Overview
Stay at Achi Starry Night Inn Yamaboshi in Komaba, Achi Village, beside the clear Achi River in southern Nagano. You can choose between a Japanese-style ryokan room and a large glamping dome, allowing you to shape your stay around indoor relaxation or more time outdoors.
Your stay brings together natural hot spring bathing, irori dining, a private stargazing sauna, and access to the night-sky experiences for which Achi is known. Selected rooms and glamping domes also welcome dogs, while an outdoor dog run gives you space to exercise together.
Sumi-e artwork appears throughout the building, with interiors supervised by Taeko Hagiwara Design Office. Each room follows its own colour theme, combining Japanese design, natural materials, and original ink art inspired by renewal and connection.
Accommodation
Choose from two suite rooms, individually designed standard rooms, and four glamping domes beside the Achi River. All accommodation is non-smoking and includes free Wi-Fi.
Koi-ai is a 50-square-metre suite with a Japanese room, separate bedroom, veranda, private bathroom, and washlet toilet. Two semi-double beds use Simmons mattresses, while additional futons can be prepared on the tatami.
The private hinoki bath is lined with smooth Towada stone and receives natural hot spring water. Both the hot and cold taps draw from the spring, allowing you to adjust the temperature and soak whenever you choose. The room looks toward the Japanese garden and is available with selected dog-friendly plans.
Kuri is the largest room at 58 square metres. It includes a Japanese room, bedroom, veranda, private natural hot spring bath, and a separate study where you can read or work. Two Simmons semi-double beds and additional futons provide flexible sleeping arrangements.
The standard rooms measure approximately 32 to 41 square metres and come in twin or double layouts. Every room has an individual colour theme, Simmons Collection mattresses, and a veranda overlooking courtyard greenery and garden stones.
Instead of a bathtub, the standard rooms have a glass-walled unit containing a shower, washbasin, and toilet. Room facilities include a television, refrigerator, water server, electric kettle, tea set, hair dryer, humidifying air purifier, and individual climate control. Selected standard rooms can be booked with a dog-friendly plan.
Four hemispherical glamping domes sit beside the main building. Each dome measures approximately 53 square metres and includes heating and air conditioning, Wi-Fi, a refrigerator, water server, electric kettle, and hair dryer.
Glamp A and Glamp D each have six semi-double beds. Glamp A faces the river, while Glamp D looks toward the mountain and forest.
Glamp B and Glamp C each have four double beds and accept dogs through selected plans. Glamp B faces the Achi River, while Glamp C has a mountain outlook.
The domes do not have private bathrooms or toilets. You use the natural hot spring bath in the main building and the shared toilets within the property.
Dining
When you stay in the ryokan building, you enjoy dinner around a traditional irori hearth. The menu is supervised by Takaaki Tsuneyasu of Nishiazabu Towa, a restaurant that received one Michelin star for three consecutive years from 2019.
Dinner focuses on carefully selected ingredients from southern Shinshu. Seasonal dishes may include premium beef, local vegetables, ayu and iwana river fish from Takumi Tenryu Ayu, and a signature hand-rolled sushi made with fried river fish.
The selected beef has a lighter fat profile and works particularly well in shabu-shabu. River fish may arrive as sashimi or grilled with salt over the hearth, allowing you to taste both its delicate flesh and crisp skin.
Dinner begins at either 5:00 p.m. or 7:00 p.m., and your table is available for 90 minutes. When you travel with your dog, a limited number of dining spaces allow you to eat together through an eligible pet plan. These seats require a reservation.
Breakfast is served between 7:00 a.m. and 9:00 a.m. You choose your starting time during check-in. The Japanese breakfast uses soft spring water from Seinaiji in Achi Village, including for the southern Shinshu Koshihikari rice and the dashi used in the rolled egg.
When you stay in a glamping dome, dinner takes place in the BBQ garden near the domes. The outdoor menu includes beef and local vegetable skewers, Dutch-oven cooking, and a large seafood paella prepared in a pan measuring around 60 centimetres across.
Breakfast arrives at your dome in a wooden box. Fresh bakery items are served with local vegetables, fruit, salad, and a yogurt drink made with milk from the Southern Alps region.
Food allergies require advance notice so that suitable adjustments can be considered.
