The Japanese do a wonderful job of taking a glass-half-full approach to all the geological activity that their archipelago, with its location on the morbidly named "Pacific Ring of Fire", is subject to. Rather than dwell on a history of debilitating earthquakes, or the possibility of cataclysmic volcanic eruptions, they just take off all their clothes and let their cares evaporate in the steam of a Japanese hot spring. Known as onsen, these hot springs in Japan can be found in almost every corner of the country, and constitute some of the best things to do in Japan.
All puns aside, onsen are a great way to relax after climbing Mount Fuji, or at the end of a hectic week of business meetings. A result of the massive quantities of heat released underground near fault convergences and volcanoes, the onsen have become a national pastime, and any tourists visiting the country shouldn't miss a chance to soak their tired tourist bones in a Japanese hot spring.
Hot springs in Japan can be found from the north to the south. The area around Mount Fuji has great natural onsen (though they do get a bit crowded during tourist season), and the Japan Alps region also has a number of excellent high altitude soaking spots. Some of the best hot springs in Japan, however, are farther off the beat track.
The Beppu onsen are located at the foot of Mount Aso on Japan's southernmost island, Kyushu. When Aso erupted sometime between 300,000 to 90,000 years ago, the blast left a 120 km caldera. There are still active volcanoes and vents within the center of the caldera, and guided tours through Mt. Aso offer some of the best (and steamiest) sightseeing in Japan. As you would expect with so much tectonic activity, Kyushu is a great place to enjoy traditional a dip in a Japanese hot spring. There are roughly 3,000 natural hot springs at Beppu, which attract 12 million tourists annually. There are numerous onsen-centered guesthouses, ranging from cheap backpacker's delights, to modern accommodations
At the opposite end of the country from the Beppu onsen, are the hot springs near Lake Toya on the island of Hokkaido. Japan's northernmost, and least inhabited island, is home to some of the least-crowded hot springs in Japan. Like most onsen in Japan, the Lake Toya hot springs are located in a mountainous national park. Like the area around Mount Fuji and Mount Aso, the Shikotsu-Toya National Park offers travelers some of the best sightseeing in Japan. And after a long day of hiking, rock climbing you can soak your tired bones in the tranquilizing waters of this Hokkaido hot spring.
More than just glorified hot tubs, onsen provide a place to socialize. One of the best places for a tourist to interact with the local population is in the calming waters of an onsen. Remember, though, many onsen are divided into men's and women's sections. And like the beaches in Spain, or the baths in Turkey, Japanese onsen are mostly enjoyed in the nude.