One important factor concerning water is its hardness -a term that refers to the presence of minerals, specifically magnesium and calcium. Water with relatively high levels of these substances is referred to as ‘hard’ water, and that with relatively low levels is referred to as soft’ water.
Compared with the rest of the world, most notably Europe and China, Japanese water is mainly soft, and it is generally believed that this has had a profound effect on the development of the country’s cuisine, and in particular its use of dashi.