Over a 900 years ago there was a monk of the Shingon sect who took it upon himself to truly test his Buddhist principles. The technique of sokushinbutsu is a very long, elaborate and painful one. It was typically performed by older monks as it is a form of suicide.
To become a mummy a monk would follow a strict diet in three 1000 day cycles. In the first thousand days the monk would have a strict diet of walnuts, hazelnuts, and nutmeg gathered from the surrounding areas. This strict regimented diet helped to strip the body of fat. Fat decomposes quickly in death.
In the second 1000 day period, the monk would eat only bark and roots of a pine tree. This accelerated the decrease in the body’s fat content as well as hydration. At the end of the second period the monk would imbibe a very poisonous sap made into a tea. The tea was made from the Japanese varnish tree. The varnish was typically applied to preserve lacquer-ware. The varnish would induce vomiting as well as massive reduction of bodily fluids. By drinking the tea the monk’s body would bio-accumulate the toxin. This toxin would later be an agent to fight of bacteria and insects that would seek to eat monk’s corpse.
When the monk was no more than a living skeleton and his body was in excruciating pain they would be placed in 3 meter stone tomb. The monk would sit in the lotus position in this tomb and he was given a bell and air tube. When the monk did not ring the bell it was presumed that he was dead and the air tube was removed.
It is believed that of the hundreds of monks that tried this technique only 16-28 actually became self-mummified. The reason the monks would endure this painful process was as a testament to their faith. All existence is suffering,and to endure this painful process allowed the monk to transcend the physical and exist solely on a spiritual level. At least that was the idea. When further study was given to the monks it was discovered that the more successful monks drank from a nearby spring. This spring was believed to contain healthy mineral waters. The mineral waters were actually heavily loaded with arsenic. Another agent that would have bio-accumulated in the monk’s system as a preservative.
Self-mummification was a very painful process, but when successful the monks body was taken up to a temple to be revered. For truly he had become a Buddha.