ISO/IEC DIS 10646

DRAFT INTERNATIONAL STANDARD
ISO/IEC DIS 10646
ISO/IEC JTC 1/SC 2 Secretariat: JISC
Voting begins on: Voting terminates on:
2020-02-18 2020-05-12
Information technology — Universal coded character set
(UCS)
Technologies de l'information — Jeu universel de caractères codés (JUC)
ICS: 35.040.10
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This document is circulated as received from the committee secretariat.
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Reference number
NATIONAL REGULATIONS.
ISO/IEC DIS 10646:2020(E)
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PROVIDE SUPPORTING DOCUMENTATION. ISO/IEC 2020
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ISO/IEC DIS 10646:2020(E)
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Foreword ............................................................................................................................................... vii

Introduction ........................................................................................................................................... viii

1 Scope ..................................................................................................................................................1

2 Normative references .........................................................................................................................1

3 Terms and definitions .........................................................................................................................2

4 Conformance ......................................................................................................................................8

4.1 General ....................................................................................................................................8

4.2 Conformance of information interchange .................................................................................8

4.3 Conformance of devices............................................................................................................8

5 Electronic data attachments ...............................................................................................................9

6 General structure of the UCS ............................................................................................................ 10

7 Basic structure and nomenclature ................................................................................................... 11

7.1 Structure ............................................................................................................................... 11

7.2 Coding of characters .............................................................................................................. 12

7.3 Types of code points .............................................................................................................. 12

7.4 Naming of characters ............................................................................................................ 13

7.5 Short identifiers for code points (UIDs) ................................................................................. 14

7.6 UCS Sequence Identifiers ....................................................................................................... 14

7.7 Octet sequence identifiers ..................................................................................................... 15

8 Revision and updating of the UCS .................................................................................................... 15

9 Subsets ............................................................................................................................................ 15

9.1 General ................................................................................................................................. 15

9.2 Limited subset ...................................................................................................................... 15

9.3 Selected subset...................................................................................................................... 15

10 UCS encoding forms ......................................................................................................................... 15

10.1 General ................................................................................................................................. 15

10.2 UTF-8 .................................................................................................................................... 15

10.3 UTF-16 .................................................................................................................................. 16

10.4 UTF-32 .................................................................................................................................. 17

11 UCS encoding schemes .................................................................................................................... 17

11.1 General ................................................................................................................................. 17

11.2 UTF-8 .................................................................................................................................... 17

11.3 UTF-16BE ............................................................................................................................. 17

11.4 UTF-16LE .............................................................................................................................. 18

11.5 UTF-16 .................................................................................................................................. 18

11.6 UTF-32BE ............................................................................................................................. 18

11.7 UTF-32LE .............................................................................................................................. 18

11.8 UTF-32 .................................................................................................................................. 19

12 Use of control functions with the UCS .............................................................................................. 19

13 Declaration of identification of features ........................................................................................... 20

13.1 Purpose and context of identification .................................................................................... 20

13.2 Identification of a UCS encoding scheme ................................................................................ 20

13.3 Identification of subsets of graphic characters ....................................................................... 21

13.4 Identification of control function set ...................................................................................... 21

13.5 Identification of the coding system of ISO/IEC 2022 .............................................................. 21

14 Structure of the code charts and lists ............................................................................................... 22

15 Block and collection names .............................................................................................................. 22

15.1 Block names .......................................................................................................................... 22

15.2 Collection names ................................................................................................................... 23

16 Mirrored characters in bidirectional context .................................................................................... 23

16.1 Mirrored characters .............................................................................................................. 23

16.2 Directionality of bidirectional text ......................................................................................... 23

17 Special characters ............................................................................................................................ 23

17.1 General ................................................................................................................................. 23

17.2 Space characters ................................................................................................................... 23

17.3 Currency symbols ................................................................................................................. 24

17.4 Format characters ................................................................................................................. 24

17.5 Ideographic description characters ....................................................................................... 24

17.6 Variation selectors and variation sequences .......................................................................... 25

18 Presentation forms of characters ..................................................................................................... 27

19 Compatibility characters .................................................................................................................. 27

20 Order of characters .......................................................................................................................... 27

21 Combining characters ...................................................................................................................... 28

21.1 Order of combining characters .............................................................................................. 28

21.2 Combining class and canonical ordering ................................................................................ 28

