Editing Big5 (section)

==Extensions==
The original Big-5 only include CJK logograms from the [[Chart of Standard Forms of Common National Characters|Charts of Standard Forms]] of Common National Characters (4808 characters) and Less-Than-Common National Characters (6343 characters), but not letters from people's names, place names, dialects, [[chemistry]], [[biology]], Japanese kana. As a result, many Big-5 supporting software include extensions to address the problems.

The plethora of variations make [[UTF-8]] (or [[UTF-16]] or the Chinese [[GB 18030]] standard, which is also a full Unicode Transformation Format, i.e. not only for simplified Chinese) a more consistent code page for modern use.

===Vendor extensions===
====ETen extensions====
In the [[ETen Chinese System|ETen]] (倚天) Chinese operating system, the following code points are added, to add support for some characters present in the [[IBM 5550]]'s code page but absent from generic Big5:

* <code>0xA3C0</code>–<code>0xA3E0</code>: 33 control characters.
* <code>0xC6A1</code>–<code>0xC875</code>: circle 1–10, bracket 1–10, [[Roman numerals]] 1–9 (i–ix), CJK radical glyphs, Japanese [[hiragana]], Japanese [[katakana]], [[Cyrillic]] characters
* <code>0xF9D6</code>–<code>0xF9FE</code>: the characters '[[wikt:碁|碁]]', '[[wikt:銹|銹]]', '[[wikt:恒|恒]]', '[[wikt:裏|裏]]', '[[wikt:墻|墻]]', '[[wikt:粧|粧]]' and '[[wikt:嫺|嫺]]', followed by 34 additional [[semigraphic]] symbols.

In some versions of ETen, there are extra graphical symbols and [[simplified Chinese characters]].

====Microsoft code pages====
{{Main|Code page 950}}

[[Microsoft]] (微軟) created its own version of Big5 extension as [[code page 950]] for use with [[Microsoft Windows]], which supports the F9D6–F9FE code points from ETEN's extensions. In some versions of Windows, the [[euro]] [[Euro sign|currency symbol]] is mapped to Big-5 code point A3E1.

After installing Microsoft's [http://www.microsoft.com/hk/hkscs/default.aspx HKSCS patch] on top of traditional Chinese Windows (or any version of Windows 2000 and above with proper language pack), applications using code page 950 automatically use a hidden code page 951 table. The table supports all code points in HKSCS-2001, except for the compatibility code points specified by the standard.<ref>{{Cite web|url=http://me.abelcheung.org/2006/09/12/what-is-cp951/|title=狗爺語錄 » Blog Archive » What is Code Page 951 (CP951)?<!-- Bot generated title -->|access-date=2006-09-27|archive-url=https://web.archive.org/web/20070222070938/http://me.abelcheung.org/2006/09/12/what-is-cp951/|archive-date=2007-02-22|url-status=dead}}</ref>

