The term grandmaster was never used by any Reiki teacher prior to the early 1980s. Therefore none of today’s more well-known teachers such as Mikao Usui, Chûjirô Hayashi or Hawayo Takata used the term.
It was introduced in the early 1980s by The Reiki Alliance. Phyllis Lei Furumoto, Hawayo Takata’s granddaughter, received the title ‘Office of the Grandmaster’ from this association.
Today some teachers of Reiki have self-nominated themselves as grandmasters or even great-grandmasters. It is generally accepted that this is a marketing ploy rather than having anything to do with the system of Reiki.