After thoroughly enjoying the famous hot springs and the demon sauna at Noboribetsu Grand Hotel, I got back in the car and headed for my next destination: Toya Onsen. I had visited Lake Toya once before, on a school trip in high school. I clearly remember staying at a lakeside hotel, though I couldn't recall which one it was. All I could picture was a grand building with a red-brick exterior. I pressed the accelerator, drifting into a little nostalgia, hoping that hotel might still be standing. It had been pouring rain when I left Noboribetsu, but by the time I arrived at Toya Onsen, the rain had completely cleared, and light was breaking through the clouds. I checked into my hotel, took a stroll along the lakeshore, and made my way toward today's sauna destination: Toya Manseikaku Hotel Lakeside Terrace. Hotels line the waterfront one after another, each offering a leisurely view of the lake. My own room commanded a sweeping, magnificent view of Lake Toya. Following Google Maps, I walked until I stood in front of Toya Manseikaku Hotel Lakeside Terrace. The moment I looked up at the building, I stopped in my tracks. A grand facade with a red-brick appearance. This was, without a doubt, the very hotel where I had stayed on that high school trip. The destination of today's sauna journey turned out to be a place steeped in my own memories — surely the sauna gods had arranged this little twist of fate. I passed through the entrance and completed the check-in procedures at the day-use counter. Toya Manseikaku Hotel Lakeside Terrace has two large bathing areas: Tsuki no Yu (Moon Bath) on the basement level, overlooking a beautiful Japanese garden, and Hoshi no Yu (Star Bath) on the top floor, featuring an infinity outdoor bath that seems to merge seamlessly with the lake. The baths rotate between men and women on alternating days, and on this particular day, the men's bath was Tsuki no Yu. I took the elevator down to the basement. The hotel's interior radiated understated luxury throughout. At the entrance to the large bath, there was something called a shampoo bar. The changing room was stocked with detox water, and the amenities on display were all high-end brands I had never seen before. The meticulous attention to hospitality at every turn only heightened my anticipation. Stepping into the large bath, I found a vast tub filled with the renowned waters of Toya Onsen, and partway along the passage leading to the outdoor area, the entrance to the sauna room appeared. Outside, the outdoor area let you soak while enjoying the beautiful garden from every angle, with a rock bath, a hinoki cypress bath, and a cold plunge bath supplied with flowing water drawn directly from Lake Toya. First, I eased myself into the outdoor rock bath. Soaking in Noboribetsu's hot springs during the day, then sinking into Toya Onsen at night — what an utterly indulgent hot spring journey. The water at Toya Onsen is a sodium-calcium chloride-sulfate-bicarbonate spring. It has a slightly yellowish, cloudy tint, feels silky smooth against the skin, and gradually warms you from the core. It's a spring with excellent heat-retaining properties that keep the cold at bay long after you step out. After savoring the hot spring, it was finally time for the sauna. The sauna room in Tsuki no Yu is remarkably spacious — and yet its design is utterly unlike a standard dry sauna. Crafted generously from domestic hinoki cypress, the space features benches arranged at irregular angles, giving it the feel of a piece of contemporary art. The beauty of its form was enough to make me stop and stare. The front wall is glass, designed so you can enjoy the sauna while gazing out at the outdoor area and the stunning garden beyond. The heater setup features two ZIEL units by Metos, making this a hybrid löyly sauna that supports both auto-löyly and self-löyly. The temperature hovers around 100°C, and the heat is powerfully intense. Sitting on the upper bench, the merciless heat envelops your entire body. Pleasant background music drifts from the speakers, creating a perfect harmony of heat and calm. After sweating to my limit, I headed for the cold plunge bath. The thermometer read 13°C. It looked large enough for around eight people. The defining feature of this cold bath is that it uses no chiller — instead, water from Lake Toya flows in directly as a natural stream. The moment I submerged myself, an overwhelming sense of exhilaration washed over me. I was struck by just how exceptional the water quality of lake water can be, and how wonderful it feels. After the cold plunge, I settled into one of the chairs in the outdoor area. Gazing at the beautifully lit garden, I felt my consciousness slowly drifting away. Returning as an adult on a sauna trip to the very hotel where I stayed as a high school student on a school trip — what a remarkable coincidence. And on top of that, being able to enjoy world-class hot springs, a sauna, and a cold plunge bath filled me with a deep sense of joy. For a while, I lost consciousness completely, adrift in a feeling of pure happiness. After that, I mindlessly cycled through sauna, cold plunge, and outdoor rest. I'll be back here tomorrow morning, but this beautiful, art-like sauna and garden of Tsuki no Yu — I can only experience it today. It may well be the last time in my life. I always approach my sauna travels with the spirit of ichigo ichie — the idea that each encounter is once in a lifetime, never to come again. I may never return to this place. And that is precisely why I give it everything I have, and savor every last moment to the fullest.

With my sauna session complete, I returned to my hotel. Dinner was done, and all that was left was to sleep. And tomorrow morning, I would head back to Toya Manseikaku Hotel Lakeside Terrace. The moment I woke up, my sauna journey would begin again. Tomorrow morning brings Hoshi no Yu on the top floor. Just imagining myself soaking in the infinity outdoor bath that merges with Lake Toya, taking in the breathtaking view, was enough to make my heart race. A miraculous day where memories of a school trip and an extraordinary sauna experience intertwined. Wrapped in the lingering glow of it all, I drifted off into a deep, contented sleep.