Editing Big5 (section)

===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"/>