In Kagoshima (and maybe other places as well) you’ll find Sunamushi Onsens. So what are sunamushi onsen? First, let’s review regular onsen. As you probably know, regular onsens are hot springs where you get naked and step into a naturally hot bath with a bunch of other naked folk, usually of the same gender. Or, if you’re lucky, you can get a private room and get in with only your girlfriend. 貸し切り！Sunamushi Onsen is similar, except there is no water, you don’t get naked, it’s not especially fun if you get in with your girlfriend, and it’s not exactly “hot” — more like, toasty. Read the warning signs!
You change into a simple yukata and no underwear before getting into to the sand pit. Once you’re ready, the ladies working at the location will dig you a shallow grave. Then you climb in, and they proceed to shovel sand all over your body, except your face.
At first the feeling of being buried by a buncha people with shovels freaked me out. But, I think that only happens to me. Once you are buried, you realize first that sand is heavy. Then you’ll notice that this sand is hot! The most popular place to have this wonderful experience is in Ibusuki.
Kagoshima is also famous for Sakurajima, a volcano… Basically right in the middle of the city. This volcano is still active, and as recently as the 1980s the city was covered in ash most of the time because of it’s frequent spurts. The region is active so it has many natural onsen, and thus, this really hot sand.
I did this way back in 2005. It felt great!