A “scenic open-air bath” can be a powerful motivator when choosing accommodation. Yet this kind of value is hard to see from room types or price lists alone. In this article, we used natural language processing to analyze reviews actually posted by guests, aggregating references to experiential quality — open-air baths, scenery, free-flowing hot spring water, and water quality — by region. Rather than relying on price or ADR, this qualitative review-based lens reveals both the regions with highly rated scenic open-air baths and, conversely, the areas where such experiences are relatively rare.

Measuring the “Density” of Scenic Open-Air Baths from Reviews

This analysis starts from positive mentions of “open-air bath × scenery” in guest reviews. Standard star ratings average together many factors — cleanliness, service, food — making it hard to see whether a scenic open-air bath is truly the main draw of a property. We therefore aggregated the share of reviews in each region that spoke positively about open-air baths (the open-air mention rate). The higher this value, the more open-air baths and scenery sit at the core of the stay experience in that region, and the more strongly guests actually remember it.

Nationwide, the densest positive mentions of open-air baths were in Shizuoka Prefecture, where the average mention rate across target properties reached 25.3%. That is roughly one in four reviews referencing the open-air bath or the view. It confirms that the seaside hot spring areas of Izu and Atami stand out for ocean-view open-air bath experiences. Niigata (21.5%), Fukushima (20.5%), Gifu (19.8%), and Gunma (18.9%) follow, lining up the inland mountain hot spring regions. The structural gap between a hot spring area’s name recognition and actual guest satisfaction is a topic we have previously examined elsewhere using a body of 955,000 reviews.

Source: HotelBank Editorial Team analysis (NLP; average open-air mention rate across target properties per region)

Notably, the well-known hot spring regions of Oita and Wakayama (Shirahama) do not monopolize the top of the ranking. Instead, the highest mention rates are found in Shizuoka with the Izu Peninsula, Niigata and Fukushima as homes of the snow-viewing open-air bath, and Gifu with Okuhida and Gero — regions where the open-air bath can be told as a story together with scenery. The differentiator is not the sheer number of open-air baths, but rather the strength of the impression left by an open-air experience that is one with the landscape.

“Breadth” and “Intensity” of Highly Rated Areas

The strength of a scenic open-air market has two axes. One is breadth — how many densely mentioned properties are distributed in the region. The other is intensity — the mention rate per property. Organizing regions along these two axes reveals each area’s personality.

Shizuoka is top-class on both axes: the count of properties with an open-air mention rate above 20% reaches our aggregation cap of 100, and the average mention rate of 25.3% is also the highest. With both supply depth and experiential density, it is the “overall leader” of scenic open-air baths. Tochigi, Nagano, and Hokkaido, on the other hand, are also broad regions with 100 target properties, but their average mention rates stay between 12% and 16%. This is because they include a wide mix of price tiers and property types — business, leisure, and ski — meaning that “headliner” and “supporting cast” properties for open-air baths coexist.

Conversely, Niigata (68 properties, 21.5%) and Fukushima (49 properties, 20.5%) do not match Shizuoka in count, but their per-property intensity stands out. The clear theme of the snow-viewing open-air bath is etched strongly into guests’ impressions of these regions.

Source: HotelBank Editorial Team analysis (NLP). Horizontal axis = number of target properties (top mentioned, capped at 100); vertical axis = average open-air mention rate.

Areas Where Scenic Open-Air Baths Are “Rare”

Areas where scenic open-air bath experiences are relatively rare are equally clear. Tokyo (open-air mention rate 6.6%), Osaka (7.6%), Okinawa (8.3%), and Kyoto (10.3%) have large lodging demand yet thin mentions of open-air baths and views in their reviews. In urban areas, stays center on business or sightseeing access, and the number of properties with an open-air bath is structurally limited.

Read in reverse, this means that any property in these regions that can offer a scenic open-air bath has a powerful differentiator on its review page. In fact, along the Tokyo Bay area, high-floor ocean-view public baths are drawing comments such as “open until 6 am” or “the view from the 15th floor is incredible” — evidence that even urban hotels can win recognition with a view × bath combination. In Okinawa the mention rate itself is low, but the appetite for a sea-view bath remains strong, leaving a meaningful upside should supply increase.

