I had put off visiting for quite a long time. I first learned of Higashidogo no Soratomomori at least back in 2018, yet somehow managed to never actually go. I kept coming up with convenient excuses — "It's probably crowded" or "It's close, so I can always go anytime" — and kept pushing the visit further and further back. For a sauna enthusiast, this was a massive blunder. That lazy state had dragged on for far too long, and so, partly to give myself a good kick, I finally made up my mind to go. I got on the expressway and drove toward Matsuyama City in Ehime Prefecture. Higashidogo no Soratomomori is a premium stay-and-soak facility for adults, built around the concept of ki-yojō — nurturing one's vital energy. I had heard it features the famous Higashidogo hot spring, known as a "beauty water" with a pH of 9.2, as well as high-quality saunas. The blue sky visible through the windshield seemed to be hinting at the extraordinary experience that awaited me. As I pulled into the parking lot, the calm, black-toned exterior immediately caught my eye. I could feel my mood lifting even before I stepped inside. I passed through the elegant entrance, checked in for a day-use bath, and headed toward the main bathing area. The interior was remarkably spacious, with plenty to offer beyond the baths themselves — a restaurant, a stone sauna, and more. The slightly dimmed lighting enhanced the quality and tranquility of the space, gently detaching me from the noise of everyday life. I changed at lightning speed and entered the main bath area, where a large indoor pool, a sauna, and a cold plunge bath welcomed me. The cold plunge bath, I was told, draws from the spring water of Tsue no Fuchi — once selected as one of Japan's Top 100 Waters. I would savor that gift to the fullest later. First, time to check out the layout. It's my personal rule: I can't truly relax until I've got a handle on the whole place. Moving out to the outdoor bath area, I found a Japanese garden world unfolding before me. Chairs for post-sauna recovery were lined up one after another, and there were nearly ten spots for reclining rest — the kind of place where you can practically drift off lying down. The outdoor rock bath and tub baths were fed with natural hot spring water. I visited in the evening, and already I could tell the nighttime atmosphere here would be something special. I couldn't help but smile — a big, silly grin spreading across my face. Having finished my survey of the facility, I washed up thoroughly and decided to start with the high-concentration carbonated spring in the outdoor bath. The moment I lowered myself into the water, it felt as though I'd plunged into ginger ale — the carbonation clung to my body with startling intensity. Until now, I had been convinced that the number-one carbonated spring was at Naruto Natural Hot Spring Arataennoyu, my home sauna — but right then and there, Higashidogo no Soratomomori seized that top spot without contest. Countless bubbles of carbon dioxide were absorbed through my skin, dilating blood vessels, boosting circulation, and warming my body with surprising speed. It was heating me up so effectively that I honestly could have gone straight to the cold plunge without stepping into the sauna at all. Still reeling from the impressive quality of the carbonated spring, I finally stepped into the sauna for my first set. The moment I opened the door to the sauna room, I was instantly captivated — by its spaciousness, and above all, by its sheer beauty. It had apparently just been renovated in 2025 and relaunched as LUMO SAUNA: a stadium-style space that can accommodate around 40 people. There was no TV, no clock — just a deep, resonant music filling the silence, soft dim lighting, and a gentle aroma drifting through the air. It was a fully immersive space that engaged all five senses. A truly beautiful sauna is one that makes you want to stay forever, to come back again and again. It's almost like appreciating a work of art. The beautiful forms and refined design naturally bring a sense of calm to the heart. Yet no sooner had I settled into that calm than an intense, unrelenting heat came surging in. I didn't check the thermometer, but my body was telling me it was well over 90°C. I gazed out at the view through the window of that beautiful sauna room and let the heat warm me to my very limits. After the sauna came the moment I'd been looking forward to: the cold plunge. As mentioned, Higashidogo no Soratomomori draws its cold plunge water from Tsue no Fuchi, one of Japan's Top 100 Waters. The moment I submerged, I was gently enveloped by the soft quality of the water and its pleasant chill of around 17°C. The depth is a generous 110 cm — enough to sink in all the way to the neck. There is a smoothness within the coldness, a magical water that makes you never want to leave. I sat completely still for a good while, slowly cooling down my heated body. Out of the cold plunge, I made my way to the outdoor recovery area in the garden-inspired space. I sank into one of the lined-up chairs. The breeze from Dogo drifted over me — it felt absolutely wonderful. Looking around, I could see plenty of others blissfully losing consciousness around me. I was the same. Despite this being only my first set, a supreme state of totonou had already arrived. I felt an acute pang of regret at having neglected this nationally acclaimed facility for so many years — and yet, alongside it, an overwhelming sense of satisfaction at the transcendent sauna experience I was now immersed in. As an aside — I hear the women's sauna is equally impressive. The concept is different, with a white-toned aesthetic, and it features a self-service löyly iki stove, along with vihta hung on the walls, filling the room with a wonderfully fresh scent, apparently. Since the concepts differ, I can't make a direct comparison, but I'd certainly love to see some vihta hanging in the men's sauna too. And if I'm really pushing my luck — I'd want them to soak the vihta in water to create a birch aroma and use that water for the löyly. Really, asking for things you don't have is a bad habit of every sauna lover. In the end, I spent about two hours bathing that day — five full sets in total. The sauna, the cold plunge, the hot spring, and the refined atmosphere were all so wonderful that I simply could not bring myself to leave the bath area. Every time I stepped into the sauna, I was pulled back toward that beautiful space. Every time I soaked in the hot spring, I was amazed again by the softness of the water and the powerful carbonation — and found myself wanting to stay forever. A facility that makes you not want to go home. That is what a truly exceptional facility is.

A meal after thorough totonou is something truly delicious. The restaurant at Higashidogo no Soratomomori is of remarkably high quality as well. Dining in that calm, refined space, the meal mercilessly stimulated my senses — sharpened to a fine edge by the sauna. I savored the food and slowly reflected on the experience of the day. With this visit to Higashidogo no Soratomomori, I had now been to every facility on my Ehime Prefecture list. A deeply satisfying completion. My next target is the neighboring Kagawa Prefecture. I've already covered most of it, but there is one facility I have yet to visit. Its name is Kotohiki Kairo. Featured in all manner of sauna magazines and consistently ranking near the top on hot spring ranking sites and national lists, it has a reputation throughout Japan as a place everyone should visit at least once in their lifetime. I'll find out just how impressive it truly is at tomorrow's visit.