Reiki is the Japanese word for Universal Life Force Energy (aka Qi, Chi, Di). It was discovered in Japan during the latter part of the 1800's by Mikao Usui. Reiki works by challenging the energy through the hands of the practitioner.
Practitioners use a technique similar to the laying on of hands, which they say will channel this healing energy through their palms. It helps to reduce tension, revitalise, re activate, re generate, heal and bring the whole system into balance. It works on 4 levels - Physical, Mental, Emotional and Spiritual.