hello, planning a trip to japan from 4/1/06 - 4/16/06, my main goal in japan is to find the coolest onsens. not too commercialized, but really authentic outdoor spas with nice natural surroundings. my destinations are from tokyo to as far as hiroshima. basically by the japan rail pass. please help, i am on a mission. also any fellow travelers with similar goals. contact me at [email protected]

When you get to Japan, go to a travel agent. There are thousands of onsens, most of which are unknown to anyone outside of Japan. A travel agent will have books devoted to onsens, with descriptions, pictures, and what they specialize in. They will be able to make your reservation for you. It will not be at all cheap. Plan on 30,000 yen per night per person.

If you just want to use the baths and not stay, some, but not all, onsens allow this for a fee of between 500 yen and 5000 yen per person. You could ask the tourist information counter in the bigger stations to help you.

You could also buy one of the many magazines devoted to onsens. Any large booik shop will carry these, and though only in Japanese, there are pictures. You could choose that way and then go...have your hotel help you reserve.

There is a lot of info about onsens on the web. There are dozens of onsen areas in Japan. There are thousands of baths at the onsen area. Typically, there are several onsen hotels and ryokan built at or near the onsen (hot springs) sources. It is common for onsen hotels to have their baths open to the public. Not all onsen baths are at hotels. Dogo Onsen is a good example of a public bath building at the hot springs.

I would highly recommend visiting Dogo Onsen, in Matsuyama, but it doesn't have "natural surroundings" or an outdoor bath. It is, however, very authentic.

In your travel area there are onsen in Hakone-Yumoto, Atami Onsen not far from Hakone, Gero Onsen just north of Nagoya, Arima Onsen near Kobe. I've been to the first three, but not Arima. You'll find outdoor baths in those onsen areas, I suppose. But I believe that most onsen, authentic onsen, are in fairly built up areas, at onsen resorts.

You ought to consider visiting Tohoku (northern Japan) and Kyushu to find the kind of onsen you say you are looking for.

A good itinerary would be to go by train north from Tokyo, visiting onsen along the way, eventually to Sapporo. Fly from there to Fukuoka and soak it up in Kyushu, flying from Kagoshima or Miyazaki back to Tokyo.

You shouldn't have any trouble finding info on rotenburo along your route. Here is one:
http://en.wikipedia.org/wiki/Image:-...a%2C_Japan.jpg

I found a wonderful book you might want to check out. The Art of the Japanese Bath, by Mark Edward harris. Black and white photographs of Japanese people enjoying many different onsen. Some particularly amazing ones in this book. Some of the ones pictured on Honshu: The cave bath at Urashima hotel, outdoor baths at Takaragawa, Jigokundai in NAgano, some onsen at the edge of the sea, etc. Great book. I now own it.