The number of a Japanese Industrial Standard (JIS) consists of an English letter symbol and four(4) or five(5) digits number. The number may have part number(s) following the 4-5 digits one and a hyphen "-." The English letter symbols showes 19 technical areas such as A for "Civil Engineering and Architecture", X for "Information Processing." Of the number, the first two digits show a prescribed division of sub-technical area and the last two are given freely. H 7501,for example, means a technical area of "Nonferrous Materials and Metallurgy" and a division of "functional materials".
JIS are also categorized into three domains ; products, methods and basic. There are about 4000, 1600 and 2800 standards respectively.