Arima Onsen is an onsen, or hot springs in Kita-ku, Kobe, Japan. This Onsen is still a hidden treasure of modern Kobe, behind Mount Rokko. It attracts many Japanese who want tranquility with beautiful natural surroundings and yet easy access from the busy cities in the Kansai metropolitan area including Osaka.
This onsen is the one of Japan's oldest, with Dogo Onsen in Ehime Prefecture and Shirahama Onsen in Wakayama Prefecture. Many documents since the 8th century AD mention this onsen.
According to these documents, among the many visitors to Arima Onsen are Gyoki, a charismatic Buddhist monk in the 7th century, and Ninsai (ÉmÉ╝), another monk in the 12th century. Ninsai was said to greatly admire Arima Onsen and helped develop it. Hideyoshi Toyotomi visited this onsen several times in the 16th century.
Arima Onsen has two kinds of springs. One is kinsen, "gold spring"), which has water colored yellow-brown from iron and salt. The other is ginsen, "silver spring"), which is colorless and contains radium and carbonate.