Arima Onsen is a hot springs in Kita-ku, Kobe-Shi, Japan, behind Mount Rokko. Arima Onsen is said to be the oldest onsen in Japan. Toyotomi Hideyoshi who was a great daimyo and later unified the political factions of Japan in the Sengoku period ,visited this onsen several times. Arima onsen contains lots of minerals and natural ingredients. It has two kinds of springs, kinsen and ginsen. The former has water colored yellow-brown and the later is colorless.