Chapter 5. Characters in Each Country

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  JIS X 0212 (about 6000 characters including KANJI, which are not included in JIS X 0208),

and

  JIS X 0213:2000 (aka JIS 3rd and 4th levels).

JIS X 0201 Roman is the Japanese version of ISO 646. Though JIS X 0201 is included in SHIFT JIS

encoding (explained later) and widely used for Windows/Macintosh, usage of this is not encour 

aged in UNIX.

JIS X 0201 Kana defines about 60 KATAKANA characters. This is widely used by old 8bit com 

puters. In deed, SHIFT JIS encoding was designed to be upward compatible with 8 bit encoding

of JISX 0201 Roman and JISX 0201 Kana. Note this CCS is not included in ISO 2022 JP encoding

which is used for e mail and so on.

JIS X 0212 is not widely used, probably because it cannot be included in SHIFT JIS, the standard

encoding for Japanese version of Windows and Macintosh. And more, this CCS may be obsolete

when JIS X 0213 will be popular, since JIS X 0213 has many characters which are included in JIS X

0212. However, the advantage of JIS X 0212 over JIS X 0213 is that all characters in JIS X 0212 are

included in the current Unicode (version 3.0.1) while not all characters in JIS X 0213 are.

JIS X 0208 (aka JIS C 6226) is the main standard for Japanese characters. Strictly speaking, it

was originally defined in 1978 and revised on 1983, 1990, and 1997. Though 1997 version has 77

more characters than original 1976 version and shape of more than 200 characters are changed,

almost softwares don't have to care about the difference between them. However, be careful of

that ISO 2022 JP encoding (explained below) contains both JIS X 0208 1978 and JIS X 0208 1983.

1978 version is called 'old JIS' and later is called 'new JIS'. Characters in JIS X 0208 are divided

into two levels, 1st and 2nd. Old 8bit computers rarely implemented the 2nd level.

Usage of numeric characters and Latin alphabets in JIS X 0208 is not encouraged because these

characters are also included in ASCII and JIS X 0201 Roman, either of which is included in all

encodings. When converting into Unicode, these characters are mapped into 'fullwidth forms'.

All of these coded character sets (except for JIS X 0213) are included in Unicode 3.0.1. A part of JIS

X 0213 characters are not included in Unicode 3.0.1.

There are a few different tables for conversion between non letter characters in JIS X 0208 and

Unicode. This is a problem because this may deny 'round trip compatiblilty'. Problems and So 

lutions for Unicode and User/Vendor Defined Characters (

http://www.opengroup.or.jp/

jvc/cde/ucs conv e.html

) discusses this problem in detail.

5.1.3 Encodings

There are three popular encodings widely used in Japan.

  ISO 2022 JP (aka JIS code or JUNET code)