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For me one of the great strengths of Reiki is its simplicity. You learn some history, you learn the hand positions, you receive your attunement, and you start daily self treatment in addition to any reiki you do on others. That's it! No chanting, no incense, no chakras.
Now many reiki practitioners choose to add extras. They bring out the crystals, the chakra charts, and prescribe meditations and chants to help keep the energy flowing between treatments.
While these things are nice additions, they are additions. Reiki does not require meditation, chanting, or an understanding of your chakras. Reiki works anyway. It is, for lack of a better phrase, idiot proof. You just do the hand positions and channel the Reiki and the Reiki will do the work always for the highest good where it is wanted and needed. Period.