The Reiki Symbols - Ongoing Research
by James Deacon
2005

EXCERPT:

Takata-Sensei taught that the Reiki symbols were sacred and as such should be kept secret - not shown to the uninitiated. To this end, her students were required to memorize the symbols and were not permitted to keep written copies of them.
[Takata-Sensei believed that the symbols should be treated with respect – even the practice sheets used by students in her Reiki classes had to be disposed of respectfully, rather than simply crumpled up and dumped in a bin.]
While the four symbols used in Usui Shiki Ryoho and Usui Reiki Ryoho are still considered by many of us to be Sacred (or at least, of sacred significance), ever since two of the symbols (the SHK and the HSZSN) were first revealed in a Reiki book: ‘The Challenge To Teach Reiki’ by A.J. MacKenzie Clay, (published in 1992), the belief in the need to keep them secret is no longer generally considered relevant.