Although collections in ISO/IEC 10646 are defined for technical reasons, the Japanese government defines sets of CJK ideographic characters for non-technical reasons. For example, Kyouiku Kanji [4]is a set of CJK ideographic characters for elementary school education. It has 1006 characters. Another set, Jouyou Kanji, contains 2136 CJK ideographic characters for use in official government documents. Governments in Mainland China, Taiwan, Hong-Kong, and Korea also define sets of CJK ideographic characters.

Characters covered by commercial fonts in Japan are slightly different from ISO/IEC 10646 collections for some reasons (backward compatibilities with Shift JIS, for example). Machine-readable descriptions of font-covered subsets make it easier to compare different fonts having different coverage.