ISO/IEC 10646:2017

INTERNATIONAL ISO/IEC
STANDARD 10646
Fifth edition
2017-12
Information technology — Universal
Coded Character Set (UCS)
Technologies de l'information — Jeu universel de caractères codés (JUC)
Reference number
ISO/IEC 10646:2017(E)
©
ISO/IEC 2017

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ISO/IEC 10646:2017(E)

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© ISO/IEC 2017, Published in Switzerland
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ISO/IEC 10646:2017 (E)
CONTENTS
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 General structure of the UCS .9
6 Basic structure and nomenclature . 10
6.1 Structure . 10
6.2 Coding of characters . 11
6.3 Types of code points . 11
6.4 Naming of characters . 12
6.5 Short identifiers for code points (UIDs) . 12
6.6 UCS Sequence Identifiers . 13
6.7 Octet sequence identifiers . 13
7 Revision and updating of the UCS . 14
8 Subsets . 14
8.1 General . 14
8.2 Limited subset . 14
8.3 Selected subset. 14
9 UCS encoding forms . 14
9.1 General . 14
9.2 UTF-8 . 14
9.3 UTF-16 . 15
9.4 UTF-32 (UCS-4) . 16
10 UCS Encoding schemes . 16
10.1 General . 16
10.2 UTF-8 . 16
10.3 UTF-16BE . 16
10.4 UTF-16LE . 16
10.5 UTF-16 . 16
10.6 UTF-32BE . 17
10.7 UTF-32LE . 17
10.8 UTF-32 . 17
11 Use of control functions with the UCS . 17
12 Declaration of identification of features . 18
12.1 Purpose and context of identification . 18
12.2 Identification of a UCS encoding scheme . 19
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ISO/IEC 10646:2017 (E)
12.3 Identification of subsets of graphic characters . 19
12.4 Identification of control function set . 19
12.5 Identification of the coding system of ISO/IEC 2022 . 20
13 Structure of the code charts and lists . 20
14 Block and collection names . 21
14.1 Block names . 21
14.2 Collection names . 21
15 Mirrored characters in bidirectional context . 21
15.1 Mirrored characters . 21
15.2 Directionality of bidirectional text . 21
16 Special characters . 22
16.1 General . 22
16.2 Space characters . 22
16.3 Currency symbols . 22
16.4 Format characters . 22
16.5 Ideographic description characters . 23
16.6 Variation selectors and variation sequences . 23
17 Presentation forms of characters . 24
18 Compatibility characters . 25
19 Order of characters . 25
20 Combining characters . 25
20.1 Order of combining characters . 25
20.2 Combining class and canonical ordering . 26
20.3 Appearance in code charts . 26
20.4 Alternate coded representations . 26
20.5 Multiple combining characters . 26
20.6 Collections containing combining characters . 27
20.7 Combining Grapheme Joiner . 27
21 Normalization forms. 27
22 Special features of individual scripts and symbol repertoires . 28
22.1 Hangul syllable composition method . 28
22.2 Features of scripts used in India and some other South Asian countries . 28
22.3 Byzantine musical symbols . 28
22.4 Source references for pictographic symbols . 29
23 Source references for CJK ideographs . 29
23.1 List of source references. 29
23.2 Source references file for CJK ideographs . 32
23.3 Source reference presentation for CJK Unified ideographs . 34
23.4 Source references presentation for CJK Compatibility ideographs . 37
24 Source references for Tangut ideographs . 37
24.1 List of source references. 37
24.2 Source reference file for Tangut ideographs . 38
24.3 Source reference presentation for Tanguts ideographs . 39
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ISO/IEC 10646:2017 (E)
25 Source references for Nüshu characters . 39
25.1 List of source references. 39
25.2 Source reference file for Nüshu characters . 39
26 Character names and annotations . 40
26.1 Entity names . 40
26.2 Name formation . 40
26.3 Single name . 41
26.4 Name immutability . 41
26.5 Name uniqueness . 41
26.6 Character names for CJK ideographs . 42
26.7 Character names for Tangut ideographs . 42
26.8 Character names for Nüshu characters . 42
26.9 Character names for Hangul syllables . 43
27 Named UCS Sequence Identifiers . 44
28 Structure of the Basic Multilingual Plane . 46
29 Structure of the Supplementary Multilingual Plane for scripts and symbols (SMP) . 48
30 Structure of the Supplementary Ideographic Plane (SIP) . 51
31 Structure of the Tertiary Ideographic Plane (TIP) . 51
32 Structure of the Supplementary Special-purpose Plane (SSP) . 51
33 Code charts and lists of character names . 52
33.1 General . 52
33.2 Code chart . 52
33.3 Character names list . 52
33.4 Summary of standardized variation sequences . 53
33.5 Code charts and lists of character names . 54
Annex A (normative) Collections of graphic characters for subsets . 2611
A.1 Collections of coded graphic characters . 2611
A.2 Blocks lists . 2617
A.3 Fixed collections of the whole UCS (except Unicode collections) . 2620
A.4 CJK collections. 2623
A.5 Other collections . 2624
A.6 Unicode collections . 2628
Annex B (normative) List of combining characters . 2629
Annex C (normative) Transformation format for planes 01 to 10 of the UCS (UTF-16) . 2630
Annex D (normative) UCS Transformation Format 8 (UTF-8) . 2631
Annex E (normative) Mirrored characters in bidirectional context . 2632
Annex F (informative) Format characters . 2633
F.1 General format characters . 2633
F.2 Script-specific format characters . 2635
F.3 Interlinear annotation characters . 2636
F.4 Subtending format characters . 2636
F.5 Shorthand format characters . 2637
F.6 Invisible mathematical operators . 2637
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ISO/IEC 10646:2017 (E)
F.7 Western musical symbols . 2637
F.8 Language tagging using Tag characters . 2638
Annex G (informative) Alphabetically sorted list of character names . 2640
Annex H (informative) The use of “signatures” to identify UCS . 2641
Annex I (informative) Ideographic description characters . 2642
I.1 General . 2642
I.2 Syntax of an ideographic description sequence . 2642
I.3 Individual definitions of the ideographic description characters . 2643
Annex J (informative) Recommendation for combined receiving/originating devices with internal
storage . 2645
Annex K (informative) Notations of octet value representations . 2646
Annex L (informative) Character naming guidelines . 2647
Annex M (informative) Sources of characters . 2650
Annex N (informative) External references to character repertoires . 2674
N.1 Methods of reference to character repertoires and their coding . 2674
N.2 Identification of ASN.1 character abstract syntaxes . 2674
N.3 Identification of ASN.1 character transfer syntaxes . 2675
Annex P (informative) Additional information on CJK Unified ideographs . 2676
Annex Q (informative) Code mapping table for Hangul syllables . 2679
Annex R (informative) Names of Hangul syllables . 2680
Annex S (informative) Procedure for the unification and arrangement of CJK ideographs . 2681
S.1 Unification procedure . 2681
S.2 Arrangement procedure . 2685
S.3 Source separation examples . 2685
S.4 Non-unification examples . 2690
Annex T (informative) Language tagging using Tag Characters . 2692
Annex U (informative) Characters in identifiers . 2693


