science

Regional indicator symbol

Regional indicator symbol is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Regional indicator symbol rather than just read about it. In short: The regional indicator symbols are a set of 26 alphabetic Unicode characters (A–Z) 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 October 2010 as part of the Unicode 6.0 support for emoji, as an alternative to encoding separate characters for each country flag.

Key takeaways

Regional indicator symbol belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Regional indicator symbol to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Regional indicator symbol from memory before moving on to harder problems.

Reference excerpt

The regional indicator symbols are a set of 26 alphabetic Unicode characters (A–Z) 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 October 2010 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 (and, de facto, recognize), instead leaving it entirely to the system implementation as to which flags to include (see: partially recognized state). They are encoded in the range U+1F1E6 🇦 REGIONAL INDICATOR SYMBOL LETTER A to U+1F1FF 🇿 REGIONAL INDICATOR SYMBOL LETTER Z 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 (although it represents a specific region, not a specific flag for that region). Out of the 676 possible pairs of regional indicator symbols (26 × 26), only 270 are considered valid Unicode region codes. These are a subset of the region sequences in the Common Locale Data Repository (CLDR):

All 256 regular region sequences in the CLDR 249 officially assigned ISO 3166-1 alpha-2 codes 6 exceptional reservations (Ascension Island, Clipperton Island, Diego Garcia, Ceuta and Melilla, Canary Islands, and Tristan da Cunha) 1 user-assigned temporary country code (Kosovo) Two of the 35 macroregion sequences in the CLDR (EU and UN) All 12 deprecated region sequences in the CLDR (strongly discouraged—intended for backward compatibility only)

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 (emoji tag sequences) is used for regional flags, such as England 🏴󠁧󠁢󠁥󠁮󠁧󠁿, Scotland 🏴󠁧󠁢󠁳󠁣󠁴󠁿, Wales 🏴󠁧󠁢󠁷󠁬󠁳󠁿, Texas 🏴󠁵󠁳󠁴󠁸󠁿 or California 🏴󠁵󠁳󠁣󠁡󠁿. It uses U+1F3F4 🏴 WAVING BLACK FLAG 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 U+E007F CANCEL TAG. Flag of England is therefore represented by a sequence U+1F3F4, U+E0067, U+E0062, U+E0065, U+E006E, U+E0067, U+E007F. In the tenth revision the Unicode consortium was considering U+1F3F3 🏳 WAVING WHITE FLAG 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 🏳️‍🟧‍⬛️‍🟧.

Unicode block

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 two most famous proposed emoji flag symbols included Japan (🇯🇵) and the United States (🇺🇸). However, neither Australia (🇦🇺) nor Canada (🇨🇦), both of which are among other most famous flags, was among other emoji flag symbols that were proposed. The proposed symbols included eight other national flags: China (🇨🇳), Germany (🇩🇪), Spain (🇪🇸), France (🇫🇷), the UK (🇬🇧), Italy (🇮🇹), South Korea (🇰🇷) and Russia (🇷🇺). 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 (26×26) for each possible two letter combination of A–Z. They would represent political entities based on ISO 3166 such as "JP" for Japan, "US" for the United States and "EU" for the European Union or Internet ccTLDs (country code top-level domains). 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 "the main purpose of such [regional indicator symbol] pairs is to provide unambiguous roundtrip mappings to certain characters used in the emoji core sets" specifically two of the most famous national flags like 🇯🇵 and 🇺🇸, as well as eight other national flags like 🇨🇳, 🇩🇪, 🇪🇸, 🇫🇷, 🇬🇧, 🇮🇹, 🇰🇷 and 🇷🇺.

Worked examples

Example 1 — a first encounter with Regional indicator symbol

Start with the simplest possible case. Write down what Regional indicator symbol claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Regional indicator symbol before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Regional indicator symbol ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Regional indicator symbol

In research: Regional indicator symbol appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Regional indicator symbol in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Regional indicator symbol is common in secondary-school and first-year university syllabi. It links to neighbouring topics Country codes, Emoji, Representations of flags, so understanding it makes those chapters shorter.
In everyday life: Look for Regional indicator symbol outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Regional indicator symbol in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Regional indicator symbol means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Regional indicator symbol out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Regional indicator symbol in simple terms?

Why does Regional indicator symbol matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Regional indicator symbol?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Regional indicator symbol.