Self-mummified monks, also known as living mummies or sokushinbutsu (即身仏), are buddhist priesters, who willingly mummified themselves in the quest for nirvana.
The bodies of these ascetic monks are exposed in a few Buddhist temples in northern Japan.
But the three-step quest to become a living mummy was a long and grueling process:
First step: During 1000 days, the monk had to follow a strict diet meal plan composed of nuts and seeds, and engage in rigorous physical training to strip the body of fat.
Second step: During another 1,000 days, the monk had to eat only bark and roots in gradually diminishing amounts. Toward the end, to lose body fluids, the monk started drinking tea from the sap of the urushi tree made with water from a sacred spring at Mt. Yudono. The sap is a poisonous substance normally used to make Japanese lacquer bowls. The sacred spring is full of arsenic. The concoction created a germ-free environment within the body and helped preserve whatever meat was left on the bone.
Third step: After 2000 days of suffering, the monk would retreat to a cramped underground chamber connected to the surface by a tiny bamboo air pipe, where they would meditate until dying. After 1000 days, the monk was dug up, cleaned and if the body was well-preserved, the monk was deemed a living mummy.
You may have already understood it. Just a few monks, who attempted self-mummification were successful. The fortunate candidates achieved Buddha status and were enshrined at temples. As many as two dozen of these living mummies are in the care of temples in northern Honshu. This buddhist quest of nirvana, or self-mummification, was outlawed by the Japanese government in the late 19th century.