(), also known by its full name , is a character encoding scheme created to provide a complete index of characters used in the Chinese, Japanese, Korean, Vietnamese Chữ Nôm and other historical Chinese logographic writing systems. The , which published the character set, also published computer software and TrueType computer fonts to accompany it. The Mojikyō Institute, chaired by , originally had its character set and related software and data redistributed on CD-ROMs sold in Kinokuniya stores.

Conceptualized in 1996, the first version of the CD-ROM was released in July 1997. For a time, the Mojikyō Institute also offered a web subscription, termed " WEB" (), which had more up-to-date characters.

, Mojikyō encoded 174,975 characters. Among those, 150,366 characters (≈86%) then belonged to the extended Chinese–Japanese–Korean–Vietnamese (CJKV)For Korean, Hanja are referred to. For Vietnamese, Chữ Nôm. family. Many of Mojikyō's characters are considered obsolete or obscure, and are not encoded by any other character set, including the most widely used international text encoding standard, Unicode.

Originally a paid proprietary software product, as of 2015, the Mojikyō Institute began to upload its latest releases to Internet Archive as freeware, as a memorial to honor one of its developers, , who died that year. On 15 December 2018, version 4.0 was released. The next day, Ishikawa announced that without Furuya this would be the final release of Mojikyō.

Premise The encoding was created to provide a complete index of characters used in the Chinese, Japanese, Korean writing systems and Vietnamese Chữ Nôm logographic scripts. It also encodes a large number of characters in ancient scripts, such as the oracle bone script, the seal script, and Sanskrit (Siddhaṃ). For many characters, it is the only character encoding to encode them, and its data is often used as a starting point for Unicode proposals. However, has much looser standards than Unicode for encoding, which leads to have many encoded glyphs of dubious, or even unintentionally fictional, origin. As such, while many non-Unicode characters are suitable for addition to Unicode, not all can become Unicode characters, due to the differing standards of evidence required by each.

Composition The fonts () are TrueType fonts that come in a ZIP file and are each around 25 megabytes; the different fonts contain different numbers of characters. Also included is a Windows executable that implements a graphical character map, the " Character Map" (), .English name from the title of the window produced by running the executable; Japanese name from the icon of the executable.Also called the "Mojikyō Cmap". allows users to browse through the fonts, and copy and paste characters in lieu of typing them on the keyboard. As opposed to the regular Windows character map, or for that matter KCharSelect, which both support TrueType fonts, displays the numbered encoding slot of the requested character. In order for to work, all fonts must be installed.Into the system fonts directory .

Encoding When referring to a character encoded in , the format MXXXXXX is often used, similar to the U+XXXX format used for Unicode. A difference, however, is that encodings displayed this way are decimal, while Unicode's U+ encoding is hexadecimal.

From the earliest days of Unicode, has both influenced—and been influenced by—the standard. Glyphs originating from first appear in a proposal to the Ideographic Rapporteur Group (IRG),As of 2019, the IRG rebranded as the Ideographic Research Group. which is responsible for maintaining all CJK blocks in Unicode, on 18 April 2002. In May 2007, played a minor role in an eventually successful series of proposals to encode the Tangut script in Unicode;The history of the encoding of the Tangut script is quite complicated, see for a full listing of all the related proposals and a timeline. already had within its encoding 6,000 Tangut characters by October 2002.

The Unicode Standard's Unihan Database refers to as the "Japanese KOKUJI Collection" (), abbreviated "JK". For example, ,Ideographic Description Sequence: an ideograph read in Japanese as , has a J-SourceThis is a column name in the Unihan database; ⟨J⟩ here is short for "Japanese glyph source". The full name of the column is . Under Han unification, there are nine such sources. See §3.1 of UAX#38 for a complete list and more information. equal to JK-66038. All Unicode characters with a JK-prefixed J-Source originate from .Other J-Source prefixes exist, such as J4, meaning the character originates from JIS X 0213:2004. According to Ken Lunde, a subject matter expert in character encodings and East Asian languages, as of Unicode 13.0, 782 ideographs in Unicode originate from , split somewhat evenly between two blocks: CJK Unified Ideographs Extension C, with 367, and CJK Unified Ideographs Extension E, with 415. Not all Unicode characters with origins (JK-prefixed J-Sources) have the same representative glyph in the code chart as in the font;That is to say, a glyph made up of the same radicals in the same positions. some characters had their shapes changed before final encoding, as investigation showed the shapes assigned by the Mojikyō Institute were wrong.Errors in large collections of ideographs are, of course, not uncommon. Such errors even accidentally occur in well funded government-produced collections, such as the famous kanji from unknown sources in the Japanese Industrial Standards Committee's JIS X 0208 double-byte character encoding standard. All of these JIS X 0208 error kanji (Ghost characters, ; e.g., ) have made their way into Unicode despite not being "real" kanji.

Blocks it encoded 174,975 characters. Among those, 150,366 characters then belonged to the extended CJKV family. Many of the encoded characters are considered obsolete or otherwise obscure, and are not encoded by any other character set, including the international standard, Unicode. Each character has a unique number, and the characters are organized into blocks.

puts CJKV characters in different blocks according to their traditional Kangxi radical. Common radicals containing an especially high number of characters, such as Radicals 9 () and 162 (), are split further by stroke order.For proof, see the list in the Mojikyō Character Map, .

No unification Unlike Unicode, purposely avoids Han unification; no attempt at compactness of the encoding is made, nor is there an attempt to keep all common characters below U+FFFF as there is in Unicode.

Unicode, on the other hand, sorts its CJK into blocks based on how common they are: the most common are generally put into the Basic Multilingual Plane, while those that are rare or obscure are put into the Supplementary Planes.

License is proprietary software under a restrictive license. Originally, the Mojikyō Institute tried to prevent its character data from being used, and threatened those who published conversion tables to and from its character set. In July 2010, the Mojikyō Institute abandoned its legal efforts to stop at least one Japanese user from publishing conversion tables or converting characters encoded in to Unicode or other character sets. Mere data, sometimes including the shapes of letters, are considered in many jurisdictions to be common property as they do not meet the threshold of originality.See also: fictitious entry; trap street.

Due to this legacy, however, disallowed data as of 2020.

Collected writing systems Living Chinese — Hanzi Japanese — Kanji, Kana (including Hentaigana) Korean — Hanja Latin alphabet with diacritics Cyrillic script with diacritics

Dead or obsolete Ancient Chinese Oracle bone script Seal script Taiwanese kana Vietnamese — Chữ Nôm Sanskrit — Siddhaṃ Tangut script Sui script

See also Han unification JIS X 0208 List of CJK fonts TRON

References

Notes