What is "sokushinbutsu"

refers to a practice of Buddhist monks observing austerity to the point of death and entering mummification while alive. This process of self-mummification was mainly practiced in Yamagata in Northern Japan between the 11th and 19th century, by members of the Japanese Vajrayana school of Buddhism called Shingon ("True Word"). The practitioners of sokushinbutsu did not view this practice as an act of suicide, but rather as a form of further enlightenment.

It is believed that many hundreds of monks tried, but only 24 such mummifications have been discovered to date. There is a common suggestion that Shingon school founder Kukai brought this practice from Tang China as part of secret tantric practices he learned, and that were later lost in China.