Honmyōkai Shōnin is believed to be the oldest self-mummified monk in the Yamagata prefecture of Japan. Born Togashi Kichihyoei in 1623, he received samurai training and served as a vassal to a feudal lord. He joined a Buddhist seminary in 1661 and developed a disciplined ascetic lifestyle for years before deciding to mummify himself.
Honmyōkai is self-mummified via the Shingon Buddhist practice of sokushinbutsu – reaching enlightenment through extreme asceticism which results in the practitioner’s death. This process is incredibly long and drawn-out, taking upwards of ten years to complete.
To mummify himself, Honmyōkai maintained a strict diet called mokujikigyō for roughly nine years, involving eliminating all foods in favour of pine needles, resin, seeds, and berries to consume body fat. On May 8, 1681, Honmyōkai sealed himself in a stone chamber to meditate until he died. After his death, his body was further smoke-dried with charcoal and incense before being reburied.
His body was later exhumed in 1683. Found to be completely preserved, he was enshrined in Honmyō-ji temple as a Buddha.
As he is housed in a temple and regarded as an object of worship, Honmyōkai has not been subject to any known physical examination.
Jeremiah, Ken. (2010). Living Buddhas: The Self-Mummified Monks of Yamagata, Japan. Jefferson, North Carolina, USA: McFarland & Company Inc.
Wikipedia retrieved from: https://en.wikipedia.org/wiki/Sokushinbutsu. Retrieved October 12, 2017.