Here is the article which an American scholar with a Ph.D. who studied at The University of Tokyo wrote about our hot spring.
This hot spring, Owakudani onsen, is among the top three finest natural mineral hot springs in Japan, along with the world famous Kusatsu onsen in Gunma prefecture, and Beppu onsen, located in Kyushu`s Oita prefecture. The superior nature of the waters here has been recognized by many notables, including Dr. Erwin Von Balz, the renowned German professor of medicine who was invited to Japan by the Meiji Japanese government to educate the Japanese in medicine. Aside from occupying his prestigious position as professor of medicine at the Tokyo Imperial University, Dr. Balz frequently embarked on various journeys around Japan in search of the very finest springs.
He was in search of those waters that would be most effective, medically speaking, in fostering the health of the Japanese people. What Dr. Balz found was that there were two superior hot springs in Japan, one located in Kusatsu, and the other right here, in proximity to Tokyo, at the Sengokuhara region`s Owakudani onsen. He then made an official proposal to the Meiji emperor in 1887, delineating the fact that these two superior hot springs should be employed by the Japanese government to maintain the health, both physically and mentally, of the Japanese people.
Also, Dr. Balz communicated to the emperor that these springs offer an opportunity to truly refresh the mind and spirit from the many worries human beings experience in modern industrial society. Because of Dr. Balz and his proposal to the Meiji emperor, the emperor purchased the area around Owakudani. Meanwhile, Shibusawa Eiichi, the progenitor of Meiji Japanese capitalism, had purchased almost all of the Sengokuhara area and created pasturelands, in the hope of promoting the intake of dairy products and meat for Japanese people to strengthen their bodies, and become the equals of the westerner.
At the same time, this area was known as the pasturelands and farms that provided the meat and dairy for many foreign visitors and illustrious dignitaries that were staying at the famed Fujiya hotel in Miyanoshita in Hakone. The Owakudani area is famous for its high levels of volcanic activity, which produces high volumes of extremely hot, sulfurous water that includes a rich variety of other natural minerals (18 types of minerals in all).
This rich natural mineral water is absolutely among the very best volcanic spring waters in the entire world. Japan, although dangerous at times due to its high volcanic activity and frequent earthquakes, paradoxically, enjoys probably the best hot springs in the world. And, Owakudani is among those very few select hot springs that have been recognized by experts as the best in Japan.
This is why this hot spring is most likely the best spring you will ever encounter in your travels, unless you plan to visit Kusatsu or Beppu. It is the hope of the Takahashi family, the owners of the Fuji Hakone Guest House, that many tourists from around the world who visit Japan will avail themselves of these truly wonderful, healthful waters.
The Takahashi family opens their doors with kindness, wishing from the heart that many world travelers can experience these rare, valuable and rich mineral waters.