Hy?gaiji (, translated to "characters from outside the table/chart"), also hy?gai kanji (?) and j?y?gai kanji (), are Japanese kanji outside the two major lists of J?y?, which are taught in primary and secondary school, and Jinmeiy?, which are additional kanji that officially are allowed for use in personal names.
Because hy?gaiji is a catch-all category for "all unlisted kanji", there is no comprehensive list, nor is there a definitive count of the hy?gaiji. The highest level of the Kanji kentei (test of kanji aptitude) tests approximately 6,000 characters, of which 3,000 are hy?gaiji, while in principle any traditional Chinese character or newly coined variant may be used as hy?gaiji; the traditional dictionaries the Kangxi Dictionary and the 20th century Dai Kan-Wa jiten contain about 47,000 and 50,000 characters, respectively, of which over 40,000 would be classed as hy?gaiji or non-standard variants if used in Japanese.
While many j?y?-kanji are printed using simplified forms (shinjitai, in opposition to traditional forms), hy?gaiji are officially printed with traditional forms such as ?, even if some simplified variants are officially recognized in print, such as the simplified ?, from the traditional ?.
The Jinmeiy?-kanji list (used for names) recognizes in most cases the traditional form along with the simplified form (when one exists).
However, other unofficial simplified forms exist, known as extended shinjitai (, kakuch? shinjitai) - these come by applying the same simplification processes as in the development of shinjitai. The newspaper Asahi Shimbun developed its own simplified characters, known as Asahi characters, and they have their own Unicode code points. Some of these simplifications are part of the standard JIS X 0208 and later versions. Among extended shinjitai, only a few are de facto frequently used, including ?, ? (extended shinjitai for the j?y?-kanji ?, ?) or ?, ? (extended shinjitai for the hy?gaiji ?, ?).
The issue of variant non-J?y? character forms becomes apparent when using many commonly available Japanese fonts. While characters not frequently used generally retain their traditional forms, those commonly used in Japanese writing frequently are reproduced in their unofficial simplified form (extended shinjitai), rather than their official printed form. Well-known examples include:
Some characters are provided in both their official and simplified forms, as is the case with ? (official printed form) and ? (simplified variant), but most of these characters are provided in one form only. Thus, unlike the aforementioned "Asahi characters", simplifications are not comprehensive, meaning that hy?gaiji are rendered as a mix of both standard classical forms and unofficial simplifications. This is perhaps most obvious in the archaic kanji spelling of pan ("bread"), . The characters, both hy?gaiji, are displayed with a simplified and an unsimplified "barley" radical side-by-side, which can be visually jarring. The lack of an unsimplified variant in many fonts leaves the user with no choice but to reproduce the word as shown above.
The use of hy?gaiji in computer fonts was brought to the fore with the 2007 launch of Mac OS X v10.5 "Leopard". This release included the fonts Hiragino Mincho Pro N and Hiragino Kaku Gothic Pro N, which reproduce hy?gaiji in their official printed forms.
A related weakness (though less relevant to modern language use) is the inability of most commercially available Japanese fonts to show the traditional forms of many J?y? kanji, particularly those whose component radicals have been comprehensively altered (such as ? in ?, ? in ?, and ? in ? or ?, rather than their traditional forms as used in ?, ?, and ?). This is mostly an issue in the verbatim reproduction of old texts, and for academic purposes.
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Hy?gaiji are often used in the names of wagashi, which draw from ancient literature.
Modern Mandarin Chinese borrowings into Japanese are typically rendered with katakana as per any gairaigo, however they may be sometimes stylistically spelled with their original Chinese characters and given a non-standard borrowed pronunciation, many of these characters are technically classified as Hy?gaiji due to the difference in common character use between the languages.