Loaded with major ions — the essential minerals (Ca, Mg).
Buoyancy
Standard buoyancy
LowHigh
Soft water — natural, classic buoyancy.
BicarbonatesSodiumCalcium
Marugame Onsen sits in the castle town of Marugame on Shikoku's north coast, overlooking the Seto Inland Sea and dominated by one of Japan's twelve surviving original castle keeps, a national treasure dating to the early seventeenth century. The sodium-bicarbonate spring water provides a smoothing, revitalising soak long favoured by the local townspeople who have maintained a bathing culture tied to the castle town's civic identity across many generations. Visitors combining onsen relaxation with a visit to the hilltop castle are rewarded with sweeping views across the sea toward the bridges of the Seto Ohashi linking Shikoku to Honshu.
Insider tip — Marugame is famed for its compact hilltop castle, one of the few original-construction tenshu towers surviving in Japan, and its bicarbonate onsen provides an excellent post-sightseeing recovery. The spring water bubbles up through limestone and sandstone from the Shikoku mountain fringe, arriving at surface level smooth and faintly effervescent. Sanuki udon, the thick wheat noodles for which Kagawa is nationally celebrated, is best followed by a long evening soak in the mineral waters. Weekday evenings are noticeably quieter and the bath house is essentially a local neighborhood gathering spot.