====IBM code pages====
In contrast to Microsoft's code page 950, IBM's [[CCSID]] 950 comprises single byte code page 1114 (CCSID 1114) and double byte code page 947 (CCSID 947).<ref name="ccsid950">{{cite web|title=CCSID 950 information document|archive-url=https://web.archive.org/web/20141202001630/http://www-01.ibm.com/software/globalization/ccsid/ccsid950.html|archive-date=2014-12-02|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid950.html}}</ref><ref>{{cite web|title=CCSID 1114 information document|archive-url=https://web.archive.org/web/20160327100728/http://www-01.ibm.com/software/globalization/ccsid/ccsid1114.html|archive-date=2016-03-27|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid1114.html}}</ref><ref>{{cite web|title=CCSID 947 information document|archive-url=https://web.archive.org/web/20141201232116/http://www-01.ibm.com/software/globalization/ccsid/ccsid947.html|archive-date=2014-12-01|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid947.html}}</ref> It incorporates ETEN extensions for lead bytes {{mono|0xA3}},<ref>{{cite web|url=https://demo.icu-project.org/icu-bin/convexp?conv=ibm-950_P110-1999&b=A3&s=ALL#layout|title=Lead byte A3: ibm-950_P110-1999|work=ICU Demonstration - Converter Explorer|publisher=[[International Components for Unicode]]}}</ref> {{mono|0xC6}},<ref name="rfc1922">{{citation|mode=cs1|id=<nowiki>RFC 1922</nowiki>|title=Chinese Character Encoding for Internet Messages|url=https://tools.ietf.org/html/rfc1922|first1=HF.|last1=Zhu|first2=DY.|last2=Hu|first3=ZG.|last3=Wang|first4=TC.|last4=Kao|first5=WCH.|last5=Chang|first6=M.|last6=Crispin|publisher=[[IETF]]|work=Requests for Comments|date=1996|doi=10.17487/rfc1922|doi-access=|access-date=2022-01-01|archive-date=2021-04-29|archive-url=https://web.archive.org/web/20210429165037/https://tools.ietf.org/html/rfc1922|url-status=live|url-access=subscription}}</ref><ref>{{cite web|url=https://demo.icu-project.org/icu-bin/convexp?conv=ibm-950_P110-1999&b=C6&s=ALL#layout|title=Lead byte C6: ibm-950_P110-1999|work=ICU Demonstration - Converter Explorer|publisher=[[International Components for Unicode]]}}</ref> {{mono|0xC7}}<ref>{{cite web|url=https://demo.icu-project.org/icu-bin/convexp?conv=ibm-950_P110-1999&b=C7&s=ALL#layout|title=Lead byte C7: ibm-950_P110-1999|work=ICU Demonstration - Converter Explorer|publisher=[[International Components for Unicode]]}}</ref> and {{mono|0xC8}},<ref name="rfc1922"/><ref>{{cite web|url=https://demo.icu-project.org/icu-bin/convexp?conv=ibm-950_P110-1999&b=C8&s=ALL#layout|title=Lead byte C8: ibm-950_P110-1999|work=ICU Demonstration - Converter Explorer|publisher=[[International Components for Unicode]]}}</ref> while omitting those with lead byte {{mono|0xF9}} (which Microsoft includes), mapping them instead to the [[Private Use Area]] as user-defined characters.<ref name="rfc1922"/><ref>{{cite web|url=https://demo.icu-project.org/icu-bin/convexp?conv=ibm-950_P110-1999&b=F9&s=ALL#layout|title=Lead byte F9: ibm-950_P110-1999|work=ICU Demonstration - Converter Explorer|publisher=[[International Components for Unicode]]}}</ref> It also includes two non-ETEN extension regions with trail bytes {{mono|0x81–A0}}, i.e. outside the usual Big5 trail byte range but similar to the Big5+ trail byte range: area 5 has lead bytes {{mono|0xF2–F9}} and contains IBM-selected characters, while area 9 has lead bytes {{mono|0x81–8C}} and is a user-defined region.<ref>{{cite web|url=https://public.dhe.ibm.com/as400/products/clientaccess/win32/files/globalization/T_Chinese_big51999.pdf|title=IBM Traditional Chinese Graphic Character Set for IBM BIG-5 Code|publisher=[[IBM]]|year=1999|id=C-H 3-3220-131 1999-04|access-date=2022-01-01|archive-date=2021-11-22|archive-url=https://web.archive.org/web/20211122211354/https://public.dhe.ibm.com/as400/products/clientaccess/win32/files/globalization/T_Chinese_big51999.pdf|url-status=live}}</ref>

