Jigoku Onsen (地獄温泉)
Onsen
Entrance: Adult 400円, Child 200円
Tubs: 3 Outdoor (one mixed), 2 Indoor (separate)
Located on the slope of Mt. Aso, you're best off to stop off at a convenience store on the west side of Aso to get one of their photocopied maps detailing all of the onsen. There are signs in kanji (and occasionally romaji) that help a lot, once you're in the right area.
You buy a pass at the main building (to the left as you walk into the complex), which you then get stamped as you go into the 3 different onsen areas of the complex.
"The rocky outdoor baths (separate gender), "Roteniwaburo", are quite nice. The water temperature is great, they're rarely crowded, and the view is spectacular.
The Sparrow Bath, "Suzumenoyu" is mixed gender, and has very acidic water, so take off any jewlery before entering. The bath itself has an irregular, compartmentalized shape, with some parts covered with a roof. This is a great bath to bring your friends of opposate gender, although it may get crowded at times."
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When I visited this bath in Golden Week '06, it was very full of old men, and maybe two women tightly wrapped in big towels. In the Lonely Planet's introduction to Onsen, it was mentioned that some people would stay in onsen for months on end, if they could just place a tock on their lap to stay in one place while they sleep. Seeing the men here, I believe it - it doesn't look like they've moved for months. Anyway, I'd suggest you visit here at non-peak times.
Transated Official Site
Mt. Aso area attractions
Kyushu Onsens - mjryoung
Mixed
Community
Japan
Kumamoto
Aso
Traveling through Kyushu
An index largely of onsen, Hot Springs, in Kyushu. Much of this info came from other sources on the net, and the rest came from a trip I made with my wife in 2006. If you have any corrections to the info I have here, please email me at slycker[at}gmail;dot:com
Other Japan Maps:
Tokushima ken
Mie ken
Resources:
as linked on individual locations
Specific Sources:
Jens Olsen
mjryoung
Secret Onsen