ISO/IEC 10646:2020
(Main)Information technology — Universal coded character set (UCS)
Information technology — Universal coded character set (UCS)
This document specifies the architecture of the UCS; defines terms used for the UCS; describes the general structure of the UCS codespace; 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), and the Supplementary Special-purpose Plane (SSP); defines a set of graphic characters used in scripts and the written form of languages on a world-wide scale; specifies the names for the graphic characters and format characters of the BMP, SMP, SIP, TIP, SSP and their coded representations within the UCS codespace; specifies the coded representations for control characters and private use characters; specifies three encoding forms of the UCS: UTF-8, UTF-16, and UTF-32; specifies seven encoding schemes of the UCS: UTF-8, UTF-16, UTF-16BE, UTF-16LE, UTF-32, UTF-32BE, and UTF-32LE; specifies the management of future additions to this coded character set. NOTE The determination of suitability of these characters for use as identifiers in programming languages is not specified by this document but can be found in an external reference. See Annex U.
Technologies de l'information — Jeu universel de caractères codés (JUC)
General Information
Relations
Buy Standard
Standards Content (Sample)
INTERNATIONAL ISO/IEC
STANDARD 10646
Sixth edition
2020-12
Information technology — Universal
coded character set (UCS)
Technologies de l'information — Jeu universel de caractères codés (JUC)
Reference number
ISO/IEC 10646:2020(E)
©
ISO/IEC 2020
---------------------- Page: 1 ----------------------
ISO/IEC 10646:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO/IEC 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/IEC 10646:2020 (E)
CONTENTS
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
© ISO/IEC 2020 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/IEC 10646:2020 (E)
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 . 32
24.1 List of source references. 32
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
iv © ISO/IEC 2020 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/IEC 10646:2020 (E)
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) . 55
33 Structure of the Supplementary Special-purpose Plane (SSP) . 56
34 Code charts and lists of character names . 57
34.1 General . 57
34.2 Code chart . 57
34.3 Character names list . 57
34.4 Summary of standardized variation sequences . 58
34.5 Code charts and lists of character names . 58
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
© ISO/IEC 2020 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO/IEC 10646:2020 (E)
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 . 2785
N.1 Methods of reference to character repertoires and their coding . 2785
N.2 Identification of ASN.1 character abstract syntaxes . 2785
N.3 Identification of ASN.1 character transfer syntaxes . 2786
Annex P (informative) Additional information on CJK Unified ideographs . 2787
Annex Q (informative) Code mapping table for Hangul syllables . 2790
Annex R (informative) Names of Hangul syllables . 2791
Annex S (informative) Procedure for the unification and arrangement of CJK ideographs . 2792
S.1 Unification procedure . 2792
S.2 Arrangement procedure . 2796
S.3 Source separation examples . 2796
S.4 Non-unification examples . 2801
Annex T (informative) Language tagging using Tag Characters . 2803
Annex U (informative) Characters in identifiers . 2804
vi © ISO/IEC 2020 – All rights reserved
---------------------- Page: 6 ----------------------
ISO/IEC 10646:2020 (E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members
of ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work.
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 ISO
documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC
Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or on the
ISO list of patent declarations received (see www.iso.org/patents) or the IEC list of patent declarations
received (see http://patents.iec.ch).
Any trade name used in this document is information given for the convenience of users and does not constitute
an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organiza-tion (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/
foreword.html.
This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 2, Coded character sets.
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 1:2019 and ISO/IEC
10646:2017/Amd 2:2019.
This edition includes the following significant changes with respect to the previous edition:
— New scripts covered: Chorasmian, Dives Akuru, Dogra, Elymaic, Gunjala Gondi, Hanifi Rohingya, Khitan
Small Script, Makasar, Medefaidrin, Nandinagari, Nyiakeng Puachue Hmong, Old Sogdian, Sogdian, Ye-
zidi, Wancho;
— Existing scripts significantly extended: Georgian, CJK Unified Ideographs (Extension G);
— New symbol sets: Chess Symbols, Symbols for Legacy Computing;
— New set of Emoji symbols.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
© ISO/IEC 2020 – All rights reserved vii
---------------------- Page: 7 ----------------------
ISO/IEC 10646:2020 (E)
Introduction
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
world as well as additional symbols.
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.
The UCS is an encoding system different from that specified in ISO/IEC 2022. The method to designate UCS from
ISO/IEC 2022 is specified in 13.2.