IBM refers to the euro sign update of their Big-5 variant as CCSID 1370, which includes both single-byte ({{mono|0x80}}) and double-byte ({{mono|0xA3E1}}) euro signs.<ref name="ccsid1370">{{cite web|title=CCSID 1370 information document|archive-url=https://web.archive.org/web/20160327104212/http://www-01.ibm.com/software/globalization/ccsid/ccsid1370.html|archive-date=2016-03-27|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid1370.html}}</ref> It comprises single byte code page 1114 (CCSID 5210) and double byte code page 947 (CCSID 21427).<ref name="ccsid1370"/><ref>{{cite web|title=CCSID 5210 information document|archive-url=https://web.archive.org/web/20141129231704/http://www-01.ibm.com/software/globalization/ccsid/ccsid5210.html|archive-date=2014-11-29|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid5210.html}}</ref><ref>{{cite web|title=CCSID 21427 information document|archive-url=https://web.archive.org/web/20160327035914/http://www-01.ibm.com/software/globalization/ccsid/ccsid21427.html|archive-date=2016-03-27|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid21427.html}}</ref> For better compatibility with Microsoft's variant in [[IBM Db2]], IBM also define the pure double-byte code page 1372<ref>{{cite web|archive-url=https://web.archive.org/web/20160317015819/http://www-01.ibm.com/software/globalization/cp/cp01372.html|archive-date=2016-03-17|url=http://www-01.ibm.com/software/globalization/cp/cp01372.html|url-status=dead|title=CPGID 01372: MS T-Chinese Big-5 (Special for DB2)|work=IBM Globalization - Code page identifiers}}</ref> and the associated variable-width CCSID 1373, which corresponds to Microsoft's code page 950.<ref>{{cite web|url=http://icu-project.org/icu-bin/convexp?conv=ibm-1373_P100-2002|title=ibm-1373_P100-2002|work=ICU Demonstration - Converter Explorer|publisher=[[International Components for Unicode]]|access-date=2022-01-01|archive-date=2021-05-26|archive-url=https://web.archive.org/web/20210526173749/https://icu4c-demos.unicode.org/icu-bin/convexp?conv=ibm-1373_P100-2002|url-status=live}}</ref>

IBM assigns CCSID 5471 to the HKSCS-2001 Big5 code page (with CPGID 1374 as CCSID 5470 as the double byte component),<ref>{{cite web|archive-url=https://web.archive.org/web/20141129233053/http://www-01.ibm.com/software/globalization/ccsid/ccsid5471.html|archive-date=2014-11-29|url-status=dead|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid5471.html|work=IBM Globalization - Coded character set identifiers|publisher=[[IBM]]|title=CCSID 5471: Mixed Big-5 ext for HKSCS-2001}}</ref><ref>{{Citation|title=International Components for Unicode (ICU), ibm-5471_P100-2006.ucm|url=https://github.com/unicode-org/icu/blob/master/icu4c/source/data/mappings/ibm-5471_P100-2006.ucm|date=2007-05-09|access-date=2022-01-01|archive-date=2023-08-13|archive-url=https://web.archive.org/web/20230813202101/https://github.com/unicode-org/icu/blob/main/icu4c/source/data/mappings/ibm-5471_P100-2006.ucm|url-status=live}}</ref> CCSID 9567 to the HKSCS-2004 code page (with CPGID 1374 as CCSID 9566 as the double byte component),<ref>{{cite web|archive-url=https://web.archive.org/web/20141129212819/http://www-01.ibm.com/software/globalization/ccsid/ccsid9567.html|archive-date=2014-11-29|url-status=dead|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid9567.html|work=IBM Globalization - Coded character set identifiers|publisher=[[IBM]]|title=CCSID 9567: Mixed Big-5 ext for HKSCS-2004}}</ref> and CCSID 13663 to the HKSCS-2008 code page (with CPGID 1374 as CCSID 13662 as the double byte component),<ref>{{cite web|archive-url=https://web.archive.org/web/20141129213320/http://www-01.ibm.com/software/globalization/ccsid/ccsid13663.html|archive-date=2014-11-29|url-status=dead|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid13663.html|work=IBM Globalization - Coded character set identifiers|publisher=[[IBM]]|title=CCSID 13663: Mixed Big-5 ext for HKSCS-2008}}</ref> while CCSID 1375 is assigned to a growing HKSCS code page, currently equivalent to CCSID 13663.<ref>{{cite web|archive-url=https://web.archive.org/web/20141129231410/http://www-01.ibm.com/software/globalization/ccsid/ccsid1375.html|archive-date=2014-11-29|url-status=dead|url=http://www-01.ibm.com/software/globalization/ccsid/ccsid1375.html|work=IBM Globalization - Coded character set identifiers|publisher=[[IBM]]|title=CCSID 1375: Mixed Big-5 ext for HKSCS}}</ref>