Onsen and Wellness
The communal bath receives natural water from the Komaba Onsen source. The water is classified as an alkaline simple hot spring.
Hinoki wood covers the walls, filling the bathing space with a gentle cypress scent. Towada stone lines the floor and bath, providing a smooth surface with better grip when wet.
You can use the communal hot spring from 3:00 p.m. until 9:00 a.m. the following morning. The overnight schedule gives you time for an evening soak, a late bath after stargazing, or an early visit before breakfast.
The Koi-ai and Kuri suites also have private baths supplied with natural Komaba Onsen water. Standard rooms and glamping domes do not have private onsen facilities.
The private stargazing sauna allows your travelling party to use the complete space without sharing it. After heating your body, you can cool down in a bath filled continuously with spring water before resting outdoors beneath the Achi sky.
Sauna sessions are offered at set times from the afternoon until late evening. Use is included during your stay, although you need to arrange your session according to availability. Operating times can change on the day.
Guests with Tattoos
When you stay in Koi-ai or Kuri, you can use the private natural hot spring bath inside your room without entering a shared bathing area.
Before using the communal hot spring bath or the private stargazing sauna, you need to notify Yamaboshi in advance and follow the access arrangement provided for your stay.
Standard rooms and glamping domes do not include private baths. The two suites provide the clearest choice when guaranteed private hot spring access is important.
Facilities
The lounge opens from 3:00 p.m. to 10:00 p.m. and gives you a comfortable place to sit between bathing, dinner, and evening activities. From 9:00 p.m., the space also operates as a bar lounge.
The irori restaurant serves dinner and breakfast when you stay in the ryokan building. Its hearth-centred layout combines traditional cooking with a clean Japanese interior.
Outside, the BBQ garden provides the dining area for glamping stays. A nearby fire-pit space lets you sit beside the flames while listening to the river and surrounding trees.
The private stargazing sauna includes a sauna room, spring-water cooling bath, and an outdoor rest area. You reserve the complete facility for your travelling party rather than sharing it with others.
A fenced dog run gives you somewhere to exercise with your dog during the stay. Pet-friendly accommodation is available through selected suite, standard-room, and glamping plans.
Free Wi-Fi is available throughout the property. All rooms are non-smoking, with a separate smoking area provided. The building does not have meeting or banquet rooms and is not fully barrier-free.
Free outdoor parking is available for up to 20 cars.
Activities
Visit Heavens Sonohara for the Night Tour, one of Achi’s best-known evening experiences. A gondola takes you away from the village lights to a higher viewing area where you can spend time beneath the night sky. Yamaboshi participates as an official accommodation partner for the program.
During the day, Heavens Sonohara also gives you access to views of the Southern Alps and trekking routes around Fujimidai Kogen. Seasonal operating dates and transport schedules change throughout the year.
The Achi River flows directly beside Yamaboshi and provides opportunities for stream fishing. Day permits are available at the property, although fish cannot be cooked or stored after you return.
From early April to early May, red, white, and pink flowering peach trees brighten roads across Achi Village. Selected river-facing domes may also give you views of the blossoms during the main season.
The Hirugami Onsen morning market opens every day of the year. Local vegetables, fruit, pickles, processed foods, and handmade products change according to the season.
Other nearby places include Komatsunagi no Sakura, Chogakuji Temple, the Manchurian-Mongolian Reclamation Peace Memorial Museum, Tsukimido, and sites connected to the legends and literature of the Ina Valley.
You can also spend the evening at Yamaboshi, moving from the natural hot spring to the private sauna before sitting beside the glamping fire pit.
Additional Features
Check-in begins at 3:00 p.m., and check-out is by 10:00 a.m. Breakfast times are selected during check-in, while dinner and sauna sessions follow set time slots.
Yamaboshi is around seven minutes by car from Iida-Yamamoto Interchange and approximately 25 minutes from JR Iida Station. When you arrive by highway bus at the Komaba stop, a taxi transfer can be arranged, with the fare paid by you.
Pet-friendly stays require an eligible accommodation plan. The currently linked pet rules allow up to two indoor dogs under 10 kilograms in each assigned room and require proof of recent rabies and combination vaccinations.
You need to bring your dog’s regular food, bowls, bedding, toilet supplies, towels, and other daily items. Selected dinner plans also allow you to eat with your dog, although the number of available tables is limited.