A graphic character will be assigned only one code point in the standard, located either in the BMP or in one of
the supplementary planes.
viii © ISO/IEC 2020 – All rights reserved
---------------------- Page: 8 ----------------------
ISO/IEC 10646:2020 (E)
Information technology — Universal
Coded Character Set (UCS)
1 Scope
This document
— specifies the architecture of the UCS;
— defines terms used for the UCS;
— describes the general structure of the UCS codespace;
— specifies the assigned planes of the UCS: the Basic Multilingual Plane (BMP) of the UCS, the Supplemen-
tary Multilingual Plane (SMP), the Supplementary Ideographic Plane (SIP), the Tertiary Ideographic
Plane (TIP), and the Supplementary Special-purpose Plane (SSP);
— defines a set of graphic characters used in scripts and the written form of languages on a world-wide
scale;
— specifies the names for the graphic characters and format characters of the BMP, SMP, SIP, TIP, SSP and
their coded representations within the UCS codespace;
— specifies the coded representations for control characters and private use characters;
— specifies three encoding forms of the UCS: UTF-8, UTF-16, and UTF-32;
— specifies seven encoding schemes of the UCS: UTF-8, UTF-16, UTF-16BE, UTF-16LE, UTF-32, UTF-32BE,
and UTF-32LE;
— specifies the management of future additions to this coded character set.
NOTE – The determination of suitability of these characters for use as identifiers in programming languages is not specified by this
document but can be found in an external reference. See Annex U.
2 Normative references
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
latest edition of the referenced document (including any amendments) applies.
ISO/IEC 2022 Information technology — Character code structure and extension techniques.
ISO/IEC 6429 Information technology — Control functions for coded character sets.
Unicode Standard Annex, UAX #9, The Unicode Bidirectional Algorithm:
http://www.unicode.org/reports/tr9/tr9-42.html
Unicode Standard Annex, UAX #15, Unicode Normalization Forms:
http://www.unicode.org/reports/tr15/tr15-50.html
Unicode Technical Standard, UTS #37, Ideographic Variation Database:
http://www.unicode.org/reports/tr37/tr37-12.html
Unicode Standard Version 13.0, Chapter 4, Character Properties
http://www.unicode.org/versions/Unicode13.0.0/ch04.pdf
Section 4.3, Combining Classes – Normative
Section 4.5, General Category – Normative
Section 4.7, Bidi Mirrored – Normative
Unicode Standard Version 12.1, Age Property:
https://www.unicode.org/Public/13.0.0/ucd/DerivedAge.txt
© ISO/IEC 2020 – All rights reserved 1
---------------------- Page: 9 ----------------------
ISO/IEC 10646:2020 (E)
Note – Parts of this document which use machine-readable format are available as electronic data attachments. See Clause 5.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
3.1
base character
graphic character which is not a combining character
Note 1 to entry – Most graphic characters are base characters. This sense of graphic combination does
...
FINAL
INTERNATIONAL ISO/IEC
DRAFT
STANDARD FDIS
10646
ISO/IEC JTC 1/SC 2
Information technology — Universal
Secretariat: JISC
coded character set (UCS)
Voting begins on:
20201008
Technologies de l'information — Jeu universel de caractères codés (JUC)
Voting terminates on:
20201203
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO
ISO/IEC FDIS 10646:2020(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO/IEC 2020
---------------------- Page: 1 ----------------------
ISO/IEC FDIS 10646:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO/IEC 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO/IEC 2020 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/IEC 10646:2020 (E)
CONTENTS
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
© ISO/IEC 2020 – All rights reserved iii
---------------------- Page: 3 ----------------------
ISO/IEC 10646:2020 (E)
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 . 32
24.1 List of source references. 32
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
iv © ISO/IEC 2020 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/IEC 10646:2020 (E)
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) . 55
33 Structure of the Supplementary Special-purpose Plane (SSP) . 56
34 Code charts and lists of character names . 57
34.1 General . 57
34.2 Code chart . 57
34.3 Character names list . 57
34.4 Summary of standardized variation sequences . 58
34.5 Code charts and lists of character names . 58
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
© ISO/IEC 2020 – All rights reserved v
---------------------- Page: 5 ----------------------
ISO/IEC 10646:2020 (E)
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 . 2785
N.1 Methods of reference to character repertoires and their coding . 2785
N.2 Identification of ASN.1 character abstract syntaxes . 2785
N.3 Identification of ASN.1 character transfer syntaxes . 2786
Annex P (informative) Additional information on CJK Unified ideographs . 2787
Annex Q (informative) Code mapping table for Hangul syllables . 2790
Annex R (informative) Names of Hangul syllables . 2791
Annex S (informative) Procedure for the unification and arrangement of CJK ideographs . 2792
S.1 Unification procedure . 2792
S.2 Arrangement procedure . 2796
S.3 Source separation examples . 2796
S.4 Non-unification examples . 2801
Annex T (informative) Language tagging using Tag Characters . 2803
Annex U (informative) Characters in identifiers . 2804
vi © ISO/IEC 2020 – All rights reserved
---------------------- Page: 6 ----------------------
ISO/IEC 10646:2020 (E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical
Commission) form the specialized system for worldwide standardization. National bodies that are members
of ISO or IEC participate in the development of International Standards through technical committees
established by the respective organization to deal with particular fields of technical activity. ISO and IEC
technical committees collaborate in fields of mutual interest. Other international organizations, governmental
and non-governmental, in liaison with ISO and IEC, also take part in the work.
