Here is a photo of a bronze statue side by side with a CT scanned photo of the same statue which reveal that the mummified remains of a monk is inside! The statue currently resides at the Buddha Drenthe Museum in the Netherlands and a subsequent investigation discovered that the monk lived over 1,100 years and that his skeletal remains was encased inside the statue which depicts the Buddha.

Here is the Buddha statue about to be examined by the to CT scanning machine.

This mummy is seen to be the immediate only Buddha of the high priest.

The Path to Enlightenment.

As part of the Japanese Buddhist esoteric system, monks who died while in a meditative state were mummified and were referred to as a “Zen Contemplation Mummy”. Naturally, strict meditation such as this can open the path of enlightenment but it is thought that the acquisition of eternal life can be achieved rather than the death of the death. This practice today is quite rare but it is still practiced in the Shonai region of Yamagata Prefecture in Japan where monks who died while meditating are still mummified as well as some remote temples in China.

source: Wikipedia

The Buddhist monks underwent a long and intense meditative training during their tenure in this world and it seems that followers of this ascetic chose to encase his skeletal remains inside the bronze statue as a type of memorial for the years of devotion to the Buddha. It is interesting to note that 18 other skeletons have been identified inside other Buddha statues in Japan.