Loaded with major ions — the essential minerals (Ca, Mg).
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
BicarbonatesSodiumCalcium
Fukaya, in northern Saitama Prefecture, is the birthplace of Shibusawa Eiichi, the nineteenth-century industrialist and social reformer whose image now appears on Japan's ten-thousand-yen banknote, celebrated as the father of Japanese capitalism for his role in establishing over five hundred modern companies during the transformative Meiji era. Fukaya Onsen Saitama draws on sodium and bicarbonate thermal waters from the deep alluvial aquifers of the north Kanto Plain, providing restorative baths in a city whose distinctive red-brick architecture — produced by the Fukaya brick kilns that supplied materials for Tokyo's historic Marunouchi district development — creates a unique visual character among the farming communities of northern Saitama. The Fukaya Flower World gardens, the Shibusawa Eiichi Memorial Museum documenting his remarkable entrepreneurial legacy, and the historic red-brick civic hall make Fukaya a culturally distinctive destination for thermal wellness.
Insider tip — Fukaya is renowned across Japan as the birthplace of Shibusawa Eiichi, the father of Japanese capitalism, and its sento draws bicarbonate thermal water at 41°C from the Kanto basin's deeper strata. The historic brick architecture that defines Fukaya's city centre, inspired by Tokyo Station's red-brick design, gives the town an elegantly retro ambiance rarely found this close to Tokyo. The bathhouse water is notably soft and pleasant on the skin. Combining the sento with a walk through the town's heritage brick district makes for a rewarding day trip from Omiya or Kumagaya.