Chinese (script, RSP full variant set)

Note: This LGR contains 62 code points from the Unicode block: CJK UNIFIED IDEOGRAPHS EXTENDED B.

For the second level, the repertoire has been augmented with the ASCII digits, U+0030 to U+0039; the ASCII lowercase letters, U+0061 to U+007A; and U+002D HYPHEN-MINUS, for a total of 19,722 repertoire elements.

Unlike many other non-Latin Second Level Reference LGRs, the Chinese Script LGR includes the basic ASCII Latin letters (a to z) because it is common practice in Chinese text to mix Chinese and ASCII. Therefore including these letters is not seen as creating added confusability or security risks in the context of a Second Level LGR for the Chinese script. It is also supported by current IDNA practice, see [200], for example.

Any code points outside the Chinese Script repertoire that are targets for out-of-repertoire variants would be included here only if the variant is listed in this file. In this case they are identified as a reflexive (identity) variant of type “out-of-repertoire-var”. Whether or not they are listed, they do not form part of the repertoire.

Repertoire Listing: Each code point or range is tagged with the script or scripts with which the code point is used and one or more other character categories. For each repertoire element, one or more references document sufficient justification for inclusion in the repertoire; see the “References” below.

Variants

Unlike other LGRs for this script, which only incude the variant definitions needed when used as standalone in their zone, this LGR contains the full set of variants needed for zones shared by more than one script. Where appropriate, cross-script variants have been defined to mutually exclude labels from different scripts that could otherwise be substituted by the users. To meet the requirement for variant transitivity, additional in-script variants may be defined as needed. Once a label has been delegated for one script, any of its variant labels consisting entirely of cross-script variants would be blocked. Any label containing at least one code point that is not a cross-script variant would be considered distinct. Because of that, even large numbers of defined cross-script variants generally do not lead to a high percentage of labels experiencing a collision across scripts.

The definition of variants included in this LGR contributes to the definition of variants in the Common LGR. Even though this LGR contains the full set of variants affecting this script, use of the Common LGR is required for actual mitigation of issues caused by using multiple languages or scripts in the same zone. For details, see Section 3, "Use of Multiple Reference LGRs in the Same Zone" in [Level-2-Overview].

This LGR defines both semantically interchangeable variants (same pronunciations as well as the same meanings) and visually identical variants. Many, but not all, of the semantic variants lead to variant label dispositions of “allocatable” as described below, all other variant labels are “blocked”. For details, see Sections 6 and 7 of [Proposal-Chinese].

Source References for Variants

The source reference cited for each variant mapping entry indicates whether the variant mapping is same or different from the rules of CDNC, dotAsia, JGP and KGP, or is based on input during the Root Zone LGR integration process.

For example, a value of “201” means the variant mapping matches dotAsia in both code point and variant type, a value of “202” means the variant mapping matches dotAsia only in code point but not variant type, while a value of “203” means the variant mapping matches no dotAsia code point.

A value of “701” means the variant mapping agrees with input received during the Root Zone integration process in both code point and variant type.

Additional variants

Where variants exist between the Chinese, Japanese and Korean scripts, out-of-repertoire variants may be defined with an out-of-repertoire-var mapping type. As result of integration, including the effects of cross-script transitivity, the number of cross-script variants listed for these scripts may be larger than defined in Section 6, “Variants” in [Proposal-Chinese].

When integrated to be used with another script LGR in the same zone, this LGR may inherit additional blocked cross-script variants by integration; they may not be listed here unless they reflect resulting in-script variants. Always use an applicable merged, or Common LGR created by integration for determining cross-script collisions of labels. However, the list of in-repertoire variants in this LGR is exhaustive.

Variant Mapping Types

The LGR uses the following variant types (the prefix “r-” here marks a type used in a reflexive variant mapping, that is, it represents an instance of the original code point at that location, see Section 5.3.4 in [RFC 7940]):

• blocked — variant labels containing a blocked variant will receive a disposition of “blocked”.
• r-simp, simp, simp-1, simp-2 — variant labels that are created with these types or “both” or “r-both” represent an all-simplified label and receive a disposition of “allocatable” unless they contain a mix of “simp-1” and “simp-2”. In that case, such variant labels will receive a disposition of “blocked”.
• r-trad, trad, trad-1, trad-2 — variant labels that are created with these types or “both” or “r-both” represent an all-traditional label and receive a disposition of “allocatable” unless they contain a mix of “trad-1” and “trad-2”. In that case, such variant labels will receive a disposition of “blocked”.
• both, r-both — a variant of either type may be part of either an all-simplified or an all-traditional variant label.
• r-neither — variant labels containing that type together with any other non-reflexive variant type will receive a disposition of “invalid”.

The variant types (“simp-1”, “simp-2”, “trad-1”, “trad-2”) and the corresponding actions reduce the number of multiple allocatable labels, limiting the number to no more than 5 per label. This case can occur for labels containing code points that are part of a small number of variant sets that have multiple traditional or simplified variants.

Note that a label containing only reflexive mappings, including “r-neither”, but not “out-of-repertoire-var” is an original label and receives a disposition of “valid”. (See also “Chinese-specific Actions” below.)

