Mummification has been known at least since the time of the ancient Egyptians, and has been practiced in many cultures since then, and this fascinating film looks at mummification in Japan.
The phenomena discussed in this documentary, however, is somewhat different, as it is the process of self-mummification of Buddhist monks, which has been used in the Vajrayana Shingon sect in Japan.
The process was somehow discovered by the founder of the Shingon sect, Kukai, whose own body is similarly preserved, but this film is centred around four mummies from the same sect in the north of Japan.
They have been preserved for the past 200-400 years, and scientists have been trying to discover how someone can mummified themselves in this way; it turns out to be possible given a very strict diet which members of the sect intent on self-mummification undertake.
As the organs have not been removed, as in traditional mummification, the body is first prepared through what amounts to starvation, then a special diet including lacquers and pine bark, and in the end what appears to be the ingestion of arsenic.
It is quite remarkable how far all of this is from the Middle Path declared by the Buddha, but of course, as with any extremism, the mummies became objects of admiration and worship, and are held sacred till this day.