My Understanding of the Abntahkarana symbol used in reiki is that it is from Alice Bailey chnneled from her Tibetain guide.
It is used in William Rands Tibetain Reiki. The Rand manual, of which I have photcopies of the atahkarana stuff does say this.
My own first expierience of the idea of it was as a bridge to the higher chakras, but then like so many things infomation fromone source does contridict info from another one.
Rand does give 2 versions of the symbol. One male the other female. It seems strange to me that most masters when using it only use one or the other and not both. To me for balance both should be used (If of course you use it at all)
Namaste
Rob
Truth is not a property of language because language has not been able to express abstract ideas as efficiently as concrete items