Here’s the answer to another common question:
How old is Reiki?
Next time someone asks you this question, you could consider replying something along these lines.
If you wish to ask how old the healing energy that is passed from the Source to the patient through the practitioner is, then this energy would have to be at least as old as life itself. That is, very old, relative to a human life.
If you wish to ask how old the laying on of hands for healing purposes is, that is also quite old. There are references of healers using laying on of hands in the Bible and many other ancient texts. Whether these people were channelling Reiki or not, we may never know. Many people practice healing by laying on of hands today without calling it Reiki.
And finally, if you wish to ask about the more formalized healing system that requires attunements and uses symbols to channel energy, this system is, at the date of writing this article, less than 100 years old. It was discovered in 1922 by Dr Mikao Usui in Japan.