Reiki - pronounced as ray - key is a Japanese art of healing. In Japanese language, the word "Rei" means Universe and "Ki" means energy.
Reiki means Universal Energy. Reiki is not affiliated with any particular religion or religious practice.
Reiki was introduced by Dr. Mikao Usui.
Which is now being used by Reiki healer across the world.
Disclaimer:
It is one of the oldest forms of healing known to mankind. Originally it was developed in Tibetan Buddhist Practice that was re-discovered in the late 1800's by Dr.Mikao Usui.
Dr. Mikao Usui was born on 15th August 1865. It was his desire to find a method of healing that was unattached to any specific religion and religious belief, so that his system would be accessible to everyone. Dr. Usui travelled all over Japan, China and Europe in pursuit of knowledge and studied a wide range of subjects.
Dr. Usui attended his own training rediscovery course in a cave on Mount Kurama. Dr. Usui fasted for 21 days on the mount. On the morning of the 21st day, Dr. Usui was beginning to become frustrated with his situation. As he was about to give up and leave, that a great spiritual energy came down to him and he became enlightened.