The Reiki symbols are considered sacred symbols and their existence is known from ancient times in Japan, Tibet and India.
They existed before the use of Dr. Usui and therefore they have not only their origin in Reiki. Therefore, the first two symbols of Reiki are thought to have their origin in Sanskrit.
There are a total of 5 symbols, although there are others that people is using in Reiki therapy which also have value, although they are not part of the traditional Usui Reiki system.
Reiki symbols have a major effect on the way they work, since they directly access to the source of Reiki allowing the practitioner of this art to experiment and transmit Reiki to others.
Reiki symbols can be activated in many ways. For instance, they can be activated through drawing them with the hand, visualizing them or vocalizing their name, whether silently to yourself or aloud.
The essential thing is not the method that one chooses to use Reiki, but rather our aim when we channel and use it. For some, it is enough to meditate on the symbol to activate its strength and power.