Suntory Tennensui Natural Water is a still natural mineral water produced by the Japanese company Suntory since 1991. The water is drawn from deep underground sources in four mountainous regions of Japan: the Minami Alps, Kita Alps, Okudaisen, and Aso. Rainfall and melted snow gradually pass through layers of rock and soil that act as a natural geological filter. During its underground journey, the water acquires small amounts of calcium, magnesium, and other naturally occurring minerals. After extraction, it undergoes fine filtration and brief high-temperature sterilization without the removal of its natural minerals. It is then bottled under controlled conditions at dedicated facilities located near the sources. The product contains no added carbon dioxide or preservatives. Its low mineral content contributes to a mild, clean, and unobtrusive taste characteristic of Japanese soft waters.