====ChinaSea font====
[[ChinaSea]] fonts (中國海字集)<ref>{{cite web|author=黃國書|url=http://ftp.isu.edu.tw/pub/Windows/Chinese/font/chinasea/csw10_exp.txt|title=Chinasea 1.0 中國海字集|publisher=ISU FTP|access-date=2016-12-05|archive-url=https://web.archive.org/web/20050319032136/http://ftp.isu.edu.tw/pub/Windows/Chinese/font/chinasea/csw10_exp.txt|archive-date=2005-03-19|url-status=dead}}</ref> are Traditional Chinese fonts made by ChinaSea. The fonts are rarely sold separately, but are bundled with other products, such as the Chinese version of [[Microsoft Office 97]]. The fonts support Japanese kana, [[kokuji]], and other characters missing in Big-5. As a result, the ChinaSea extensions have become more popular than the government-supported extensions.{{as of?|date=May 2019}} Some Hong Kong [[Bulletin board system|BBSes]] had used encodings in ChinaSea fonts before the introduction of HKSCS.

===='Sakura' font====
The [https://web.archive.org/web/20060904023817/http://input.foruto.com/jptxt/ 'Sakura' font] (日和字集 Sakura Version) is developed in Hong Kong and is designed to be compatible with HKSCS. It adds support for [[kokuji]] and proprietary dingbats (including [[Doraemon]]) not found in HKSCS.

====Unicode-at-on====
Unicode-at-on ([[:zh:Unicode補完計畫|Unicode補完計畫]]), formerly BIG5 extension, extends BIG-5 by altering code page tables, but uses the ChinaSea extensions starting with version 2. However, with the bankruptcy of ChinaSea, late development, and the increasing popularity of HKSCS and [[Unicode]] (the project is not compatible with HKSCS), the success of this extension is limited at best.

Despite the problems, characters previously mapped to Unicode Private Use Area are remapped to the standardized equivalents when exporting characters to Unicode format.

====OPG====
The web sites of the [[Oriental Daily News]] and [[Sun Daily]], belonging to the [[Oriental Press Group Limited]] (東方報業集團有限公司) in Hong Kong, used a downloadable font with a different Big-5 extension coding than the HKSCS.

===Official extensions===
====Taiwan Ministry of Education font====
The Taiwan Ministry of Education supplied its own font, the Taiwan Ministry of Education font (臺灣教育部造字檔) for use internally.

====Taiwan Council of Agriculture font====
Executive Yuan introduced a 133-character custom font, the Taiwan Council of Agriculture font (臺灣農委會常用中文外字集), that includes 84 characters from the [[Radical 195|fish radical]] and 7 from the [[Radical 196|bird radical]].

====Big5+====
The [[Chinese Foundation for Digitization Technology]] (中文數位化技術推廣委員會) introduced Big5+ in 1997, which used over 20000 code points to incorporate all CJK logograms in Unicode 1.1. However, the extra code points exceeded the original Big-5 definition (Big5+ uses high byte values 81-FE and low byte values 40-7E and 80-FE), preventing it from being installed on Microsoft Windows without new codepage files.

====Big-5E====
To allow Windows users to use custom fonts, the Chinese Foundation for Digitization Technology introduced Big-5E, which added 3954 characters (in three blocks of code points: 8E40-A0FE, 8140-86DF, 86E0-875C) and removed the Japanese kana from the ETEN extension. Unlike Big-5+, Big5E extends Big-5 within its original definition. [[Mac OS X 10.3]] and later supports Big-5E in the fonts LiHei Pro (儷黑 Pro.ttf) and LiSong Pro (儷宋 Pro.ttf).

