Loaded with major ions — the essential minerals (Ca, Mg).
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
BicarbonatesSodiumCalcium
Sabae Onsen in Sabae city, Fukui Prefecture, serves the self-proclaimed spectacles capital of the world, a compact industrial city that manufactures over ninety percent of Japan's eyeglass frames and a significant share of global production, its precision optical industry rooted in a diversification strategy pursued during the Meiji era to supplement the area's traditional textile economy. The sodium-bicarbonate spring water offers gentle, skin-smoothing baths that relax the fine motor tension accumulated by the craftspeople who perform the intricate assembly work central to Sabae's optical heritage. The combination of artisanal industrial precision and traditional onsen bathing culture creates a distinctly Sabae expression of the Japanese work-and-rest philosophy.
Insider tip — Sabae Onsen serves Japan's self-styled eyeglass capital, a city that produces roughly 90% of the country's domestic spectacle frames in small precision workshops. The bicarbonate spring water flows at 40°C into a quiet public bathhouse where craftspeople unwind after hours at lathe and polishing wheel. The bath interiors are occasionally decorated with locally crafted tile and glasswork, making the space as visually distinctive as the city's industry.