Is a Japanese concept translated as "Universal Life Energy" by Hawayo Takata.
The phrase was used by Mikao Usui to describe an energy that he had contacted through years of self-preparation and dedication. The following description of Reiki is taken from Hawayo Takata’s journal when she was a beginning student of Chujiro Hayashi, circa 1935.
"The power (Reiki) is unfathomable, immeasurable, and being a universal life force, it is incomprehensible to man."