CJK Compatibility Ideographs explained

Rangestart:	F900
Rangeend:	FAFF
Script1:	Han
1 0 1:	302
3 2:	59
4 1:	106
5 2:	3
6 1:	2
Sources:	KS X 1001 Big5 IBM 32 JIS X 0213 ARIB STD-B24 KPS 10721-2000
Note:	^[1] ^[2] Range was initially part of the Private Use Area in Unicode 1.0.0,^[3] and removed from it in Unicode 1.0.1.

CJK Compatibility Ideographs is a Unicode block created to contain mostly Han characters that were encoded in multiple locations in other established character encodings, in addition to their CJK Unified Ideographs assignments, in order to retain round-trip compatibility between Unicode and those encodings. However, it also contains 12 unified ideographs sourced from Japanese character sets from IBM.

The block has dozens of ideographic variation sequences registered in the Unicode Ideographic Variation Database (IVD).^{[4] [5]} These sequences specify the desired glyph variant for a given Unicode character.

Character sources

Sources for the original collection of CJK Compatibility Ideographs include:

• South Korean KS X 1001 (U+F900 - U+FA0B, 268 characters)
• Taiwanese Big5 (U+FA0C - U+FA0D, 2 characters)
• "IBM 32": 32 Japanese characters from IBM (U+FA0E - U+FA2D; see below)

In ensuing versions of the standard, more characters have been added to the block from:

• South Korean KS X 1001 (U+FA2E - U+FA2F, 2 characters)
• Japanese JIS X 0213 (U+FA30 - U+FA6A, 59 characters)
• Japanese ARIB STD-B24 (U+FA6B - U+FA6D, 3 characters)
• North Korean KPS 10721-2000 (U+FA70 - U+FAD9, 106 characters)

The "IBM 32" characters

IBM Japanese double-byte EBCDIC includes several kanji which do not exist in, or do not round-trip from, JIS X 0208. These were included as gaiji in extensions to Shift JIS and EUC-JP from IBM (e.g. code page 942), NEC, the Open Software Foundation, and Microsoft (e.g. Windows code page 932). However, they were not used as a source for the original Unified Repertoire and Ordering (URO). Instead, 32 of the IBM extension kanji, those which had not been included in the URO from other sources, were included in the CJK Compatibility Ideographs block in the range U+FA0E - U+FA2D.

Of these 32 characters:

• 19 are unifiable with characters in the URO, and are therefore compatibility ideographs in the strict sense.
• One is a kyūjitai form of a kokuji whose extended shinjitai form exists in the URO . Both are hyōgai kanji, and are variants of the jinmeiyō kanji (i.e. Kummerowia). U+FA20 was assigned a normalisation to U+8612, even though the 龜 and 亀 components, while both forms of radical 213, are not usually considered unifiable.
• The remaining 12 are kokuji characters which are actually unified ideographs (with the property, and which do not change upon normalisation). In spite of their inclusion in the CJK Compatibility Ideographs block and their algorithmically generated character names beginning with "", they are not duplicates of characters in the original CJK Unified Ideographs block in any respect;^{[6] [7]} 11 of these 12 are completely non-duplicate, while was later unintentionally duplicated in CJK Unified Ideographs Extension B as . They are as follows:

Block

History

The following Unicode-related documents record the purpose and process of defining specific characters in the CJK Compatibility Ideographs block:

		Count	L2 ID	WG2 ID	IRG ID	Document
1.0.1	U+F900..FA2D	302		N782
				N2667
				N3525
				N3590
				N4111
				N4103
3.2	U+FA30..FA6A	59		N1935
				N2003
				N2095
				N2142	N710
				N2103
				N2197
				N2221
				N2221R
				txt)
				N2273
				N2295
4.1	U+FA70..FAD9	106		N2253
				N2375
				N2403
				N2478
				N2493
				N2541
				N2540
				N2566
				N2572
				N2573
				N2569
				N2569R
				N2776	N1062
				N2924R
				N3899
				N4111
				N4103
5.2	U+FA6B..FA6D	3		doc)
				appendix)
				doc)
6.1	U+FA2E..FA2F	2		N3747
				doc)

See also

• CJK Compatibility Ideographs Supplement

Notes and References

1. Web site: Unicode character database. The Unicode Standard. 2023-07-26.
2. Web site: Enumerated Versions of The Unicode Standard. The Unicode Standard. 2023-07-26.
3. Book: https://www.unicode.org/versions/Unicode1.0.0/ch03_5.pdf . 3.5: Private Use Area . 0-201-56788-1 . The Unicode Standard, Version 1.0, Volume 1 . 1991 . . 118–119.
4. Web site: Ideographic Variation Database. Unicode Consortium.
5. Web site: UTS #37, Unicode Ideographic Variation Database. Unicode Consortium.
6. Web site: PropList.txt . Unicode Consortium.
7. Web site: Known Anomalies in Unicode Character Names . These 12 characters are unified CJK ideographs, not compatibility ideographs, despite their names. . Unicode Technical Note #27 . . 2021-06-14 . Asmus . Freytag . Rick . McGowan . Ken . Whistler.