Sennin (sage ninja/hermit/immortal) is the word for the people who were the first ninja, along with the gyoja (hermit warriors), yamabushi (mountain ascetic warriors) and the shugenja (shugendo). They were ninjas with great individual skill. A ninja on the cover of Black Belt magazine. ... Yamabushi were Japanese mountain ascetics and warriors, mostly of the Shingon sect of Buddhism. ... Shugenja were the 7th century practitioners of the Japanese religion of Shugendo. ...
In japanese mythology, the sennin are immortal hermits that live in the mountains. There are about 500 of them, some of them are Tobosaku, Chokaru, Seiobo and Gama-sennin.
The Sennin were known for their high degree of enlightenment, splendid health, and according to some ancient myths, their ability to attain immortality.
Davey Sensei, and by extension the Sennin Foundation Center for Japanese Cultural Arts, is affiliated with a number of elite organizations, which serves to illustrate the group's close ties with Japan and the nature of the Sennin Foundation's programs.
The Sennin Foundation, Inc. --A federally tax-exempt, nonprofit corporation, which is headquartered in California, and which promotes the study of Japanese cultural arts for personal transformation.
Sennin onsen is not difficult to get to, it just takes a long time.
The bath was located right in front of the Sennin onsen cottage, and is probably the most exposed bath I have ever been in, except it is located deep in the mountains which prevents all the stupid tourists from going.