Self-mummification is a rare practice undertaken by Buddhist monks in Tibet, Japan and Mongolia. The purpose is to reach Nirvana, thus becoming a Buddha, and escaping from the cycle of death and rebirth. Many years of training are required even to attempt this, but a successful outcome is proved if the body does not decay after death.
In order to achieve self-mummification the monk will severely restrict his diet, completely cutting out all fat and moisture, living mainly on nuts, berries and leaves. He may ingest some plants which are toxic to bacteria, thus inhibiting bodily decomposition after death. It is also thought that he may consume the sap of a tree, the resin, which acts like an internal embalming fluid.
When the monk is fully prepared, both physically and mentally, he will be seated in the lotus position in a small cave, or perhaps buried alive with a small air hole,holding a bell which he rings to signify to the outside world that he is still alive. When the bell is no longer heard it is understood that he has passed on.