21.3 Appearance in code charts .................................................................................................... 28

21.4 Alternate coded representations ........................................................................................... 28

21.5 Multiple combining characters .............................................................................................. 28

21.6 Collections containing combining characters ......................................................................... 29

21.7 Combining Grapheme Joiner .................................................................................................. 29

22 Normalization forms........................................................................................................................ 29

23 Special features of individual scripts and symbol repertoires ........................................................... 30

23.1 Hangul syllable composition method ..................................................................................... 30

23.2 Features of scripts used in India and some other South Asian countries ................................. 30

23.3 Byzantine musical symbols ................................................................................................... 31

23.4 Source references for pictographic symbols .......................................................................... 31

24 Source references for CJK ideographs .............................................................................................. 31

24.1 List of source references........................................................................................................ 31

24.2 Source references file for CJK ideographs .............................................................................. 35

24.3 Source reference presentation for CJK Unified ideographs ..................................................... 37

24.4 Source references presentation for CJK Compatibility ideographs ......................................... 40

25 Source references for Tangut ideographs ......................................................................................... 40

25.1 List of source references........................................................................................................ 40

25.2 Source reference file for Tangut ideographs .......................................................................... 41

25.3 Source reference presentation for Tanguts ideographs .......................................................... 42

26 Source references for Nüshu characters ........................................................................................... 42

26.1 List of source references........................................................................................................ 42

26.2 Source reference file for Nüshu characters ............................................................................ 42

27 Character names and annotations .................................................................................................... 43

27.1 Entity names ......................................................................................................................... 43

27.2 Name formation .................................................................................................................... 43

27.3 Single name ........................................................................................................................... 44

27.4 Name immutability ............................................................................................................... 44

27.5 Name uniqueness .................................................................................................................. 44

27.6 Character names for CJK ideographs ...................................................................................... 45

27.7 Character names for Tangut ideographs ................................................................................ 45

27.8 Character names for Nüshu characters .................................................................................. 45

27.9 Character names for Khitan Small Script characters .............................................................. 46

27.10 Character names for Hangul syllables .................................................................................... 46

28 Named UCS Sequence Identifiers ..................................................................................................... 47

29 Structure of the Basic Multilingual Plane .......................................................................................... 49

30 Structure of the Supplementary Multilingual Plane for scripts and symbols (SMP) ........................... 51

31 Structure of the Supplementary Ideographic Plane (SIP) .................................................................. 54

32 Structure of the Tertiary Ideographic Plane (TIP) ............................................................................ 54

33 Structure of the Supplementary Special-purpose Plane (SSP) ........................................................... 55

34 Code charts and lists of character names ......................................................................................... 55

34.1 General ................................................................................................................................. 55

34.2 Code chart ............................................................................................................................. 55

34.3 Character names list .............................................................................................................. 55

34.4 Summary of standardized variation sequences ...................................................................... 57

34.5 Code charts and lists of character names ............................................................................... 57

Annex A (normative) Collections of graphic characters for subsets ..................................................... 2743

A.1 Collections of coded graphic characters ............................................................................. 2743

A.2 Blocks lists ........................................................................................................................ 2750

A.3 Fixed collections of the whole UCS (except Unicode collections) ........................................ 2753

A.4 CJK collections................................................................................................................... 2756

A.5 Other collections ............................................................................................................... 2757

A.6 Unicode collections ........................................................................................................... 2761

Annex B (normative) List of combining characters .............................................................................. 2763

Annex C (normative) Transformation format for planes 01 to 10 of the UCS (UTF-16) ........................ 2764

Annex D (normative) UCS Transformation Format 8 (UTF-8) .............................................................. 2765

Annex E (normative) Mirrored characters in bidirectional context ...................................................... 2766

Annex F (informative) Format characters ........................................................................................... 2767

F.1 General format characters ................................................................................................. 2767

F.2 Script-specific format characters ....................................................................................... 2769

F.3 Interlinear annotation characters ...................................................................................... 2770

F.4 Subtending format characters ........................................................................................... 2770

F.5 Shorthand format characters ............................................................................................. 2771

F.6 Invisible mathematical operators ...................................................................................... 2771

F.7 Western musical symbols .................................................................................................. 2771

F.8 Language tagging using Tag characters .............................................................................. 2772

Annex G (informative) Alphabetically sorted list of character names ................................................... 2774

