SC2/WG2 N2535
JTC1/SC2/WG2/IRG N956
Date : 2002-11-21
ISO/IEC JTC1/SC2/WG2/IRG
Ideographic Rapporteur Group(IRG)
Source/Contribution Identifier :Ideograph Radical Ad Hoc

Meeting :20th IRG Meeting in Hanoi, Vietnam

Title :

Ideograph Unification

Status :For use by the IRG

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The IRG follows the unification rules given in ISO/IEC 10646, Annex S. The examplesof the rules in Annex S are, however, typical examples, and not meant to be exhaustive. Thismeans that there have been many cases where it wasn’t clear whether two forms should beunified or not.
The Unification Ad Hoc group was requested to provide more detailed guidelines to theIRG on the issue of how to deal with doubtful cases.
The Ad Hoc group recommends that the IRG maintain a standing document listing thespecific components which should be unified, and those which should not be unified. Theselists should initially be populated with the examples from Annex S, and they should beupdated as the IRG editors encounter more examples. As with Annex S, it should beunderstood that the examples in the standing document are not exhaustive.
For doubtful cases, the Ad Hoc group notes that the best thing to do would be to follow acourse of action which could most easily be corrected if it proves to be wrong.
Where characters are from two different national or regional standards, then themappings between those standards and ISO/IEC 10646 become a normative part of thestandard. As such, neither incorrect unifications nor incorrect disunifications can be easily
corrected. IRG editors should use the greatest possible care to make sure that no errors are
made in unifying or disunifying such characters.
The situation is different for characters which are derived from other sources.
Characters from dictionaries or informal and private character collections can be unified anddisunified more easily.
For these characters, it seems clear that an incorrect unification can be fixed more easily
than a false disunification. This is because although new characters can be added to ISO/IEC
10646, they can never actually be removed. Existing characters can be deprecated, whichmeans that their use is strongly discouraged; but a character which once becomes a part ofISO/IEC 10646 is there forever.
Fixing an incorrect unification is not, however, without its own price. Some data will beencoded using the incorrectly unified character. Such data will have to be revised. Such a
cost is minor, however, compared to the difficulties that will be caused by forever having theincorrect form available to confuse users and appear improperly in documents.
Because of this, the recommendation of the Ad Hoc group is that where there is doubt as
to whether two forms should be unified or not, the null hypothesis is in favor ofunification—that is, the editors should recommend unification in the absence of evidence tothe contrary.
In the past, editors have tended to recommend disunification unless they were sure thatcharacters should be unified. The recommenation of the Ad Hoc group is that editors now
recommend unification unless they are sure that characters should be disunified.
The Ad Hoc group also recommends that a distinction be made between stroke
normalization and derived simplifications for characters used in the People’s Republic ofChina. As a rule, forms with stroke normalization should be unified, but derivedsimplifications should not (pending proof of their actually being used).

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