According to the Wikiversity REIKI page, "Reiki is an ancient Japanese science of healing". According to the Reiki article at Wikipedia, Mikao Usui developed Reiki in early 20th century Japan. The Wikipedia article cites What is the History of Reiki?, a webpage at the website of The International Center for Reiki Training.
According to "An Introduction to Reiki" at the National Center for Complementary and Alternative Medicine, "There are different beliefs about the origin of Reiki--one is that it is based on Tibetan sutras (texts of Buddhism) written by monks." According to James Deacon, the idea that Reiki originated in Tibetan texts came from Arthur Robertson, creator (in the 1980s) of a 'Tibetan' Reiki style. The idea of an ancient Tibetan origin for Reiki was popularized by Diane Stein in the 1995 book Essential Reiki: A Complete Guide to an Ancient Healing Art.
Is Reiki a science?
According to "An Introduction to Reiki", not much is known about Reiki as a science and, "accepting its teachings about its healing properties and about ki is a matter of faith".
Scientific studies of Reiki
The PubMed database has several hundred articles that mention "Reiki" and less than a hundred that incluse both "Reiki" and clinical trial.
List of published results from clinical trials
- A phase II trial of Reiki for the management of pain in advanced cancer patients by K. Olson, J. Hanson and M. Michaud in Journal of pain and symptom management (2003) Volume 26, pages 990-997.