The LGR does not define specific variant types to handle visually identical variants, but adopts “both” and “blocked” instead, as described in Section 7 of [Proposal-Chinese].

As much as possible the scheme retains the same simplified and traditional mappings as existing second level domains. It does not change the simplified type or traditional type of any variant code point; instead, it subdivides them into common simplified/traditional ones and extra simplified/traditional ones, and provides additional disposition rules to limit any allocatable variant to one of these subgroups. While it does not allow the applicant to get arbitrary mixed labels from an unconstrained allocatable label list, it does allow the applicant to select as the original label one specific desired mixed variant.

Comments on Variants

The comment for each variant mapping entry indicates not only whether it is the reflexive identity and therefore applies to those code points in a label that match the original label, but also documents whether it has been conflated with some other type originally introduced to reduce the number of multiple allocatable labels in Section 6.3.3 of [Proposal-Chinese].

For example, a variant comment of “r-both-ms” indicates that for a given code point, the variant is a code point that could in principle be used with both trad and simp (“r-both”), but because the same variant set has at least one other variant of type “simp” (or of one of the other simplified types), the variant is preferred in a traditional context, such that a “trad” label containing this variant should be “allocatable”, but a “simp” label containing this variant should be “blocked”. The “ms” in the naming convention means that the simplified aspect of the variant is “muted”, even though inherently if would have been of type “r-both”. Effectively, such a variant leads to the same dispositions as an “r-trad”, hence that is the variant type assigned to it, with only the comment indicating that the variant would have inherently been of type “r-both” but with its simp aspect muted.

Character Classes

This LGR does not define named character classes.

Whole Label Evaluation (WLE) and Context Rules

Default Whole Label Evaluation Rules

By default, the LGR includes the rules and actions to implement the following restrictions mandated by the IDNA protocol. They are marked with ⍟.

• Hyphen Restrictions — restrictions on the allowable placement of hyphens (no leading/ending hyphen and no hyphen in positions 3 and 4). These restrictions are described in Section 4.2.3.1 of RFC 5891 [150]. They are implemented here as context rule on U+002D (-) HYPHEN-MINUS.
• Leading Combining Marks — restrictions on the allowable placement of combining marks (no leading combining mark). This rule is described in Section 4.2.3.2 of RFC 5891 [150].

Chinese-specific Rules

None.

Actions

The LGR defines a number of actions that compute a label disposition based on WLE rules or variant mapping types. Some of these are common to all LGRs, and some are specific to this LGR.

Default Actions

This LGR includes the default actions for LGRs as well as the action needed to invalidate labels with misplaced combining marks. They are marked with ⍟. For a description see [RFC 7940].

Chinese-specific Actions

The LGR contains additional Chinese-specific actions as described in Sections 6 and 7 of [Proposal-Chinese]. These resolve the extended set of variant types into a disposition for variant labels of either “allocatable”, “blocked” (or “valid” for an original label that is the identity variant). Chinese-specific actions that are triggered by the LGR-specific variant types described above limit the “allocatable” variant labels to those that are either fully simplified or fully traditional labels. In addition, these actions return a disposition of “valid” for any original label, even those that are mixed between simplified and traditional (see also [RFC 3743] and [RFC 4713]). To account for original labels, reflexive variant mappings with an “r-” prefix are used. (See [RFC 7940])

Note: the only action explicitly triggered by variant type sets including variant type “r-neither” returns a disposition of “valid” for an original label.

Note that variant mapping types are not symmetric: they depend on which code point is considered the source or the target in a given mapping. As specified in [RFC 7940], mapping types are evaluated for each permutation of a label and its variants, with code points that are unchanged in a given label given the type of their “reflexive” or “identity” mapping. The actions finally evaluate the collected set of mapping types and resolve them into one of two dispositions for the variant label. Per [RFC 7940] actions are always applied one after the other, and the evaluation stops at the first action that assigns a disposition to a given label.

For more information on how to assign a variant label disposition under this LGR, see Section 8, “Assigning Variant Dispositions to Labels” in [Proposal-Chinese].

The specification of variants in this LGR follows the guidelines in [RFC 8228].

Methodology and Contributors

The LGR in this document has been adapted from the corresponding Reference LGR for the Second Level. The Second Level Reference LGR for the Chinese Script was developed by Michel Suignard and Asmus Freytag, based on the Root Zone LGR for the Chinese script and information contained or referenced therein; see [RZ-LGR-Hani]. Suitable extensions for the second level have been applied according to the [Guidelines] and with community input. The original proposal for a Root Zone LGR for the Chinese script, that this LGR is based on, was developed by the Chinese Generation Panel. For more information on methodology and contributors to the underlying Root Zone LGR, see Sections 4 and 9 in [Proposal-Chinese], as well as [RZ-LGR-Overview].

