The first plane, plane 0, the Basic Multilingual Plane (BMP), contains characters for almost all modern languages, and a large number of symbols. A primary objective for the BMP is to support the unification of prior character sets as well as characters for writing. Most of the assigned code points in the BMP are used to encode Chinese, Japanese, and Korean (CJK) characters.
The High Surrogate (U+D800–U+DBFF) and Low Surrogate (U+DC00–U+DFFF) codes are reserved for encoding non-BMP characters in UTF-16 by using a pair of 16-bit codes: one High Surrogate and one Low Surrogate. A single surrogate code point will never be assigned a character.
65,520 of the 65,536 code points in this plane have been allocated to a Unicode block, leaving just 16 code points in a single unallocated range (2FE0..2FEF).
As of Unicode 16.0, the BMP comprises the following 164 blocks:
Plane 1, the Supplementary Multilingual Plane (SMP), contains historic scripts (except CJK ideographic), and symbols and notation used within certain fields. Scripts include Linear B, Egyptian hieroglyphs, and cuneiform scripts. It also includes English reform orthographies like Shavian and Deseret, and some modern scripts like Osage, Warang Citi, Adlam, Wancho and Toto. Symbols and notations include historic and modern musical notation; mathematical alphanumerics; shorthands; Emoji and other pictographic sets; and game symbols for playing cards, mahjong, and dominoes.
As of Unicode 16.0, the SMP comprises the following 161 blocks:
Plane 2, the Supplementary Ideographic Plane (SIP), is used for CJK Ideographs, mostly CJK Unified Ideographs, that were not included in earlier character encoding standards.
As of Unicode 16.0, the SIP comprises the following seven blocks:
Plane 3 is the Tertiary Ideographic Plane (TIP). CJK Unified Ideographs Extension G was added to the TIP in Unicode 13.0, released in March 2020.6 It also is tentatively allocated for Oracle Bone script and Small Seal Script.7
As of Unicode 16.0, the TIP comprises the following two blocks:
Planes 4 to 13 (planes 4 to D in hexadecimal): No characters have yet been assigned, or proposed for assignment, to Planes 4 through 13.
Plane 14 (E in hexadecimal) is designated as the Supplementary Special-purpose Plane (SSP). It comprises the following two blocks, as of Unicode 16.0:
"Private Use Plane" redirects here. For private aircraft, see commercial aviation, business aviation, general aviation, and civil aviation.
The two planes 15 and 16 (planes F and 10 in hexadecimal) each contain a "Private Use Area". They contain blocks named Supplementary Private Use Area-A (PUA-A) and -B (PUA-B). The Private Use Areas are available for use by parties outside ISO and Unicode (private use character encoding).
"Glossary". Unicode. Retrieved 2021-09-27. https://www.unicode.org/glossary/#supplementary_planes ↩
"The Unicode Standard Version 6.0 – Core Specification" (PDF). The Unicode Consortium. February 2011. Table 3.5 "UTF-16 Bit Distribution". https://www.unicode.org/versions/Unicode6.0.0/UnicodeStandard-6.0.pdf ↩
"The Unicode Standard Version 6.0 – Core Specification" (PDF). The Unicode Consortium. February 2011. Table 3.6 "UTF-8 Bit Distribution". https://www.unicode.org/versions/Unicode6.0.0/UnicodeStandard-6.0.pdf ↩
"Roadmaps to Unicode". Unicode. Retrieved 2021-09-27. https://www.unicode.org/roadmaps/ ↩
Code points which have been allocated to a Unicode block. /wiki/Unicode_block ↩
"Announcing The Unicode Standard, Version 13.0". The Unicode Blog. March 10, 2020. http://blog.unicode.org/2020/03/announcing-unicode-standard-version-130.html ↩
"Proposed New Characters: The Pipeline". www.unicode.org. https://www.unicode.org/alloc/Pipeline.html ↩