Annex H (informative) The use of “signatures” to identify UCS ............................................................ 2775

Annex I (informative) Ideographic description characters .................................................................. 2776

I.1 General ............................................................................................................................. 2776

I.2 Syntax of an ideographic description sequence .................................................................. 2776

I.3 Individual definitions of the ideographic description characters ........................................ 2777

Annex J (informative) Recommendation for combined receiving/originating devices with internal

storage ........................................................................................................................................ 2779

Annex K (informative) Notations of octet value representations ......................................................... 2780

Annex L (informative) Character naming guidelines ........................................................................... 2781

Annex M (informative) Sources of characters ...................................................................................... 2784

Annex N (informative) External references to character repertoires ................................................... 2813

N.1 Methods of reference to character repertoires and their coding ......................................... 2813

N.2 Identification of ASN.1 character abstract syntaxes ........................................................... 2813

N.3 Identification of ASN.1 character transfer syntaxes ............................................................ 2814

Annex P (informative) Additional information on CJK Unified ideographs ........................................... 2815

Annex Q (informative) Code mapping table for Hangul syllables ......................................................... 2818

Annex R (informative) Names of Hangul syllables ............................................................................... 2819

Annex S (informative) Procedure for the unification and arrangement of CJK ideographs ................... 2820

S.1 Unification procedure ....................................................................................................... 2820

S.2 Arrangement procedure .................................................................................................... 2824

S.3 Source separation examples .............................................................................................. 2824

S.4 Non-unification examples .................................................................................................. 2829

Annex T (informative) Language tagging using Tag Characters ........................................................... 2831

Annex U (informative) Characters in identifiers .................................................................................. 2832

ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commis-

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in liaison with ISO and IEC, also take part in the work. In the field of information technology, ISO and IEC have

The procedures used to develop this document and those intended for its further maintenance are described in

the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of

document should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC

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tion (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/fore-

The committee responsible for this document is ISO/IEC JTC 1, Information technology, SC 2, Coded character

This sixth edition of ISO/IEC 10646 cancels and replaces the fifth edition (ISO/IEC 10646:2017), which has been

technically revised. It also incorporates ISO/IEC 10646:2017/Amd 1:2018 and ISO/IEC 10646:2017/Amd

This edition includes the following significant changes with respect to the previous edition:

x New scripts covered: Chorasmian, Dives Akuru, Dogra, Elymaic, Gunjala Gondi, Hanifi Rohingya, Khitan

Small Script, Makasar, Medefaidrin, Nandinagari, Nyiakeng Puachue Hmong, Old Sogdian, Sogdian, Yezidi,

x Existing scripts significantly extended: Georgian, CJK Unified Ideographs (Extension G);

This document specifies the Universal Coded Character Set (UCS). It is applicable to the representation, trans-

mission, interchange, processing, storage, input and presentation of the written form of the languages of the

By defining a consistent way of encoding multilingual text it enables the exchange of data internationally. The

information technology industry gains data stability, greater global interoperability and data interchange. This

International Standard has been widely adopted in new Internet protocols and implemented in modern oper-

ating systems and computer languages. This edition covers over 130 000 characters from the world’s scripts.

This document specifies the Universal Coded Character Set (UCS). It is applicable to the representation, trans-

mission, interchange, processing, storage, input, and presentation of the written form of the languages of the

x specifies the assigned planes of the UCS: the Basic Multilingual Plane (BMP) of the UCS, the Supplementary

Multilingual Plane (SMP), the Supplementary Ideographic Plane (SIP), the Tertiary Ideographic Plane (TIP),

x defines a set of graphic characters used in scripts and the written form of languages on a world-wide scale;

x specifies the names for the graphic characters and format characters of the BMP, SMP, SIP, TIP, SSP and

x specifies the coded representations for control characters and private use characters;

x specifies seven encoding schemes of the UCS: UTF-8, UTF-16, UTF-16BE, UTF-16LE, UTF-32, UTF-32BE, and

The UCS is an encoding system different from that specified in ISO/IEC 2022. The method to designate UCS from

A graphic character will be assigned only one code point in the standard, located either in the BMP or in one of

The following documents are referred to in the text in such a way that some or all of their content constitutes

requirements of this document. For dated references, only the edition cited applies. For undated references, the

ISO/IEC 2022:1994 Information technology — Character code structure and extension techniques.