Reiki is a Japanese practice of energy healing in which the practitioner is understood to channel a universal life energy (the name combines rei, "spiritual/universal," and ki, the vital energy) through the hands to promote relaxation, balance, and healing in the recipient. The practitioner places the hands lightly on or just above the body, moving through a sequence of positions, while the energy is held to flow to where it is needed.
Reiki was developed in early twentieth-century Japan by Mikao Usui, who taught it as a spiritual and healing discipline; it was carried to the West mid-century and has since become one of the most widespread forms of "energy" or "biofield" therapy worldwide, practised both privately and, in many places, offered alongside conventional care in hospitals and hospices as a relaxation aid. The tradition includes a lineage of attunements by which teachers are said to transmit the ability to channel Reiki, and a set of symbols used at higher levels. Presented honestly and per reputable medical bodies: Reiki is generally experienced by recipients as deeply relaxing and is regarded as safe when used as a complement to, not a substitute for, medical treatment; from a scientific standpoint, however, there is no demonstrated physical "energy" of the kind it posits and no robust evidence of specific healing effects beyond relaxation and the placebo response. It is thus best understood as a complementary relaxation and spiritual practice, valued by practitioners within a framework of universal energy and intention.