And while ancient spa towns like Bath in the UK, Vichy in France or Baden-Baden in Germany have their charm, many of us can agree that few people do it better than the Japanese. And there is one Japanese that stands out in particular — Yoshiharu Hoshino. A fourth-generation hotelier, Hoshino’s story began with the establishment of a single Japanese ryokan in Karuizawa (yes, of the whisky fame) in 1914. Today, the Hoshino Resorts group offers several brands, each of which is distinctive and highly regarded. There is Hoshinoya (luxury hotels), Risonare (countryside resorts), OMO (city hotels) and Lucy (mountain hotels), among others. But since we are on the topic of hot spring bathing, one of Hoshino Resorts’ great success stories is told via Kai, its collection of hot spring ryokan, which led to Hoshino-san being nicknamed the great “innovator of inns”.
Established 15 years ago, Kai boasts more than 20 properties today, scattered across Japan wherever a particularly wonderful natural hot spring is found. Best described as a contemporary onsen inn, what sets Kai apart from other traditional ryokan is that it combines the traditional world with the best of modern design. So while a classic property usually means you sleep on tatami and dine in-room, Kai offers a more inclusive approach. The rooms are modern but accented with local crafts and design-conscious pieces. Thoughtful activities that assist with the guest’s immersion in the locality are also a key highlight of every Kai resort.
In keeping with the ryokan custom of always being on a half-board basis, a stay at Kai will naturally include a hearty (and delicious) Japanese breakfast, usually starring grilled fish, a variety of simmered and pickled sides, miso soup and fluffy white rice. Magnificent kaiseki dinners featuring the best of local and seasonal produce are, of course, par for the course but guests will instead dine in small, semi-private rooms at a main hall versus in-room, as is the case at a traditional ryokan.
See also: Golden sands
ALPINE BLISS
Upholding the Kai pillars of Onsen, Culture and Kaiseki, Kai Alps, located in Omachi village, Nagano Prefecture, and nestled beneath the breathtaking Japanese Alps, offers the best of the white and green seasons. It is a short drive from Hakuba Valley, a key venue for the 1998 Winter Olympics. Guests come to play all day on the slopes and spend the night soaking in hot, mineral-rich waters after a hearty repast.
See also: Fan favourite
Kai Alps also falls within Shinshu, an ancient name for this mountainous part of the region — renowned for its fruits of the earth, namely apples, miso, fresh saké and buckwheat noodles. As Omachi was a former station town located along the country’s historic Shionomichi or “Salt Road”, a 120km trade route that connects Itoigawa by the Sea of Japan to the inland, the Kai Alps kitchen also pays a respectful nod to heritage by offering a breakfast that blends ingredients from both worlds, with a prime example being shiomaru ika, a special soul food dish of salt-cured squid, best enjoyed with miso mushroom soup. Those privileged enough to be invited into a local home would also discover the charming tea-time culture of ochakko-nomi, a Shinshu custom where guests are served cups of hot tea accompanied by seasonal pickled vegetables — yet another nod to the legacy of Shionomichi.
Its proximity to snowy peaks has also led to the creation of a signature culinary offering — the yukinabe or “snow pot” where hot broth is dramatically poured over wataame-capped sukiyaki, shaped like a kamakura or winter hut, as a paean to the Hida Mountains just a gaze away. At every dinner, guests are also given their own nub of freshly harvested wasabi (nearby Azumino boasts some of the country’s best horseradish, grown using pure, cold meltwater from the mountains) and samegawa oroshi grater to further elevate the experience. As a pre- or post-prandial ritual, guests are also invited to gather around the irori (sunken hearth) to swap stories while enjoying complimentary local Nagano snacks like oyaki, dumplings stuffed with nozawana (pickled vegetables), accompanied by a cup of soba cha.
Local and regional aesthetics are also celebrated at every Kai. Here, the accommodation is called Shinano (an old name associated with Nagano Prefecture and its Shinano River, Japan’s longest) Hospitality Rooms, and features charming touches, such as kirie paper-cut art by Shinshu artist Kyoko Yamagisawa, matsuzaka-washi paper lamps and jiki (porcelain) pieces by Haruya Abe who works out of Ueda city in Nagano Prefecture. Slip out of your pure flax linen yukata and into the cloud-like bedding after a spell at the onsen, which looks out onto a copse of larch trees and mountains. When dawn breaks, another invitation to the fireside is generously extended; this time for omeza-gayu (“wake up” rice porridge, a special privilege for early risers to be enjoyed with the salty tang of mashed umeboshi or pickled plums).
