Round trip mapping - SJI S to Unicode

From: Smita Desai [InConcert Software Engineer] (
Date: Fri Aug 21 1998 - 00:32:40 EDT


I would appreciate if someone could if possible, offer any background information or workarounds to the following.

According to Microsoft KnowledgeBase article Q170559, there are 398 characters that do inaccurate round trip mapping, between SJIS and Unicode. Some of the examples are as follows:
Code page 932

0x879c --> Ux222a --> 0x81be
0xed40 --> Ux7e8a --> 0xfa5c
0xed41 --> Ux819c --> 0xfa5d

According to that article, these are duplicates that do not round trip map and were added for NEC needs.

Does anyone have any background info? Is the only solution to create a table in the code, which would have a bad performance hit? If these are duplicates, then does it matter that they do not round trip map?

Any help would be greatly appreciated.

Smita Desai

Smita Desai
Software Engineer, Internationalization
InConcert, Inc.
Four Cambridge Center,
Cambridge, MA 02142
Tel - 617.499.4427
email -

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