Reiki originated in Japan in the 1920's. Mikao Usui, the founder of Reiki, created a system of healing he called Reiki. He spent the rest of his life up until his death in 1926 practicing and teaching this method of natural healing which involves the laying on of hands and distant treatment. Mikao Usui authored the principles or precepts of Reiki which he is believed to have derived from the Waka poetry of the Japanese Emperor Meiji.

One of Usui's students, Dr. Chujiro Hayashi, a medical doctor and retired Japanese naval officer, continued Usui's work after his death opening a Reiki clinic and school in Tokyo.

One of Dr. Hayashi's students, Mrs. Hawayo Takata, an American who was born in Hawaii of Japanese descent, consulted with Dr. Hayashi in Japan in 1935 about life-threatening medical problems she was having. Mrs. Takata studied Reiki under Dr. Hayashi, and in 1938 was very honored to be designated one of Hiyashi's small group of Reiki masters. Mrs. Takata brought Reiki to Hawaii and to the mainland of the United States, Canada, and Puerto Rico. Mrs. Takata's granddaughter Phyllis Lei Furumoto, is recognized as the present Reiki Grand Master and Lineage Bearer of the Reiki Alliance,  Usui Shiki Ryoho,  a worldwide organization founded in 1982 by 21 out of the 22 Reiki masters initiated by Hawayo Takata before her death in 1980. The Reiki Alliance's mission is to promote traditional Usui Reiki and to support of Reiki Masters or Teachers. Phyllis Furumoto has taught and has encouraged the  teaching of Reiki worldwide.

In 1938 two years after Hawayo Takata completed her Usui Reiki studies with Chujiro Hayashi, a Japanese student of Dr. Hayashi, Chiyoko Yamaguchi, first learned Reiki at the age of 17. Her uncle Wasaburo Sugano had brought Dr. Hayashi to teach Usui Reiki to himself and his entire extended family including Chiyoko in Ishikawa, Japan. Chiyoko studied Shoden and Okuden, the student levels of Reiki directly from Dr. Hayashi. She learned the Shihan or Teacher levels of Reiki from and was attuned in them by her uncle Wasaburo Sugano who was one of Dr. Hayashi's Shihans or Reiki Teachers.

Chiyoko Yamaguchi spent her remaining 65 years of life treating others using the Reiki she was taught by Dr. Hayashi. All of her three sons received Reiki Reiju, Her youngest son Tadao Yamaguchi began treating people with Usui Reiki in 1965 at a young age. In the late 1990s, Tadao Yamaguchi and his mother started teaching a form of Usui Reiki they called Jikiden (meaning "directly handed-down"). This Reiki was based on the Usuii Reiki Mrs. Yamaguchi learned from Chujiro Hayashi and her uncle Wasaburo Sugano and that her son Tadao Yamaguchi learned from his mother. Chiyoko Yamaguchi died in 2003. Tadao Yamaguchi currently teaches the Jikiden Reiki in Japan and worldwide and is committed to preserving and spreading the Jikiden form of Usui Reiki through the Jikiden Reiki Kenkyu Kai,  his Reiki Institute in Kyoto, Japan. All Jikiden Reiki Shoden and Okuden Students as well as all Jikiden Reiki Shihan and Shihan kaku are registered with the Jikiden Reiki Institute. Jikiden Reiki offers the traditional practice of a simple, effective and original form of Usui Reiki  taught by Dr. Chujiro Hayashi in Japan in the 1930s. Dr. Hayashi learned Reiki and the Reiki Gokai or precepts directly from Mikao Usui the founder of Reiki and was one of his 22 Reiki teachers. The Jikiden Reiki Association's primary purpose is to promote the teaching and practice of the form of Reiki that Dr. Hayashi learned from Usui and taught The word "Jikiden" means directly handed down. Jikiden Reiki is closely aligned with the Reiki Gokai (Precepts) for Health and Happiness authored by Mikao Usui and its center is the Jikiden Reiki Kenkyukai or Jikiden Reiki Institute in Kyoto, Japan. Mrs. Chiyoko Yamaguchi, the cofounder of Jikiden Reiki took her first Reiki seminar from Chujiro Hayashi in Ishikawa, Japan, in 1938 at the age of 17 and she practiced and taught Reiki in Japan until she died in 2003. The Jikiden Reiki Kenkyukai was cofounded by Chiyoko Yamaguchi and her son Tadao Yamaguchi. Mr. Yamaguchi and Jikiden teachers taught by the Yamaguchis are currently teaching Jikiden Reiki seminars worldwide. Tadao Yamaguchi's highly recommended book Light on the Origins of Reiki: A Handbook for Practicing the Original Reiki of Usui and Hayashi gives a Japanese spiritual, historical and cultural context to the practice and origins of Reiki in the world today.