A dynamic five-tier sauna that uses the rare Aji stone, a prized stone also known as the diamond of granite, across the entire wall surface. About 600 kg of sauna stones store and release heat, creating a soft, enveloping warmth that slowly heats you from the core. The humidity is fairly high, and every time the automatic löyly runs every 30 minutes, the room’s temperature and humidity surge all at once. Staff aufguss sessions by Karumaru’s aufguss team are held mainly in this sauna and are a regular highlight with strong attendance. Because it has five tiers, you can settle in at your preferred temperature zone.

A modern space that makes generous use of Kero, deadwood from European red pine over 200 years old. The one-of-a-kind design, with the inner wood and bark of Kero arranged alternately, is known as a Kero sauna found nowhere else in Japan. In the dim, calm room, the rich aroma unique to Kero wood lingers, while the heat stays dry and high-temperature. Self-löyly can be performed once every 15 minutes, and the fragrance becomes especially pronounced the moment the steam rises.

A traditional Finnish wood-stove sauna, said to be the only one of its kind in a major metropolitan area. The flickering light of the flames, the crackling sound of burning wood, the pleasant scent of timber, and a gentle warmth like sunlight all envelop the senses. The heat created by the METOS iki wood stove has a warmth that is distinct from electric stoves, and löyly may also be performed when more wood is added about every 20 minutes. Time spent facing the fire and the wood is popular as the experience that feels closest to nature among urban saunas.

A barrel-shaped steam sauna. Nine to 10 kinds of rare medicinal herbs, including Iburijakuso, naginatakōjū, and kuromoji, collected around Mt. Ibuki in Shiga Prefecture, known as a treasure trove of medicinal herbs, are slowly boiled and the steam is absorbed with the whole body. Although the temperature is around 50°C, the perceived temperature is extremely high because it is constantly filled with steam, and the aroma and components of the herbs penetrate the entire body through the nose and mouth. Wrapped in a barrel made of Japanese umbrella-pine, the serene space is for one person only, allowing you to enjoy a focused experience all to yourself.

An ultra-low-temperature cold plunge bath that feels like being struck by lightning, with single-digit water temperatures below 10°C and swirling jet streams. Powerful currents churn the water like a tornado, amplifying the chill and sending a shock so strong that your whole body trembles within seconds. The bath is 100 cm deep and you can even submerge yourself. Its piercingly intense cooling experience is surprising the first time, but once you get used to it, it becomes so addictive that other cold plunge baths feel unsatisfying. After the bath, there are plenty of relaxation spaces waiting both indoors and outdoors.

A gentle bubble cold plunge bath at around 25°C, designed so even people who dislike cold baths can soak comfortably. After cooling your core in the ultra-low-temperature Thunder Tornado, entering this bath brings a unique sense of bliss as the calm bubbles and soft water temperature combine to release tension throughout the body. With an easy-to-enter depth of 60 cm, it is also ideal for alternating cold baths in combination with Thunder Tornado.

A jet cold plunge bath at around 30°C, conceived as the "rest" in the cycle of "sauna => cold plunge bath => rest." This exquisite temperature, cooler than neutral temperature and warmer than Yasuragi, is paired with pleasant jet stimulation reaching different parts of the body, creating a euphoric feeling as if ascending to heaven. The front seats direct jets to the lower back and soles of the feet, while the back seats send jets to the lower back and thighs, making this a unique design that can be used not only as a cold plunge bath but also as an extension of totonou. With a shallow depth of 40 cm, it is suitable for long stays.

A one-person cold plunge bath that recreates an avanto, the Finnish word for a hole cut into frozen lake ice, in a transparent acrylic cylindrical tub. Installed in the rooftop air-bathing area, it gives you an extraordinary sensation as if descending into an ice hole. It is 100 cm deep and you can submerge yourself. Seeing the outside scenery through the transparent walls creates a completely different experience from other cold plunge baths, and it recreates in the city the original way avanto is used, with priority access for users of the wood-fired sauna.