Published on Jul. 31, 2023
The JIS C 6226 standard — Code of the Japanese Graphic Character Set for Information Interchange — was established in January 1978. It was the first Japanese Industrial Standard to define 6,349 kanji characters, 453 non-kanji characters, and their position codes for computer use.
International standardization of codes for information interchange, better known as character codes, that defined characters and their codes for computer use began in 1967, with ISO R 646, a recommendation by the International Organization for Standardization (ISO). Unfortunately, the 7-bit codes defined in ISO R 646 were limited to 128 characters and could not express kanji or other characters. A method was needed for extending character codes that could be used under this 7-bit limitation. The Information Processing Society of Japan had, at the time, the Standards Committee, which debated international and domestic standards pertaining to information processing. Wada Hiroshi, the chairman of the committee, proposed to the Agency of Industrial Science and Technology that an ISO R 646 extension be studied in order to express kanji characters. Later, in December 1969, the Kanji Code Committee was set up within the Standards Committee. Leadership of the committee was entrusted to Hayashi Ohki, a Japanese linguist and a school inspector belonging to the Elementary and Secondary Education Bureau of the Ministry of Education, Science, Sports and Culture. Hayashi gathered Japanese linguists and proceeded with examinations concentrating on the Kusakabe table of kanji characters given in the Gendai Kokugo Shichou [Trends in Contemporary Japanese] series by Kusakabe Jutaro. The committee examined 18 references, including leading dictionaries, typesetting tables of newspapers and printers, and survey reports on kanji characters, in addition to the Kusakabe table. In 1971, the committee compiled the provisional Kanji Table for Standard Coding, which contained 6,086 characters. The committee, unfortunately, could not reach a conclusion on the position codes and provisionally ordered the characters following the order of radicals that had been in use since the Kangxi dictionary. The committee continued to study how to sequence characters, including their position codes, but it announced the provisional plan in October 1971.
The provisional plan was picked up by the Administrative Management Agency, which recognized the need to use computers for faster processing of government information. The Administrative
Management Agency studied how often each of the kanji characters in the provisional plan appeared in the government’s Official Gazette and examined the presence of kanji characters in a further seven kanji tables. In March 1974, the Agency prepared the Analysis of Kanji Usage Frequency and Suitability for Selection as Standard Kanji Characters for Government Administrative Information Processing, which contained 2,817 characters.
The Agency of Industrial Science and Technology in April of that year requested the Japan Information Processing and Development Center to “standardize kanji codes for information interchange”. This prompted the formation of the Kanji Code Standardization Research and Study Committee with Moriguchi Shigeichi as the chair and the participation of representatives from all mainframe manufacturers. The committee looked at the Administrative Management Agency’s analysis but decided that 2,817 characters were insufficient for practical use. The committee made it its aim to determine a collection of all kanji characters needed in society at the time. After two years of examinations, the committee compiled the Japanese Industrial Standard draft — Code of the Japanese Graphic Character Set for Information Interchange, which contained a total of 6,803 characters including 6,350 kanji characters and 453 non-kanji characters, and reported it to the Agency of Industrial Science and Technology in March 1976. The basic policy behind the draft standard was to include kanji in order of frequency as determined from 37 reference materials, as well as to include kanji used in people’s names and place names. In short, the draft standard added kanji characters drawn from three sources — Administrative Management Agency materials, kanji used in nationwide land administration district surveys, and kanji used in personal names collected by Nippon Life Insurance Company — to the provisional Kanji Table for Standard Coding. The characters were divided and ordered in two levels — Level 1 with 2,965 characters and Level 2 with 3,385 characters — in consideration of how often the characters are used. Level 1 kanji were ordered according to their typical on or kun reading, whereas Level 2 kanji were ordered following the order of radicals and stroke number (Kangxi dictionary).
The Agency of Industrial Science and Technology submitted the draft standard to the Japan Industrial Standards Commission. The Kanji Coding System Expert Committee under the Information Processing Section, chaired by Moriguchi, debated the draft standard and, after a few amendments, established JIS C 6226-1978 — Code of the Japanese Graphic Character Set for Information Interchange — in January 1978. The final standard defined 6,802 characters — 453 non-kanji characters, 2,965 Level 1 kanji characters, and 3,384 Level 2 kanji characters.
The establishment of this standard paved the way for full-fledged processing in Japanese, exemplified by the announcement in September 1978 of the first Japanese-language word processor, the JW-10.