Regional Indicator

Regional Indicator Symbols are a set of 26 special characters in the Unicode Standard, corresponding to the letters A through Z. They are used to encode the two-letter country or region codes defined in ISO 3166-1, representing specific geographical areas through combinations.

In emoji, regional indicators are used to display the flags of countries or regions, e.g., 🇨🇳 (CN), 🇺🇸 (US).

Basic Information

Historical Background

Unicode 6.0 introduced regional indicator symbols to provide a unified and efficient way to represent flags, avoiding the need to assign a separate code point to each flag. As the Unicode official FAQ states: "Country and region flags are not directly encoded as individual code points in Unicode; instead, they should be encoded using this method."

How It Works

Two regional indicators placed consecutively form a code sequence representing a country or region. Systems that support this feature render them as the corresponding flag; unsupported systems may fall back to displaying the two letter codes.

Examples:

• U+1F1E8 (C) + U+1F1F3 (N) = 🇨🇳 (China)
• U+1F1FA (U) + U+1F1F8 (S) = 🇺🇸 (United States)

Valid Combinations

In theory, 26 letters can form 676 two-letter combinations, but only some are recognized as valid region codes. These valid sequences come from the Common Locale Data Repository (CLDR) and include:

• Regular region codes: 256 standard sequences included in CLDR.
• Macro-region codes: such as EU (European Union) and UN (United Nations).
• Deprecated codes: 12 deprecated sequences retained for backward compatibility.

These valid sequences are called Emoji Flag Sequences. Although their encoding is inherently geographic, in practice they are widely used to display the flags of the corresponding countries or regions.