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ISO/IEC 10646:2017 (E)
Foreword
ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commis-
sion) 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. In the field of information technology, ISO and IEC have
established a joint technical committee, ISO/IEC JTC 1.
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
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).
Any trade name used in this document is information given for the convenience of users and does not constitute
an endorsement.
For an explanation on 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 the following URL: www.iso.org/iso/fore-
word.html.
The committee responsible for this document is ISO/IEC JTC 1, Information technology, SC 2, Coded character
sets.
This fifth edition of ISO/IEC 10646 cancels and replaces the fourth edition (ISO/IEC 10646:2014), which has
been technically revised. It also incorporates ISO/IEC 10646:2014/Amd 1:2015 and ISO/IEC 10646:2014/Amd
2:2016.
This edition includes the following significant changes with respect to the previous edition:
• New scripts covered: Adlam, Bhaiksuki, , Marchen, Masaram Gondhi, Newa, Nushu, Osage, Soyombo, Tangut,
and Zanabazar Square,
• Existing scripts significantly extended: Cherokee, CJK Unified Ideographs (Extension F),
• New Emoji symbols.

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ISO/IEC 10646:2017 (E)
Introduction
This International Standard specifies the Universal Coded Character Set (UCS). It is applicable to the represen-
tation, transmission, interchange, processing, storage, input and presentation of the written form of the lan-
guages 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.

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ISO/IEC 10646:2017 (E)
Information technology — Universal
Coded Character Set (UCS)
1 Scope
This International Standard specifies the Universal Coded Character Set (UCS). It is applicable to the represen-
tation, transmission, interchange, processing, storage, input, and presentation of the written form of the lan-
guages of the world as well as of additional symbols.
This International Standard
• specifies the architecture of this International Standard,
• defines terms used in this International Standard,
• describes the general structure of the UCS codespace,
• specifies the Basic Multilingual Plane (BMP) of the UCS,
• specifies supplementary planes of the UCS: the Supplementary Multilingual Plane (SMP), the Supplemen-
tary 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.
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 12.2.
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.
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 2022:1994 Information technology — Character code structure and extension techniques.
ISO/IEC 6429:1992 Information technology — Control functions for coded character sets.
Unicode Standard Annex, UAX #9, The Unicode Bidirectional Algorithm:
http://www.unicode.org/reports/tr9/tr9-35.html
Unicode Standard Annex, UAX #15, Unicode Normalization Forms:
http://www.unicode.org/reports/tr15/tr15-44.html
Unicode Technical Standard, UTS #37, Ideographic Variation Database:
http://www.unicode.org/reports/tr37/tr37-8.html
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ISO/IEC 10646:2017 (E)
Unicode Standard Version 9.0, Chapter 4, Character Properties
http://www.unicode.org/versions/Unicode9.0.0/ch04.pdf
Section 4.3, Combining Classes – Normative
Section 4.5, General Category – Normative
Section 4.7, Bidi Mirrored – Normative
Unicode Standard Version 9.0, Age Property:
http://www.unicode.org/Public/9.0.0/ucd/DerivedAge.txt
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 not preclude the presentation
of base characters from adopting different contextual forms or from participating in ligatures.
Note 2 to entry – A base character typically does not graphically combine with preceding characters. There are exceptions for
...