Source: HotelBank Editorial Team analysis (NLP). A lower open-air mention rate indicates an area where the scenic open-air experience is relatively rare.

Kyoto Prefecture has an open-air mention rate of 10.3%, sitting on the rare side, yet its May 2026 ADR of ¥47,300 (YoY +24.7%) is among the highest in the country. It is a market evaluated on alternative axes — machiya townhouses, gardens, location — rather than open-air baths, where a different form of differentiation is at work. The meaning of “rarity” varies by region.

Water Quality and Free-Flowing Hot Spring: “Another Qualitative Axis”

Alongside scenic open-air baths, two qualitative axes of hot springs discussed in reviews are “water quality” and “free-flowing hot spring water.” Looking at properties with the densest positive mentions of water quality, the top of the list features names like Gero Onsen Suimeikan in Gifu Prefecture (293 of 1,796 target reviews, or 16.3%, mentioning water quality) and Ureshino Onsen Hotel Kasuien in Saga Prefecture (190 of 802, or 23.7%). In these cases, the character of the water itself — descriptions like “egg-white skin” or “beauty bath” — has become the brand of the property.

For free-flowing hot spring water, smaller-scale properties tend to have higher mention rates. Musouan Biwa in Toi Onsen on the western Izu coast (Shizuoka Prefecture) sees 11.1% of its 307 reviews mentioning free-flowing water, showing in the review data that the small-property strategy of emphasizing water freshness with limited room counts is clearly supported. The “visual” of a scenic view and the “felt-on-the-skin quality” of water and free-flow represent different directions of hot spring value a property can offer, and the upside lies with properties that can combine the two. Mechanically surfacing renovation candidates from review NLP is a path we have also explored.

Source: HotelBank Editorial Team analysis (NLP). Properties with the highest positive mention rates of water quality (last 24 months).

ADR and Experiential Value in Highly Rated Areas

Highly rated scenic open-air areas are not necessarily ultra-premium. Looking at regional average ADR (all-plan average) as of May 2026: Shizuoka, the leader on mention rate, sits at around ¥36,000; Gunma around ¥33,700; Gifu around ¥30,000; and Nagano around ¥30,700. On the other hand, Fukushima (around ¥25,700), Tochigi (around ¥27,700), and Niigata (around ¥27,100) carry high open-air mention rates but comparatively restrained ADR. In short, regions exist where price is still moderate against the experiential value of a scenic open-air bath. Demand-side flows of money toward premium hot spring ryokan is a related topic worth examining separately.

This can be read as a stretch of “well loved for view and water yet still priced modestly” — areas where guest-side perceived value remains. At the same time, from the operator’s perspective, regions with a clear experiential backing (high open-air mentions in reviews) have room to widen revenue opportunities through phased pricing and enriched premium plans. How to connect the qualitative strength of a scenic open-air bath to pricing strategy is the theme ahead.

Source: HotelBank Editorial Team analysis (NLP) + MetroEngines Research (ADR, May 2026)

Conclusion

Viewing scenic open-air baths through the qualitative axis of reviews surfaces regional personalities that price lists alone cannot capture. Shizuoka is the overall leader, combining supply breadth with experiential intensity, while Niigata, Fukushima, Gifu, and Gunma are highly rated regions with dense per-property mentions tied to snow-viewing and mountain open-air baths. Conversely, in Tokyo, Osaka, Kyoto, and Okinawa, the scenic open-air experience is relatively rare — which itself signals a differentiation opportunity for any urban property that can offer a view × bath proposition.

Layering in the “felt-on-the-skin” axes of water quality and free-flowing hot spring further multiplies the directions of value a property can articulate. Scenery (visual), water quality (touch), and free-flow (freshness of the water) — visualizing these through review data brings each region’s and each property’s strengths and upside into clearer relief. In highly rated regions where ADR is still modest, room remains to connect experiential value to price.