Reiki was discovered by Mikao Usui in 1922 whilst performing a twenty-one day retreat on Mount Kurama, involving meditation, fasting, and prayer. Usui said that by mystical revelation, he had gained the knowledge and spiritual power to apply and attune others to what he called Reiki. Usui was an admirer of the literary works of the Emperor Meiji and in the process of developing his Reiki system; he summarized some of the emperor's works into a set of ethical principles, which later became known as the Five Reiki Precepts. Many Reiki teachers and practitioners aim to abide by these five precepts, or principles, one translation of which is:
"The secret art of inviting happiness,
The miraculous medicine for all diseases.
At least for today:
Do not be angry,
Do not worry,
Work with diligence,
Be kind to people.
Every morning and evening, join your hands in meditation and pray with your heart.
State with your mind and chant with your mouth.
For the improvement of mind and body."
Usui Reiki Ryoho.