Japanese Salt and Foreign Salt Together with air and water, salt forms a part of the vital triad of substances essential for the maintenance of life. The human body incorporates a certain percentage of salt which plays a critical role in controlling and regulating the water content of living tissues and cells.
Natural salt is found in several forms, each of which calls for different production techniques.
In warm or tropical coastal areas with relatively low humidity, salt is often extracted from sea water through natural evaporation. By comparison with other heavily populated parts of the world, Japan has always been at a disadvantage, for it has no known rock-salt deposits or other terrestrial salt sources, while its relatively low median temperatures and heavy rainfall make reliance on natural evaporation impracticable. Until relatively recent times, importation of salt from abroad was difficult if not impossible, due to the island nation's distance from the continent. Thus, Japan was forced to develop its own salt technology, some aspects of which are not found elswhere. The scope of their research is not limited to edible salt production alone, for the growing significance of soda and soda derivatives in modern industry has if anything, increased the importance of salt as one of the indispensable raw materials necessary for the advanced technology of today .