Regional indicator symbol
The regional indicator symbols are a set of 26 alphabetic Unicode characters intended to be used to encode ISO 3166-1 alpha-2 two-letter country codes in a way that allows optional special treatment.
These were defined by as part of the Unicode 6.0 support for emoji, as an alternative to encoding separate characters for each country flag. Although they can be displayed as Roman letters, it is intended that implementations may choose to display them in other ways, such as by using national flags. The Unicode FAQ indicates that this mechanism should be used and that symbols for national flags will not be directly encoded. This allows the Unicode consortium to avoid any issues surrounding which countries to include, instead leaving it entirely to the system implementation as to which flags to include.
They are encoded in the range to within the Enclosed Alphanumeric Supplement block in the Supplementary Multilingual Plane.
Emoji flag sequences
A pair of regional indicator symbols is referred to as an emoji flag sequence.Out of the 676 possible pairs of regional indicator symbols, only 270 are considered valid Unicode region codes.
These are a subset of the region sequences in the Common Locale Data Repository :
- All 256 regular region sequences in the CLDR
- * 249 officially assigned ISO 3166-1 alpha-2 codes
- * 6 exceptional reservations
- * 1 user-assigned temporary country code
- Two of the 35 macroregion sequences in the CLDR
- All 12 deprecated region sequences in the CLDR
Some providers may internally have assigned specific codes to deprecated sequences or to unofficial ones, just like WhatsApp did by putting the Texas flag as XT.
A separate mechanism is used for regional flags, such as England, Scotland, Wales, Texas or California. It uses and formatting tag characters instead of regional indicator symbols. It is based on ISO 3166-2 regions with hyphen removed and lowercase, e.g. GB-ENG → gbeng, terminating with. Flag of England is therefore represented by a sequence U+1F3F4, SMALL LETTER G">U+E0067, U+E0062, U+E0065, U+E006E, U+E0067, U+E007F. In the tenth revision the Unicode consortium was considering instead, but from eleventh onwards it is black. Some vendors choose to include custom zero-width joiner sequences that only show up on their platform, such as WhatsApp and their Refugee Nation Flag ?️?⬛️?.
Background
In 2007 a draft proposal was presented to the Unicode Technical Committee to encode emoji symbols, specifically those in widespread use on mobile phones by Japanese telecommunications companies DoCoMo, KDDI, and SoftBank.The proposed symbols included ten national flags: China, Germany, Spain, France, the UK, Italy, Japan, South Korea, Russia, and the United States.
Encoding these flags but not other countries' flags was considered, by some, as prejudicial.
One rejected solution was to encode the ten flags but call them "EMOJI COMPATIBILITY SYMBOL-n" and represent them visually in the Standard as "EC n" instead of showing the flags they represent.
Another rejected solution would have allocated 676 codepoints for each possible two letter combination of A–Z. They would represent political entities based on ISO 3166 such as "JP" for Japan or Internet ccTLDs such as "EU" for the European Union.
The accepted solution was to add 26 characters for letters used for the representation of regional indicators, which used in pairs would represent the ten national flags and possible future extensions.
Per the Unicode Standard
specifically the ten national flags: ??, ??, ??, ??, ??, ??, ??, ??, ??, and ??.