Reference LGR for language: Korean (ko-Hang+ko-Latn) lgr-second-level-korean-hangul-language-18may21-en

This document is mechanically formatted from the above XML file for the LGR. It provides additional summary data and explanatory text. The XML file remains the sole normative specification of the LGR.

Date 2021-05-18
LGR Version 2 (Second Level Reference LGR)
Language ko-Hang (Korean Language)
Language ko-Latn (Korean Language)
Unicode Version 6.3.0

Table of Contents

1 Description

Label Generation Rules for Korean


This file specifies a reference set of Label Generation Rules for Korean using a limited repertoire as appropriate for a second level domain.


All references converge on the 26 basic ASCII Latin letters (a to z) and the 11,172 Hangul syllables contained in Unicode since version 2.0. These Hangul Syllables are sometimes called Johab, the name originating from the initial standard in which they were defined: KSC C 5601-1992 , and the encoding in which they were represented in that standard. One part of that standard also defines a subset (known as Wansung) which consists of 2,350 Hangul syllables. KSC C5601-1992 later became KS X 1001:2004.

The text in [700] recommends to only use the 2,350 Wansung code points, but given the large deployment of platforms supporting the full Johab repertoire, this recommendation is considered unnecessary in the context of this LGR.

There is no established practice of allowing Korean ideographs (Hanja) derived from China ideographs (Hanzi) in IDNA labels. Hanja characters are rarely used in Korea (North or South). Therefore it does not seem necessary to add them in a 2nd level reference LGR at this point.

Unlike many other non-Latin 2nd level reference LGRs, the Korean LGR includes the basic ASCII Latin set (a to z) because it is common practice in Korean text to mix Hangul and ASCII. Therefore it does not create confusability or additional security risks in the context of a second level LGR for the Korean language. It is also supported by current IDNA practice, see [700].

Excluded code points


Extended code points




Character Classes

This LGR defines no named character classes.


Default rules:


Actions included are the default actions for LGRs as well as those needed to invalidate labels with misplaced combining marks.

Methodology and Contributors

This reference LGR for Korean for the 2nd Level has been developed by Michel Suignard and Asmus Freytag, verified in expert reviews by Lu Qin and Wil Tan, and based on multiple open public consultations.

Changes from Version 1

Language tags have been updated.


General references for the language:

In the listing of the repertoire by code point, references starting from [0] refer to the version of the Unicode Standard in which the corresponding code point was initially encoded. Other references (starting from [100]) document usage of code points. For more details, see the Table of References below.

2 Repertoire

Repertoire Summary

Number of elements in repertoire 11209
Number of code points
for each script
Hangul 11172
Latin 26
Common 11
Longest code point sequence 1

Repertoire by Code Point

The following table lists the repertoire by code point (or code point sequence). The data in the Script and Name column are extracted from the Unicode character database. Where a comment in the original LGR is equal to the character name, it has been suppressed.

See also the legend provided below the table.

Glyph Script Name Ref Required Context Comment
U+002D - Common HYPHEN-MINUS [0] not: hyphen-minus-disallowed  
U+0030 0 Common DIGIT ZERO [0]    
U+0031 1 Common DIGIT ONE [0]    
U+0032 2 Common DIGIT TWO [0]    
U+0033 3 Common DIGIT THREE [0]    
U+0034 4 Common DIGIT FOUR [0]    
U+0035 5 Common DIGIT FIVE [0]    
U+0036 6 Common DIGIT SIX [0]    
U+0037 7 Common DIGIT SEVEN [0]    
U+0038 8 Common DIGIT EIGHT [0]    
U+0039 9 Common DIGIT NINE [0]    
U+0061 a Latin LATIN SMALL LETTER A [0], [100], [700]    
U+0062 b Latin LATIN SMALL LETTER B [0], [100], [700]    
U+0063 c Latin LATIN SMALL LETTER C [0], [100], [700]    
U+0064 d Latin LATIN SMALL LETTER D [0], [100], [700]    
U+0065 e Latin LATIN SMALL LETTER E [0], [100], [700]    
U+0066 f Latin LATIN SMALL LETTER F [0], [100], [700]    
U+0067 g Latin LATIN SMALL LETTER G [0], [100], [700]    
U+0068 h Latin LATIN SMALL LETTER H [0], [100], [700]    
U+0069 i Latin LATIN SMALL LETTER I [0], [100], [700]    
U+006A j Latin LATIN SMALL LETTER J [0], [100], [700]    
U+006B k Latin LATIN SMALL LETTER K [0], [100], [700]    
U+006C l Latin LATIN SMALL LETTER L [0], [100], [700]    
U+006D m Latin LATIN SMALL LETTER M [0], [100], [700]    
U+006E n Latin LATIN SMALL LETTER N [0], [100], [700]    
U+006F o Latin LATIN SMALL LETTER O [0], [100], [700]    
U+0070 p Latin LATIN SMALL LETTER P [0], [100], [700]    
U+0071 q Latin LATIN SMALL LETTER Q [0], [100], [700]    
U+0072 r Latin LATIN SMALL LETTER R [0], [100], [700]    
U+0073 s Latin LATIN SMALL LETTER S [0], [100], [700]    
U+0074 t Latin LATIN SMALL LETTER T [0], [100], [700]    
U+0075 u Latin LATIN SMALL LETTER U [0], [100], [700]    
U+0076 v Latin LATIN SMALL LETTER V [0], [100], [700]    
U+0077 w Latin LATIN SMALL LETTER W [0], [100], [700]    
U+0078 x Latin LATIN SMALL LETTER X [0], [100], [700]    
U+0079 y Latin LATIN SMALL LETTER Y [0], [100], [700]    
U+007A z Latin LATIN SMALL LETTER Z [0], [100], [700]    
U+AC00..U+D7A3 [11172] 가..힣 Hangul HANGUL SYLLABLE GA..HANGUL SYLLABLE HIH [1], [100], [110], [401], [700]    


