Since moving to Kyushu over a year ago, I’ve made onsen-hopping my new (although only occasional) pursuit. In a country with an abundance of volcanic activity, it seems there’s always a hot spring around every corner. So what do you need to know to enjoy one of Japan’s best natural features? Read on and see.
Onsen is the Japanese word for “hot springs” and, just like in any other country, you’ll find them clustered in areas of volcanic or geothermal activity. Japan being located on a highly volatile fault line that causes its share of volcanic eruptions, it should come as no surprise that there are onsen spread across the archipelago from Hokkaido in the north to Kagoshima on the southern tip of Kyushu. (It shocked me to learn at the time, but the Okinawan islands are not volcanic in origin. Rather, they’re the result of millenia of coral deposits building up. There is only one known natural hot spring in the prefecture and it’s located on one of Okinawa’s minor outlying islands.) If you’re looking for onsen on a map, it’s nearly always represented by this symbol – ♨.
For a hot springs to be technically classed as an onsen, the water must contain at least one of 19 specific chemical elements and be naturally 25°C (77°F) or warmer. Most onsen in japan boast about one healing property or another, whether it’s relief from indigestion or a guarantee for better skin. I can’t claim to have been miraculously cured of any ailments at a Japanese onsen, but I certainly do enjoy the feeling I have after a stint in the baths.
Many onsen are attached to a ryokan, or traditional inn (hence the term onsen ryokan). Onsen ryokan often offer outdoor baths (known as rotemburo) in some sort of attractive natural setting, such as next to a river or deep in the forest. These rotemburo can be separated by gender (one set of baths for men, another for women) or mixed. Only on a rare occasion will a mixed outdoor onsen require bathing suits. Normally, it’s birthday-suit only. In some ryokan, the staff will switch the baths around every morning – the women’s bath becomes the men’s bath and vice versa. Don’t panic if you forgot what the staff told you – blue (for men) and red or pink (for women) curtains are hung in front of the entrance to each bath so you shouldn’t have any doubts as to which one you should be entering!
In some areas of Japan, the hot springs are so abundant that a resort town will grow up around the waters. Some of these towns can be pretty charmless, full of boxy modern ryokan hotels and clogged with tour buses transporting hordes of visitors. Atami Onsen on the Izu Peninsula below Tokyo, Kinugawa Onsen north of Tokyo, and Beppu town in eastern Kyushu are some of the more concrete, developed onsen resorts in Japan. There is nothing wrong with their baths, of course, but the towns themselves lack a bit of soul. If you are searching for that quintessential “back-to-nature” onsen resort, you might be better off at Nyuto Onsen in Akita prefecture, Shuzen-ji Onsen on the Izu Peninsula, or Kurokawa Onsen in my own backyard of Kumamoto.
Don’t be confused and equate a regular ryokan bath with an onsen bath. Many ryokan maintain bathing facilities (gender separated) that are often blessed with beautiful cypress tubs or garden locations. These baths are lovely and well-maintained, but the water is not from a natural hot spring source. Still, the same bathing rules apply at both hot spring and regular baths – soap up and rinse off outside of the tubs or pool first and then enjoy a nice relaxing soak.