Ideographic Description Characters Explained

Blockname:Ideographic Description Characters
Rangestart:2FF0
Rangeend:2FFF
Script1:Common
3 0:12
15 1:4
Sources:GBK (U+2FF0–U+2FFB only)
Note:[1] [2]

Ideographic Description Characters is a Unicode block containing graphic characters used for describing CJK ideographs. They are used in Ideographic Description Sequences (IDS) to provide a description of an ideograph, in terms of what other ideographs make it up and how they are laid out relative to one another.[3] An IDS provides the reader with a description of an ideograph that cannot be represented properly, usually because it is not encoded in Unicode; rendering systems are not intended to automatically compose the pieces into a complete ideograph, and the descriptions are not standardized.

U+2FF0 to U+2FFB were introduced from GBK; U+2FFC to U+2FFF were devised later and introduced in Unicode 15.1 (2023).

Block

Ideographic Description Sequences

Ideographic Description Sequences are sequences of characters that represent a Chinese character structure as defined by the Unicode standard.

Below are the 16 characters as defined by Unicode in this block:

Unicode Char Meaning Example 1 IDS Example 2 IDS
U+2FF0 Two components combined left to right ⿰木目 ⿰丨㇍
U+2FF1 Two components combined above to below ⿱木口 ⿱丶
U+2FF2 Three components combined left to middle and right ⿲彳氵亍 ⿲丿夕乚
U+2FF3 Three components combined above to middle and below ⿳亠口小 ⿳亼目口
U+2FF4 One component fully wrapping another component ⿴囗口 ⿴㐁人
U+2FF5 One component surround three sides of another component (opening at bottom) ⿵几皇 ⿵齊虫
U+2FF6 One component surround three sides of another component (opening at top) ⿶凵㐅 ⿶乂丶
U+2FF7 One component surround three sides of another component (opening at right) ⿷匚斤 ⿷虎九
U+2FF8 One component surround top and left side of another component ⿸疒丙 ⿸耂火
U+2FF9 One component surround top and right side of another component ⿹戈廾 ⿹或壬
U+2FFA One component surround bottom and left side of another component ⿺走召 ⿺礼分
U+2FFB Two components overlapped ⿻工从 ⿻木⿻コ一
U+2FFC One component surround three sides of another component (opening at left) ⿼叉丶 ⿼コ二
U+2FFD One component surround bottom and right side of another component ⿽水丶 ⿽⺀十
U+2FFE Horizontal reflection ⿾卍 ⿾正
U+2FFF ⿿ Rotation ⿿凹 ⿿予

Two other related ideographic description characters are not encoded in this Unicode block, but of which may be used in ideographic description sequences:

Unicode Char Block Meaning Example 1 IDS Example 2 IDS
U+303E Variant but not equivalent 㬵 (U+3B35) 〾胶 (U+80F6)[4] 〾爫[5]
U+31EF Subtraction ㇯兵丶 ㇯豕一

This is the syntax of IDS in EBNF:IDS := Ideographic | Radical | CJK_Stroke | Private Use | U+FF1F | IDS_UnaryOperator IDS | IDS_BinaryOperator IDS IDS | IDS_TrinaryOperator IDS IDS IDS CJK_Stroke := U+31C0 | U+31C1 | ... | U+31E3IDS_UnaryOperator := U+2FFE | U+2FFFIDS_BinaryOperator := U+2FF0 | U+2FF1 | U+2FF4 | ... | U+2FFD | U+31EFIDS_TrinaryOperator:= U+2FF2 | U+2FF3

History

The following Unicode-related documents record the purpose and process of defining specific characters in the Ideographic Description Characters block:

See also

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. IDS are described in chapter 18.2 of the Unicode Standard 9.0 on pages 689 through 692.
  4. Web site: 「㬵(U+3B35)」和「胶(U+80F6)」为什么在《康熙字典》收录了两次? - 知乎 . www.zhihu.com . 2023-09-21.
  5. Web site: 基本集扩充字考(五・完结)附扩充块新增字考 . 知乎专栏 . 2023-09-21 . zh.