It reaches its maximum density at 4- C (about 39- F), and does not easily freeze when placed between two sheets of glass, a phenomenon that no one so far has been able to explain.

A number of "functional waters" have become known in recent years as new chemical waters; these are known as ionic water, electronic water, magnetic water, highly acidic water, biowater, ceramic water etc. and so on.

Here in Suwa, Nagano, Katsu has become popularly known as "magic" or "miracle" water since it came on the market.