Okayukaikan Oka Hotei Hot Spring

A weakly alkaline simple thermal spring with light overall mineralization (0.634 g/kg) but a respectable 60.9 mg/kg of metasilicic acid — enough to place it in the Japanese 'beauty-water' family with a subtly smoothing feel on the skin. On the anion side chloride and sulfate sit almost evenly matched, giving a sodium-led, clean-tasting profile rather than any one mineral character dominating.

東邦化工建設株式会社 三島分析センター