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 ISO
documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC
Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or on the
ISO list of patent declarations received (see www.iso.org/patents) or the IEC list of patent declarations
received (see http://patents.iec.ch).
Any trade name used in this document is information given for the convenience of users and does not constitute
an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organiza-tion (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/
foreword.html.
This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 2, Coded character sets.
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 1:2019 and ISO/IEC
10646:2017/Amd 2:2019.
This edition includes the following significant changes with respect to the previous edition:
— New scripts covered: Chorasmian, Dives Akuru, Dogra, Elymaic, Gunjala Gondi, Hanifi Rohingya, Khitan
Small Script, Makasar, Medefaidrin, Nandinagari, Nyiakeng Puachue Hmong, Old Sogdian, Sogdian, Ye-
zidi, Wancho;
— Existing scripts significantly extended: Georgian, CJK Unified Ideographs (Extension G);
— New symbol sets: Chess Symbols, Symbols for Legacy Computing;
— New set of Emoji symbols.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
© ISO/IEC 2020 – All rights reserved vii
---------------------- Page: 7 ----------------------
ISO/IEC 10646:2020 (E)
Introduction
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
world as well as additional symbols.
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.
The UCS is an encoding system different from that specified in ISO/IEC 2022. The method to designate UCS from
ISO/IEC 2022 is specified in 13.2.
A graphic character will be assigned only one code point in the standard, located either in the BMP or in one of
the supplementary planes.
viii © ISO/IEC 2020 – All rights reserved
---------------------- Page: 8 ----------------------
ISO/IEC 10646:2020 (E)
Information technology — Universal
Coded Character Set (UCS)
1 Scope
This document
— specifies the architecture of the UCS;
— defines terms used for the UCS;
— describes the general structure of the UCS codespace;
— specifies the assigned planes of the UCS: the Basic Multilingual Plane (BMP) of the UCS, the Supplemen-
tary Multilingual Plane (SMP), the Supplementary Ideographic Plane (SIP), the Tertiary Ideographic
Plane (TIP), and the Supplementary Special-purpose Plane (SSP);
— defines a set of graphic characters used in scripts and the written form of languages on a world-wide
scale;
— specifies the names for the graphic characters and format characters of the BMP, SMP, SIP, TIP, SSP and
their coded representations within the UCS codespace;
— specifies the coded representations for control characters and private use characters;
— specifies three encoding forms of the UCS: UTF-8, UTF-16, and UTF-32;
— specifies seven encoding schemes of the UCS: UTF-8, UTF-16, UTF-16BE, UTF-16LE, UTF-32, UTF-32BE,
and UTF-32LE;
— specifies the management of future additions to this coded character set.
NOTE – The determination of suitability of these characters for use as identifiers in programming languages is not specified by this
document but can be found in an external reference. See Annex U.
2 Normative references
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
latest edition of the referenced document (including any amendments) applies.
ISO/IEC 2022 Information technology — Character code structure and extension techniques.
ISO/IEC 6429 Information technology — Control functions for coded character sets.
Unicode Standard Annex, UAX #9, The Unicode Bidirectional Algorithm:
http://www.unicode.org/reports/tr9/tr9-42.html
Unicode Standard Annex, UAX #15, Unicode Normalization Forms:
http://www.unicode.org/reports/tr15/tr15-50.html
Unicode Technical Standard, UTS #37, Ideographic Variation Database:
http://www.unicode.org/reports/tr37/tr37-12.html
Unicode Standard Version 13.0, Chapter 4, Character Properties
http://www.unicode.org/versions/Unicode13.0.0/ch04.pdf
Section 4.3, Combining Classes – Normative
Section 4.5, General Category – Normative
Section 4.7, Bidi Mirrored – Normative
Unicode Standard Version 12.1, Age Property:
https://www.unicode.org/Public/13.0.0/ucd/DerivedAge.txt
© ISO/IEC 2020 – All rights reserved 1
---------------------- Page: 9 ----------------------
ISO/IEC 10646:2020 (E)
Note – Parts of this document which use machine-readable f
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.