Changes from Version Dated 25 October 2024

This version modifies the Second Level Reference LGR for the Chinese Script [Ref-LGR-und-Hani] by injecting the complete (maximal) set of cross-repertoire variants, including any imposed by transitivity. Injected variants are marked by special comments. Any character classes, context and WLE rules required for testing are also imported. In all other respects, description or annotations have not been updated to reflect the injected variants. Any LGR elements that might pose a possible conflict when the LGR is used with the Common LGR for cross-repertoire variant resolution are clearly marked. All modifications are carried out mechanically; there may be an occasional context rule or similar that is injected because its definition relates to some repertoire element even though it can never be triggered by any label valid under the modified LGR.

References

References [0] to [4] refer to the Unicode Standard versions in which corresponding code points were initially encoded. For example, a reference value of [4] means a character was first encoded in Unicode Version 3.1. References [100] and up indicate that the code point is included in one of the following source references: CDNC IDN Table, dotAsia IDN Table, JGP repertoire, KGP repertoire, and IICORE or some other list of code points. For example, a reference value of [200] means a code point listed here is included in the dotAsia IDN Table. References cited for variants indicate whether variant mappings match a source reference in mapping, variant type or both. Entries in the table may have multiple source reference values.

In addition, the following general references are cited in this document:

[Guidelines]

ICANN, “Guidelines for Developing Reference LGRs for the Second Level”, (Los Angeles, California: ICANN, 27 May 2020), https://www.icann.org/en/system/files/files/lgr-guidelines-second-level-27may20-en.pdf

[Level-2-Overview]

Internet Corporation for Assigned Names and Numbers, (ICANN),“Reference Label Generation Rules (LGR) for the Second Level: Overview and Summary” (PDF), (Los Angeles, California: ICANN, 25 October 2024), https://www.icann.org/en/system/files/files/level2-lgr-overview-summary-25oct24-en.pdf

[MSR-5]

Integration Panel, “Maximal Starting Repertoire — MSR-5 Overview and Rationale”, 24 June 2021, https://www.icann.org/en/system/files/files/msr-5-overview-24jun21-en.pdf

[Proposal-Chinese]

Chinese Script Generation Panel (CGP), “Proposal for a Chinese Script Root Zone LGR”, 26 May 2020 (PDF), https://www.icann.org/en/system/files/files/proposal-chinese-lgr-26may20-en.pdf

[Proposal-Chinese-Appendices]

Appendices to “Proposal for a Chinese Script Root Zone LGR”, 26 May 2020 (ZIP), https://www.icann.org/en/system/files/files/proposal-chinese-lgr-appendices-26may20-en.zip

[Ref-LGR-und-Hani]

ICANN, Second Level Reference Label Generation Rules for the Chinese Script (und-Hani), 25 October 2024 (XML) https://www.icann.org/sites/default/files/packages/lgr/lgr-second-level-chinese-full-variant-script-25oct24-en.xml non-normative HTML presentation: https://www.icann.org/sites/default/files/packages/lgr/lgr-second-level-chinese-full-variant-script-25oct24-en.html

[RFC 3743]

Konishi, K., Huang, K., Qian, H., and Y. Ko, “Joint Engineering Team (JET) Guidelines for Internationalized Domain Names (IDN) Registration and Administration for Chinese, Japanese, and Korean”, RFC 3743, April 2004, https://www.rfc-editor.org/info/rfc4713

[RFC 4713]

Lee, X., Mao, W., Chen, E., Hsu, N., and J. Klensin, “Registration and Administration Recommendations for Chinese Domain Names”, RFC 4713, October 2006, https://www.rfc-editor.org/info/rfc4713

[RFC 7940]

Davies, K. and A. Freytag, “Representing Label Generation Rulesets Using XML”, RFC 7940, August 2016, https://www.rfc-editor.org/info/rfc7940

[RFC 8228]

A. Freytag, “Guidance on Designing Label Generation Rulesets (LGRs) Supporting Variant Labels”, RFC 8228, August 2017, https://www.rfc-editor.org/info/rfc8228

[RZ-LGR-Hani]

ICANN, Root Zone Label Generation Rules for the Chinese Script (und-Hani), 26 May 2022 (XML) https://www.icann.org/sites/default/files/lgr/rz-lgr-5-chinese-script-26may22-en.xml

[RZ-LGR-Overview]

Integration Panel, “Root Zone Label Generation Rules (RZ LGR-5): Overview and Summary”, 26 May 2022 (PDF), https://www.icann.org/sites/default/files/lgr/rz-lgr-5-overview-26may22-en.pdf

[RZ-LGR-5]

Integration Panel, “Root Zone Label Generation Rules (RZ-LGR-5)”, 26 May 2022 (XML), https://www.icann.org/sites/default/files/lgr/rz-lgr-5-common-26may22-en.xml
non-normative HTML presentation: https://www.icann.org/sites/default/files/lgr/rz-lgr-5-common-26may22-en.html

[Unicode 11.0.0]

The Unicode Consortium. The Unicode Standard, Version 11.0.0, (Mountain View, CA: The Unicode Consortium, 2018. ISBN 978-1-936213-19-1) https://www.unicode.org/versions/Unicode11.0.0/

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. Entries in the table may have multiple source reference values. In the listing of whole label evaluation and context rules, reference [150] indicates the source for common rules. For more details, see the Table of References below.

Where stable links to certain references are not available, the data may be archived as part of [Proposal-Chinese-Appendices].