====Big5-2003====
The Chinese Foundation for Digitization Technology made a Big5 definition and put it into [[CNS 11643]] in note form, making it part of the official standard in Taiwan.

Big5-2003 incorporates all Big-5 characters introduced in the 1984 ETEN extensions (code points A3C0-A3E0, C6A1-C7F2, and F9D6-F9FE) and the Euro symbol. Cyrillic characters were not included because the authority claimed CNS 11643 does not include such characters.

====CDP====
The [[Academia Sinica]] made a Chinese Data Processing font (漢字構形資料庫) in late 1990s, which the latest release version 2.5 included 112,533 characters, some less than the [[Mojikyo]] fonts.

====HKSCS====
{{Main|Hong Kong Supplementary Character Set}}

[[Hong Kong]] also adopted Big5 for character encoding. However, [[written Cantonese]] has its own characters not available in the normal Big5 character set. To solve this problem, the [[Hong Kong Government]] created the Big5 extensions [[Government Chinese Character Set]] (GCCS) in 1995 and [[Hong Kong Supplementary Character Set]] in 1999. The Hong Kong extensions were commonly distributed as a patch. It is still being distributed as a patch by Microsoft, but a full Unicode font is also available from the Hong Kong Government's web site.

There are two encoding schemes of HKSCS: one encoding scheme is for the Big-5 coding standard and the other is for the [[ISO 10646]] standard. Subsequent to the initial release, there are also HKSCS-2001 and HKSCS-2004. The HKSCS-2004 is aligned technically with the ISO/IEC 10646:2003 and its Amendment 1 published in April 2004 by the International Organization for Standardization (ISO).

HKSCS includes all the characters from the common ETen extension, plus some characters from simplified Chinese, place names, people's names, and Cantonese phrases (including [[Cantonese profanity|profanity]]).

{{as of|2020}}, the most recent edition of HKSCS is HKSCS-2016; however, the last edition of HKSCS to encode all of its characters in Big5 was HKSCS-2008, while the characters added in more recent editions are mapped to ISO 10646 / [[Unicode]] only (as a [[CJK Unified Ideographs]] horizontal glyph extension where appropriate).<ref name="irgn2430">{{cite web|url=https://appsrv.cse.cuhk.edu.hk/~irg/irg/irg53/IRGN2430.pdf|title=Submission of Macao's Vertical Extension (UNC Characters), Horizontal Extension, and IVSes Registration for MSCS|author=Macao Special Administrative Region Government|date=2020-06-11|id=[[ISO/IEC JTC 1/SC 2]]/WG 2 [[Ideographic Research Group|IRGN]] 2430|access-date=2020-07-02|archive-date=2020-06-23|archive-url=https://web.archive.org/web/20200623040740/https://appsrv.cse.cuhk.edu.hk/~irg/irg/irg53/IRGN2430.pdf|url-status=live}}</ref> Additionally, similarly to Hong Kong's situation, there are also characters that are needed by Macao but is neither included in Big5 nor HKSCS, hence, the ''Macao Supplementary Character Set'' was developed, comprising characters not found in Big5 or HKSCS; this, however, is also not encoded in Big5. The first batch of 121 MSCS characters were submitted for inclusion in or mapping to Unicode in 2009,<ref name="irgn1580">{{cite web|url=http://appsrv.cse.cuhk.edu.hk/~irg/irg/irg32/IRGN1580MacaoCharsFromMISCS.pdf|title=Submission of Characters from Macao Information Systems Character Set|author=Computer Chinese Characters Encoding Workgroup|date=2009-06-12|id=[[ISO/IEC JTC 1/SC 2]]/WG 2 [[Ideographic Research Group|IRGN]] 1580|archive-url=https://web.archive.org/web/20150104014324/http://appsrv.cse.cuhk.edu.hk/~irg/irg/irg32/IRGN1580MacaoCharsFromMISCS.pdf|archive-date=2015-01-04|url-status=dead}}</ref> and the first final version of MSCS was established in 2020.<ref name="irgn2430"/>