IN A MOUNTAIN VILLAGE
Picturesque and bijou, the little mountain hamlet of Hirayu Onsen in Gifu Prefecture is the oldest of Okuhida’s five hot spring villages. Known for its high-quality, sulphurous waters, it is home to one of the group’s newer auberges, Kai Okuhida. Having opened in September 2024, the 24th addition to the Kai family combines hot spring therapy with all the comforts of a traditional Hida inn. Spread across a few buildings — two for rooms, a bathhouse and an annex — the modern-looking structures stand out stylishly amid the village’s rustic surrounds. Often covered with thick powdery snow from December to early March, it is a magical winter destination and an ideal base from which to explore Shirakawa-go’s Unesco-rated beauty and the foodie haven of Takayama. This winter, Kai Okuhida has also launched a complimentary shuttle bus service to make exploring even easier for its guests, with daily trips to both destinations. All you need to do is book your seat in advance with the concierge.
But should you wish to stay in (and why wouldn’t you?), there is much to occupy mind, body and soul. More than half of Kai Okuhida’s 49 rooms come with their own private onsen on the terrace, making hot spring bathing more bearable for the bashful, as well as breathtaking mountain views. Even if all you want to do is laze, read and snack, a quick nip to the village store would ensure you want for nothing (don’t forget to buy a real onsen egg, which can be spotted just outside the shop, bubbling away in a mesh netted bowl in crystal clear waters), while the supremely comfortable beds, dramatically covered by a modern headboard made using the renowned Hida technique of wood-bending called mageki, are the ultimate invitation to lounge.
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The gourmet brigade, however, comes to Hida primarily for one reason: beef. One of Japan’s most sought-after wagyu, famed for its melt-in-the-mouth flesh and stunningly marbled fat, prime Hida beef can be enjoyed by guests during their stay as part of Kai Okuhida’s kaiseki-style dinners. Those who need an encore would do well to spend afternoons exploring the lively restaurant scene in nearby Takayama.
Other complimentary experiences at Kai Okuhida include introductory talks by the resident yumori (bath keeper) on the basics of hot spring healing, stretching exercise sessions and Hida no Takumi, a woodworking experience honouring Hida craftsmen who have been deftly yet gracefully bending wood for centuries. The bonus? You get to create (and keep) your own furoshiki bag with curved wood handle. All these activities take place in the annex building, outside of which is a footbath, designed to let guests fully enjoy the experience of gazing at the mountains throughout the various seasons. In winter, the nearby garden will have its own little igloo, where you are invited to enjoy hot whistea (similar to a hot toddy but made using whisky and tea) and local snacks.
If you are planning to visit when it is warmer, be sure to visit Kamikochi, home to some of Japan’s most splendid mountain scenery. Pack along a picnic to enjoy by the banks of the Azusa River, go trekking amid champagne-fresh air. Or if you prefer, the resort is also not far from the Shinhotaka Ropeway and its double-decker gondola cars, the first of their kind in the country, and which will give you unrivalled views of the Okuhida region. For those who have scheduled their trip for April or October, you are in luck as that is when the biannual Takayama Festival — regarded as one of Japan’s most beautiful and vibrant — happens. Expect to see exquisite, centuries-old yatai (floats), karakuri (puppet shows), a mikoshi (portable shrine) procession and a host of traditional performances.
Beyond the mountains
For a ryokan experience with an aquatic difference, here are some other Kai properties to explore
By the lake
Located by the shores of Lake Poroto in Shiraoi, Hokkaido, Kai Poroto is a homage to the Ainu people of Japan’s northernmost island. The Upopoy National Ainu Museum is just next door, making it easy for you to gain insight into and experience Ainu culture firsthand. The cone-shaped bathhouse is inspired by traditional Ainu architecture. You can also sign up for a sachet amulet workshop at the resort to make your own charm to ward off evil using the local ikema plant.
By the waterfall
Amid lush nature by the Natori River, Kai Akiu nestles gently in the hills west of Sendai in Miyagi Prefecture. With a 1,400-year-old history as a hot spring destination, Akiu has long been favoured by the samurai class who considered it a retreat and place of rest. Two hot springs feed the on-site baths and a short walk will take you to the Rairaikyo gorge, where the mildly energetic can enjoy a 1km nature trail. Be sure to enjoy afternoon tea inspired by the refined aesthetics of Lord Masamune Date, featuring local Miyagi specialties such as zunda (sweet edamame paste).
By the sea
Beppu is considered to be Japan’s premier hot spring destination. Located in Oita Prefecture and overlooking Beppu Bay, Kai Beppu offers relaxation and fun alongside stunning sea views. Interestingly, there is a game arcade, and meals here naturally star the freshest seafood — the result of the Pacific Ocean meeting Beppu Bay via the Bungo Current. A prime tourist attraction in the area is the Beppu Jigoku (pictured below) or Seven Hells — spectacular hot springs that are just meant for viewing as temperatures can reach boiling point. As temperamental as it is mysterious, it was equally loathed and feared by locals in bygone days.
