Reiki is a Japanese technique that promotes deep relaxation and healing.  It's done through touch therapy.  A warm and soothing energy flows from the hands of the practitioner, into the client, releasing tension, helping to balance the clients central nervous system.  Reiki, as a spiritual energy, operates at an even higher and faster vibration than the Chi in the the physical body, so it can move through all parts of the human energy field to break through energetic blockages and promote healing, to the body, mind, and spirit.  Reiki encourages a sense of well-being, and assists the physical body's own healing ability to operate more effectively and efficiently.  Reiki can also be used in a similar way to treat animals.