IDN Policy

GMO Registry offers Japanese Internationalized Domain Names (IDN) in all GeoTLDs. This page describes policy and technical requirements for IDN registrations.

Syntax Requirements for IDN Domain Names

  • - The "A-label" must be valid according to the IDNA2008 rules. This is tested by decoding the A-label to a UTF-8 string, and then re-encoding. If the re-encoded string matches the original string, this test is passed.
  • - The A-label must be a valid domain name in its own right (ie length and composition rules for ASCII domain names must also successfully be passed).

Compliance with Standards

GMO Registry GeoTLDs are operated in compliance with the following standards:
RFCs 5890 - 5893 (also known as IDNA2008).
These are the proposed technical standards for
Internationalized Domain Names for Applications, released in 2010. The RFCs establish IDN-related definitions, protocols, and rules for using specific code points in IDNs.

Variant Policy

It is GMO Registry policy to block
variant Variant IDNs (as defined in the Registry Operator's IDN tables
and IDN Registration Rules) from registration.
Our IDN tables do not contain variant characters.
Different code points are treated as different characters.

Special Characters

The following characters are special characters to which additional rules apply.


Any IDN string containing one of the above characters, must include at least one other katakana (or hiragana or han) character. This is called a CONTEXTUAL rule, defined in RFC5892.

Mixed Scripts

IDN strings may contain mixed scripts. (ie. may be composed of both ASCII and Japanese characters, provided the string meets the above conditions regarding special characers.
Every registered domain name must be associated with a specific language or script.

IDN Tables

The IDN table for the folowing language supported by GMO Registry GeoTLDs can be downloaded here.

Character tables for every language/script supported are published in the IANA repository.
Compliance with these standards and policies is achieved through use of internal testing of software prior to deployment, and mechanisms for fault reporting which allow registrars and other stakeholders to report issues with implementation.
Widely-deployed and tested third-party libraries such as GNU libidn are used where possible, as these offer increased assurance of compliance.

Scope of Policy

This polic y is applicable to the following Top Level Domains.

  • .dnp
  • .gmo
  • .nhk
  • .suzuki
  • .otsuka
  • .kddi
  • .jcb
  • .nico
  • .goo
  • .yodobashi
  • .goldpoint
  • .mtpc
  • .canon
  • .toshiba