (Sanskrit: स्वेच्छामृत्यु) {Sva (self) + iccha (will) + mrityu (death)} is an adjective which means - having death at one’s own power or dying at one’s own will It is also called Iccha-mrityu (इच्छा मृत्यु) meaning self-willed death but it is not to be confused with immortality or self-inflicted death. Shantanu had granted to his son Gangaputra Devavrata, also known as Bhishma, the supernatural power of Svecchamrityu. Mahabharata records that Bhishma did choose the time and manner of his own death.
In the course of his visit to Amarnath cave, Swami Vivekananda had the vision of Lord Shiva in the cave and was blessed with the boon of death-at-will (iccha-mrityu). He had predicted that he would not live forty years, he did not.
Acquintances of Mahatma Sisir Kumar and Pandit Dinabandhu Vedantaratna also attest to the fact that they have willed their own death.
The Svadhishthana Chakra is the Abode of the Tattva Apas; one conquers death with the awakening of this chakra. As one of the twenty-six siddhis that form part of Kundalini yoga, Iccha-mrityu siddhi gives the yogi the power to die at will. According to Aurobindo the sadhaka of Integral yoga aims at complete liberation from all attacks of illness, and the power to prolong life at will – Iccha-mrityu.