Over one thousand years ago a priest known as Kuukai founded the Buddhist sect of Shingon in Northern Japan. Based on the sect’s belief that physical punishment was the path to enlightenment, the practice of Sokushinbutsu, or self-mummification, was born: a decade-long process of slowly poisoning the body in the hopes of achieving successful mummification of the tissues.   It is widely held that hundreds of Buddhist monks may have attempted self-mummification, but only around two dozen self-mummified bodies have been discovered to date.

Monks who embarked down the path of self-mummification endured as much as ten years of torturous physical regimens in order to prepare the body for death.   For the first one thousand days, a monk would consume nothing but seeds and nuts while maintaining rigorous daily exercise in order to rid their entire body of fat.   The next one thousand days are spent eating nothing more than roots and bark, and drinking tea made from Urushi tree sap, a poison routinely used as a lacquer.

The poison in the tea slowly built up in the body over time, making the tissues too toxic for maggots and other carrion feeders to eat.   In his final days, the monk would assume the lotus position in an impossibly-small stone tomb underground.   With a breathing tube to the surface and a string attached to a bell, the monk would ring the bell each day and, once the bell stopped ringing, the air tube and the tomb were both sealed.

After another period of one thousand days, the temple monks would see if the self-mummification had been a success by opening the stone tomb.  Most of the time the process failed, the monk inside ended up a decomposed body; but if the monk had successfully mummified himself, his body, still in the lotus position, would be taken to the temple for viewing and worshipped as a Buddha.

Although roughly two dozen mummified sokushinbutsu have been found in Japan, only around sixteen of them can be visited in a tourist capacity.   The majority of the monks who underwent this process successfully did so at Dainichi-Boo Temple on Mount Yudono, and this is where the most famous monk, Shinnyokai Shonin, is located.   It is thought that the high levels of arsenic found in the springs around the temple may have aided the monks in self-mummification.