I woke up just after five in the morning, as expected. I could still feel the lingering warmth of the previous night's sauna in my body as I slowly pulled myself out of bed. Even on the road, my routine never changes. A quiet morning walk, a hot shower to wake up every cell in my body, a proper breakfast to fill my stomach. Then I checked out of the hotel. It was a Sunday. I took the Uchibo Line from Kaihin-Makuhari Station, transferred at Soga Station, and stepped off at Kimitsu Station at 8:15 a.m. My destination was SATOYAMA TERRACE, located in Futtsu City, Chiba. Since the facility is a fair distance from the station, I called a car rental shop the moment I arrived. I was grateful to the staff who happily accommodated my rather unreasonable request — "I know it's short notice, but can I rent a car right now?" — and after taking care of the paperwork, I got behind the wheel. There's a particular thrill in driving through unfamiliar territory. I pressed the accelerator and pulled into my destination right at opening time, 9 a.m. SATOYAMA TERRACE is an outdoor sauna facility surrounded by lush nature, and it's a mixed-gender venue where swimwear is required. Why did I adopt the strategy of arriving the moment it opened? Because this type of stylish co-ed sauna fills up with couples and groups of young people by early afternoon. For a solitary sauna enthusiast like myself, reaching a deep meditative state amid their sweet murmurs and cheerful squeals is nothing short of a Herculean task. That's exactly why I aimed for the silence of early morning, before anyone else arrived. And yet, my strategy fell apart almost immediately. Despite entering right at opening time, there were already several couples and groups inside. Well, I suppose everyone thinks alike. That said, it was only a handful of people — hardly crowded. There seemed to be plenty of personal space. I shook it off, watched the mandatory orientation video at the reception, rented a swimsuit while suppressing my impatience, changed in the locker room, and finally stepped into the sauna area. SATOYAMA TERRACE has two saunas, each with a distinct concept. I decided to start with the Yama Sauna (Mountain Sauna). The moment I opened the door, a heavy, dense heat wrapped itself around my entire body. The room temperature was around 90°C, but the humidity was so high that sweat began pouring out almost immediately. The design of the sauna room was simply outstanding. Benches were arranged at varying heights like a mountain landscape, and two actual trees were growing right up through the seating. In the center stood a glass-enclosed fireplace, where you could watch the flames dancing. The crackling of burning firewood, the scent of wild herbs, the flickering of the fire. Every one of my senses was overwhelmed. The layout was designed with socializing in mind, but as luck would have it, the couples sharing the room with me didn't say a single word. Each of them had their eyes closed, quietly lost in their own world. They too had chosen this time to genuinely love the sauna and face themselves in earnest. I silently paid them my respects, and sank into deep meditation myself. When I finally reached my limit and stepped out of the sauna room, it was time for the moment I'd been waiting for — the cold plunge bath. The greatest appeal of SATOYAMA TERRACE lies in this cold plunge bath, fed by a continuous flow of natural groundwater nurtured by the satoyama hills. Two temperature options are available: a regular 16°C bath and a single-digit 9°C plunge that varies by season, and both are generously spacious. I first eased my body into the 16°C bath. An overwhelming sense of refreshment washed over me, along with a softness of water that seemed to cling gently to the skin. Good water quality is something your skin knows best. The flow was substantial and constant, and when I let it pour over my head like a waterfall, every cell in my body seemed to cry out in delight. After the cold plunge, it was time for some outdoor relaxation. I sank my full weight into an infinity chair while taking in the sweeping view of the satoyama landscape. The fresh morning air and scent of the forest tickled my nostrils. When I closed my eyes, I found myself wondering whether I was really still in Chiba. It felt as though I had wandered into some untouched wilderness far, far away. The outdoor relaxation area is expansive, with around 30 chairs lined up, so no matter how many guests arrive, the tragedy of having nowhere to sit should never occur. For my second set, I headed to the other sauna — the Taki Sauna (Waterfall Sauna). When I opened the door, I found myself in a truly peculiar space. The floor was wet, and the front wall of the sauna room was a waterfall built from stacked stones, with groundwater cascading down it continuously, filling the room with a cool, refreshing air. The temperature was around 70°C, I'd say. Various plants including vihta were hung from the waterfall, and the air was thick with the deep scent of the forest. Because the temperature is lower, you can stay in longer, and it might be the ideal environment for whisking. However — and this was a letdown — my body simply wouldn't warm up. Even after more than ten minutes inside, my heart rate refused to rise. Concluding that this wouldn't let me draw out the full pleasure of the cold plunge, I immediately took an unconventional detour: back to the Yama Sauna first, then straight to the cold plunge bath. For my second set, I was embraced once again by the exquisite groundwater, then made my way back to the outdoor relaxation area. Glancing around, I noticed the number of guests had grown, and the atmosphere was gradually getting livelier. Looking toward the reception, I could see a line forming, and new guests were filing steadily into the sauna area. In a situation like this, a solitary visitor who values solitude starts to feel a little out of place. If the noise starts to cause stress, the precious totonou I've worked so hard for will be completely undone. The wise move would be to make the next round my last. For my third set, I returned to the Yama Sauna and sweated it out thoroughly. And for the finale, I did a cold-cold contrast bath: first the 9°C single plunge to rapidly constrict my blood vessels, then moving to the 16°C cold bath. After the intense shock came a melting, silky softness. That gradient of temperature difference guided me into a state of absolute bliss. My sauna session at SATOYAMA TERRACE had reached a perfect finale.

After finishing the sauna and getting changed, I climbed back into the rental car to find it was still only 10:30 a.m. The one thing I had decided in advance was to come to SATOYAMA TERRACE first thing in the morning — but as for what to do afterward, I had absolutely no plan. I started the engine and began running the numbers in my head. From here, taking the expressway, I could get back to Makuhari in about an hour. Which meant I could visit one more facility before lunch. The instant I realized that, my next destination and plan were decided in a flash. The next stop: Mainichi Sauna Tokyo Makuhari. Now that I had come all the way out to the depths of Chiba's satoyama hills, the thought of exploring nearby sightseeing spots or tracking down some local specialty food did cross my mind. A normal person would probably do exactly that. But I am not a normal person. In a sauna trip, the sauna is the top priority — everything else is merely a footnote. A scenic landmark holds far less pull on my heart than an undiscovered cold plunge bath of extraordinary quality. In pursuit of my next totonou, I pressed the accelerator once more.