I waffled quite a bit and here is my edited answer based on my experience and the writings of Taggart King (Reiki Evolution):
Reiki is a mindful and respectful way of living and being in relationship with others and the universe. From this it developed into a healing therapy. It was formalised in Japan by Mikao Usui. Reiki can be translated as spiritual energy. (I recognise this translation as pure consciousness.) Reiki is experienced as engaged awareness, as meditation; it is a space for clarity and connection. It results in feelings of ease and relaxation.
Mikao Usui was a Tendai Buddhist and he taught reiki as a method to achieve personal perfection. Reiki was not primarily a healing system to be used for others but a time of self development in order to move towards enlightenment or a ‘gift of satori’.
Usui taught these precepts as the foundation of his teachings. Adhering to these precepts can foster our spiritual development and a way of being in life. Students were introduced to the Buddhist concept of ‘oneness’, that we are all connected. In the West, distance healing is an expression of oneness. All healing practices can be related to the concept of oneness. In sharing space we have an impact on each other; calling someone to mind is just sharing a non-physical space.
Although reiki was traditionally learned for one’s own development and practice, today most people experience reiki for the first time by receiving it from someone else. Starting with our own journey of reflection and understanding is a necessity to understand our place in the world and to make sense of the life we are living, whether or not we decide to work with or for others.
Why reiki? For different reasons. Some people have reiki to ameliorate aches and pains, to recuperate, to relax. Some come because they feel stuck and can’t find a way to move forward. Some people just feel drawn to it and feel better for it. At some point there may be a shift for a person and they find themselves drawn to studying reiki. This can be to develop personal practice or to begin the journey to working with others either formally or informally.
How would I describe reiki? It is often subtle and how it is experienced is different for different people, sometimes different from one session to the next. As with most meditative process it is difficult to describe and easier to find a relationship with it by receiving it.
I will be writing more about reiki. It is available to everyone. It informs my yoga practice and impacts on me daily. I wrote this some time ago but this feels like a good time to share it: