In Japan the term refers to the practice of Buddhist monks observing asceticism to the point of death and entering mummification while alive.
[2] There is at least one "self-mummified" 550-year-old corpse in existence: that of a Buddhist monk named Sangha Tenzin in a northern Himalayan region of India, visible in a temple in Gue village, Spiti, Himachal Pradesh.
[4] According to Paul Williams, the sokushinbutsu ascetic practices of Shugendō were likely inspired by Kūkai, the founder of Shingon Buddhism,[6] who ended his life by reducing and then stopping intake of food and water, while continuing to meditate and chant Buddhist mantras.
[7] A mountain-dwelling religion called Shugendō emerged in Japan as a syncretism between Vajrayana Buddhism, Shinto and Taoism in the 7th century, which stressed ascetic practices.
[10][9] The monk abstained from any cereals and relied on pine needles, resins, and seeds found in the mountains, which would eliminate all fat in the body.
[11] 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").