This item is from the Millennium Edition of the alt.healing.reiki FAQ, by Scott Maxfield (v2.001).
The views expressed herein do not necessarily reflect those of the author or of the posters to the newsgroup alt.healing.reiki
No guarantee or warranty is expressed or implied in any form and no liability is accepted for any harm arising from use or misuse of this information. In medical matters always seek the advice of a qualified medical practitioner.
There are more systems than I care to enumerate and they are sometimes little more than a chance for one-upmanship by saying "mine is better". They all are based on the same Reiki energy (since there is only one Reiki energy). They differ in the name (which is often trademarked), in the symbols used, in the attunement process (both of these normally being jealously guarded secrets) and in the details such as the hand positions used in treatments. All systems ultimately derive from the system originally introduced by Mikao Usui. I wouldn't consider them to be improvements on the original, only different, sometimes actually detracting through the inclusion of needless ritual and elaboration.
"What Reiki is not" has a little to say on ritual.