Hot water percolates up out of the ground from one end of Japan to the other. The Japanese word for a hot spring is onsen, and there are more than 3,000 of them in the country, more than anywhere else on earth – it’s like Iceland on steroids. In Japan, it is not an unusual or even decadent way to pass time soaking in a tub of bubbling hot water. Here are some that are considered to be the holy grail of the onsen world.
1. Best Riverside Onsen (Gunma, Central Honshū)
Japanese onsen maniacs often pronounce Gunma-ken's onsen to be the best in the country - and it's difficult to argue this point. Takaragawa means "treasure river", and its several slate-floored pools sit along several hundred metres of riverbank. Most of the pools are mixed bathing, with one ladies-only bath. The alkaline waters are said to cure fatigue, nervous disorders and digestive troubles.
2. Best Inner-City Onsen
Azabu-Jūban is the urban onsen par excellence. As you ease into the tubs here, you'll have to pinch yourself to believe that the seething masses of Tokyo are only just outside the door. The bland exterior of the place belies the reward inside: the steamy, mineral-rich water piped up from 500m below ground and the classic bathhouse atmosphere. Surprisingly, there's a small rotemburo (open air onsen) for each gender and weekends feature live traditional music in the tatami tearoom.
3. Best Island Onsen
Jinata Onsen (Shikine-jima, Izu-shotō)
The setting of this onsen couldn't be more dramatic: it's located in a rocky cleft in the seashore of lovely little Shikine-jima, an island only a few hours' ferry ride from downtown Tokyo. The pools are formed by the seaside rocks and it is one of those onsen that only works when the tide is right. You can spend a few lovely hours here watching the Pacific rollers crashing on the rocks. And, there are two other excellent onsen on the island when you get tired of this one.
4. Best Onsen Town
Kinosaki (Kinosaki, Kansai )
Kinosaki, on the Sea of Japan coast in northern Kansai, is the quintessential onsen town. With seven public baths and dozens of onsen ryokan, this is the place to sample the onsen ryokan experience. You can relax in your accommodation taking the waters as it pleases you, and when you get tired of your ryokan's bath, you can hit the streets in a yukata (light cotton robe) and geta (wooden sandals) and hit the public baths. It doesn't hurt that the town is extremely atmospheric at night, and the local winter speciality, giant crab, goes down pretty nice after a day of onsen-hopping.
5. Best Rotemburo
Sawada-kōen Rotemburo Onsen (Dōgashima, Izu-hantō)
If you like a view with your bath, you won't do any better than this simple rotemburo perched high on a cliff overlooking the Pacific Ocean. Early in the day, you can have it all to yourself. Of course, if you don't mind a crowd, it's a great place to watch the sunset.
6. Best Hidden Onsen
Lamp no Yado (Noto-hantō, Central Honshū)
The Noto-hantō peninsula is about as far as one can go in Central Honshū, and the seaside is about as far as one can go on Noto-hantō. A country road takes you to a narrow path, from where you have to climb down a switchback hill on foot. No wonder this property has been a refuge for centuries of Japanese seeking to cure what ails them. Even if one night here now costs what people would have once spent over weeks here, it's a worthy splurge for a dark-wood and tatami room on a cove, with its own rotemburo and Sea of Japan views through craggy rocks.
7. Best Semitropical Onsen
Urami-ga-taki Onsen (Hachijō-jima, Izu-shotō)
Even in a country of lovely onsen, this is a real standout: the perfect little rotemburo located next to a waterfall in lush semitropical jungle. It is what they are shooting for at all those resorts on Bali, only this is the real thing. Sitting in the bath as the late-afternoon sunlight pierces the ferns here is a magical experience. It is also free.
8. Best Onsen/Beach Combination
Shirahama (Shirahama, Wakayama-ken, Kansai)
There is something peculiarly pleasing about dashing back and forth between the ocean and a natural hot-spring bath - the contrast in temperature and texture is something we never tire of. At Shirahama, a beach town in southern Kansai, there is a free onsen right on the beach. And Sakino-yu Onsen is just spectacular.
9. Best Onsen/Sand Bath Combination
Takegawara Onsen (Beppu, Kyūshū)
Sometimes simplest is best. This traditional Meiji Era onsen first opened in 1859, and its smooth wooden floors transport you back to a Japan of neighbourhood pleasures-unpretentious, relaxing and accessible to all. There are separate (and very hot) baths for men and women. Takegawara also offers heated sand baths in which, wearing a cotton yukata, you are buried up to your neck with hot sand for 10 to 15 minutes, followed by a rinse and a soak in an adjacent onsen bath.
10. Best Mountain Onsen
Takama-ga-hara Onsen (Northern Japan Alps, Central Honshū)
High, high up in the Japan Alps, if you want to soak in this wonderful free riverside rotemburo, you are going to have to hike for at least a full day. It is located in a high natural sanctuary with mountains on all sides. To tell the truth, even if it took three days of walking to get here, it would be worth it. Some Japanese say that this is the highest rotemburo in Japan. You can spend the night nearby in a creaky old mountain hut.
The article 'Lonely Planet's top 10 Japanese hot springs' was published in partnership with Lonely Planet.