Code Point
A code point, code point sequence, or code point range. For a range, starting and ending code points are shown separated by ".." and the count is given in "[ ]".
The shape displayed depends on the fonts available to your browser.
Shows the script property value from the Unicode Character Database. Combining marks may have the value Inherited and code points used with more than one script may have the value Common. For any code point range, all members have the same script value.
Shows the character or sequence name from the Unicode Character Database. For ranges both the first and last name are shown, if different.
Links to the references associated with the code point or sequence, if any. For any code point range, all members share the same references.
Required Context
Link to a rule defining the required context a code point or sequence must satisfy. If prefixed by “not:” identifies a context that must not occur.For any code point range, all members share the same required context.
The comment as given in the XML file. However, if the comment for this row consists only of the code point or sequence name, it is suppressed in this view. By convention, comments starting with “=” denote an alias. If present, the symbol ⍟ marks a default item shared among a set of LGRs.

3 Variant Sets

This LGR does not specify any variants.

4 Classes, Rules and Actions

4.1 Character Classes

The following table lists all named and implicit classes with their definition and a list of their members intersected with the current repertoire (for larger classes, this list is elided).

Name Definition Count Members or Ranges Ref Comment
implicit Tag=sc:Hang 11172 {AC00-D7A3}   Any character tagged as Hangul
implicit Tag=sc:Latn 26 {0061-007A}   Any character tagged as Latin
implicit Tag=sc:Zyyy 11 {002D 0030-0039}   Any character tagged as Common


Members or Ranges
Lists the members of the class as code points (xxx) or as ranges of code points (xxx-yyy). Any class too numerous to list in full is elided with "...".
A named or implicit class defined by all code points that share the given tag value (ttt).
An anonymous class implicitly defined based on tag value and for which there is no named equivalent.

4.2 Whole label evaluation and context rules

The following table lists all named rules defined in the LGR and indicates whether they are used as trigger in an action or as context (when or not-when) for a code point or variant.

Name Regular Expression Used as
Anchor Used as
Ref Comment
leading-combining-mark (start)[∅=[[∅=\p{gc=Mn}] ∪ [∅=\p{gc=Mc}]]]     [120] RFC5891 restrictions on placement of combining marks
hyphen-minus-disallowed (((start))← ⚓︎)|(⚓︎ →((end)))|(((start)..\u002D)← ⚓︎)   C [120] RFC5891 restrictions on placement of U+002D (-)
extended-cp (start)(end)         code points from the extended range


Used as Trigger
This rule triggers one of the actions listed below.
Used as Context
This rule defines a required or prohibited context for a code point C or variant V.
This rule has a placeholder for the code point for which it is evaluated.
Regular Expression
A regular expression equivalent to the rule, shown in a modified notation as noted:
⚓︎ - context anchor
Placeholder for the actual code point when a context is evaluated. The code point must occur at the position corresponding to the anchor. Rules containing an anchor cannot be used as triggers.
(...)← - look-behind
If present encloses required context preceding the anchor.
→(..) - look-ahead
If present encloses required context following the anchor.
(... | ...) - choice
When there is more than one alternative in a rule, the choices are separated by the alternation operator (...|...).
start or end
(start) matches the start of the label; (end) matches the end of the label.
. - any code point
. matches any code point.
[\p{ }] - property character set
Set of all characters matching a given value for a Unicode property [\p{prop=val}]. Note: uppercase “\P” defines the complement of a property set.
∪, ∩, ∖, ∆ - set operators
Sets may be combined by set operators ( = union, = intersection, = difference, = symmetric difference).
∅= - empty set
Indicates that the following set is empty because of the result of set operations, or because none of its elements is part of the repertoire defined here. A rule with a non-optional empty set never matches.
(^$) - empty label
The regex (^$) matches the empty label. Used as a context rule, it always fails to match, thus disallowing the affected code point in any label. By convention, it is used for context rules that disable code points that are not part of the repertoire, yet explicitly listed in the LGR as excluded or for optional future extension.

Note: The following rules are defined but not used in this LGR: extended-cp.

4.3 Actions

The following table lists the actions that are used to assign dispositions to labels and variant labels based on the specified conditions. The order of actions defines their precedence: the first action triggered by a label is the one defining its disposition.

# Condition Rule / Variant Set   Disposition Ref Comment
1 if label matches leading-combining-mark invalid   by default, labels with leading combining marks are invalid
2 if any label (catch-all)   valid   catch all (default action)


{...} - variant type set
In the “Rule/Variant Set” column, the notation {...} means a set of variant types.

5 Table of References

The following lists the references cited for specific code points, variants, classes, rules or actions in this LGR.

[0] The Unicode Consortium. The Unicode Standard, Version 6.3.0, (Mountain View, CA: The Unicode Consortium, 2013. ISBN 978-1-936213-08-5)
Any code point cited was originally encoded in Unicode Version 1.1
[1] The Unicode Consortium. The Unicode Standard, Version 6.3.0, (Mountain View, CA: The Unicode Consortium, 2013. ISBN 978-1-936213-08-5)
Any code point cited was originally encoded in Unicode Version 2.0
[100] Internetstiftelsen i Sverige (IIS), Korean
[110] KS X 1001:2004, Code for Information Interchange (Hangueul and Hanja)
[120] RFC5891, Internationalized Domain Names in Applications (IDNA): Protocol
[401] The Unicode Consortium, Common Locale Data Repository.- CLDR Version 28 (2015-09-16)- Locale Data Summary for Korean [ko]-
Code points cited are from the set of Main Letters
[700] KRNIC (.kr cctld Korean Register)