Hitou, or hidden hot springs, are the holy grail for onsen lovers. Often difficult to access, usually exposed to the elements and generally for mixed bathing, hitou are not for the shy or faint-hearted. But for those with fewer inhibitions who enjoy a steaming soak under open skies, surrounded by pristine nature, hitou are the perfect place to relax and rejuvenate and feel at one with the universe.

I had a taste of that sense of abandon and oneness with nature when we visited Toshichi Onsen, deep in the Hachimantai mountains of Iwate Prefecture in northwestern Japan.

 It was our first stop on a short onsen-hopping trip to the Tohoku region in late spring, when enough snow had melted to allow visitors to navigate the roads without danger.

Saiunsou is the only place to stay at Toshichi Onsen, which, at 1,400 meters above sea level, is said to be the highest altitude for a natural onsen in the entire Tohoku region, and has been described as the onsen in the wildest natural surroundings in Japan.

Given the reputation of the place as one of Japan’s best hitou, we were not exactly expecting Saiunsou to be a luxury ryokan, but nevertheless, we were shocked by the dilapidated condition of the wooden cabins we saw upon arrival.

Saiunsou in mid-May is still surrounded by large patches of snow.

Our surprise and hesitation grew as one of the staff showed us to our room, leading us along a dangerously slanting corridor, which he explained was the result of heavy snow weighing down on the building during the winter months, which pushed the entire structure into the ground in a lopsided way.

Our room was one of just a handful with a toilet and washing-up area. I later discovered that we also had a modern heater that we could turn on at the touch of a switch, unlike the other rooms where the heaters had to be lit with a match or grill lighter.

Another surprise was, despite being so basic, Saiunsou was packed. Clearly, guests come for the delights of the onsen itself, and the lack of creature comforts was not going to discourage them.

We had arrived early enough to take a dip in the outside baths while it was still light so we could enjoy the sight of scrubby mountains, with patches of left-over snow around us.

Heavy snowfall prevents access to Toshichi Onsen during the winter months.

But first, as is customary, we washed up in the indoor bathrooms before heading outside to the natural baths that line the mountain slope. The temperature of the hot spring rises as you go up the slope, so that the onsen pool at the very top is the hottest of all.

There are separate indoor and outdoor baths for men and women but the 6 main outdoor baths with the best views, are for mixed bathing.

After washing up in the women’s indoor bathroom, I headed outside wrapped in the extra towel I had brought for the occasion. Although wearing a towel, or anything, for that matter, is not normally allowed inside an onsen bath, here women may soak in the open air hot spring baths wearing a towel or wrap-around, which they can bring along or buy at the inn’s shop for about Y1,000.

The wooden planks laid out as pathways in between the outside rotenburo baths were wet and slippery but the air was crisp and the sky was a vast azure canvas.

Toshichi onsen

The wooden planks leading to the baths are rickety.

Most of the bathers were men, one of whom had come all the way from southwestern Kyushu, taking a plane to Tokyo then the shinkansen train to Morioka in Iwate prefecture and renting a car from there.

The onsen water at Toshichi is a muddy blue-white, 100 per cent natural (that is, the water has not been diluted or recirculated) and full of minerals. 

The muddy, mineral-rich hot spring onsen baths.

As I sank into one of the baths that was not too hot, I could feel the smooth mineral-rich soil under my feet. I smothered it all over my face, hoping it would turn my skin as silky and soft as a newborn baby’s. 

While my skin felt good after the soak, sadly I was not transformed as much as I had hoped. Perhaps it takes more than a few visits to reap the benefits of these legendary onsen waters.

It was still light outside and the air was refreshingly cool. All we could see around us were the vast, open sky, the mountains and pools of grey-blue water.

After our bath we headed to dinner, which is served between 6 and 8PM and is a very casual affair in the communal dining room where seating is on a first come first served basis. 

Given the dilapidated nature of the place, we were not expecting a gourmet meal — but much to our delight, the fresh vegetables and other local dishes were delicious. 

I enjoyed the small bamboo shoots cooked in a miso sauce, deep-fried tara-no-me (a bitter mountain vegetable) and other local vegetables, many of which were new to me, making the experience all the more enjoyable. Another local specialty we enjoyed was kiritanpo nabe, a hot pot full of vegetables, sliced pork or chicken, meatballs and kiritanpo, which is a cylindrical rice cake toasted on a skewer.

Although the onsen at Saiunsou is open for bathing 24 hours a day, the outside baths are reserved for women between 7 and 8PM, so I took the opportunity to enjoy the soothing hot waters freely, without any cumbersome coverings.

It was pitch dark and for several peaceful but slightly unnerving moments, I was entirely alone outside under a starry sky, wondering what I should do if a bear or other wild animal should stray into the bathing area.

Back in our small but tidy room, there was little to do, since there was no TV and internet access was unreliable. Reading was difficult, due to the poor lighting. We wished we had brought along a pack of cards, even though we seldom play any kind of games.

With the heater on we were warm enough and too tired to be bothered by the flat, over-used futon, so with little to do, we turned in early.

We woke up the next morning and hurried outside for a last-minute soak before a hearty breakfast of miso soup full of vegetables, grilled fish and a wide variety of other local dishes in the communal dining room. 

toshichi onsen

The outside bathing area is even more atmospheric in the early morning mist.

There are a number of famous spots nearby, such as the so-called Dragon Eye, created by melting snow on Kagami-numa Lake from late May to early June. The snow on the lake melts in a way that creates a ring of bluish-green water around leftover snow in the middle.

dragon eye

The Dragon Eye is just a 5-minute drive from Saiunsou.


The Onuma Nature Trail, located across the street from the Hachimantai Visitor Center,  is an easy two-hour walk around Onuma lake.


The area is famous for the unfortunately named skunk cabbage, which is known more poetically in Japanese as “mizubasho,” or water banana.

A section of the stunning Tamagawa River that we we came across by chance while driving south-west from Hachimantai.

Lake Tazawa, located to the south of Hachimantai in Akita Prefecture, is Japan’s deepest lake at 423 meters.

Nestled in the Towada-Hachimantai National Park, near the top of Mt Hachimantai, where heavy snows prevent access for several months in the winter and it is cool even in the summer, Saiunsou is only open to guests from late April until the end of October. Standard rooms with no toilet or washing up facilities start at around Y12,000 including dinner and breakfast. There are communal toilets and a large sink in the hallway. Rates during the busy season (Golden Week from April 29 to May 5, summer and early autumn) and on Saturdays and before a national holiday are higher.

The easiest way to get there is to rent a car at Morioka Station and drive up the Hachimantai Aspite Line or Jukai Line highways. 

Despite the lack of the usual luxuries provided at more upmarket onsen ryokan, the simplicity of the inn and the feeling of being enveloped by the surrounding mountains and fresh air made our visit to Saiunsou at Toshichi Onsen one of the most memorable, and enjoyable, in our many years of hot spring hopping.