I have taught a lot of people visiting Japan from overseas.One of their reasons why they choose to come to Japan is learning more about traditional way of Reiki in the country where it started.
However they are quite disappointed that no Japanese people they talked to knows about it.
They come to me and ask me WHY?
Reiki is NOT as popular as many of other countries in Japan.
In 1922, Mikao Usui was spiritually awakened and received Reiki energy on Mt. Kurama in Kyoto, Japan. Soon after, he founded the Usui Reiki Ryoho Gakkai (Usui Reiki healing society) in Tokyo. Usui treated and saved a lot of people especially after the big earthquake; "Kanto daishinsai" (Great Kanto earthquake) in 1923. Reiki spread soon and Usui was recognized a master of healing touch.
After Usui's death in 1926, one of his students Chujiro Hayashi took a major role of transmitting Reiki. He initiated and trained Hawayo Takata; a Japanese-American woman borned and lived in Hawai. She returned to Hawai and started teaching Reiki (the style of Reiki Hawayo taught is now referred to as Western Reiki.). Reiki became very popular and has spread in western countries.
While Reiki got internationally well known, it faded in Japan.
Japan lost the World War II, and had to re-construct the country and catch up on western countries. People worked so hard and forgot about the luxury time to feel the subtle energy.
Reiki was re-imported into Japan in 80's and has been spreading again.
But still you can't talk about Reiki or spirituality with random people in Japan.
Many of foreigners have the image that Japan is a spiritual country.
I would say many of Japanese people are superstitious, but still very skeptical about something they can't see.
Without any scientific proof, many people think it's scum or cult religion or you are just one of the crazy people. So you have to know who you are talking to when it comes spirituality otherwise you might be judged in wrong way.
But I've been feeling that a lot of people started listening their inner voice and aware of what is more important for us these days. I hope more people realize how human were living in beauty of nature with respect and enjoy all the benefit of energy that was gifted from the universe.