Reiki is a spiritual practice developed in 1922 by Japanese Buddhist Mikao Usui that uses a technique commonly called palm healing as a form of complementary and alternative medicine and is sometimes classified as oriental medicine by some professional bodies. Through the use of this technique, practitioners believe that they are transferring healing energy in the form of ki through the palms.
The Japanese word Reiki meaning "mysterious atmosphere / spiritual power" is a loanword from the Chinese word língqì , which some Chinese-English dictionaries translate as "spiritual influence (of mountains etc) / cleverness / ingeniousness"; This Japanese compound joins the words rei , meaning "ghost, spirit, soul / supernatural, miraculous, divine; ethereal body", with ki , meaning "gas, air / breath / energy / force / atmosphere / mood / intention / emotion, attention", here meaning qi, which means "spiritual energy / vital energy / life force / energy of life". Some Reiki translation equivalents from Japanese-English dictionaries are: "feeling of mystery", "an atmosphere (feeling) of mystery", and "an ethereal atmosphere (that prevails in the sacred precincts of a shrine); (feel, sense) a spiritual (divine) presence."
There are two main branches of Reiki, commonly referred to as Traditional Japanese Reiki and Western Reiki. Within both Traditional and Westernised forms of Reiki, there are three forms of degrees, commonly referred to as the First, Second, and Master/Teacher degree. According to Reiki practitioners and Masters, at First Degree, a Reiki practitioner is able to heal themselves and others, at Second Degree is able to heal others distantly (commonly called distant healing) with the use of specialised symbols, and at Master/Teacher level is able to teach and attune others to Reiki.
Systematic reviews of randomised clinical trials conducted in 2008 and 2009 suggested beneficial results of Reiki in some areas of health such as pain and anxiety, stress and hopelessness, though areas of health in which no beneficial effects were observed included functional recovery after ischaemic stroke, diabetic neuropathy, and anxiety and depression in women undergoing breast biopsy, though most of the trials used suffered from methodological flaws such as small sample size, inadequate study design, and poor reporting, and it was concluded that the evidence was insufficient to suggest that Reiki is an effective treatment for any condition, and therefore the value of Reiki remains unproven. The 2009 review detected a significant therapeutic effect of Reiki, though as with the 2008 review, methodological and reporting limitations of limited existing Reiki studies were present and therefore could not definitively concluded Reiki's effectiveness.

